# Could you have designed a better Warbird?



## Burmese Bandit (Dec 13, 2008)

So...all the Sidney Camm, Kurt Tank, Kelly Johnson etc etc etc wannabees out there...


*Could you have designed a better Warbird for any side, using only the technology known and in use at the time, staying within reasonable cost parameters, yet making enough of a difference to have been worth producing?*

I will start with my idea for a german warbird very similar to the FW 190, staying within the rules I have set out above.


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## Burmese Bandit (Dec 13, 2008)

The warbird I have designed draws upon three of the proven designs of WW II - the La-7, the FW-190, and (I'll bet very few will expect what's coming) the Do335!

First, it will be a twin-prop push-pull design, like the Do 335 ... but with this difference: whereas the Do 335 used two EQUAL engines to pull and push, I will use two engines - one main engine, and one auxiliary engine - the BMW 801 in front, and the Argus 411 in the rear.

Why? 

First, it would solve the 335's problem of having to abolish the tail landing gear and introducing a nosewheel configuration - that would have caused training and production problems. An Argus 411 with 485 horsepower, together with a short-radius small four-blade propeller, could easily have been mounted in the tail fuselage behind the pilot, and the arc of the propeller would not extend below the vertical tail. 

Furthermore, on the production side, using the Argus 411 as the rear engine would sidestep the 'engine shortage' problem perennially afflicting the Luftwaffe.

In addition, with the 1600 hp of the BMW and the 450-485 hp of the Argus, we have a fighter with a total hp of around 2100 ... in my mind, just about right for the balance of speed, weight and agility needed by fighters. 

And, of course, both of these engines were air-cooled. Very important in terms of resistance to battle damage and field maintenance. 

I shall continue...


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## Burmese Bandit (Dec 13, 2008)

...to continue:

Since to balance the aircraft with its heavy (700 lbs) rear Argus engine, the nose would need to be moved forward, we will have an airplane resembling the long nosed FW 190 dora 9 - but with a fatter nose for the radial - plus a thick rear fuselage similar to the LaGG-7. A short radius 4 bladed propeller splitting the vertical tail behind will be seen, which of course means that the vertical tail has two sections, an upper and a lower. Since the propeller does not extend lower than the vertical tail, a normal tailwheel landing gear can be used.

The canopy will be a bubble. Either a full bubble that extends back, or the canopy similar to the LaGG-7 or the P-51 B with the Malcolm hood. For reasons of production simplicity simplicity, and in order to have the option of opening the canopy in flight and sticking your head out to get a better look (so essential when landing in bad weather!) I will opt for this solution. 

The wings will only be about 25% than the normal FW 190 wings - this will give a wingspan of about 37-38 feet, 4-5 feet wider than the 190. The longer nose and wider wings will reduce the roll rate of this fighter compared to the 190, but not by very much. It should still do quite a creditable roll.

Total weight should be about 10,000 lbs for the fast fighter version, which I will continue to describe...


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## Burmese Bandit (Dec 13, 2008)

...why 10,000 lbs?

The FW 190 with two cannon, 550 rounds of ammo, fuel, oil, pilot, etc, etc, ready to fight and fly, is quoted by many reliable sources as weighing 8500 lbs or near as to make no difference.

Add the 700 lbs of the Argus, add the structural and wing strength wing reinforcements, add the extra fuel the Argus will consume, and we have something like 1,300 lbs. That's 10,000 lbs.

At 2100 hp and 10,000 lbs we have a power loading of 4.8 lbs per hp. That's a very good ratio...

...to be continued...


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## Burmese Bandit (Dec 13, 2008)

Now in an 8500 lbs bird, an extra 500 lbs will most likely make a small but visible difference to its performance and handling. Whereas in a 10,000 lbs bird, another 500 lbs will probably make almost no difference at all...

So, what if we have a slightly higher figure of 10,500 lbs for our hyothetical fighter - what could we do with that extra 500 lbs?

We could put in 150 rounds of ammo and another four 20 mm cannon. 

Two NEW CANNON in the nose cowling, two ORIGINAL cannonin the wing roots, AND TWO MORE in a slightly bulged belly in a reverse nose cowling under the bottom of the plane.

(The russians showed that it was entirely possible to put 20 mm guns in the fat nose cowling or radial engined fighters with the LaGG 7. I see no reason why we should not be able to take this one step further, and put two more in the belly in a reverse nose cowling position.)

I have done a weight estimate, and 4 more 20 mm cannons and 150 rounds more 20 mm ammo seem to be quite plausible for a weight budget of 500 lbs. 

Very well then - we have our 2100 hp fighter with push/pull engines with six centerline 20 mm cannon weighing in at 10,500 lbs and with a wing loading similar too, or just slightly higher than, the FW 190.

What sort of performance and handling and, perhaps, other advantages - or disadvantages - could we reasonably expect from our hypothetical fighter?

to be continued...


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## Burmese Bandit (Dec 13, 2008)

First, though, a word on armament...

550 rounds plus 150 rounds is 700 rounds. There are six cannon, therefore there will be about 115 rounds a cannon. That will mean a fire time of around ten seconds if you fire all six cannon at once, or twenty seconds if you fire three and three. Yes, this could be a limitation on the fighter's capabilities. I shall discuss more on this later..

but to continue...


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## Burmese Bandit (Dec 13, 2008)

...to continue our performance expectations on our "FW 335" (heh) or as I would prefer it now to be called, the "Burmese 190" (someone kick that conceited ass BB please!) (OK I'll be serious now) what type of performance could we reasonably expect from this FW 190/Do 335/LaGG-7 hybrid?

Well, I think that the increase in level speed would be modest - about the same as the Dora-9, say about 420 mph max. That's still a 30 mph increase over the FW 190 A mid series. Let's be conservative and call it 415 mph. 

The increase in climb, due to the increased hp and greater wingspan wing, would be slightly better, IMHO.

It is in the DIVE that I expect a much greater performance boost - and of course a faster dive also makes for a faster zoom climb out of the dive. Our new Burmese 190 should dive almost as fast as a P-47. It has the same hp, it has slightly less weight but has slightly less drag, so it should perform very, very well in the dive. 

Note that with two engines rotating propellers in opposite directions, this plane should be easier to fly - especially in situations where from flying in a gentle cruise you have to suddenly pour on the power. If done badly in an ordinary FW 190 the sudden increase in torque could snap roll the aircraft. While the auxiliary engine of the Burmese 190 will not cancel out the torque completely (as is the case in the 335) it should reduce the torque to a fairly manageable level so that a sudden increase in power would not tend to throw the plane into a snap roll followed by a spin.

The longer nose, and the concomitant forward movement of the cockpit, also means that the pilot can now see around the nose - very, very useful for taxi-ing, for landing in poor weather, and for ground attack. 

And of course, the big rear engine gives you a very, very solid defense, even against cannon shells, from a rear attack. 

To be continued...


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## drgondog (Dec 13, 2008)

Burmese Bandit said:


> ...to continue:
> 
> The wings will only be about 25% than the normal FW 190 wings - this will give a wingspan of about 37-38 feet, 4-5 feet wider than the 190. The longer nose and wider wings will reduce the roll rate of this fighter compared to the 190, but not by very much. It should still do quite a creditable roll.
> 
> Total weight should be about 10,000 lbs for the fast fighter version, which I will continue to describe...



Adding the structure to transmit and distribute torque from the second engine as well as the additional weight of the structure to sustain structural integrity to support a large mass near the tail in high G pull out, plus the engine weight itself plus the proposed armament and ammo, and still keep the weight in the P-51D range?

The long fat nose proposed, combined with a tail dragger design, will certainly make it tougher to taxi than the 335 design. The increased longitudinal moment of Intertia with significant masses fore and aft will introduce possible stability and control issues in pitch and might force larger horizontal stabilzer area (and weight and drag).

What is your airfoil choice? If you go laminar flow like the 51 you can keep drag lower than other type airfoils but that has disadvantages also.

The two engines to boost your speed performance, in radial engine design is pretty much going to boost your fuel consumption -----> driving larger fuel cells/capacity depending on your Cruise and Range criteria ----> driving more weight, less climb performance, slightly lower horizontal speed, longer take off run, heavier landing gear. 

Because you need more fuel you have to think continuously about keeping the fuel tanks around the empty cg - otherwaise, for eaxample, draining a fwd or aft located tank will screw up your cg and play hob with static margin and stability in different flight profiles.

There was a reason the 335 would have made a poor fighter against other fighters except for speed... which required the maximum Hp available.

I'm not saying a really competent airframe design team couldn't make your concept work but I have mentioned a couple of things that would cause me to ask - "How do we solve this" and "what is the objective of this design over single engine"


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## Burmese Bandit (Dec 13, 2008)

Excellent points drgondog - I shall try to respond to each of them!

"...Adding the structure to transmit and distribute torque from the second engine as well as the additional weight of the structure to sustain structural integrity to support a large mass near the tail in high G pull out, plus the engine weight itself plus the proposed armament and ammo, and still keep the weight in the P-51D range?..."

The mass (of the rear Argus) would actually be much nearer the center of the "Burmese 190" than to the tail. I realise this is difficult to envisage without a diagram - I intend to put up a sketch within a week. For the moment let's say that the rear engine looks lie a P-39 installation, but one in which the engine and the pilots cockpit are moved further forward. I of course freely and humbly admit I am no engineer - but neither am I a total ignoramus either. I think all that I proposed above could be done within the 10,500 lbs limit.

"...The long fat nose proposed, combined with a tail dragger design, will certainly make it tougher to taxi than the 335 design. The increased longitudinal moment of Intertia with significant masses fore and aft will introduce possible stability and control issues in pitch and might force larger horizontal stabilzer area (and weight and drag). ..."

The problem with taxi-ing vision with the 190 and the P-47 was more wing than nose. Sitting on the ground at a high angle of attack caused the wing to block all vision forward, which was why the 190 usually had a crewman on the wing to call out directions to the pilot when taxi-ing. Moving the cockpit forward would not solve the nose problem, but it would solve the wing problem...the pilot could stick his head out of the cockpit and see, not over the nose, but around it. 

Now about two engines consuming more fuel - there's a way around that. I shall come to that in a later post. 

The most important point... the CG shifting as fuel is consumed...I intend to keep the wings free of all armament (which is why my proposed six cannons have a centerline configuration) and keep all the fuel IN THE WINGS.


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## Burmese Bandit (Dec 13, 2008)

...but before I go on into an explanation of how I would solve the rest of the problems that drgondog has so saliently pointed out above, I would like to explain WHY I chose this concept.

The main reason is that this fighter could have been built using, in the main, OFF THE SHELF PARTS already in production at the time. The landing gear and the tailwheel for the 190 could have been used (we know that the fighter bomber version of the FW 190 routinely took off at 10,800 lbs (4900 kg) : so, too, much of the airframe forward of the cockpit. I suspect even the wings of the FW 190 could have been used, too, with 2-ft wing root extensions to each wing (similar to the wing root extensions that were used to build the P-47 N). 

Remember that in my first post I said the goal of the design was to build a better warbird at a reasonable cost and in a reasonable timeframe. This was the reason why I propose this design.

To be continued....


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## Burmese Bandit (Dec 13, 2008)

And now to reply to the very intelligent question drgondog posed..

"..."what is the objective of this design over single engine" ..." ?

The objectives are these:

To have TWIN ENGINE reliability - yes, yes, I know that if the main engine 
was destroyed, the 450/485 hp of the Argus might not have been enough to keep the Burmese 190 flying...but it would be quite possible to keep the plane in a shallow dive, and if your main engine failed at, say, 3000 feet it should be possible to extend your shallow dive at a 25:1 to cover a distance of 75000 feet - that's 15 miles. Let's be conservative and say 10. If your main engine is damaged over enemy territory, that's 10 miles nearer to your own lines. 

To have REAR PROTECTION. I have mentioned this already.

And ... this is where I think I can (partly) get around the problem of fuel consumption...


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## Burmese Bandit (Dec 13, 2008)

.... to be able to cruise on the MAIN ENGINE, and to shut down the rear engine on long cruises...

Since the rear engine is embedded in the rear fuselage anyway, and since the four bladed short radius rear propeller can be neatly masked by the vertical and horizontal tails in the 'feathered' position, unlike conventional twin engined aircraft there will be little drag penalty with one engine stopped. I would expect cruise speed with the main engine only operating to be lower, but not dramatically lower, than cruise speeds with both engines operating.


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## Burmese Bandit (Dec 13, 2008)

Other objectives of the twin design, which are the ability to carry very heavy armament and an increase in level speed and climb, and a dramatic increase in dive speed, have already been explained.

Whew. Let me rest for a bit now.... will be back.


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## kool kitty89 (Dec 13, 2008)

One of the advantages of the Do 335's engine arrangement is that each engine cancelled the other's torque. (at similar settings) This works because the props rotate in opposite directions and the engines have the same performance and same type of propeller. This elliminates the need to trim the aircraft to counter torque. (except with an engine out)

When you introduce 2 very different engines with very different performance characteristics. This creates the opposite situation than above, with countering torque being more problematic than with a single engine. 
Assuming they still counter rotate, the Argus engine will counter some of the torque of the BWM radial, but changes in power settings and altitude will result in torque changes necessitating trim changes (or pilot imput) to counter it.
The difference will be particularly noticable at altitude as the Argus engine was designed for relatively low altitude operation. (there would be a particularly noticable jump at the BMW's supercharger gear change altitude)

To minimize this effect, you'd have to develop a version of the As 411 with a 2-speed supercharger with altitude power curves matched as closely as possible to the BMW 801, and would have to be further developed to follow later developments of the 801.


You also may run into problems designing a satisfactory cooling ducting arrangement for the As 411 that also minimizes drag.


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## drgondog (Dec 13, 2008)

Burmese Bandit said:


> Excellent points drgondog - I shall try to respond to each of them!
> 
> "...Adding the structure to transmit and distribute torque from the second engine as well as the additional weight of the structure to sustain structural integrity to support a large mass near the tail in high G pull out, plus the engine weight itself plus the proposed armament and ammo, and still keep the weight in the P-51D range?..."
> 
> ...



So let's pause and make sure my comments, even if incorrect, are at least clearly conveying my thoughts.

1. New engine and drive shaft and propeller combination as well as additional structure and heat shield behind the cockpit adds minimal ~ 600-800 pounds? 

2. Heavy six x 20mm combination in nose adds another 150-200 pounds over a six x .50 combo in a P-51D, including the additional structure to absorb recoil.

3. 20mm ammo ~ 900 rounds compared to 1800 .50 about the same? but must focus on location close to cg.

So, compare weights and balances to the Mustang. Mustang has one significant variable to cg location - the 85 gallon fuse tank aft of cockpit and cg - not as much weight as your engine/prop combo - and designed for normal cg when fuel consumed. The aft engine stays in your fighter - so,

a. Your wing probably needs to move back to get the aerodynamic center backwards toward the aft engine - or the forward engine need to move forward to compensate the moment arms about the Cg. Maybe you can move the cockpit forward to get the pilot weight to contribute.

Forward movement of cockpit/pilot a probable better choice than extending nose for primary engine as the latter adds weight for more airframe structure and raises longitudinal moment of intertia. Ballast is terrible idea and to be avoided

b. While a Mustang sheds the weight of the fuselage tank fuel, your fighter keeps 600-800 pounds of the engine combo. That will be a climb and cruise penalty in every condition vs Mustang - all things being equal... 

c. You have much better firepower but pay another permanent weight penalty with the 6 x 20mm cannon.

d. Unclear what extra weight is incurred in channeling cooling air to the aft engine or what effect to parasite drag.

e. Difficult to conceive of many off the shelf major components other than landing gear and engines.

f. There is no reason why it should not have a decent roll rate - at least as good as the Mustang.

In the comparison of the Mustang vs your design - you have to ask yourself what could be carved out of a P-51D to compensate for say 600 plus extra pounds of steel alone for your extra engine, remembering that the P-51H as a near new design only carved about six hundred out of the D airframe - so when you start with a 37 foot wing and EXTEND the fuselage to compensate for the aft weight w/o adding ballast... where are you going to sacrifice structural integrity?

The thing that nags me the most is the contemplation of the longitudinal moment of intertia (large for fighter) when you place such large masses as engines fore and aft of cg, as well as the question about how the airplane responds with an 'airfoil' behind the trailing edge of elevator and rudders?

There is a reason the DO 335 would have been nice against bombers but probably never in a manuevering fight with fighters.

this is interesting, and comments are speculative on my part.


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## Burmese Bandit (Dec 13, 2008)

Ah, drgondog, I am so glad you added your comments!

Yep, some points did nag me during the thought concept phase of this design...

1. The cooling and airflow for the Argus behind. My thought was a duct behind the cockpit in the mode of the P-39. However, I confess I have not give as much thought to this as to other parts of the design.

2. The cg shift as the ammo is used up had occurred to me too. At present I am still thinking about it...still, my proposed location for the ammo, in the nose behind the BMW 801, is not too far from the cg.

3. I confess that the 'airfoil' behind the tail and rudder is completely uncharted territory for me, and I suspect, for many on this forum too. Perhaps someone - I am sure there must be one or more than one, it's one of the reasons why I joined this forum - could give us some insights?

4. I totally agree that forward movement of the cockpit is a better idea than simply extending the nose. 

5. Hmmm....perhaps my design will come in overweight (what else is new?)

6. The engine symmetry point about the Argus and the BMW is an excellent point. I shall think deeply about this. 

Will be back! And the original point of this thread was not to say so much that "THIS could have been done" as to promote discussion, thought, and enlightenment.

I see that this is beginning to happen...and I am very, very glad.


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## Burmese Bandit (Dec 13, 2008)

A point: one of the factors in my choice of the V-12 cylinder air cooled Argus was not just availability, but the "taper" from front to back from the fat BMW to the relatively slimmer Argus, so that a low drag airframe boatailing smoothly from front to back could be built.

Just for clarification!


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## MikeGazdik (Dec 14, 2008)

I would have developed a wing form, similar to the Mustang, for the Messerschmitt. Just smaller in scale to be near the same wing area. I would have left the armament in the nose of the Messerschmitt though. Just used the North American wing to utilize bigger fuel cells, and better main gear, and an overall stronger wing.

Not sure if I would keep it laminar flowing. I just like the structure of the P-51 wing. Two main spars, fuel in between, main gear stows away just ahead of the front spar.


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## Burmese Bandit (Dec 14, 2008)

At present we're discussing the design of an improved 190 here Mike - I'm going to get around to my thoughts on an improved liquid cooled inline later. 

However, in passing I would like to note that one of the problems with having an inline V-12 is that what you gain in small frontal area, you lose in having little space to mount weapons on the cowl or in the Vee between the cylinders. This was why Willy could never mount anything bigger than 13 mm HMGs on the cowl of the 109. (Yes, one of the K models mounted two 15 mm guns, but the bumps on the fuselage were so huge I shudder to think of what they would have done to the drag)


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## kool kitty89 (Dec 14, 2008)

The Do 335 was powered by a liquid cooled (inverted) V-12 and had cowl mounted 20 mm cannons. (granted the larger DB 603 rather than the Bf 109's DB 601/605) But it has more to do with the nose design than the engine size. (the Bf 109 having a relatively small nose, and it may not have even been able to mount guns the size of the .50 Browning)

Also note the 15 mm cowl guns on the Bf 109K is a mistake, this was never a planned armament. (the Bf 109's nose was too small to practically fit them there, plus I don't think production of the 15mm MG 151 went into le late war period)


There is a significant advantage to the V-12 though, the engine cannon mounting to fire through the spinner allows a centraly mounted (possibly large) unsynchronized gun (important as some significant weapons couldn't be synchronized). This is the only way the MK 108 could be mounted on the centerline of a fighter with a nose mounted tractor angine. (granted the engine layout had to permit it, not feasible on the V-1710 or Merlin due to supercharger placement, but possible on the Jumo 210, 211, 213, DB 601, 605, 603, the Hispano-Suiza 12Y -and subsequent Russian derivatives)


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## Burmese Bandit (Dec 14, 2008)

Now a point I want to ask drgondog and other engine experts on this forum:

I am almost sure, though not completely sure, that the total weight of the Merlin and the radiator and the coolant liquid on the P-51 was more than the BMW 801 with its cooling fan and cowl flaps. Who can give me numbers on this?


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## Kurfürst (Dec 14, 2008)

Weight of Merlin 61, complete:







In addition, you need the weight of oil, coolant and intercooler fluids. Unfortunately, I don't have the weight for the BMW 801.


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## Burmese Bandit (Dec 14, 2008)

Ah, half my question answered! 

Thank you kindly, Kurfurst!

Now who has the other half.... I need it to think about whether the 700 lb argus was really that much of a "cg problem" (considering the point that the Pony had a radiator behind the wing in about the same position that I plan to put the Argus) plus that 85 gallon tank above. 

I hope the very experienced members of this forum can help me!


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## drgondog (Dec 14, 2008)

Burmese Bandit said:


> Ah, drgondog, I am so glad you added your comments!
> 
> Yep, some points did nag me during the thought concept phase of this design...
> 
> ...



The need for a tractor/pusher config is driven by speed objectives not achieved with a single engine. I would question the value of using two engines not matched for reasons of maintenance and commonality of parts?


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## FLYBOYJ (Dec 14, 2008)

Some other thoughts from MY world....

Limit stress panels installed with screws - use as many cam lock panels as possible for ease of maintenance. If screws have to be used because of a panel in a stressed area, use screws that can be turned with a Phillips or straight screwdriver. To be real fancy, have screws with an opposite threaded center point on the head so an easy out could be installed if the screw head is stripped out.

Install all quick disconnects on plumbing, control cables and electrical connections that go to the engine. Build a "QEC" (Quick Engine Change) unit that allows the engine mounts and engine to be removed. Design all oil and coolant drains (if liquid cooled) so they drain down and do not flow on to structure. Have "two hand access" to all filters. Install magnetic chip detectors in the low points of the oil systems with easy access so if the engine is "making metal" it could be easily detected. 

Have flush "indented" jack points so no jack adapter needs to be used to jack the aircraft. Use disk brakes that have pads that could be removed without removing the entire wheel. Have all axle nuts installed with standard size nuts so special removal tools could be avoided. Lastly, use common greases and lubricants through out the aircraft.

Interchangeable control surfaces - no left or right ailerons or elevators. One piece horizontal and vertical stabilizer that is bolted to the tail and can be removed in one piece. If the aerodynamics work - a symmetrical outer wing panel so that to is common left to right...

Structure - common hardware, avoid specially made bolts and pins. Design the structure in bolted "segments" so heavily damaged portions of the airframe could be unbolted and changed out rather than undertaking timely airframe repairs.


All these wonder aerodynamics and performance wants won't mean a thing if the aircraft cannot be easily maintained.

My 2 cents - avoid the stock market!


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## renrich (Dec 14, 2008)

Lindberg chose a single engine AC to fly the Atlantic because with two engines you are twice as likely to have an engine failure. The remaining engine would not allow the completion of the mission.


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## kool kitty89 (Dec 14, 2008)

> 1. The cooling and airflow for the Argus behind. My thought was a duct behind the cockpit in the mode of the P-39. However, I confess I have not give as much thought to this as to other parts of the design.



The P-39 had the radiator and oil cooler mounted directly below engine, but the intake for the cooling ducting was located at the wing roots. The scoop directly behind the cocpit canopy of the P-39 is for the carburetor. 
Putting the cooling air intake on the top of the fuselage would require a fairly larger scoop and long ducting running to the bottom of the engine. (it being an inverted V-12)
The simplest configuration would be to add a belly scoop, possibly similar in apearance to the P-51's. Though that would likely result in the loss of the ability to carry external stores under fuselage.


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## The Basket (Dec 14, 2008)

My perfect aircraft fighter design ends up as a Grumman Bearcat or Hawker Sea Fury.

Put the most powerful engine around the smallest lightest airframe and give it some cannon...teardrop canopy and some toughness so it can take a good beating...plenty of agility...radial engine so it can lose a few cylinders and still come home.

Not sure about your twin design. Why have 2 engines when 1 can do? Making something more expensive and doubling your logistics as you need spares and training for two different engines.


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## Burmese Bandit (Dec 14, 2008)

Ah, many have taken the time to reply!

I shall try to reply to all, starting with a new face...the scottish basket

Simple reason - availability. In a perfect world I would have a single powerful engine of 2500 hp driving counterotaing props in front. But this is 1941, (see premise at beginning of thread)that engine is still three or so years away, and the war won't wait for me!

Have to leave now. Will be back with looooong post!


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## Burmese Bandit (Dec 14, 2008)

Have to attend to some business now, but a quick reply to

Flyboy J: the BMW was designed by the Bavarians as an integral unit, with cowl and fan integrated. Most probably it was already a quick change unit!

I have sources such as Wiki on the weight of the BMW but I don't completely trust them. Could someone help me on this...weight of BMW with cooling fan? I suspect it would be less than the total merlin 61 which at nearly 1200kg is about 2620 lbs. 

I need to know this before I can finalise my reply to drgondog's very incisive and helpful posts.


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## FLYBOYJ (Dec 14, 2008)

Burmese Bandit said:


> Flyboy J: the BMW was designed by the Bavarians as an integral unit, with cowl and fan integrated. Most probably it was already a quick change unit.


But did they have quick change cables and plumbing? Did they use screws or cam locks around panels? Did plugs and fittings had to be safety wired? Many WW2 aircraft had "QECs" but just because they used the term didn't mean they were maintenance friendly.


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## davparlr (Dec 14, 2008)

Kurfürst said:


> Weight of Merlin 61, complete:
> 
> 
> In addition, you need the weight of oil, coolant and intercooler fluids. Unfortunately, I don't have the weight for the BMW 801.



wikipedia claims the BMW 801 dry weight is 1,055 kg (2325 lbs), or about the same weight as the PW R2800 (2360 lbs).


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## kool kitty89 (Dec 14, 2008)

The 2-stage models of the R-2800 (ie Helcat and Corsair) were somewhat heavier at ~2,500 lbs. (the -10 was 2480 lbs)

http://www.enginehistory.org/ModDesig/SecI.pdf

The single stage (turbocharger sperate) of the P-40B/C/D (the -21, and 59/63) weighed 2,265 lbs. The 2800 hp -57C engine of the P-47M/N (and XP-47J) weighed 2315 lbs. (all dry)

Also the single stage 2-speed supercharged R-2800-39/41/43 of the B-26 weighed 2300 lbs. (and had somewhat poorer altitude performance than the BMW 801D)


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## Watanbe (Dec 15, 2008)

sounds like your designing an epic bomber destroyer Burma.


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## kool kitty89 (Dec 15, 2008)

Burmese Bandit,

Wth all the trouble of your proposed design, just replacing the BMW engine with a 2-stage R-2800 model would seem a lot less trouble. (the Centaurus would be somewhat more difficult due to size differences)

You'd have 2,000 hp in the early part of the war, somewhat less than your proposed combo, but much more power at altitude with an engine only moderately heavier than the historical one (compensated by a shorter nose or longer rear fuselage). The dimentiuons were very similar to the BMW engine as well, and a tight cowling with large spinner and cooling fan would of course be used to minimize drag. (actually done with the R-2800 on the XP-47J) Overall modifications would be relatively small. (probably similar to the changes made to the Dora)

You wouldn't have the problems of using 2 different engine types and the complexity of the mid mounted engine with extension shaft driving a pusher propeller.


The disadvantage would be the need of a larger propeller and taller langing gear. though depending on the propeller used the gear maybe able to stay the same, but requiring 3-point take-off and landing -which was already common for the Fw 190 iirc)

Without your other changes you'd end up with an a/c of the Bearcat or Tempest/Sea-Fury type. 

With your wing changes, a longer span and area (not as extreme as the Ta 152) could be a good idea, as could carrying fuel in the inboard wings. (just outboard of the cannon) However I'd keep the original fuelelage fuel tanks and have moderately sized fuel tanks in the wings. (max internal fuel capacity of around 200 US gallons, ~250 gallons if you want a long range fighter, so 33-58 gallons in each wing)

To improve foreward visibility and peripheral vision on the ground, raise the coucpit slightly and use a taller canopy. (similar to the change from the "birdcage" to the hooded canopy Corsair) Possibly raise the rear fuselage as well to improve streamlining with the larger canopy and reduce the necessary size of the vertical stabilizer for adequate stability.

I think a low drag airfoil of 15% at the root is reasonable, tapering to 9% at the tip. (same as with the actual 109's wing) Use a fairly broad wing with a moderate taper (similar to the 190's) but increase span to 42-45 ft and area to 240-250 ft. (the longer span and resulting higher aspect ratio will also improve the lift to drag ratio and coeficient of lift -though using the low-lift/low-drag airfoil will reduce the latter) 

I'm not so keen on the lower nose guns (it's getting kind of bulky, and possibly interfere with external stores on the belly), I think the 2 upper 20 mm and wing root 20 mm are good, keeping the 250 rpg at the wing roots and another 200 rpg for the upper nose guns (if possible). Then add provisions for on cannon outside the propeller arc in each wing for added guns for bomber killing missions. (another pair of 20 mm guns, or a pair of MK 108's which can't be synchronized, and thus have to be mounted here and there's no possibility for a motorkanone placement with a radial engine)

I think this could result in an aircraft in the 10,500 lb range. (it would seem reasonable for ~800-1000 mi range and a top speed around 440 mph)


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## Burmese Bandit (Dec 15, 2008)

First of all, I would like to thank drgondog, FlyboyJ, koolkitty89, Watanabe, Daveparl, The Basket, Kurfurst, MikeGadzik....wait....yes, that's all for now. Unless someone new posts while I'm typing this looong reply. Which is quite possible...

Thank you, all of you, for taking the time and for your insights. And here, I think I should make a small apology, for I believe I was not QUITE clear on what I was trying to do.

I said " Could you have designed a better Warbird for any side, using only the technology known and in use at the time, staying within reasonable cost parameters, yet making enough of a difference to have been worth producing?"

One of the key phrases in that premise was "...for any SIDE." This meant that if you were, say, designing for the Allied side, you couldn't use a DB series engine to put into your super spitfire, or a BMW engine to put into an improved uber Hurricane. And in the same way...you couldn't use an R-2800 to put into the "uber 190" that the Germans were going to be using! And of course the allied side couldn't use the "minegeschloss" shell technology for their cannons....etc etc etc...

(I believe this answers your post, koolkitty89....but thank you nonetheless. Your points are, as always, very good.)

And I would humbly like to be clear on another point in the premise..."....using only the technology known and in use AT THE TIME..." This means that your design can't use revolver cannon for a plane that's going to have to be ready to fight in 1944 at the latest, or use the Griffon for a plane that's going to fight in the Battle of Britain, or use the R-4360 for a bomber that's going to bomb Germany in 1943.... I think we all get the picture? And of course no use of such things as titanium components for engines and airframes before 1945!

And finally, another constraint in the premise is "...reasonable cost parameters." This means no Rolls-Royce hand-built "R" engines for a 1,000 - 5,000 plane production run. 

Yep, that's right. If you've read Anthony Williams "The Foresight War" and others like it in the WW 2.1 genre, those are the design limitations set up for the hypothetical designer who has arrived back into 1939 or 1940 WITH the hindsight of the 21st century, but WITHOUT its advances in technology. Take the bricks that were available at the time, with the labour available at that time, and see if you could have built a better house than the architects of that time!

And now, that having been said, let's continue...

Having digested the thoughts and excellent suggestions and criticisms of all you kind posters, I have decided to do what Watanabe so shrewdly pointed out - change my design to be an epic....bomber destroyer and ground attack aircraft. 

There are many reasons. Oh, I could still have built a fighter within the 10,500 lbs self-imposed limit, by giving up the two belly 20 mm and doing other design changes, but I have chosen not to...because...

I have ANOTHER design coming - an "uber 109" - which uses a single DB 605 engine and is light, maneuverable, and yet carries eight MG 131 HMGs and has an airframe which I believe is superior to the 109 in drag reduction. It's actually a much less technologically ambitious design than this one, yet it has design characteristics which have not, AFAIK, have been seen before. The goal is a plane with the maneuverability of the Me 109 F with an armament heavier than the G and a speed higher than both. Oh, yes, and affordable and buildable by the technology of the time too.

So, I've decided that my uber 190 is going to fill the heavy end of the spectrum because it's ideally suited to do so, by virtue of its high hp from its two engines, and my next project, the uber 109 referred to above, will fill the light fighter end of the spectrum, so that both could work together in tandem. Against the hordes of Stormoviks. Against the hordes of B-17s and 24s. 

(In passing - why don't I design uber spitfires and ponies and jugs or even a better Stormovik? I will. Later. I just loved the challenge of designing from the Axis end first.)

Enough already. Let's get back to designing the uber 190


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## Burmese Bandit (Dec 15, 2008)

I have arrived at the conclusion: actually the uber 190 is a Burmese FW 47.

Why?

Let's look at the P-47. Big 2300 lb radial in front. 600 lb turbosupercharger in the back. Total output 2300 hp. Fat belly carrying chin air scoop for the intercooler and pipes for said turbo. Said belly still capable of carrying centerline stores. Tail dragger. Two waste gate air outlets in rear fuselage for discharge of hot turbo gases. 

Now, the Burmese uber 190...

Big 2300 lb 1700 hp (1942 version) BMW in front. 700 lb 485 hp Argus in back. Total output 2185 hp. Fat belly carrying chin air scoop for Argus and two 20 mm belly cannon. Said belly still capable of carrying centerline stores. Tail dragger. Two air outlets in rear fuselage for discharge of exhaust gases and cooling air for the Argus. 

The slight extra weight of the Argus and firewall against the turbo is counter balanced by the weight of the top and belly 20 cannon in the nose of the uber 190. Thus we have a good cg balance. 

A two-part vertical tail, reminiscent of the 335, at the back of the uber 190 will be a crucial difference in side view. Said tail will not be lower than belly - unlike the 335 - as radius of 4 blade Argus rear pusher propeller is smaller. 

Same teardrop canopy for both designs. 

A shorter, 37 foot 240 sq foot wing for the uber 190. Takeoff weight for bomber destroyer version, 12000 lbs. This will give a wing loading of 50 lbs per square foot. At 2185 hp (yes, I know the later versions of the Argus developed 700 hp as used in the Si 204, but for the time being I'll stick with the 485 hp Argus) this will give a power loading of just under 5.5 lbs per hp - about the same as the early Spits. 

Regarding the ammo supply and the fuel, I intend to reverse the 47 design, and put the ammo where the 47 has its fuel and the fuel in the wings. Why? I intend for the outer fuel tanks to be used up first, and the inner later...in this way the outer wings will be fairly light when combat begins, as the outer tanks will have had their fuel used up in the climb to combat height and the cruise to the battle area, and thus the uber 190 will enter combat with a better roll capacity.

Regarding armament...I intend to keep ammo at average levels, at only 800 20 mm cannon shells, but I intend to add an extra pair of 20 mm in the wing roots to get a total of EIGHT 20 mm cannon! Two in the upper nose, two in the belly, two in each wing root! This will give a total of only nine seconds firing time if you fire all eight at once (MG 151/20 with electrical synchronization fires at 700 rpm less 10% or so), but it will give 36 seconds if you fire them two at a time. The electrical firing system of the German 20 mm shells should make this two position firing switch easy to make. 

I believe all this can be done within the new 12000 lb limit. 

I believe that, apart from the possible control problems arising from the rear propeller acting as a close coupled canard, and the problem of matching the power curves of the Argus and the BMW as closely as possible, this design is quite plausible. (Of course, I would greatly appreciate the input and criticisms of the many, many people far more talented than me on this forum! )


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## Burmese Bandit (Dec 15, 2008)

Well...suppose we COULD build such a monster...what sort of performance could we expect from it? And how could we use it tactically?

I believe performance will be very similar to, again, the P-47, with the exception of performance at high altitudes. On the deck and at mid levels they should be almost performance twins. My shorter span wing and slightly less hp will penalise the climb versus the Jug slightly, but better the dive. And it should roll better in theory and even better at half fuel in actual combat. Of course, the FW control system should make it an excellent 'transitioner' too - rolling first one way, and then suddenly another. 

How should and would it be used tactically?

It should be used in the 'dive-shoot-dive and run like hell' against high flying bombers. Against them it should climb into a height superior to the bomber stream - say 8000 meters, about 27000 feet - and move to a position dead astern. Then dive through the escorts, using the tremendous dive speed possible with high hp and heavy weight, and fire one long burst as it closes into the bombers. With eight guns that's 80-90 cannon shells per second. A four second burst will throw about 330 shells at the target bomber. Pilot Arnauld Average of the Luftwaffe will hit with about 3% - that's 10 shells, grouped close together, Pilot Edgar Experten will hit with 20 or even 30 shells. Bottom line, Arnauld severely damages B-17, Edgar chalks up one more viermot kill. 

Then DIVE and TWIST and RUN because now they'll have two or even four angry ponies on their tail each! With the P-47's diving speed or even better, and the superb transitioning ability inheirited from the 190 design, I think there's a fair chance of escape. Remember the ponies can't chase them too far because they might be leaving the bomber stream open to a secondary attack. Climbing back after chasing too far is time and fuel consuming. 

One good pass, then dive and run. That's the way to use them. They must never fight the ponies and jugs and 38s...except in a head-on attack situation. Then, if they have any ammo left, they should not run away but attack. With eight guns, two engines, armour, the chances are on their side. 

Against the Stormoviks. the opposite should be done...they should hang back, stay at a higher altitude beyond the effective range of the rear gunner, and fire the guns two at a time. The Stormovik can neither run, evade, nor fight back effectively. Its armour is its only hope. But with 36 seconds of fire available, sooner or later even the flying tank will go down. If enemy fighters should suddenly appear and break through the escort, shallow dive and run if they are behind, attack if they are in front.

Whew. That's QUITE a lot. I shall rest now...


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## The Basket (Dec 15, 2008)

It takes about 4 years from first flight to the aircraft earning its keep in terms of numbers and shooting down enemy.

So if your aircraft wants to be fully operational in 1942...you is looking first flight in 1938...would anyone want your design in '38? 

Your aircraft seems to big and complex. I would go for a twin in the P-38 mode or a big single engine fighter like the P-47.


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## Watanbe (Dec 15, 2008)

It appears you have designed a very lethal bomber destroyer. Basically a flying cannon with two engines  

I could see it working but the chance of doing serious damage on 1 pass (which is probably what they would get) is not that high. The plane would be expensive to produce and mince if caught by fighters. Would you work it in cooperation with fighter escort like the Me410 and Ju88 bomber destroyers or rely on its speed to get it out of there?

What do you think about the 1943 style head on attack?


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## fly boy (Dec 15, 2008)

i would make a combo of the p-51 p-47 the 190 the 109 and the spitfire


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## 109ROAMING (Dec 15, 2008)

Burmese Bandit said:


> Regarding armament...I intend to keep ammo at average levels, at only 800 20 mm cannon shells, but I intend to add an extra pair of 20 mm in the wing roots to get a total of EIGHT 20 mm cannon! Two in the upper nose, two in the belly, two in each wing root! This will give a total of only nine seconds firing time if you fire all eight at once (MG 151/20 with electrical synchronization fires at 700 rpm less 10% or so), but it will give 36 seconds if you fire them two at a time. The electrical firing system of the German 20 mm shells should make this two position firing switch easy to make.



Is it possible to syncronize 6 20mm's through the propeller all being at various different distances from the propeller? has that ever been done before? if it hasn't I can sure see why

Turning into a bomber destoyer? one quick point ,say this did all happen and you were a german avoiding all other possible problems .For a combat instance I interecepted a raid with this "Fw 47" of B-17's B-24's and with the amazing armament I was able you shoot down say 2 B-17's .I'm then in a plane with the weight of 8 20mm's and with a big bullseye that quite a few P-51/47's are not just staring at????


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## 109ROAMING (Dec 15, 2008)

fly boy said:


> i would make a combo of the p-51 p-47 the 190 the 109 and the spitfire




Wanna try?


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## drgondog (Dec 15, 2008)

I believe I would, given hindsight, mated the Merlin to the Mustang on day 1.. and let the evolution of the H and the P-82 take it's natural course two years earlier.


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## Burmese Bandit (Dec 16, 2008)

Basket: my planned operational dated is 1944. All the elements I describe, the MG 151/20, the BMW, the Argus, were available is 1940. Thus I score on the historical plausibility index...

As I explained above, designs in this thread are limited to what was available at the time. I would have loved to have designed a bomber destroyer for the Axis with a R-4360 and counter rotating props. Or some other even better engine designs that came out in 1946. 

As for using the twin engine on each wing solution which led to the 38, the 110, the Mosquito, etc etc etc, problems of wing weight leading to poor roll limit heavy twins in actual combat - something the USAAF and the Luftwaffe and the RAF found out when they tried to use above examples as fighters. 

Watanabe: I have based my damage estimates and hit probability on actual USAAF and Luftwaffe research of the time. See Bronson in this forum, and Antony Williams' EXCELLENT site, for gun and cannon info.

109 Roaming: ditto. 

Watanabe, 109 roaming: regarding LW escape maneuvers see actual reports by allied pilots on dogfighting at the time plus advisorys and manuals by RAF and USAAF on fighting LW. Warnings of the transition tactic used by FW 190 flyers are especially prominent. 

Drgondog: Yep, me too! But that point you raised belongs more in the "How would you develop...." thread!


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## Burmese Bandit (Dec 16, 2008)

Additional info: Luftwaffe estimate of 20 mm shells needed to knock down a b-17-

16-20

LW estimate of hits scored by an average pilot - 2.5% to 4% of total shots fired

Experten of course would double or treble that number

This is why even experten flying the 109 against the B-17 could not knock them down...one 20 mm motor cannon in the nose just aint gonna cut it. And why even experten flying the FW 190 with the wing cannon found it difficult, for even 4 20 mm cannon would only damage, but not kill, the Boeing beast!

Of course the B-24 with its highly inflammable hydraulic fluid was a much easier target.


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## Jabberwocky (Dec 16, 2008)

Well, there are lots of things you could do to aircraft from the get-go to improve performance, considering the level of technological advancement and refinement that went into aircraft over the 1939-1945 period.

I'm a RAF fan and my personal favourite aircraft of the war is the Typhoon. If you take a whole lot of minor improvements that happened to the Typhoon airframe (new aerials, gun shrouds, tail wheel doors, internal mass balance, new propeller, new exhaust, internal rear view mirror) and add them all together, then you end up with an startling improvement in performance. 

The Typhoon improved its level speed from about 390 mph at best altitude (~18,000 - 20,000 ft) to about 415 mph at the same alt on the same power over the course of three years of refinements. 25 mph for what are essentially minor modifications to the airframe is not bad. What if they had all been there from the start? What if the Camm had designed the Tempest II from the start, instead of progressing from the Typhoon

Suppose that a couple of things happened in the Typhoon design process:

1. Sir Sydney Camm ignores both the incorrect advice of the RAE about the effect of thick, Hurricane style wings on performance and RAF's concerns about the vulnerability of wing radiators and goes with thinner, better performing wings and no chin radiator (also putting a larger fuel tank in the fuselage). Result: Better speed and dive performance at the cost of a little range, although climb performance may of suffered (although it mostly depends on wing profile and size);

2. Napier goes to Bristol in 1940 instead of 1942 to sort out some of the kinks in the Sabre, meaning a reliable engine by 1941;

3. Napier has the necessary funding to develop a two speed, two stage supercharger for the Sabre, meaning a 2,000 hp + engine that delivers rated second stage power to about 22-23,000 feet, instead of about 15-16,000 feet;

4. Camm redesigns the rear fuselage to eliminate the problem of rudder flutter and sympathetic vibrations buckling the rear fuselage at the tail joint;

5. A larger, Tempest V/II style tail is fitted to deal with torque on takeoff;

6. The cockpit seals are redesigned, meaning that carbon dioxide and other nasty gasses don't flood into the cockpit;

7. Bubble canopy from the get-go (already somewhat present on the Whirlwind), improving visibility;

8. Spring tab ailerons fitted from the start, notably improving roll performance, always a Typhoon weak spot;

9. Four bladed prop fitted from the start, improving acceleration;

10. Gun-bays redesigned, allowing more ammunition to be carried (think it was about 20 more rounds per gun at the end of the war);

11. All the little improvements previously mentioned are already there

So, with all of the redesigns what do you get?

First of all you get better reliability and serviceability. Operational readiness, the Typhoons major bugbear in the first 12 months of operations, is radically improved. No to-ing and fro-ing with the RAF about whether its going to get cancelled or not. No welding fishplates to the rear fuselage. No erks standing by with a fire extinguisher on start-up for 18 months. Pilots don't have to continually wear oxygen masks in the aircraft.

Second, overall speed is significantly improved. The big difference comes from eliminating the thick draggy wings (a la Tempest) and the honking great chin radiator. I'm not going to put an estimate down on paper, but with the thick wind and chin rad, the Tyffie could still do 417 mph at 20,000 feet

Thirdly, high level performance is DRAMATICALLY improved. Thin wings and a two stage, two speed supercharger mean that the speed and climb of the Typhoon at higher altitudes (say, above 18,000 ft) is transformed. Maybe not in the same league as the later Spitfires, but at least as good as the Merlin 61 powered Mk IX up to 25-26,000 feet.

Fourthly, the Typhoon becomes a fighter. With more speed, more power at altitude and, very importantly, a better rate of roll (spring tab ailerons) the Typhoon gets turned back into an offensive, manuverable fighter, instead of a 400 mph brick that rolls like an elephant stuck in tar. 

This means offensive Rhubarbs and Rodeos at 25,000 feet across Europe and right through the Northwestern German border. No stooging about at 12,000 feet over France, looking for ground targets while being subject to flak and being bounced by all and sundry. The Typhoon's range was about 175 miles better on internal fuel than that of a Spitfire IX and range with 2 x 45 gal drop tanks was bang on 1,000 miles. Guesstimate a combat range of 350 miles, maybe more with larger D/Ts. How about the image of Typhoons escorting Lancasters and Halifaxes to Essen and Dusselfdorf, or perhaps further?

Fifthly, and finally, the aircraft becomes available earlier than historically. With a reliable Sabre, no faffing around with the Tornado/Tempest/Fury line until later in the war, no changing RAF/RAE design requirements and no redesign of minor items, the Typhoon becomes available at least 4-6 months earlier than in the actual historical timeline. That means that the Spit V has some help on hand when the FW 190s start to really make their presence felt in late 1941.

Purely hypothetically, the RAF could of had an aircraft with similar (if not the same, or perhaps a little better at altitude) performance to the Tempest in mid-1941. Around 365-375 mph on the deck, 425-435 mph at 25,000 feet, 3,600 ft/min + rate of climb, good rate of roll (never great though) and 1,000 mile range. 

You can repeat this whole process for the Spitfire as well. Maybe put in a 30 gal rear fueslage tank from the start, 20 mms properly installed, better fuselage skinning and panel design for reduced drag, new profile radiators, wheel well covers, rear wheel cover, wide track, forward raked landing gear, small forward wing tanks, metal skin ailerons, internal bullet proof windscreen, better tail/rudder design, revised elevator design, multi ejector stacks, more aerodynamic windscreen, fully sealing fuel tanks, larger capacity nose tanks, revised wing spar design, revised rudder balance, stronger control linkages, frise type ailerons, blown canopy ect, ect, ect


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## kool kitty89 (Dec 16, 2008)

Spring tabs aren't necessarily the best way of improving the aileron performance. (short of hydraulic boosting) If the Typhoon used a cable control system like the Spitfire and hurricane, control could be signficantly improved by switching to push tubes. (used on all operational WWII US fighters iirc, as well as the Fw 190)

Also boost tabs could be used. (as used on the Corsair's ailerons) 
Boost-tabs


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## Jabberwocky (Dec 16, 2008)

I theorised adoption of spring tabs because the British had been researching them since the 1920s and they were well known in the country at the time, unlike push rods, which very few British aircraft used to to best of my knowledge.

The British experimented with spring tabs all through the war. There is a very interesting Hellcat test here

http://www.wwiiaircraftperformance.org/f6f/jv224.pdf

showing the difference in rolling speed between a Hellcat with and without spring tabs fitted. The spring tabs helped the Hellcat to roll up to 19 deg/sec faster, although at some speeds its was only boosted by 1-2 deg/sec. 360 deg roll time was cut by up to 2 seconds, which is a big improvement.


Boost tabs and spring tabs appear to be virtually the same thing, unless I am mistaken. Maybe it is a difference in nonclamenture?


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## Burmese Bandit (Dec 16, 2008)

AHEM. 

(with apologies to Lewis Carrol, forgive me my sins, Rev Dodgson...)

"T'was brillig, and the silv'ry Tiffs,
did gyre and gimball-roll in the Wind
All mimsy were the Boeing planes,
And the main planes outraided!"

Ok...silly time over...back on Topic.

Jabberwocky, thanks for an excellent post. One quick point, however. The reason why the 20 mm was so late into entry into the RAF was the terrible reliability problems of the early cannons. See Antony Williams' excellent site. 

I shall now try to describe the companion I have designed for the " Burmese FW 47" which is my uber 109.


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## Burmese Bandit (Dec 16, 2008)

Just one point before I do, though - I do agree that having two engines in my FW 47 presents a maintenance and supply headache for the ground staff. Against that, however, I would like to point out that the Argus gained an excellent reputation for reliability and the ability to resist battle damage in actual use by the Luftwaffe on the Eastern Front.


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## Burmese Bandit (Dec 16, 2008)

Now I want to describe the design I've thought up for an uber 109, the flying mate of the "Burmese FW-47" I've posited above. As I've posted before, the aim is to have a dogfighter with the maneuverability of the 109 Frederich combined with the speed of the Gustav and a firepower stronger than both. As a bonus it would have potentially greater range and better pilot vision. The design constraints are that it has to be ready to be in service by early 1944 at the latest and it has to use components that were at least in production, and preferably in mass production, at the time.

As you will see this second design is actually less technologically ambitious than the previous one, but for all that it has a number of design elements which I consider to be quite innovative...as in my previous design. 

My uber 109 will be designed from the get-go to have the choice of two engines: either the DB 605 at 1475 hp or the Jumo 211 at 1400 hp. In this way it will already have a production advantage in that shortages of one or the other engine could be compensated for. It will be a single liquid cooled engine design, with a tractor propeller in front and a narrow frontal area. 

So far, a conventional design. However, I now intend to do something radical...I intend to split the supercharger, having one supercharger behind the engine, and a second supercharger behind the pilot's seat. The second supercharger will be run by a powershaft that comes out of the engine, goes between the pilot's legs, and goes behind the pilot's seat The output of the first charger will feed into the second, as in the Merlin 60 series ....a two stage supercharger. . 

Why should I do this complex arrangement, when Rolls Royce, for example, were perfectly happy to have a conventional arrangement of two superchargers one behind the other?

Well, the answer is - efficient intercoolers and aftercoolers. With my split supercharger design, I can compress the air with the first supercharger behind the engine, and then send the supercharged air (which has been unavoidably heated by the supercharger, and thus has less density than it should have) through an intercooled pipe towards the supercharger at the back. The intake for the intercooler will be in the wing root. The intercooler will increase the density of the air as it enters the second supercharger, where it will be further compressed - and, unavoidably, re-heated - as it exits the second supercharger. From there it will be piped to the engine...but not before it is aftercooled, through an aftercooler having its intake in the other wing root. 

Thus we should be able to get at least an extra 100 hp out of each engine, and most likely something like 150 hp. I shall be conservative and claim only an output of 1600 hp for the DB and 1500 hp for the Jumo. Also, the best speed height should increase, from about 20,000 feet to about 23-25,000 feet. 

Now about the Radiator. This, too, is something of an innovation. I intend to put my Engine and oil Radiators in the rear fuselage of my design, but unlike the mustang's square radiator, mine will be oblong, fairly tall in height and slim It will take its cooling air from a chin intake, with a venturi tube wide at the chin intake, narrowing as it moves under the belly of the aircraft, and widening again as it moves up behind the pilot's seat. The heated air from the radiator will exhaust directly under the vertical tail, and that exhaust will have two flaps on each side to regulate the airflow to achieve the optimum Meredith effect. Thus the exhaust air will not only contribute thrust but that thrust will be exactly on the centerline of the airplane's direction of flight. Think of it as akin to the jet thrust of a single engine jet fighter.

The tail itself will be a T-tail....like the F-104 starfighter, so as to have the horizontal tail above the wing turbulence, and to avoid the airflow blanketing effect of the horizontal tail on the vertical tail when maneuvering at high angles of attack. 

The rear supercharger and the rear radiator will tend to make this design tail heavy, which I will compensate by...HAVING THE ARMAMENT IN FRONT OF THE ENGINE. Yes, that's right, in front of, not over, under, or between the vee of the engine block. The armament will be a 13 MM EIGHT BARREL GATLING firing the excellent german 13 mm HMG bullet. It will fire through the spinner, which will be hollow to accommodate the gatling, in a gun position reminscent of the P-39 ...but where the P-39 had a pilot between the engine and the gun, here the gun is directly in front of the engine. The spinner will be spun by a short shaft from the engine going under the gatling and driving a gearbox. 

Why the 13 mm? Well, an eight barrel 13 mm strikes the exactly the right balance between gun weight, fire rate, short length, amount of ammo, and mission necessity. Too long a gun barrel will make the nose excessively long, although some of the length of the gun will be absorbed by the spinner. The lighter 13 mm ammo will also allow a greater amount of ammo to be carried. Since this design is mainly going to fight other fighters, it should do very well against the light Yaks, and well against fighters such as the pony and spit, though not too well against the heavy armoured Jug. 

Gatling rotary barrel technology, by the way, was well known to all the sides in WW II. It was a tried and true mature technology. The Gatlings will be driven electrically, of course. I see no reason why 6000 rpm or even more couldn't be fired with eight barrels. 

Ah, but now someone may ask - "That's all very well, but the space at the nose is small - just about enough to put your eight barrel gatling - where are you going to put your 1200 or 1600 rounds of ammo? And won't that ammo so near the nose cause a cg shift as it is used up?"

And the answer is....the belted ammo is going to be put in a very conventional place, in the same place near the cg where the 109 had its HMG ammo, but the belt will be transported to the gatling by two ROTATING HELIX CYLINDERS. This is, by the way, similar to the helix magazine used by the Calico 9mm Carbine with 100 rounds in today's modern times. If the two magazines are put one behind the other I see no reason why up to 1800 rounds couldn't be carried. Thus the cg shift problem is solved. 

Fuel tanks will be in the wings, with inner and outer fuel tanks. 

So we now have:

A fighter with a two stage supercharger with both intercooling and aftercooling, radiator providing direct thrust from the tail, centerline armament with no need for synchronization, a T-tail for better handling especially at high angles of attack, and wings free of armament. 

A bubble canopy would be provided, for good all around view. 

Weights would closely resemble the Gustav, perhaps only slightly heavier - let's say 8000 lbs. If the outer wing tanks carried additional fuel, say 9000 lbs. 

The Me-109 landing gear and wing could be re-used to speed up production. The wing would however have wingtip extensions to expand total area from 175 sq feet of the normal 109 wing to 180 sq feet. The extensions should add about 2-3 feet to total wing span. The wings would, of course, lose their wing mounted radiators and the engine would lose its chin oil radiator, though it would have the chin air scoop I mentioned above. 

At 1600 hp and 8000 lbs power loading of 5 lbs per hp and wing loading of 45 lbs per sq foot. 

And so....

IMHO, this design is a fighter with a high rate of fire, a bullet adequate enough to kill fighters, very good maneuverability, high speed, and good high altitude performance - superior to the Frederichs and Gustavs and even in some respects to the Kurfursts, and available in numbers by early 1944!

Now, gentlemen, thoughts and criticisms please.


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## Burmese Bandit (Dec 16, 2008)

A point on maintenance, though.

The nose guns of the earliest P-51s, which were in a place similar to the helix drive on my uber 109 design, (except they were down under the nose instead of at the top of the nose) caused problems in maintaining the engine of those early ponies. I suspect the helix drive would, too, in my design. 

The solution would seem to be to make the entire nose as one quick change detachable unit - The engine, gearbox, spinner, the cowling, the chin intake, the 13 mm gatling.


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## FLYBOYJ (Dec 16, 2008)

And what is this fighter going to made out of?


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## Burmese Bandit (Dec 16, 2008)

As I posted before - engines: available in 1941
Airframe: fuselage new, wings of 109. Available ditto.
Gatling: new. But technology pre WW I. Could well have been done.
Other design elements also very plausible in 1940 AFAIK.


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## FLYBOYJ (Dec 16, 2008)

What material? Aluminum? Wood? Steels? All the above and were located?


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## kool kitty89 (Dec 16, 2008)

On the issue of the Gatling gun, it may be derived from old technology, but just look how long it took GE to develop a practical modern weapon from it. (not to mention getting respectable performance)
Honestly I think a revolver cannon is more realistic for this timeline, and event that would be pushing it. (You may be able to get 4-6 synchronized MG 131's in there though, with 32-4800 rpm and total gun weight of ~68-102 kg) 

However, I think 2x wing root cannons along with an engine cannon is an excellent choice for a fighter. (as Tony Williams arranges it in his "ideal fighter armament" and as used on the Ta 152)


It should also be noted that your proposed "surface intercooling" was used on the early models of the P-38 (pre-J), albeit along the leading edge of the outboard wing rather than the fuselage, but proved rather inadequate at altitude, somewhat unreliable, dangerous in certan circumstances, and particularly vulnerable to battle damage. (many of the same issues as evaprative engine cooling)


I may have chosen the He 100 as a starting point rahter than the Bf 109. (cleaner airframe, better canopy design, promising armament arrangement -2x wing root guns plus a motorkanone with no cowl guns) Using a streamlined belly radiator, similar to the semi-retractible one on the He 100D-1, or possibly a low drag fixed one. (though a belly mounted radiator usually elliminates the capability for a belly mounted drop tank) An extended wing span would probably be needed to keep wingloading reasonable (LE slats are a possibility as well). Provisions to accept the Jumo 211 as an alternate engine would also be a good idea.

A compact annular radiator as used by Junkers (also used on dome DB engines, including the DB-600 on early Ju 88 prototypes, and the DB-603 on several aircraft) It has the advantages of low weight, very compact arrangement, limited vulnerable area, and does not take up space in the fuselage or wings. (a compact radiator directly below the engine has similar advantages, and will also allow somewhat better visibility over the nose)


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## Jabberwocky (Dec 16, 2008)

Burmese Bandit said:


> AHEM.
> 
> One quick point, however. The reason why the 20 mm was so late into entry into the RAF was the terrible reliability problems of the early cannons. See Antony Williams' excellent site.



Couple of points in reply. The Hispano 20 mm was hardly 'late' into RAF service: it was flying on operational Spitifres by the end of the Battle of Britain, having undergone testing since mid 1939.

Yes, these early cannon armed Spitfires were susceptible to jams. However, early RAF Hispano reliability problems were mostly to do with their installation, which was initially on its side in the Spitfire, a poorly designed drum feed mechanism and wing flex in the Spitfire. 

Most of these problems were resolved by the time the Spitfire Mk Vb appeared in early 1941. None of these jamming problems were extant in the Typhoon. The reason it went with the 12 x .303 set up initially was simply that Spitfires and Hurricanes had priority for the armament and Hispano production hadn't caught up with demand. 

Note too that the Hurricane, Whirlwind and Beaufighter had significantly less jamming problems with their cannon installations than the early installations in the Spitfire. The development of a better belt feed motor and slightly redesigned wing structure in the Spitfire 'C' wing also improved reliability.


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## Burmese Bandit (Dec 17, 2008)

Excellent points all of you...let me try to reply to you one by one..

Flyboy: Aluminium. Steel too heavy, Wooden construction theoretically possible but not practical as Germany did not have enough skilled woodworkers, and also inadequate aircraft glue production facilities. See the history of the ill-fated Tank attempt to build a wooden reply to the British Mosquito. Of course the armour will be steel. 

Kool Kitty...THIS was why I wanted input from the other members of the forum! Hmmm....your comment about possible problem of the Gatling had maed me think. I shall, pending more research, accept your comments as complete fact...and that makes me think that I should revise my armament to 6 MG 131s in a staggered triple two-gun row. Quite doable in the space constraints, but now I shall have to have three helix feeds per side. AAARGH! Changes, changes...

Yep, I read Tony's ideal gun armament essay. However, I think that 13 mm is the way to go...I'll explain in my next post. 

Regarding surface intercooling, the reason why it was so vulnerable to damage in the P-38 was, as you pointed out, the intercooling was done on the wing leading edges, a rather large target for an enemy. I propose to do it in the fuselage, and there will be armour protecting that area anyway - it's the side armour for the pilot. Thin armour, only 4 mm, but any attack from the rear will strike that armour at VERY high angles, so should be adequate up to 15 degrees on each side from the rear.


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## Burmese Bandit (Dec 17, 2008)

But first, Jabberwocky: in reply to your earlier post...The Tiffy in all its variants, particularly its later ones, is one of my favourites in the fighter heavyweight division, and I've always wondered whether it would not have been possible to mount two engine cannons in the troughs of the H-block Sabres. 

And yep, my opinion of that chin radiator is the same as yours...


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## kool kitty89 (Dec 17, 2008)

Another point though, I don't think such intercooling arrangement if completely necessary. A kiquid cooled core type intercooler is easy to group together with the oil coolers and/or radiator in any case. (and the small increase in drag will certainly be less problematic than the drag and other problems resulting from the added fuselage bulk, weight, and complexity of such an arrangement)

However I don't think a 2-stage supercharger is even necessary. In the case of the DB-605 early models were already rated for fairly high altitude, though this decreased as the boost limit (and power output) increased. (high alt performance remained the same, or slightly improved with MW 50, but the higher boost could obviously only be obtained at lower altitudes)

The high altitude performance of these engines could not match the altitude performance of the high altitude 2-stage Merlin 61 (and similar V-1650-3) but it was fairly similar to the medium altitude rated 2-stage Merlins like the Merlin 66. However the altitude performance of these model Merlins was considered more than necessary and thus the FS (high speed) gearing was reduced somewhat to give a moderately lower critical altitude. (the V-1650-7, low blower or MS gear was unchanged)

However the DB 605 also was fitted with a larger single-stage supercharger (actually taken from the DB 603), this was used on the DB 605 AS and D models and gave high altitude performance fairly comperable to the V-1650-7.

Also, MW 50 (water-methanol injection) aclt both as an anti-detonant and a charge cooler (intercooling effect), and is used when an intercooler is most needed. (and at normal or cruise power an intercooler was not necessary)


I don't see why similar improvements couldn't be made to the Jumo's single-stage supercharger. 

The WWII German inline engines (DB 600/601/605, Jumo 211, and DB 603) relied on lower boost preasures (less powerful supercharger needed) than their allied counterparts and somewhat lower operating RPM, but instead had a much larger displacement and managed to remain comperable in size and weight to their British and American counterparts. 
The French used a similar approach with the Hispano Suiza 12Y and 12Z, and thus so did the Russians with their derivatives of the 12Y -M-105 etc-, and a similar with the unrelated Mikulin AM-35/38 and derivatives)

The Jumo 211 was somewhat bulkier than the Merlin, DB-601, or 605 (despit the 605 being larger in displacement). However the Jumo engine developed into the much more powerful (and somewhat heavier) 213, which was now comperable to the DB 603 or Griffon. This woould be the exception to the German engines, as the 213 ran at higher RPM and was actually smaller in displacement to the Griffon. Similarly it produced a relatively high power/displacement (for whatever that's worth). In this engine's case a 2-stage supercharger ie 213E/F, was needed for good high altitude performance.


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## kool kitty89 (Dec 17, 2008)

A note on the Sabre that I hadn'y known was that it used a double-sided centrifugal impeller on the supercharger (like the Whitle engine and sbsequent developments).

http://www.ww2aircraft.net/forum/engines/napier-sabre-engine-10528.html


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## FLYBOYJ (Dec 17, 2008)

Burmese Bandit said:


> Excellent points all of you...let me try to reply to you one by one..
> 
> Flyboy: Aluminium. Steel too heavy, Wooden construction theoretically possible but not practical as Germany did not have enough skilled woodworkers, and also inadequate aircraft glue production facilities. See the history of the ill-fated Tank attempt to build a wooden reply to the British Mosquito. Of course the armour will be steel.


Did you know that you would have to make wing and landing gear attach points out of steel or magnesium? Heavier aluminum alloys such as 7075 were not were not around in the time period mentioned for the development of this fighter. Many WW2 aircraft used steel more than one would expect.


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## kool kitty89 (Dec 17, 2008)

How common was it to have steel wing spars?


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## Burmese Bandit (Dec 17, 2008)

Flyboy: thanks for that input. I will put it to good use.

Koolkitty, AFAIK it was NOT common to have steel wing spars, however some Japanese aircraft towards the end of WWII had steel wing spars due to an acute shortage of aluminium.

Now regarding the reason why I have picked the 13mm as the weapon of choice for fighters versus the 151/20 for my Bomber destroyer...

Many of the arguments I will make will be seen in other threads, in particular the 'best armed fighter' thread. I believe the ideal fighter weapon for a gunfighter aircraft designed to deal mostly with other fighters is a weapon firing a projectile that is just powerful enough to get the job done, that fires the maximum amount of bullets in the minimum amount of time, that has the greatest projectile speed possible, and that is as light as possible. Oh, and that has the lightest ammo possible combined with the largest ammo storage possible. 

And this points to the MG 131. Light enough at 17 kg per weapon, a good though not spectacular projectile speed, and fairly light ammo. Firing at 900 rpm with the potential for more. Bullet with explosive ammo, not as much either weightwise or percentage wise as the 20 or 30 mm, but adequate enough to kill Spits, Ponies, and Yaks. Only against the 37 would it struggle to be effective, and even then large numbers of hits could do the job.


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## FLYBOYJ (Dec 17, 2008)

kool kitty89 said:


> How common was it to have steel wing spars?


AFAIK it wasn't, at least not in WW2 - but the most inboard sections may of connected to a steel fitting. The problem here is dissimilar metal corrosion, but there is no getting around it.

Also consider some aircraft had their wings constructed conventionally and were skinned with corrugated aluminum and then had sheet aluminum riveted to that. I believe the P-38 and B-17 were constructed in such a manner.


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## Burmese Bandit (Dec 17, 2008)

My next 'paper aircraft' design will attempt to design a better Stormovik than the Il-2, and also a better Tank killer on the Axis side. Back again when I have more time from work...


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## fly boy (Dec 17, 2008)

109ROAMING said:


> Wanna try?



if I could I would and then it might look like a flying brick but whatever


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## 109ROAMING (Dec 17, 2008)

fly boy said:


> if I could I would and then it might look like a flying brick but whatever




 ......




......


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## kool kitty89 (Dec 18, 2008)

On the wing construction issue, I think a some of the composite wood/metal (and fabric) constructed Russian aircraft had steel spars. At least the I-16 did.
I'm not sure about other such aircraft (wooden winged Yaks and LaGG-3's or La-5/7's), but the wooden construction would reduce the dissimilar metals issue. 
In the I-16's case the wing was actually construced with aluminum ribs and aluminum skin on the leading edge and center section with fabric covering the rest. 

I believe the Hurricane also had steel alloy spars. (which makes sense given the extensive use of steel in the rest of its construction)


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## Burmese Bandit (Dec 18, 2008)

Before I go on to my next paper airplane, I have decided, after digesting the excellent points made by various contributors to this thread, to redo the design of my uber 109. The engine will still be either a DB 605 or a Jumo 211, available in 1940/41. The rest of the design will stay the same. Where I have decided to make a change is in armament. 

In the age of aerial gun combat, there was always a tradeoff between gun and ammunition weight, bullet speed, bullet weight, and amount of bullets thrown at a target in a given time. Ideally the fighter gun and ammo would weigh next to nothing, have enough bullets for a full minute of fire, shoot a hundred or more rounds a minute, recoil like a feather, and shoot shells with a speed and trajectory like a laser beam and which were also capable of bringing down an enemy with a single hit. But gun designers only achieve such results in their dreams. 

I am determined to mount all my guns on the centerline, and if possible to avoid synchronization. Why? Well, synchronization is complex, and even the German electric ammo system leads to a loss of 10% in the rate of fire. The fleeting seconds - or even one second - which was the norm for target time inside the gunsight in air combat in WW II needed every round thrown at the target as fast as possible. And centerline gun installations were the most elegant solution to multiple guns mounted and sighted in one plane. (There are many threads explaining gun performance in WW II fighters - one of the best is the 'best armed fighter' thread very near this one...). And of course mounting all the guns on the centerline frees up the space in the wings for the fuel, which IMHO is the only place they should (for cg, space, and separation from pilot reasons)be. 

The practical problem with my design is that while it's possible in theory to mount multiple guns in front of the engine, in the nose, firing through the spinner, in practice unless you have a multibarrel gatling, fitting more than four guns in the nose will be a problem due to the space needed for the helix belt drives carrying the ammo from the cg point to the guns in the nose. More than two drives per side will pose a problem, limiting the nose guns to four. 

Since I'm going to have only four guns, I want to have guns that fire as fast as possible while having as heavy a shell as possible...and that are light, too. Oh, and I'll need a fairly short barrel gun to fit into the nose space. And, I believe, the answer is a little brother of the Mk 108 - a 20 mm short barreled cannon firing a lower power version of the 151/20 shell for a faster firing rate. And, of course, since it will use steel stampings and a blowback system, like the Mk 108, it should be much cheaper, too. 

I believe a 30 kg gun weight for a 20 mm short barrel with 800 rpm is quite achieveable in the technology available in 1940/41. With 4 guns in the nose, that's 3200 rounds a minute, or 53 rounds per second. Using the excellent Luftwaffe estimates for rounds on target by an average pilot, that translates to 1.33 rounds per second on target, or 4 rounds in a 3 second burst. 

The Fragile Yaks would probably go down with that, and serious damage if not destruction would be done to a somewhat sturdier Spitfire or a Mustang. A Lavochkin would suffer slightly less, and a Jug might survive....

Could the gun experts here, in particular the very knowledgeable Mr. Bronson, comment?


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## FLYBOYJ (Dec 18, 2008)

kool kitty89 said:


> On the wing construction issue, I think a some of the composite wood/metal (and fabric) constructed Russian aircraft had steel spars. At least the I-16 did.
> I'm not sure about other such aircraft (wooden winged Yaks and LaGG-3's or La-5/7's), but the wooden construction would reduce the dissimilar metals issue.
> In the I-16's case the wing was actually construced with aluminum ribs and aluminum skin on the leading edge and center section with fabric covering the rest.
> 
> I believe the Hurricane also had steel alloy spars. (which makes sense given the extensive use of steel in the rest of its construction)


Figure about a 500 hour life expectancy on anything made from wood. Its also harder to repair than aluminum.


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## kool kitty89 (Dec 19, 2008)

> Before I go on to my next paper airplane, I have decided, after digesting the excellent points made by various contributors to this thread, to redo the design of my uber 109. The engine will still be either a DB 605 or a Jumo 211, available in 1940/41. The rest of the design will stay the same. Where I have decided to make a change is in armament.



The DB 605 wasn't available in 1940/41, I don't think the DB 601E was even entering service until 1942 with the Bf 109F-4. The Jumo 211F might have been available in that time frame.


And on the armament, to be clear, you are planning on having four 20 mm cannons firing through the spinner?


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## Burmese Bandit (Dec 19, 2008)

Yes, Kool Kitty. In my previous post I stated that the design would start in 1941 with the aim of mass production by 1944. The DB 605, while not in service then, well well visible on the technological horizon.

Armament, yes. The short barrel short cartridge 20 mms should be equivalent in recoil to three long barrel ones. The Spinner will need a large hole, I would estimate 300 mm, but that can be faired.


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## tomo pauk (Dec 19, 2008)

Hi Bandit al,

If I may add a few points for the Uber-190: instead of building a whole new aircraft (extra engine, new wings etc), I'd rather whip BMW engineers to either die or to produce a 801 with a decent supercharger. So, 1900+Hp available early in 1943, together with 2*20mm 2*30mm would make the new FW-190 a tough nut for anything allies could field in these days. B-17 P-47 included 

Or mount that DB-603 in the 190, instead in many of planes of doubtful value.


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## Burmese Bandit (Dec 19, 2008)

Tomo, the 30 mm had a whole bunch of problems. First, it could be used only as an inline engine mounted gun on single engine fighters - the reasons can be seen in many other threads on this site. Second, if you put it in the wings, the tremendous recoil would warp the wings and cause not only instability but inaccuracy of fire.

And the 109 was too physically small to take the 603.

Regarding superchargers, every country was going flat out to build the best. Britain and Rolls Royce just happened to be better.


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## kool kitty89 (Dec 19, 2008)

The Recoil of the MK 108 was not that great relatively speaking. (in fact, the dispursion on the Bf 109's engine mount was lower than that of the MG 151/20, probably due to the MK 108's recoil smoothing operating principal) but mounting in the outer wings will hgave inherantly worse accuracy at most ranges.

The DB 603 was more or less interchangeable with the Jumo 213, similar size, weight, and mounting/connection points. (the latter done intentionally by Jumo to compete in the 603's market)


The BMW 801's supercharger limited altitude performance, but was not a major limiting factor on max power output. If you want more power early on put more work into an 18 cylinder version. (ie 802)

That siad, careful design of the supercharger, with a well matched impeller and diffuser will result in a supercharger that sucks up less power with less charge heating. (hence the difference between the Merlin I/II/III/XII and Merlin 45/50 etc, and the similar change between the 2-speed Merlin X and XX)
Charge heating reduces the engine efficiency (higher heat, lower charger density) and reduces the maximum boost limit. (detonation occurs earlier)


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## Burmese Bandit (Dec 19, 2008)

Yep, agree. 

Looking in the 'best armed fighter' thread I see that a majority of posters and authorities cited seem to agree that centerline is the most efficient and deadly (to the enemy) way to go for fighter armament, with opinion split between bullet power and rate of fire.


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## Burmese Bandit (Dec 20, 2008)

In designing a warbird - even a 'paper airplane' - one has to take many things into consideration, and before I go on to a new paper airplane, I'd like to explain that one of the factors in my design of a fighter and a bomber destroyer is the safety of the pilot.

Statistical studies have shown that there is a direct correlation between the overall effectiveness of an air force's fighter arm and the total number of hours flown, especially combat hours, by its pilots. No matter how many aces you may have in the beginning of a war, in a long war of attrition they will, sooner or later, die. They have to be replaced by new aces, and new aces are made, not born. They have to learn - mostly - the hard way, and that means surviving the first ten or thirty air combats...

And one of the keys to that survival, in addition to tactical awareness, speed and maneuverability of your machine, is battle resistance to enemy fire. This is why my designs have machinery, in addition to armour, behind the pilot's seat.


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## Burmese Bandit (Dec 20, 2008)

Oh, BTW, I have just posted an explanation of 'Base Bleed' with regard to artillery (and other) types of shells in the 'best armed fighter' thread, and I think this will explain why I think it is a good design point to have the radiator exhaust of my planned uber 109 in the extreme tail - I believe it should give a speed advantage of between 2% to 5% over the Me-109's wing radiator design.


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## tomo pauk (Dec 21, 2008)

Burmese Bandit said:


> Tomo, the 30 mm had a whole bunch of problems. First, it could be used only as an inline engine mounted gun on single engine fighters - the reasons can be seen in many other threads on this site. Second, if you put it in the wings, the tremendous recoil would warp the wings and cause not only instability but inaccuracy of fire.
> 
> *As pointed out by koolkity, MK-108's recoil was easily manageable by 190's wings*
> 
> ...



As for 30mm cannons in wings: was there really much of a problem regarding the mounting in FW-190?


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## Burmese Bandit (Dec 22, 2008)

30 mm wing cannon in the FW 190: it was tried by the Luftwaffe - as a bolt-on field conversion kit which had two 30 mm high-velocity103's under the wings - but AFAIK abandoned after a brief period of battlefield usage because the heavy recoil made the otherwise excellent cannon just too inaccurate. (If someone has documented evidence to the contrary, could you please let me know? Thanks!)


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## kool kitty89 (Dec 22, 2008)

The MK 108 could be mounted internally in the outer wings in place of the 20 mm weapon. 

This installation was satisfactory and was used operationally on the Fw 190A-8/R2
(this configuration was also used on the D-11/12/13)


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## Venganza (Dec 22, 2008)

Burmese Bandit said:


> My next 'paper aircraft' design will attempt to design a better Stormovik than the Il-2, and also a better Tank killer on the Axis side. Back again when I have more time from work...



Burmese Bandit, Sergei Vladimirovich Ilyushin beat you to it, or at least had a pretty good try at it in the form of the IL-10. From what I've read of it, it was an excellent plane (plagued at first by various teething problems, some serious - like engine fires[!], some not so serious). It was heavily armored with a much better rear gunner position than the IL-2, relatively fast, at about 340 mph at 8500 feet, and it was rated nearly as manueverable in the horizontal plane as an FW-190F at low altitude. When it was tested against an ace, Hero of the Soviet Union Captain V. Popkov in an La-5FN, it put its rear gunner's gunsight several times on the Lavochkin before the La-5FN got on its tail. It was obsolete by the time it saw service in Korea, but in service in the closing months of the GPW (WWII), it was probably the best attack plane around. Burmese Bandit, it'll be interesting to see what you come up with as a "Super Shturmovik". The IL-10 would be a good start. I don't think you'll have much problem coming up with something better than the Hs-129 Panzerknacker or the Ju-87G.

Venganza


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## Graeme (Dec 22, 2008)

Venganza said:


> "Back off - way off!"
> 
> R.J. McReady, Helicopter Pilot, The Thing



Hi Venganza. John Carpenter's version of "The Thing" has to be one of the best all time sci-fi/horror films made. Watched it again last night. One of your favourites?


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## Kurfürst (Dec 22, 2008)

Burmese Bandit said:


> Tomo, the 30 mm had a whole bunch of problems. First, it could be used only as an inline engine mounted gun on single engine fighters - the reasons can be seen in many other threads on this site. Second, if you put it in the wings, the tremendous recoil would warp the wings and cause not only instability but inaccuracy of fire.



They put it into the wings in the 109K-6. 



> And the 109 was too physically small to take the 603.



I don't think so - the dimensions of the 603 and the 605 were rather similiar, and the similiar, interchangable Jumo 213 was built into the 109 during the war - they even put a BMW 801(?) in one of the 109 protos IIRC!


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## Burmese Bandit (Dec 22, 2008)

Thanks again to all the posters, and to Venganza, new to this thread. 

Now regarding my improved Stormovik...I am still finalizing the paper design, but at this point I'd like to digress, since this thread has (to my pleasure) grown way beyond the point I first imagined. I thought that only two to three posters would be interested. I was wrong - how pleasant to be so wrong!

In the first post and in a subsequent post, I explained that the point of this intellectual excercise in designing a paper airplane was to see if you could have built a better house with the bricks and straw that were available at the time, _*and to have built it at time when it was needed*_. 

Now do you see, Venganza? Of course Ilyushin designed a better replacement for the Il-2 - it was 1944, the war was nearly over, the Soviet factories were in high gear - heck, overdrive - and pleeeeeenty of experience and a BRAND NEW engine was at hand!

BUT...

the point of my intellectual excercise was - could someone have taken the basic building blocks available in 1939, and it 2 years have designed an Il-2 that was BETTER than the Il-2....and have it ready for service WHEN IT WAS DESPERATELY NEEDED, in the desperate days of 1941 and 42?


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## Burmese Bandit (Dec 22, 2008)

And I believe that I could have done so. Yes, yes, I have now the hindsight that was not available in 1939, but apart from that I will rigourously - well, at least as rigourously as I can - limit my house to the bricks and straw that was available in 1939. No 2000 HP engine in 1939. No b-20 cannon either. 

But, i have to stop now - work calls. And a loooong post is needed. So I'll leave with a hint....read the beginning of Antony Williams' EXCELLENT article on tank busting aircraft, and if possible, read the whole thing.


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## Venganza (Dec 22, 2008)

Graeme said:


> Hi Venganza. John Carpenter's version of "The Thing" has to be one of the best all time sci-fi/horror films made. Watched it again last night. One of your favourites?



Too right! I've watched that movie so many times I've lost count. I thought the phrase kind of captured the angry look on my avatar. Hope your summer got off to good start.

Venganza


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## Venganza (Dec 22, 2008)

Burmese Bandit said:


> And I believe that I could have done so. Yes, yes, I have now the hindsight that was not available in 1939, but apart from that I will rigourously - well, at least as rigourously as I can - limit my house to the bricks and straw that was available in 1939. No 2000 HP engine in 1939. No b-20 cannon either.
> 
> But, i have to stop now - work calls. And a loooong post is needed. So I'll leave with a hint....read the beginning of Antony Williams' EXCELLENT article on tank busting aircraft, and if possible, read the whole thing.



I understand Burmese Bandit. No slight against your engineering skills. I should have read the whole thread to understand what the exact premise was. It'll still be interesting to see what you come up with, and I'll give that article you mention a look. And I'll no doubt have some pearls of wisdom to add to the thread when it turns to the "Super Shturmovik".

Venganza


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## Burmese Bandit (Dec 23, 2008)

An apology to the readers of this thread is needed.

I had intended to post my concept on what a better Stormovik would be like, and indeed I already have the text typed. But before I do that...

I intend first to give my ideas on _what a better Hs-129 should and would have been. _

Why? 

The reason is that not only will it finish the trilogy of Axis Aircraft I always intended to 'paper build', but after I have finished it I will post my thoughts on how the duo, the BB-47 and the BB-109 should have been used tactically on the Western Front, and how the trio of the BB 129 plus the other two should have used tactically on the Eastern Front. (For reasons of Clarity I have decided to call my paper aircraft BB 47 and BB 109 and BB 129 now - may the gods of engineering forgive this poor Burmese for his presumption... ) This will provide fertile ground for all the enthusiasts who may, at present, for various reasons, be hesitant and wary of posting in what they might feel to be a 'pure engineering' thread (always supposing, of course, that they will accept the initial premise that the planes themselves could have been built and the proposed performance goals met) and in this way, this thread would become even more livelier, and attract more posters, than it does now. 

For, after all, this was the main reason for my starting this thread in the first place - not to show off my (considerably deficient) engineering skills, not to impress anyone with my (definitely spotty) knowledge of WWII armament technology, but to try to stimulate debate that will make the debaters think 'out of the box'. There is a lot of debate in this forum that is predictable, not because the intellectual capabilities of the debaters are low - they most definitely are not - but because the events and hardware they are debating are frozen in history: the progress of WW II, the specific power output of the Merlin 61 at a certain altitude, et cetera, et cetera. 

A new (BUT historically plausible) set of facts will open a new box, wider and deeper than the old, which will allow all of us to think 'out of the box'. Think of my aircraft as those from an alternate history of WW II set in a planet in a space-time different from ours - World War 2.1, if you like!


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## Venganza (Dec 23, 2008)

Well said, Burmese Bandit. As I mentioned in a previous post, I don't think you'll have much trouble designing a better Hs-129.

Venganza


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## Burmese Bandit (Dec 24, 2008)

And with that having been said...let's go to the BB-129!


Some of my basic thinking behind the thinking of the BB 129 will be stated, so that the design can be fully appreciated...

I believe in the concept of having a ground attack aircraft designed first and foremost to destroy heavy armoured vehicles is necessary, particularly for a war which is fought on a front of vast distances and relative small armies to cover that distance (read: the Eastern Front 1941-44). In designing the paper airplane I admit freely to being heavily influenced by this forum's own TONY WILLIAMS (a big hand for this big Brit!) although, as you'll see, I end up with a plane different from his ideal radial engine pusher design. 

But the basic parameters are the same as his. It should be armoured. It should have gun, not rocket armament, and the gun armament should be at least 37 mm. It should also be as small a size as possible, and as agile as an armoured aircraft carrying a heavy gun can be. It should have engines and other systems as battle damage resistant as possible. 

To these basic design constraints I'm adding some of my own. It should be capable of operations even when the temperature is way to the south of the zero mark and also when the ground of your airfield decides to do its gigantic mud soupbowl imitation. Even though it will - it must - be a heavy beast, it should also be capable of taking off in as short a distance as possible. 

And, of course, it MUST have some sort of rear defence. Preferably one that can be credible enough to cause any Russian pilot to mentally wince and touch his lucky charm before he charges in to attack. 

And, of course, as we have said before, it has to use the materials available at the time, and have a projected cost that's plausible!

So - we've set the ground (or should I say air?) rules - what can we do or design that engineering teams in the WW II era that were very, very competent haven't designed already?

As someone much better than me said a long time before "_Let's cut to the chase!_" So without further ado, here comes the summary of my proposed design in one sentence. 

It's a twin powerpod, four-Argus engine push-pull prop design with a tandem triplane wing configuration, central engine supercharging, a retractable nosewheel gear with a twin tail and a counterrecoil 50 mm gun firing downward at a 5 degree angle with two 13 mm guns for defense. 

(Do I hear somebody saying "*Holy Imagination Overkill Technologically Overreaching Pretentious Crap Burmese Bat-man!* "?  )

To be continued....


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## Burmese Bandit (Dec 24, 2008)

In my last post I outlined the basic form of my BB-129. I shall now try to explain the design in detail. 

First, the choice of the Argus as the powerplant. This is a 12 cylinder air cooled Vee, which not only has a slim frontal area but earned a reputation for reliability in the harsh battlefield environment of the Eastern Front. Its only weakness, a lack of power (common to all air cooled vee designs, by the way) producing only 485 hp at 3100 rpm. By mounting four Argus in a push-pull configuration we get about 2,000 hp. And only two powerpods, one on each wing. 

Weight - I'm thinking of a total weight, with 15 mm nose armour, 6 mm belly and 10 mm pilot side armour, and of course the monster gun, of which I'll describe later, of 8000 kg (17,600 lbs). The Twin Argus in each power pod will be set far ahead of the wing, and with the armour of the crew pod and the heavy gun the plane will be very nose heavy...which will be counterbalanced by the fifth argus driving a central supercharger behind the gunner in the fuselage.

The main wing is a high wing, which span out to the power pods and beyond. The power pods are under and forward of the wing, with the front spinner level with the nose of the airplane - and from that nose, a short span biplane wing extends to either side till it mates with the underside of each power pod. Thus seen from the front, the planform will look like a two oblong rectangles joined together: a central fuselage, two powerpods on left and right, and two wings joining the top and bottom of the powerpods. The upper wing continues on past the powerpod, but the bottom wing stops there. In effect, it is a one and a half wing biplane, with the lower wing ahead of the upper, main wing. The lower wing is effectively what is called a 'canard' wing.

Such a design should give this plane a great structural strength, which will be necessary in the event of battlefield damage. With this one and a half wing design, I feel confident that we can get 450 square feet of total wing area on a total span of only 40 feet. This will lead to a wing loading of just under 40 lbs per square foot, which I think is just the right balance between low speed maneuverability and low altitude stability. The fuselage, housing the central supercharger, will continue to a tapered twin tail having two tails, like the Me 110. Each vertical tail will have its controls separated as widely as possible so that one can remain functional even if the other is damaged. 

The front underwing, like the main wing, will have flaps. When these flaps are used together with the flaps in the main wing and with also the horizontal tail providing lift, we have in effect three wings - one in front, one mid, and one in the back of the plane. When the front underwing (the canard) is used to lift and the tail used to spoil lift, this plane should be able to pitch up faster than conventional planes. 

I intend to use a page from the design of the P-61, and supplement my ailerons with spoilers on top of each wing, with them deploying differentially so that when one wing's ailerons go down the spoilers on the opposite wing will go up. This should create a roll faster than could be achieved with ailerons alone. The P-61 black widow at nearly twice the weight of this design was very, very maneuverable for such a huge aircraft, so I believe that this design should also be quite maneuverable...I think it should be just slightly less agile than the Stuka. Certainly much, much more maneuverable than the Hs 129.

The nosewheel will be offset, as in the A-10, and for the same reasons. 

To be continued....


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## Venganza (Dec 24, 2008)

Wow, Burmese Bandit, is all I can say! (Not really, I'm going to say a few more things.) Could you come up with a schematic of the beast?; I'd love to see it - I may take a crack at it myself just so I can visualize it better. It might have terrified the Soviets just by its appearance alone (the visual equivalent of the sirens on the Stuka). This is definitely not your grandparents' Hs-129, so to speak.

Venganza


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## Clay_Allison (Dec 24, 2008)

Actually, I think the better fighter was designed. The He-100 which was not accepted for production reasons broke a world speed record at the time and it wasn't even a racing plane. If you just look at the pictures and how beautifully streamlined it was, you know it would fly like a dream, probably competitive with Mustangs. Just put 6 13mm MG 131s on it and it's probably the most intimidating dogfighter type fighter of the war.


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## magnocain (Dec 24, 2008)

Ok, here I go. I'll call it the F4U-4h

I would start with a standard F4U-4. Lengthen the landing front landing gear slightly so that it could carry a torpedo. In the empty space behind the cockpit there would be options for; a cramped fold-down seat for a passenger, a bomb bay, an extra fuel tank, or a pair of cannon (20mm-37mm depending on pilot choice and mission) firing through extended barrels and groves in the fuselage (similar to the Gladiator). Also a .30in MG fixed in the tail with a rear view mirror for the pilot to shoot it with (to scare the unwary fighter).

The image is the illustration of a congruent space on a Yak fighter.


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## Burmese Bandit (Dec 24, 2008)

This seems to be a regular feature of this thread - another apology from its starter. Yes, I owe this thread a schematic, and not just one but *THREE* - the BB 47 that started all of this, the BB `09 with its heavy nose armament and its T-tail, and of course the BB 129. I intend to post the schematic when I get around to it (_stares at the round 'tuit' given to him by the resident aviation thread joker_) but now my old and bruised Tee square is gathering dust as I try to do 1,001 things at once. I ask the forbearance of all those who have graced this thread with over 1,200 views as to date. Vengenza, if you want to post your own schematic before I do, by all means do. Let's see how close you get to my design! BTW I thank whoever was responsible for giving a star to this thread - I certainly wasn't expecting one!  

And again BTW, if other posters wish to elaborate on their own ideas, PLEASE feel free to do so in this thread, but ...the only request I will make...try to group it in one, or a series of closely grouped posts, please? The reason I make this request is because even I can't submit all my paper designs in one post, and I'm sure those who try to do the same with other aircraft will have the same problem too. So we might have a situation where posts describing two different aircraft will weave in and out of each other, and this might confuse the reader.

*And now to resume the description of the BB - 129...*

Why the fifth Argus in the fuselage centrally charging the other four in the two powerpods? Well, apart from the balance reasons I have already stated, the engine and massive superchager in the fuselage will probably provide complete immunity to rear attack by 20 or even 23 mm within 5 degrees each side of the rear, and the side armour an excellent amount of protection against 12.7 mm attack for 20 degrees or more on each side and good protection against 20 mm for about 10 degrees each side at least

Even if rear attack destroys the central supercharger the unsupercharged output of the four Arguses should give at least 50% remaining power, good enough for a limp-home-after-dropping-all-unnecessary-weight escape strategy if the rest of the plane and powerplant are not too heavily damaged...and of course, as I have posted before, the tandem triplane configuration where the underwing mates with the power pod which in turn mates with the main wing should give this design a very high structural strength. 

And now we see another reason for having two engines in each powerpod (separated of course by an armoured firewall) - battle damage redundancy. With an attack from the front, the front engines will soak up the fire but at the same time protect the rear engines, thus ensuring at least 50% power available. Probably more, as air cooled engines will take more than one hit before they finally give up the ghost and stop producing power. Same in an attack from the rear. Even in a worst case scenario, an attack from the rear destroying both the left rear engine, the central engine and supercharger, and the right rear engine, we should still have 25% power left...enough to make a controlled crash landing scenario, some miles away from the combat zone, plausible. 

Continuing on the theme of defense, I intend to put a rear gunner sitting back-to-back with the pilot, with an armament of two MG 131s (perhaps an MG 131Z) with a rate of fire uprated to 1200 rpm. This again looks quite plausible, as the ordinary MG 131 had a rof of 900 rpm and the cartridge was not too powerful. This gun should have a deterrent effect much better than the MG 81Z of the Stuka, and almost equal to the more powerful double 12,7 HMG rear armament of some late model Stormoviks. (I would also decree an upper body weightlifting program for german rear gunners, too!)

With a power to weight ratio higher and a wing loading lower than the Lancaster, with a much shorter wingspan, with the engine weight in the wings closer to the center, and with the spoiler/aileron system too, I see no reason why the BB 129 should not be at least as good, or IMHO much better, at 'corkscrewing' than the great Lancaster. At 3000 feet height (about the right height for a ground-pounder attack aircraft) and a maximum drop in the corkscrew of 500 feet, there is enough margin for error for this maneuver to be done safely. Should the BB 129 suddenly grow a tail of Yaks or La-7s attacking from the rear, the Corkscrew maneuver should be used. This, combined with the two 13 mm, the armour, the structural strength and the redundancy, and the rear charger engine and supercharger, should give the pilot and gunner a good chance of escape from a rear attack!

My next post will describe the offensive armament...


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## Burmese Bandit (Dec 25, 2008)

Oh, er, by the way, Magnocain, it's just not possible for any gun bigger than, say, 30 mm to fire through the propeller by interruptor mechanisms, whether the mechanisms are electrical or mechanical. The reason is that the bigger cartridge cases of these guns cause variations in propellant burn time so that sooner or later a mistimed shot will hit your own propeller, with results that you wouldn't want to even think about...if you were the pilot. The Germans tried to mount their 30 mm guns in a belly installation for the FW 190 but gave up for the reasons stated above. A 37 mm gun firing through the propeller with interruptor mechanism would have even worse results...


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## Burmese Bandit (Dec 25, 2008)

And now, the reason for the existence of this plane: and another reason for my needing 2000 hp: the reason why this plane weighs 8000 kg (17600 lbs) all up: the reason why I think this plane would have been a world beater....

...the armament.

Unlike other tankbusting designs which use the BK 3.7 or its equivalents, I intend to use the 50 mm Mk 214 A for this plane. And I think this installation would have worked, unlike the unhappy history of the Mk 214 A, mated with other planes - eg the Me 262.. 

But why this cartridge and this gun? And why should this tremendously powerful and heavy gun work in this design when it wouldn't work in other designs?

First, a heavy gun with heavy recoil will work only in a heavy plane that can soak up the recoil. The JU 87 G had two BK 3.7 cannon that had a muzzle energy of 263,000 joules each. That's equivalent to a single gun of 526,000 joules. The 50 mm cannon round (50 x 420 R) firing the round with the heaviest recoil, the 2 kg (4.5 lb) steel-core armour-piercing round, has a muzzle energy of 716,000 joules. That's about 33% more power than the two 37s fired in unision. The JU 87 G weighs 6500 kg. all-up. At 8000 kg my design is about 22% heavier than the 87 G. 

So: a gun with 33% more equivalent power in a plane that's 22% heavier. That's about a 10% increase in effective recoil over the JU 87 G. It's doable, unlike the grotesque mating of the BK 7.5 75 mm gun with 2,120.000 joules muzzle energy in the HS 129 B airframe that weighed only 5250 kg all up! Compared to that, my design has only one-third the recoil in an airframe that's 50% heavier!

The gun itself, mounted on the centerline, will also have a hydraulic damper as was the case with the 75 mm cannon of the HS 129 B. The damper will allow the entire gun and ammunition to move backwards, but only for a short distance - I don't want to disturb the cg too much. The gun is angled down slightly - say about 5-7 degrees - for aiming ease, and also to counterbalance the nose pitch down that will happen as this gun is mounted just under the center of lift. As the nose pitches up as the gun is fired, the gun is also moving slightly to the rear of the plane, which will make the plane slightly tail heavy, which will counteract the nose pitch down with a tail pitch down effect. When combined with the fact that this design, because of the canard tandem triplane wing, has excellent pitch control, I think we have basically solved the recoil problems that plagued the HS 129 B in its anti tank role.

Note that I am proceeding from the worst case scenario concerning recoil, which is the MK 214 A firing the 2 kg (4.5 lb) steel cored shell. I plan to have my design fire the 0.9 kg (2lb) tungsten-cored shell, with a much faster muzzle velocity AND a much lower recoil. With this shell, I think my design would be as steady as the P-39 in firing...which should lead to a very, very good accuracy of fire. (Incidentally, the tungsten round could pierce 72 mm of armour at 500 meters and as much as 130 mm of armour at 100 meters!)

As for the weight, the Mk 214 A is listed as 490 kg. Let's say 900 kg for the gun, ammunition, hydraulic damper system, and other necessary accessories. With a total all up weight of 8000 kg in the BB 129 this is perfectly plausible. 

So much for the recoil and the weight...what about the size?

Well, the Mk 214 A is about 4.5 meters in total. I think about 3.5 meters should be absorbed into the fuselage, leaving about 1 meters to project ahead of the nose. This is a manageable length, especially if it is enclosed with a fairing to ensure smooth aerodynamic properties. 

Since only about 50-60 rounds of ammo will be carried for the heavy gun, it will need a spotting gun for ranging, and also for emergency self-defense in case of a frontal attack by aircraft. I propose the MG 151 high velocity cannon in the 15 mm variant, with a shell that explodes with a bright flash on striking heavy armour. 

That's all for now...in my next post I will propose how this design might be used tactically, in conjunction with my other two designs.


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## Burmese Bandit (Dec 25, 2008)

Regarding the 50 mm, some further elaboration...Yes, I could have put the 37 mm Flak 43 (in a twin gun installation) with no less than 240 x 2 or 480 rounds a minute for this design - that twin gun would have weighed just slightly more than the monster MK 214 A. I thought for a long time about whether to go down that route.

It was attractive. I could have put 80 rounds per gun for a total of 160 rounds, with 10 seconds of fire at the full double-gun simultaneous fire or 20 seconds at single gun fire. This would certainly have killed anything on the ground except tanks, give at least a 50% probability of kill against tanks, and if there was ammo left give an excellent chance in head-on defence against enemy fighters...

But in the end I chose to put the MK 214 A as the primary weapon. For tank killing a weapon like this monster is the ONLY sure one that will guarantee kills against the top, side, or even sometimes the front armour of any tank the Russians fielded except for the late war Stalins. 

However, the option to put two Flak 43s in an aircraft mounting is there. That's one good thing about having a big design...it allows you to have choices.


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## Burmese Bandit (Dec 26, 2008)

Before we go into tactics, a thought on performance. What sort of performance could we expect from this beast?

Well, if we look at the power to weight ration, we have 2000 hp or just under against a weight of 17600 lb - that's just under 9 lb per hp, which is about 10% better than the Ju 87 G with 10 lb per hp. The wing loading is about the same for both aircraft, and therefore basically the basic performace should be the same - IF - the drag for both aircraft are the same....

I think that they will be. The BB 129 does have a stubbier wing and that canard which produces more drag, plus of course the two powerpods on each wing. However, against that the JU 87 G has two huge guns in pods on each wing, plus the fixed undercarraige, plus 10% less relative power. 

I suspect my design will have about the same speed figures as the 87. but be more agile - and have much better takeoff performance, especially at full load. Taxing should be miles better with the nosewheel of the BB 129 and landing, of course, better. 

Since the HS 129 had worse performance in all areas and worse agility than the 87 this design should be better in performance and handling than the HS 129 in all respects.


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## Burmese Bandit (Dec 26, 2008)

a quick point: there were reliability issues with the MK 214 A and it was constructed very late in the war. However, I have looked at the gun design, and there is nothing that I can see that would preclude it from having been built much earlier if the decision to do so had been made. Further, I believe that the reliability issues could have been worked out...and of course, we have the Flak 43 which was actually used and found to be reliable...to fall back on.


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## tomo pauk (Dec 27, 2008)

Bandit, what about mounting 2 Bramos instead of 5 Argus engines. Again some 2000HP on board, and much more less logistical trouble.

As for the (main) armament: single 3,7cm would do until something heavier is developed. And some unguided rockets under the wings to make the Hs-129 a real general purpose attack platform.


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## Burmese Bandit (Dec 27, 2008)

Bramos - I thought about it, but what if an attack from the front takes out one of the Bramos? As I said in post no. 98, fifth para, self quote here...

_And now we see another reason for having two engines in each powerpod (separated of course by an armoured firewall) - battle damage redundancy. With an attack from the front, the front engines will soak up the fire but at the same time protect the rear engines, thus ensuring at least 50% power available. Probably more, as air cooled engines will take more than one hit before they finally give up the ghost and stop producing power. Same in an attack from the rear. Even in a worst case scenario, an attack from the rear destroying both the left rear engine, the central engine and supercharger, and the right rear engine, we should still have 25% power left...enough to make a controlled crash landing scenario, some miles away from the combat zone, plausible_.

The reason why I don't want rockets for my tankbuster is given in the start of Tony William's excellent essay on tankbusting aircraft - rockets are just too dang inaccurate. 

And I did give an alternate 3.7 armamaent, Tomo. It's the FlaK 43. an excellent weapon.


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## Burmese Bandit (Dec 27, 2008)

Here is the quote from Tony Williams regarding small cannon and rockets as useless against Tanks...

_" The ineffectiveness of air attack against tanks should have caused no surprise because the weapons available to the fighter-bombers were not suitable for destroying them. Put simply, the heavy machine guns and 20 mm cannon were capable of hitting the tanks easily enough, but insufficiently powerful to damage them, except occasionally by chance. The RPs and bombs used were certainly capable of destroying the tanks but were too inaccurate to hit them, except occasionally by chance."_


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## Clay_Allison (Dec 28, 2008)

If I was going to design a new fighter for WWII using technology of the day, I think it would be a V-engined pusher that would look a bit like a baby P-38 with a blunter nose, split tail, short wide elliptical wings for fast climb and tight turns.

Pusher designs were unfairly overlooked during WW-II, they provide certain advantages in maneuverability due to less disrupted airflow over the control surfaces. Also it allows for nose armament without fighting the engine block for space.

Weapons would be where it would really hang its hat, with 4 20mm cannon in the nose, aligned to shoot as tight as possible for easy tracking and kills on shorter bursts. It would be equally at home dogfighting other fighters or intercepting bombers.

Sounds awesome to me, hell if I know if it would work.


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## Burmese Bandit (Dec 28, 2008)

Clay, see the Bell XP-52. Here - Bell XP-52


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## Clay_Allison (Dec 28, 2008)

You know, I was researching pusher planes after I posted and the Swedes has a pusher (Saab 21) that they liked quite a bit, powered by a DB 602. They kept it into the mid 50s. 

Sadly (like the AG-42 rifle) it was never really used in anger because Sweden remained neutral.


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## Burmese Bandit (Dec 28, 2008)

Pushers have one drawback - no rear gunner possible...and you need an ejection seat.

That said, I think that if 4-7 years of research into high powered pushers had been done before WW II, we might have seen some very interesting designs indeed!


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## Venganza (Dec 29, 2008)

Clay_Allison said:


> You know, I was researching pusher planes after I posted and the Swedes has a pusher (Saab 21) that they liked quite a bit, powered by a DB 602. They kept it into the mid 50s.



Interestingly enough, Clay, they developed it into a jet, the Saab 21R, one of the very few piston-engined aircraft to be developed into a production jet aircraft. The only other one that comes to mind is the Yak-3, which was developed post GPW into the Yak-15, with a copy of the Me-262's Jumo engine slung underneath the front. It preserved the tail-wheel landing gear and mixed construction of the Yak-3. It was the lightest jet fighter ever, at around 7,000 lbs. if my memory serves me. By the way Burmese Bandit, still working on my visual interpretation of your BB-129. It will be interesting to see how close it gets to your idea. I'll be lucky if it looks as similar to your conception as the Commonwealth Kangaroo did to a P-51D.

Venganza


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## Clay_Allison (Dec 29, 2008)

Burmese Bandit said:


> Pushers have one drawback - no rear gunner possible...and you need an ejection seat.
> 
> That said, I think that if 4-7 years of research into high powered pushers had been done before WW II, we might have seen some very interesting designs indeed!


I never thought rear gunners did much good. They never had more than a single .50 to shake at the enemy, and if one was enough to down an enemy fighter, why did the fighters have 6?


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## Burmese Bandit (Dec 29, 2008)

Rear gunners are valuable not so much for their _shooting skills _as for their _eyes_.

If we look at the analysis of fighter kills done by the US, UK, Nazi Germany, the Russians, etc etc, one fact leaps out - the great majority of pilots shot down were _shot down from the rear,_ and they _never saw the plane that shot them down until the bullets were striking them_!

This is why the great aces in the air had what was joking called the "fighter pilot neck syndrome" - their heads and eyes were continually swiveling round amd round, looking for the enemy ambush. There's an ace saying "If it's a fair fight, you didn't set it up right". 

The greatest of all, Hartman, gained most of his kills by ambush hit-and-runs. If you're a soccer fan...and remember the German soccer team of the 1970s...think of him as Gerd Muller with wings and machine guns! 

So, for fighter planes with space limitations, no rear gunner means you have to have a fighter pilot neck. Only rare human beings can do this 24/7 in the air. No matter how often it's drilled into you, your mind gets tired and you stare in one direction just a little too long...and the next thing you know, your ass is on fire!

This is why bomber and attack planes have a rear gunner. 

Of course, if your plane can neither run worth a damn or maneuver worth a ****, then you need a gunner with superb shooting skills...


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## tomo pauk (Dec 29, 2008)

Burmese Bandit said:


> Bramos - I thought about it, but what if an attack from the front takes out one of the Bramos? As I said in post no. 98, fifth para, self quote here...
> 
> _And now we see another reason for having two engines in each powerpod (separated of course by an armoured firewall) - battle damage redundancy. With an attack from the front, the front engines will soak up the fire but at the same time protect the rear engines, thus ensuring at least 50% power available. Probably more, as air cooled engines will take more than one hit before they finally give up the ghost and stop producing power. Same in an attack from the rear. Even in a worst case scenario, an attack from the rear destroying both the left rear engine, the central engine and supercharger, and the right rear engine, we should still have 25% power left...enough to make a controlled crash landing scenario, some miles away from the combat zone, plausible_.
> 
> ...




The reason I suggested 2 engines instead of 5 is that five Arguses on a single plane is the over-engineering (the main reason when something german malfunctioned in WWII). So, instead of trouble of installing 5 engines, I'd rather add a rear gunner or something really useful IMO.

As for rockets, that is for the word 'general' in the 'general attack plane'. I've checked out Tony's articles site years ago BTW 

3,7cm Flak 18/36 or the 43*, it doesn't make any difference for the ground attack (check out videos of Ju-87G attacking tanks - single shots!!) 

*I know that it was an excelent gun


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## DerAdlerIstGelandet (Dec 29, 2008)

Burmese Bandit said:


> Rear gunners are valuable not so much for their _shooting skills _as for their _eyes_.
> 
> If we look at the analysis of fighter kills done by the US, UK, Nazi Germany, the Russians, etc etc, one fact leaps out - the great majority of pilots shot down were _shot down from the rear,_ and they _never saw the plane that shot them down until the bullets were striking them_!
> 
> ...



Burmese has it right.

The tail/rear gunner is best suited as an extra set of eyes. Of course the gunner is also valuable for the occasional fighter pilot who gets careless, forgets about the gun and comes up your tail.


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## Venganza (Dec 30, 2008)

OK, Burmese Bandit, you asked for it you got it. My pathetic attempt to portray your BB-129. Don't laugh too hard. It may not be anything like you envisioned, but I kind of like it. I didn't do a planform because I'm still confused (not hard to do to me) about the exact wing configuration which I'm pretty sure I botched up in this profile. To explain a little about my interpretation, I put the supercharger Argus in the center of the plane to try and not mess up the c/g too much. The Argus engines have two-bladers like the FW-189 because with less than 500 h/p per engine, anything more than two-blades is a waste of metal (I mean, you wouldn't want a 5-blade Rotol on them). The armoured crew compartment is based on that of the attack version of the FW-189, partly because I had no good idea how you saw the crew compartment (other than the pilot and gunner being back to back) and because I like the way it looks. I have the main landing gear retracting into the fuselage a la the Ar-234 because with the engine and wing arrangement it made sense. I might have had the gear retracting backwards, but the space was taken up by the supercharger Argus. If nothing else, I hope you're amused by my attempt. If you could provide me with just some rough sketches, I could fix (or scrap and completely redo) my version and also do the planform. At any rate, here it is, warts and all. Enjoy!

Venganza


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## Burmese Bandit (Dec 30, 2008)

You got 80% of it right - Kudos to you!

Where you missed, though,(and this is more my fault of inadequate description than yours of inadequate visualization,I think) is in the fact that the powerpod mates smoothly with the main wing, and the rear propeller has a driveshaft that goes right through the main wing to drive a prop that turns behind the main wing. 

Furthermore I would have the air and cooling intakes for the fifth argus in the main wing roots so as to keep the belly clean for possible ordnance stations. And, of course, mud on takeoff is better avoided this way...

The landing gear (this is something I forgot to fully describe, again) is behind the rear engine, and continues neatly behind the powerpod with half the wheel visible in the folded back flight position, like the stormovik, a very useful thing to have in a belly landing.

And I definitely would have a cockpit with more view! 

But apart from that, A FANTASTIC JOB!!!


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## Burmese Bandit (Dec 30, 2008)

The main reason for the powerpod mating with the main wing: structural strength. There is a beam that connects the junction of the powerpod which mates to the canard with the junction of the powerpod which mates to the main beam. This creates a box girder rectangle which is very, very strong.


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## Venganza (Dec 30, 2008)

Burmese Bandit said:


> You got 80% of it right - Kudos to you!
> 
> Where you missed, though,(and this is more my fault of inadequate description than yours of inadequate visualization,I think) is in the fact that the powerpod mates smoothly with the main wing, and the rear propeller has a driveshaft that goes right through the main wing to drive a prop that turns behind the main wing.
> 
> ...



Thank you! I knew I didn't do the wing correctly, but I couldn't quite visualize how you planned to do it, with the mainwing attached to the forward mounted powerpods. I wondered about how to do the cooling for the fuselage mounted Argus, and having the intakes in the wings makes more sense than having them on the fuselage not just for ordnance carrying reasons, but also for giving a cleaner underfuselage in case of a crashlanding. I wondered about the landing gear too - I also thought that the wheels should be partially exposed, as on the IL-2 and the A-10, for the reason you mention. The cockpit on the FW-189 ground assault prototype had horrendous vision, of course, but nothing that a little armored glass couldn't improve. I may try to correct my interpretation, with the additional information you gave me. Stay tuned.

Venganza

P.S. Do you envision the plane having an internal bombbay? If all the ordnance is external, I can make the fuselage slimmer (with the limiting factor being the mid-mounted Argus), which would also cut down on drag (once the ordnance's dropped), lower the weight and make it a smaller target head-on.


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## Vraciu (Dec 31, 2008)

Hi!

I'm making a Allied (English-American) heavy bomber, something between B-17F or G, B-24D and Lancaster B.III, I want to make a universal bomber - to operate during day and night. I forecast there'll be two versions: B.IE (for ETO and MTO) and B.IP (for PTO and China/Burma/India).

It'll be four-engine mid-wing aircraft with full metal fuselage. Engines: there are two options I think: RR Merlins or P&W R-2800. The piston engine would make a bomber more aerodynamical, but its unresistant for flak and one bullet can exclude it from the action. Radial engine is more resistant and gives more power. In spite of all I prefer P&W, but my design studio (I'm the chef and one worker heh) can process version with Merlins (B.IE-Mr, for PTO piston engine isn't a good idea).

Work in progress and Happy New Year to all, in Poland is 22:29 only.


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## Burmese Bandit (Dec 31, 2008)

Vengenza: no internal bombay. This is designed to be a big gun plane, with the possibility of the guns being deleted and a large, jettisionable belly rocket pod mounted later should rocket accuracy improve enough later in the war to replace guns. 

I intend...alas, I cannot give you a time frame....but I intend, as another member of this forum told me in a PM, to buy and learn to use the X-plane software, and then to design all three of these planes and then post the results here. Then you can not only see them but fly them! 

Vraciu: THIS is the reason why I started this thread! I want to see some really imaginative solutions. Here are some thoughts I had to make an alternate B-29. Feel free to make use of them!

(1) We know that if there had been enough research money available, the Rolls Royce Griffon, a 2,000 hp class narrow frontal area engine, could have been available in numbers with the bugs worked out in 1943. Let's start your bomber on the premise that Rolls Royce sold the rights to the US Gov in 1941 and the USG promptly gave the patents and drawings to Continental Allision etc and told them to push the design and guaranteed them a contract. By 1943 a stable 2050 hp design is ready. 

(2) Now with that 2050 hp design you throw in a new twist: central supercharging, as I used in the BB 129. Only this central is not for protection purposes, but for increasing the power of the engines which will be embedded in the wings, like the B-36. Since each of the wing engines will no longer have the duty of powering the supercharger we should get a profit of 200 hp per engine. Thus we have griffons of 2250 hp per engine in the wings. Just about right to power the 120,000 lb (50,000 kg) BB-29...or the Vraciu 29.

(3) Result: a B-29 without the huge draggy radial engines. only smooth slim blisters driving pusher engines! At 30,000 feet a maximum speed of 400 mph should be possible, and on long trips overwater you could have the option of shutting down one or two of the engines to save fuel with very little drag penalty... lots of possibilities open up!!!


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## Venganza (Jan 1, 2009)

Burmese Bandit said:


> Vengenza: no internal bombay. This is designed to be a big gun plane, with the possibility of the guns being deleted and a large, jettisionable belly rocket pod mounted later should rocket accuracy improve enough later in the war to replace guns.
> 
> I intend...alas, I cannot give you a time frame....but I intend, as another member of this forum told me in a PM, to buy and learn to use the X-plane software, and then to design all three of these planes and then post the results here. Then you can not only see them but fly them!



Burmese Bandit, great idea about making the planes in 3D and flyable! I was actually thinking about trying to turn my interpretation of the BB-129 into a 3D model. I think I will try, even if you come up with your own model - I kind of like what I've done so far and I may continue it, maybe I can call it VG-129, with due credit to you as the inspiration, of course. Happy New Year!

Venganza


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## Burmese Bandit (Jan 1, 2009)

And a happy one to you, too!

BTW, in response to those who have called my design overengineered - actually I wanted to respond a long time before, but things got in the way...

There is a difference between what engineers call a graceful failure design and a catastrophic failure design. In a graceful failure design failure takes place gruadually, allowing time for response to avoid catastrophe, whereas in a catastrophic failure design a single failure destroys everything. Think of a bicycle chain. If one link in the chain fails, the bicycle stops moving. That's catastrophic failure. Think of a toothed gear. If one tooth breaks, the gear still can spin another gear - it'll run a bit rough, that's all. That's graceful failure.

My five engines are a graceful failure system. One engine breaks, the others soldier on. Supercharger engine is damaged, other engines continue at a lower output. And so on, in other situations.


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## Vraciu (Jan 1, 2009)

Well, if we want to have RR Griffons in, hmmm... I'll call my bomber ABC (Avro/Boeing/Consolidated) Achilles, have anyone precise plans of this engine to copy them to the bomber plan?

The next thing we ought to do are wings. I think that longer Lancaster's wings will be enough. But with tail I have bigger problem. I don't know which'll be better: double, as in Lancaster or B-24 or single, as in B-17 or authentic B-29.

Work in progress,
Chris


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## Burmese Bandit (Jan 1, 2009)

Wings: If you want to put the engines in the wings I think a B-36 wing scaled down to 120 feet should do it.

And keep the B-29 tail. MUCH easier to blend in the tail gunner position smoothly!

And while we're on the subject, don't forget to keep the revolutionary design features of the B-29: the central cylinder mating with the wing and two bomb bays in front and behind, with cylindrical bomb carriage leading to two relatively small bomb bay doors in the underside. This feature allowed the fuselage to be cylindrical, and only smallish doors to be cut into the fuselage, thus tremendously improving strength.

You will need to think about how to best site the radiators for maximum efficiency and minimum vulnerability.


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## Vraciu (Jan 1, 2009)

Hmmm, BB, in original project I wanted to make an Allied bomber AD. 1942/43, so from B-29 I'll get hermetic cabin (did I write it correct in English?) and two bomb bays. Other technical wonders from Superfortress weren't available in this time. But my Achilles' fuselage will be more oval than cylindrical, in order to carry more bombs. 
Radiators: I think we can put them in wings behind engines and armour them. I haven't got better ideas than this.

Work in progress


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## Burmese Bandit (Jan 1, 2009)

Oh, 1942!

That changes a few things...

The 2050 hp Griffon is not too plausible for 1942, since it was producing 1730 hp in 1941. So your 1942 bomber (if it uses wing embedded pusher prop griffons) will have 1730 hp + say 170 hp bonus with central supercharging, for 1900 hp - 7600 hp total. That will enable you to design an 85-96,000 lb bomber with about a 120 foot wingspan. 

That weight should let you get armoured circular rear radiators, out of which the pusher props would emerge. Since we are moving the supercharger weight from the wings to the fuselage, the wings should be able to take the weight of the armour. However, the armour will be rather thin - I suspect about 5 mm only - so is it worth the trouble? It will stop only long range glancing shots by 20 mm cannon. 

You will also have to forego the remote controlled turrets. I don't think that's possible by 1942.
.


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## Vraciu (Jan 1, 2009)

Yes, we must say goodbye to remote controlled turrets, but they can appear in lateer versions. I think that 2,000 hp Griffon in late 1942 will be possible (if we tell engineers that they should hurry). During the production more powerful engines will be installed in bombers.
I think that 8 mm armour plates is maximum that we can install. It'll stop some bullets and will increase crew's morale.
I'm thinking about undercarriage now. Main with front wheel or with tailwheel?
Main in wings, but as in B-24 (between engines) - but there we reduce fuel tanks' capacity; or in engines' nacelles (as in Lancaster or B-17). But if we place them in nacelles, we'll increase aerodynamical defiance. In B.IP version we must concentrate on range, but in B.IE high speed is very desirable (Luftwaffe!).

What do you think?


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## Burmese Bandit (Jan 1, 2009)

If you put the engines in the wings as in the B-36, you might as well go the whole hog and go for high speed and height. So I would suggest the lighter, 86,000 lb version. 

You will need a high wing for the pusher props to clear the ground. 

Main with front wheel as in B-24. Europe is not the pacific, battle ranges are shorter. You have the central fuel tank as in the B-29. And for long range missions the rear bomb bay could hold fuel.


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## Vraciu (Jan 1, 2009)

> the engines in the wings as in the B-36



I don't think that problems with pushing engine (Do 335, B-42) can be solve in 1942/43. B-36 is in 1946, that's *four* years later. Four years - compare B-17B and B-29 and you'll see the difference.
High wing could be problematic in fight against fighters (B-24), I'd prefer mid-wing.
I think that now we can start making fuselage. Front of bomber comes from Lancaster, but bombardier's compartment is moved forward. 
Canopy of pilots' cabin comes also from Lancaster because it provides very good visibility.
*
Has anyone plans of RR Griffon?*

Work in progress


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## Clay_Allison (Jan 2, 2009)

I think the Lancaster was nearly ideal as a bomber but I would change the gunner layout so that they had more low side mounted blister guns.

I hate belly guns on a bomber, at least how the B-17 had them, with the hydraulics respoonsible for both getting the man out of the bubble AND for dropping the landing gear. That was just callous and it forced a friend's grandfather to belly land his plane on his gunner. 

If you had side guns angled down and to the left and right, the pilot could just "lean" if the enemy fighters were coming up from dead below and give his guys a clear shot.


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## Vraciu (Jan 2, 2009)

The next step with making fuselage are bomb bays. I want to make all fuselage besides bombardier's compartment wider to carry more bombs. Next, if we want to have two bombays, we must move wings towards end of plane, because with undercarriage with front wheel it must have good stability when it's full load.

Work in progress


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## Soren (Jan 2, 2009)

I'd design something like the Heinkel P.1078 I believe (It looks very promising):


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## Vraciu (Jan 3, 2009)

I'm making defensive weaps of my bomber now.
I decided to have:
-forward turret from Lancaster, but with 12,7 Brownings
-upper turret over rear bomb bay (2x12,7)
-two side gunners stations, both with 2x12,7
-ball turret behind rear bomb bay (2x12,7)
-tail gunner station with - there are four options: 
- 2x12,7 (as in B-17)
- 4x12,7 (my proposition)
- 2x12,7 + 1x20 (as in B-29)
- 2x20 (British Hispanos) (my proposition)

Which of these options will be the best you think?

Work in progress


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## Burmese Bandit (Jan 3, 2009)

First, soren: The premise of this thread is that your plane must be ready in time to make a difference to the war.

That being so...yes, the heinkel is a wonderful design. But could it plausibly have been in service to make a difference to the war?

Vraciu: Again, this thread is a serious intellectual excercise - you know that already, I know, from your posts - so I want you to think seriously about your choices.

There were very good reasons driving the choices behind aircraft designers in WWII. Center of gravity, the state of the art in wing research, material and weapon and powerplant availability, skilled labour - heck, even internal politics got into the act. 

I want you to think of all of these.

Now, coming back to your design. You haven't said which nation you thought of producing your bomber. If the answer is Britain then forget the 20 mm - the air ministry wanted 20 mm turrets in its heavy bombers even before the war, but cost, (non)availability of 20 mm cannon, and weight at the end of the tail considerations kept 20 mm being put into tail turrets till the end of the war. Even the Germans couldn't achieve that. Only the americans did that with a single 20 mm in the tail in the B-29 and it took a 124,000 lb design to take it.


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## Soren (Jan 3, 2009)

Burmese Bandit said:


> First, soren: The premise of this thread is that your plane must be ready in time to make a difference to the war.
> 
> That being so...yes, the heinkel is a wonderful design. But could it plausibly have been in service to make a difference to the war?



Well if the He1078A design and the HeS.011 engine had been given top priority then maybe, but I can't say for sure. Seems like it wouldn't have been ready before mid 45. 

A better choice would be much more plausible: Simply prioritizing the Jet engines earlier, cause the a/c designs the Germans had were already far ahead anything else. Had the Jumo 004E been put on the Me-262 from the start, then the Allies could've kissed their bomber campaign goodbye.

The Jumo 004E would give the Me-262 a performance of well over 900 km/h, much better reliability and most importantly the range to attack the Allies over England.


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## Burmese Bandit (Jan 3, 2009)

Well, since Vraciu is building a heavy bomber, but not along the lines I proposed, then I think I will...

(a) assemble a plausible timeline scenario in which my own heavy bomber design would be designed and built, ready by 1943

(b) explain the design of said bomber

(c) explain how said bomber's tactical and strategic use would have been better than the B-17 or B-24


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## Vraciu (Jan 4, 2009)

I made list of all versions of my bomber:
ABC Achilles B.IE, 4xRR Griffon engine (2,000 hp x 4 = 8,000 hp), entered service 1942
ABC Achilles B.IP, 4xRR Griffon engine (1,900 hp x 4 = 7,600 hp), entered service 1942
ABC Achilles B.IIE, 4xRR Griffon engine (2,250 hp x 4 = 9,000 hp), entered service late 1943
ABC Achilles B.IIP, 4xRR Griffon engine (2,250 hp x 4 = 9,000 hp), entered service late 1943/early 1944
ABC Achilles B.IIIE, 4xNapier Sabre engine (3,000 hp x 4 = 12,000 hp), entered service late 1944/early 1945
ABC Achilles B.IIIP, 4xNapier Sabre engine (2,750 hp x 4 = 11,000 hp), entered service early 1945

Im finishing my scheme of bomber in 1:72 scale, unfortunately it's too big for A3 paper, I won't have tail gunner's compartment on scheme, but the rest is on their places.

Work in progress


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## Clay_Allison (Jan 4, 2009)

I've been thinking of a fighter concept for Finland in the Continuation War. The idea is for an all-plywood 4000 pound fighter powered by Swedish license-built DB-601 based on the French VG-33s captured by the Nazis.


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## Venganza (Jan 4, 2009)

Clay_Allison said:


> I've been thinking of a fighter concept for Finland in the Continuation War. The idea is for an all-plywood 4000 pound fighter powered by Swedish license-built DB-601 based on the French VG-33s captured by the Nazis.



Sounds cool, Clay. Should go like a bat out of Hell. Always thought the Arsenal VG-33 was a great-looking plane.

Venganza


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## Clay_Allison (Jan 4, 2009)

Venganza said:


> Sounds cool, Clay. Should go like a bat out of Hell. Always thought the Arsenal VG-33 was a great-looking plane.
> 
> Venganza


It wouldn't be armored but I know those Finns were daredevils. Give them a light, fast agile plane and they'd probably take to it like a polar bear to ice.


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## Burmese Bandit (Jan 5, 2009)

The very first problems you will encounter are:

glue...and woodworkers.

The reason why the germans, with all their technology, could not build a german 'Moskito' were those. Germany simply did not have enough woodworkers with the necessary skills to build plywood - balsa aircraft. And there was only one supplier of the necessary glue, called 'Tego-film' which was good enough to use in aircraft.

I suggest you do research as to whether there were sufficient woodworkers with the skill level necessary in Finland at that time. If there were, then your project is plausible. If not, it dies at birth!

If that plane comes out in 1942 or earlier the glue problem will not exist since the 'Tego-film' factory was destroyed by bombing only in 1943. However I suggest that you build a shadow factory or three just in case, too!


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## Venganza (Jan 5, 2009)

Burmese Bandit said:


> The very first problems you will encounter are:
> 
> glue...and woodworkers.



With Finland being something like 90% forest, I have to believe that they would have had plenty of skilled woodworkers that could be trained to build airplanes. In terms of the glue - they had captured Soviet planes that were wooden or had wooden parts (I-153, I-16, LaGG-3, etc.). Even without the German glue plant, perhaps the Finns could have reverse-engineered how the Soviets used glue on their wooden parts? Of course that still leaves the problem of making the glue, even if they figure out how to.

Venganza


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## Clay_Allison (Jan 5, 2009)

Very interesting point. The idea is supposed to debut in 1942 to have enough fighters available for the continuation war. I'll have to assume for the sake of the intellectual exercise that they acquired the gluemaking secrets from germany in '42 and set up their own factories in Finland

Like Venganza said, finland being heavily forested and home craftsmen being more the rule than the exception, I believe the woodworkers would be there. In fact, the Finns came up with a late war program, trying to make a Bf 109 clone out of wood that was promising but too late.



www.aviastar.org said:


> Conceived to make maximum use of indigenous materials with emphasis on suitability for operation from small Finnish front-line airfields under the most severe climatic conditions, the Pybrremyrsky (Whirlwind) was designed by Dipl-Ing Torsti R Verkkola. Powered by a 12-cylinder inverted-Vee Daimler-Benz DB 605AC engine rated at 1475hp, the Pyorremyrsky had a single-spar wooden wing with plywood skinning and a fuselage of steel-tube construction with detachable metal panels forward and a wooden ply-covered mono-coque aft. Armament comprised one engine-mounted 20mm MG 151 cannon and two 12.7mm LKK/42 machine guns, provision being made for two 200kg bombs underwing. Prototype construction was slowed by the preoccupation of the VL with higher priority programmes, and work on the Pyorremyrsky, which had languished for several months, came to a halt with the Finnish-Soviet Armistice of 4 September 1944. Somewhat surprisingly, construction of the fighter was resumed later, in January 1945. A DB 605AC engine was removed from a Bf 109G and installed in the prototype, which flew for the first time on 21 November 1945. The Pyorremyrsky could outclimb the Bf 109G-6 and was more manoeuvrable, but, as no funds were available for the purchase of new aircraft for Ilmavoimat and sufficient Bf 109Gs remained to equip the Ilmavoimien fighter force that was permitted under the Armistice terms.


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## Jabberwocky (Jan 6, 2009)

Burmese Bandit said:


> ...the air ministry wanted 20 mm turrets in its heavy bombers even before the war, but cost, (non)availability of 20 mm cannon, and weight at the end of the tail considerations kept 20 mm being put into tail turrets till the end of the war. Even the Germans couldn't achieve that. Only the americans did that with a single 20 mm in the tail in the B-29 and it took a 124,000 lb design to take it.



Not true.

The Germans had a 20 mm in the front of a He-111 by 1941, used for straffing. They also mounted up to 10 MG 151/20s in Me 323s!

The RAF had a 2 x 20 mm turret flying in a Lancaster test bed by early 1944, but decided that it was simpler to retain the .303 armament, as the war was expected to be over within 6-8 months! The RAF preferred deterrence over destruction when it came to defending its bombers.

The Lincoln prototypes also flew with similar 2 x 20 mm turrets.


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## Burmese Bandit (Jan 6, 2009)

Jabberwocky, 

I said turrets. The germans did indeed experiment with 20 mm turrets. But the cannon they had in their production machines were handheld. 

The turret in the Lancaster was cancelled also mainly because of weight problems.

Only in the bigger Lincoln were 20 mm turrets feasible. As a general rule of thumb, any plane smaller than 60,000 lbs cannot have twin gun 20 mm turrets unless some major compromises in either bombload, fuel, speed, or ammunition for guns carried are made. Only when we start getting to the 75000 lb and above stage does 20 mm become feasible...


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## Burmese Bandit (Jan 7, 2009)

Clay: Armament.

I have always wanted to try this out on a regular 109, but your plywood powerhouse would do just as well!

We'll assume that your aircraft will be based closely on the 109. 

Remove the oil cooler under the nose, and split it into two smaller oil coolers. Put one each with the radiators under the wings.

Now we have a clean underbelly. Put two MG 131s or equivalents under the belly in a smooth conformal pack. Keep the two MG 131s or equivalents on top.

On the engine mount the Jackhammer, the 30mm MG 108.

Result: for medium range high volume of fire, 4 MG 131 x 800 + rpm = 3200/3300 rpm. 

And for short range explosive kill, the Mg 108.

The 131 is for the Yaks, the 108 is for the Stormoviks. Both found in high numbers on the front.


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## Burmese Bandit (Jan 8, 2009)

Oh, yes, and Clay...think about whether having automatic wing leading edge slats are more trouble than they are worth, especially for a country with a low (for that time) industrial base. I think we should try for maximum simplicity...


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## Clay_Allison (Jan 8, 2009)

Burmese Bandit said:


> Oh, yes, and Clay...think about whether having automatic wing leading edge slats are more trouble than they are worth, especially for a country with a low (for that time) industrial base. I think we should try for maximum simplicity...


Well, my idea was not to have a clone of the 109, read up and you'll see it was the VG-33 I was looking at. Wooden, maximum streamlining, maximum ease of production, could be trimmed dorn to 2000 Kg. 

I've been reading about the production issues with the DB 601, and how hard it was to get. I'm thinking it should be replaced in my scenario by the Allison, also. 

God knows there's no way I could get Merlins.


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## Burmese Bandit (Jan 8, 2009)

Well...I think your best scenario would then be to build a plane that was so superior that even the Germans would want to buy and license it, and then all the problems would be solved at a single stroke.

Here are my thoughts.

Building a highly streamlined, light, fast, and easy to produce plane, you will have to have some sacrifices. The first will be armament.

I suggest no cannon, only four MG 131 firing through the hub. How? Take two 131, bolt them together barrel to barrel. Now stagger two more 131 behind them and bolt them together dittp The Vee of the 601 can take a maximum 70 mm diameter. The four 131 should just about fit.

Result: you have a centerline installation and no propeller interruption penalty. 3600 rpm. All for a total gun weight of only 68 kg. The bullets are not too powerful, but should be good enough for the light Yaks. Stormoviks would be a bit of a problem though.

Have an annular cowl, like the FW 190 D. Easier to engineer. Same total drag as wing radiators but much easier to fit and service. 

Have your vertical tail in front of the horizontal tail, like the Corsair. This will make your plane more maneuverable at high angles of attack, such as climbing turns. 

BTW I read about your template plane and it weighed over 3300 kg take off weight. That's about the same as a 109 Frederich.


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## Jabberwocky (Jan 8, 2009)

Burmese Bandit said:


> Only in the bigger Lincoln were 20 mm turrets feasible. As a general rule of thumb, any plane smaller than 60,000 lbs cannot have twin gun 20 mm turrets unless some major compromises in either bombload, fuel, speed, or ammunition for guns carried are made. Only when we start getting to the 75000 lb and above stage does 20 mm become feasible...



Oh, so now its *twin* 20mm turrets? Well, even the B-29 doesn't cut it in that respect

As for 20 mm turrets in aircraft less than 75,000 lbs, you can find plenty of examples if you look harder at some lesser known types, particularly seaplanes.

The Japanese fitted a single Type 99 20 mm cannon were fitted to the H6K (tail turret), H8K (tail, dorsal, nose turrets).

The Germans also put 20 mm turrets on some He 177 variants, the Bv 138 (nose and stern turrets), the Do 18 and Do 24 (both with powered dorsal turret), Do 26 (bow turret) and some Fw 200 variants (foward powered dorsal turret).

The Italians were also going to fit a remotely fired stinger type 20mm to their P.108 successor, the P.133, but were invaded before the prototype could fly. 

Over the 75,000 lbs limit, the Germans had the BV 222 with three powered 20 mm turrets (in a 110,000 lbs aircraft) and the aforementioned Me 323. The Russians also fitted two single 20 mm turrets to the Pe-8, in 1936.


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## Burmese Bandit (Jan 8, 2009)

A point of ammo, Jabberwocky. I remarked that (perhaps it's my fault - I didn't make myself clear) compromises in "...either bombload, fuel, speed, or ammunition for guns carried are made..." 

Just how many rounds - or, a better standard of measurement, how many seconds of fire - did those 20 mm turrets you speak of, have?


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## fly boy (Jan 8, 2009)

109ROAMING said:


> Wanna try?



as in i would take parts of each plane like the mustang engine and the p-47s chances of liveing ( very high) and armorment package of the 109 and 190 and then make it all look great like the spitfire


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## Clay_Allison (Jan 8, 2009)

Burmese Bandit said:


> Well...I think your best scenario would then be to build a plane that was so superior that even the Germans would want to buy and license it, and then all the problems would be solved at a single stroke.
> 
> Here are my thoughts.
> 
> ...


Ok, this is awesome because I've been thinking about this all day. Armament and pilot protection would have to be heavily reduced. Extra features would have to be dropped, like wing slats etc.

I think I would have retractable landing gear, but they would be hand-cranked to save weight and complexity.

My armament plan would be 2x 20mm cannons, tightly wing mounted with 300 rounds each. Pilots would hunt in pairs like Germans and be taught to hold their fire until they were in close range. If the next target procedes smoothly from the first, keep going. If not, disengage and give them no chance to avenge their dead. More often than not, tight Soviet formations will give a pair of hunters a chance for multiple kills. 

20mm cannons give great bang-for-buck in terms of weight, and a close range attack from above on an Il-2 would still crush the airframe.


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## 109ROAMING (Jan 9, 2009)

fly boy said:


> as in i would take parts of each plane like the mustang engine and the p-47s chances of liveing ( very high) and armorment package of the 109 and 190 and then make it all look great like the spitfire




Just like in a computer game?


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## DerAdlerIstGelandet (Jan 10, 2009)

fly boy said:


> as in i would take parts of each plane like the mustang engine and the p-47s chances of liveing ( very high) and armorment package of the 109 and 190 and then make it all look great like the spitfire



Good luck, your plane will never get off the ground. If it does, it will weigh a few tons and fly like a bus.


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## Burmese Bandit (Jan 10, 2009)

Dang it...please, to some posters, who shall remain nameless, please listen..

This is supposed to be a serious thread, and a serious attempt to design planes. Even if those planes never get past the paper stage, we are attempting to be serious here. 

Now some posters - I don't quite know if they are attempting to be humourous or not - but some posters seem to think that designing airplanes is as easy as cutting and pasting pieces of text from here and there into a word document and publishing it as original work. 

Herewith a very, very brief designing 101.

When designing a Warplane, we must think of its role first. What is it expected to do? Chase after enemy planes and shoot them down, and if the enemy planes themselves are attempting to shoot it down, to maneuver violently to escape them?

This is the description of the type of plane known as the fighter plane. High speed and maneuverability, and an armament powerful and accurate enough to shoot down your expected opponent, are a must. There are many, many other considerations, but these are at the top of the list.

Or do we want a plane that can carry a load of bombs a certain distance, drop them accurately enough to be worth carrying that distance, strong and fast and defensively well armed enough to have a credible chance of dropping those bombs, and also of getting back to base more or less in one piece?

This is the description of the type of plane known as the bomber. High bomb carrying capacity, accurate bombing ability, and long range are at the top of the to-do design list here. 

To be continued...


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## Burmese Bandit (Jan 10, 2009)

Now when you design an airplane, the very first thing you start with is the powerplant. _Every _other decision you make on the design starts from that. 

This thread has the premise that everything be credible in time, space and money, which means that the powerplant should credibly be in operation during the time which you plan the plane to be built.

For the mission you need to take into account where you will put your equipment. Where will you put the engine? In front in the nose, or in front of the wings, or embedded in the wings? Why? And what of the engine acessories? Radiators, if necessary, oil coolers, always necessary, superchargers or turbochargers, fuel and oil tanks? Bombs, bomb racks, guns? Ammunition tanks? Will you have armour around them, and if so, how much?

Once you have decided on that the age old problem of aircraft design, weight, comes into play. All of the above (and a lot more we haven't included!) is dead weight - this means that it's not contributing anything to the airplane's strength. You need structures like the airplane fuselage and Wing spars to give strength to the plane, and don't forget these have weight, too. They have to carry themselves and the weight of the rest of the plane as well. 

And how will we balance this weight so that the aircraft is neither too nose nor tail heavy? We have to think of that.

And, of course, wing design - what type of airfoil design we will use - is an art in itself.

All this shows that aircraft design, even a paper aircraft, is a very, very complex design indeed, which is why most paper aircraft designers take a proven aircraft as a template and make a few changes here and there. Wildly mixing and matching aircraft any old how - like, say, saying you're going to mate the wings of the spitfire with the body of a mustang and then add the leading edge slats of the 109 - is just a pipe dream.

I took a very deeeeep breath when designing the BB 129 because it was unlike any template that had been seen before. But I have put a lot of deep thought into it, and I think that design will fly....when I finish X-planing it someday i will post the file here.


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## Clay_Allison (Jan 10, 2009)

Burmese Bandit said:


> Now when you design an airplane, the very first thing you start with is the powerplant. _Every _other decision you make on the design starts from that.
> 
> This thread has the premise that everything be credible in time, space and money, which means that the powerplant should credibly be in operation during the time which you plan the plane to be built.
> 
> ...


that's why all of my "designs" are existing proven airframes with power plant changes, armament additions and subtractions, and (sometimes) different construction materials and armor compromises.


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## Soren (Jan 11, 2009)

I was thinking about this:

A Fw-190 Dora with somewhat lenghtened wings, from 10.5m to 12.5m. And the powerplant would be the Jumo 213EB running on C3 fuel producing some 2,500 PS take off power with MW50.

Features would be much like the Dora-13:

Automated engine prop control
Gyro gunsight
Autopilot
Pressurized cockpit
GM-1 high alt boost
2x 20mm MG-15/20's + 1x 30mm Mk108

I'd suspect performance to be around ~800 km/h at altitude, ~6,000 ft/min climb rate, 15.5 to 16 km ceiling.


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## jrb53 (Jan 11, 2009)

*Could you have designed a better Warbird for any side, using only the technology known and in use at the time, staying within reasonable cost parameters, yet making enough of a difference to have been worth producing?*

No  

Jack


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## Burmese Bandit (Jan 11, 2009)

Soren, interesting. A few questions. 

When is this plane supposed to enter service?

Why are the wings lengthened? What effect do you think it will have on the planes's roll and turn rates?

Weight...what type of take off weight were you thinking of? (Remember you have both the Methanol and Nitrogen installations, which will add weight.)
And power to weight ratio, and wing loading?


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## Soren (Jan 11, 2009)

Burmese Bandit said:


> Soren, interesting. A few questions.
> 
> When is this plane supposed to enter service?



Sometime in late 44 if it gets priority status.



> Why are the wings lengthened? What effect do you think it will have on the planes's roll and turn rates?



The reason I want to lengthen the wings is to ensure good maneuverability at high altitude. The extra few meters of wing will add very little in weight, maybe 50kg and the increased Aspect Ratio will increase lift decrease drag, greatly improving the L/D ratio and improving turn performance. So turn performance will improve. As to roll rate, it will decrease vs the original 190, but that's no problem, it'll still be very good. (The Ta152H which featured 14.5m long wings still featured great roll rate) 



> Weight...what type of take off weight were you thinking of? (Remember you have both the Methanol and Nitrogen installations, which will add weight.)
> And power to weight ratio, and wing loading?



I think it'll weigh around 4,400 to 4,475 kg. The wing area will probably be 20.5 m^2, and the engine out 2,500 HP.

So it would be a 214 Kg/m^2 pure wing-loading (L/W ratio will be good because of wing design) and a 1.76 Kg/HP power-loading, which is very good. The new prop added on the Dora-13 Ta152 also improved thrust.


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## Burmese Bandit (Jan 12, 2009)

Excellent Soren. Clear now. 

A suggestion on armament. Do you think 6 x MG 131 would work better against the Mustangs than the 2 x 20 mm? (this of course will lead to a discussion much like the "Best Armed Fighter" thread.)


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## Soren (Jan 12, 2009)

I greatly prefer the 2x 20mm cannons + the 1x 30mm cannon arrangement. 

Also I don't like the idea of too many guns in the wings, the holes in the leading edge of the wing and the petruding barrels will disturb the airfoil over the wing. Hence why German fighter a/c usually had litte to no wing armament, esp. later in the war.


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## Soren (Jan 12, 2009)

Another interesting idea could be the He-162 with a HeS.011 engine and 4x 20mm MG151/20s as armament. One could add swepped wings to the a/c, but the original wings are really good enough to begin with so no need for that. Automatic LE slats would also prove beneficial. I'd probably also widen some of the fuselage slightly to incorperate more fuel and the extra guns and their ammo. Some streamlined topwing fuel droptanks like those tested on the Fw190 I'd make available for long range missions, but the main task would still be homeland defense.

Performance I'd suspect to be phenomenal, a 1,000 + km/h top speed, 7,500 ft/min climb rate, 14.5 km ceiling. 

Now as to when it would enter service, well too late to alter the course of the war, but my guess is very late 44 if given absolute priority status.


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## Vraciu (Jan 12, 2009)

Well, I finished Achilles' project, but unfortunately nobody of my friends has A3 scanner, so I put it here later.
It could carry about 20-22,000 lbs bombs, it has 14 .50 Brownings (2 in forward turret, 2 in upper turret, 2 in Sperry ball turret, 4 in side gunners compartment -2 on each side-and 4 in tail gunner compartment.
Crew - 11: bombardier, forward gunner, pilot, co-pilot, radio-operator, navigator, upper gunner, ball turret gunner, 2 side gunners and tail gunner.
Length: 28,51 m

I have few ideas for Allies to make Achilles more efficient bomber than Lancaster, B-17 or B-24. I'll post them soon.


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## Clay_Allison (Jan 12, 2009)

Considering that it wasn't new technology, only more refined application of it, the best think I could possibly do is create a P-51D in 1938.

I'd like to see it powered by a RR Griffon though. I have long thought that it was a magnificent engine that was derailed in development by the BoB.


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## Burmese Bandit (Jan 13, 2009)

Absolutely agree! First engine in the world with four valves per cylinder, first with grooves in the engine block for oil...the 'firsts' go on and on...


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## Clay_Allison (Jan 14, 2009)

I think a Griffon powered P-51D armed with 20mm Cannon would be the ultimate WWII fighter. 

Just because I'm not wise enough to leave well enough alone. 4 wing guns and two cowl guns would be a scary experiment.


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## SoD Stitch (Jan 14, 2009)

My "vote" would be for a P-38 with Merlin engines. The only true weakness of the P-38 was the Allison V-1710 engines; great at low levels (<25,000'), not so great at altitude. I think the P-38 would've been a world-beater with Merlins installed, instead of V-1710's.


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## Clay_Allison (Jan 15, 2009)

SoD Stitch said:


> My "vote" would be for a P-38 with Merlin engines. The only true weakness of the P-38 was the Allison V-1710 engines; great at low levels (<25,000'), not so great at altitude. I think the P-38 would've been a world-beater with Merlins installed, instead of V-1710's.


The Allisons in the P-38 were excellent at altitude in fact. The size of the installation allowed for full size turbochargers that smaller single-engine fighters were unable to fit. 

Their only real struggle was actually with wave turbulence caused by going near the speed of sound in dives. a vacuum would form around the tail surfaces, rendering them useless and often trapping pilots in a steep dive with only one chance to save themselves, thicker air at low alt. That and the lack of an ejector seat. bail out of one any way but off the wing and you were liable to get cut in half.


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## Soren (Jan 15, 2009)

Clay_Allison said:


> I think a Griffon powered P-51D armed with 20mm Cannon would be the ultimate WWII fighter.



Well the Griffon was quite heavy, and that would limit performance.

However I think that if the airfoil design was changed to a more lift efficient one along with the introduction of the Griffon engine, then it would likely be one of the best out there.


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## Burmese Bandit (Jan 15, 2009)

Griffons were heavy, true, but with liquid inline engine fighters used in the 'zoom and boom' style of fighting, weight was far less of a consideration than total hp. Besides, as an engine and its support structure is only about 15-25% of the total weight of a fighter, if a 25% increase in weight in an engine and its support structure results in a 25% increase in hp (or even slightly less) then overall, the power to weigh ratio still increases.


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## Soren (Jan 15, 2009)

Oh I agree, it's just a matter of how much the performance increases over the original and how soon it can be applied. I don't see it entering service before 45 in the shape of the P-51H which featured a 2,270 HP V-1650-11 engine plus a refined airframe structure. And seeing that the German were fielding jets by that time, the P-51H would've been a waste of resources, atleast if the Allies were looking for a fighter able to compete with the German fighters.

If it's all about a new engine, well then I'd put my money on jet technology, making sure that I get new jet engines into service. Imagine Jumo 004E equipped Me-262's in mid 1944, that would make an invasion of France impossible, and in the east the VVS would've been rid from the skies. 

That Hitler delayed the jet engine programme is really a blessing for us all, cause that is definitely one area the Germans could've succeeded in taking advantage of and turned the tide with.


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## red admiral (Jan 15, 2009)

> That Hitler delayed the jet engine programme is really a blessing for us all,



What nonsense. It was full steam ahead from 1938/39 with the Air Ministry desparately throwing more and more money at projects and being frustrated when results didn't happen. Its extremely unlikely the 004 project could be sped up any more compared to OTL given all the problems it faced, let alone have a improved reheated version in service as well at the same time.

If we are to imagine 004E equipped Me 262 in mid 1944 why not also imagine F-84s and F-86s as well. Its about as reasonable.


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## tomo pauk (Jan 15, 2009)

Soren said:


> Oh I agree, it's just a matter of how much the performance increases over the original and how soon it can be applied. I don't see it entering service before 45 in the shape of the P-51H which featured a 2,270 HP V-1650-11 engine plus a refined airframe structure. And seeing that the German were fielding jets by that time, the P-51H would've been a waste of resources, atleast if the Allies were looking for a fighter able to compete with the German fighters.
> 
> ...



Both Griffon and P-51 were available in 1943, not the case with 262/004E combo. So, a piston engined plane capable of 750 km/h in 43 it is (would've been...).


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## Burmese Bandit (Jan 15, 2009)

Yep. And IF the strategic decision to give away the rights to Griffon development to an American Company had been taken in 1940 we may have had a 2000 hp + Griffon coming off in numbers in the production lines by January 1943!!!


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## Clay_Allison (Jan 16, 2009)

Soren said:


> Well the Griffon was quite heavy, and that would limit performance.
> 
> However I think that if the airfoil design was changed to a more lift efficient one along with the introduction of the Griffon engine, then it would likely be one of the best out there.


something about the weight of the Griffon, due to the weight of the aft gas tank, the Mustang was butt heavy, especially on takeoff. A little more nose weight to balance would be no bad thing.

Also I agree with B.B. if the patent was leased to Packard on the cheap and they were allowed to continue development in 1938 when IIRC, the decision was made to concentrate on the Merlin, we have 1750 Hp in 1942 as we kick off the war. Even P-40s wouldn't fly heavy with that kind of power plant and a popellar with 4 big blades instead of three thin ones.


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## Burmese Bandit (Jan 17, 2009)

Trying to upload Clay's wooden Finnish Fighter based on the Me 109...


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## Burmese Bandit (Jan 17, 2009)

Dang I did it...but it's way too big...how do I shrink it???


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## AMCKen (Jan 22, 2009)

SoD Stitch said:


> My "vote" would be for a P-38 with Merlin engines. The only true weakness of the P-38 was the Allison V-1710 engines; great at low levels (<25,000'), not so great at altitude. I think the P-38 would've been a world-beater with Merlins installed, instead of V-1710's.



Nah! A de Havilland Hornet with Griffons. : )


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## Venganza (Jan 22, 2009)

Burmese Bandit said:


> Dang I did it...but it's way too big...how do I shrink it???



How's this?


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## Burmese Bandit (Jan 25, 2009)

And here are two piccies -


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## Burmese Bandit (Jan 25, 2009)

The top one is the Fokker 13 project.

The Lower one is the Jona J-10 project, which I got from Red Admiral's re-drawing of it.


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## Soren (Jan 25, 2009)

red admiral said:


> What nonsense. It was full steam ahead from 1938/39 with the Air Ministry desparately throwing more and more money at projects and being frustrated when results didn't happen. Its extremely unlikely the 004 project could be sped up any more compared to OTL given all the problems it faced, let alone have a improved reheated version in service as well at the same time.



Complete and utter rubbish by red admiral once more. 

The Jet programme was delayed several times red admiral, read your history man!



> If we are to imagine 004E equipped Me 262 in mid 1944 why not also imagine F-84s and F-86s as well. Its about as reasonable.



You're such a joke! 

I suggest you cut your losses now and don't come back before you've gotten atleast some sense of reality.

F-86's, omg


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## Clay_Allison (Jan 25, 2009)

Burmese Bandit said:


> Dang I did it...but it's way too big...how do I shrink it???


I *LOVE* this design based on my concept. Excellent work, you even put in the wider landing gear that fixes my only issue with the 109.


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## Burmese Bandit (Jan 26, 2009)

Er, clay, just in case you got the wrong idea...

that isn't my drawing. It's a drawing of the Finnish 109 based design, a plane which was built as a prototype and a few production examples in 1944-45.

I dont want to be accused of plagiarism!


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## red admiral (Jan 26, 2009)

As before;

The Development of the Junkers Jumo 004B—The World's First Production Turbojet by C. B. Meher-Homji

does not agree with the nonsense you're posting.


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## Clay_Allison (Jan 26, 2009)

Burmese Bandit said:


> Er, clay, just in case you got the wrong idea...
> 
> that isn't my drawing. It's a drawing of the Finnish 109 based design, a plane which was built as a prototype and a few production examples in 1944-45.
> 
> I dont want to be accused of plagiarism!


Well, I thought you drew it. I knew about the Finnish 1944-45 design, but I didn't know that was it. Props for finding it anyway.


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## Vraciu (Mar 9, 2009)

I was able only to make some photos of my drawing:


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## gjs238 (Mar 31, 2009)

*PART I: High altitude*
A *real P-39*.

Turning the clock back to United States Army Air Corps Circular Proposal X-609 issued in February 1937, the Bell entry could have been a far superior machine than the P-39 ended up to be and would have better equipped the Allies in the critical early years of WWII.

With existing technology, the plane could have started the war with a better wing, greater fuel capacity (providing endurance equal to or greater than the P-40), the General Electric turbocharger, gun exhaust flash suppressors, improved compass, and proper sealing/venting of nose armament fumes. Armament would be the 20m Hispano-Suiza cannon instead of the 37 mm Oldsmobile T9 and two Browning M2 .50" machine guns in the nose. Two M2's in underwing gondolas could be optional, added/removed in the field as desired.

While the mid-engine arrangement permits heavy nose armament and a smooth streamlined nose profile, it also allows a simple turbocharger installation not requiring extensive ductwork like the P-47.

The USAAC decision to emasculate this interceptor was a serious error. Some sources say this was done due to a change in philosophy to ground attack/close support. For that, an unsupercharged, air cooled engine powered plane would have excelled - please read below.

*PART II: Low altitude ground attack/close support*
Two competing entries:

*From Seversky/Republic:*
A P-35 developed to accept a Pratt Whitney R-2800.
In other words, a P-43 Lancer with R-2800 sans turbocharger.
Or a slimmed-down P-47 with R-2800 sans turbocharger if the R-2800 was not available in time for the above.
(Please note that I'm not suggesting a modification of the P-43 or P-47, but a different evolution of the P-35 that would have led to a different P-43 or P-47.)

*From Curtiss:*
A P-36 Hawk developed to accept a Pratt Whitney R-2800.
In other words, a P-40 with R-2800.
(Please note that I'm not suggesting a modification of the P-40, but a different evolution of the P-36 that would have led to a different P-40.)

These planes would be well armed with a generous fuel supply for long range loiter time.

The development of these planes would have provided a more cost-effective, lighter, perhaps greater performance aircraft than the F4U Corsair (which I think was the only other plane being developed at so early a date around the R-2800) but whose development dragged on for some time.


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## Clay_Allison (Mar 31, 2009)

gjs238 said:


> *PART I: High altitude*
> A *real P-39*.
> 
> Turning the clock back to United States Army Air Corps Circular Proposal X-609 issued in February 1937, the Bell entry could have been a far superior machine than the P-39 ended up to be and would have better equipped the Allies in the critical early years of WWII.
> ...


I'd be interested in a two-stage-three-speed supercharged P-47. That would have really brought down the cost per unit.


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## Burmese Bandit (Jun 7, 2009)

Reviving this thread...

I have been reading one of my favourite authors - the British writer of fiction, and also historian of WW II LEN DEIGHTON...and I was struck by has statement that the Hurricane was probably the most underrated aircraft of WWII. 

It could be produced in half the time of the Spitfire, was only 10% slower with the same engine, copuld be repaired much faster and easier, was MUCH forgiving of bad and panicky flying by inexperienced rookie pilots, it was a better and steadier gun platform than the Spitfire. And it was a better landing aircraft too. Probably over the course of the war Spitfires killed many, many more pilots than the Hurricane through landing accidents and high speed stalls than the Hurricane. 

And it seems to me that the Hurricane's blunt and large nose airframe would lend itself to excellent adaptation for a radial. 

So here is my suggestion.

In 1937 the Hawker company decides at the last minute to produce the Hurricane with a radial rather than the Rolls Royce inline. Since Bristol doesn't have an engine in that class yet, the Pratt and Whitney Double Wasp is chosen. Hurricane debuts at about 1,000 horsepower. Experiments with engine driven fans and close cowling are made. 

By 1940 the Hurricane has matured into a 1,200 hp close cowled engine fan cooled airplane with 12 browning .303 machine guns in its wings. A teardrop bubble canopy has been fitted, it being discovered that this (due to the Hurricane's original shape) is not reducing the speed at all. 

I suspect the comparitive stats against the 1030 hp merlin engined spitfires of 1940 would be

Level Speed: The Hurricane is 25-30 mph slower.
Climb: The Hurricane's climb is at least equal to superior to the 1940 Spit, since the Hurricane's heavier weight is offset by 170 more hp and an longer span wing. 
Turn: the Hurricane is again about equal. Its heavier weight is counterbalanced by its larger wing area. 
Dive: The Spit is faster initially, but in a prolonged dive the Hurricane overtakes the spit. 
Battle damage tolerance: The Hurricane is clearly superior.
Quick Repair on Ground: Ditto.
Engine Reliability: Ditto.
Takeoff/Landings in bad weather: Ditto.
Gunpower: The Hurricane is tremendously superior. 
Suitability for the green rookie pilot, hurriedly rushed to the squardrons due to the tremendlous pilot losses in the Battle of Britain: Again the Hurricane wins hands down. 

What do you guys think?


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## Venganza (Jun 7, 2009)

Burmese Bandit said:


> I have been reading one of my favourite authors - the British writer of fiction, and also historian of WW II LEN DEIGHTON...and I was struck by has statement that the Hurricane was probably the most underrated aircraft of WWII.
> 
> It could be produced in half the time of the Spitfire, was only 10% slower with the same engine, copuld be repaired much faster and easier, was MUCH forgiving of bad and panicky flying by inexperienced rookie pilots, it was a better and steadier gun platform than the Spitfire. And it was a better landing aircraft too. Probably over the course of the war Spitfires killed many, many more pilots than the Hurricane through landing accidents and high speed stalls than the Hurricane.



That's interesting. The Hurricane has never been a favorite of mine. I've always considered the Hurricane to be one of the most *overrated* aircraft of the war. With that huge, thick wing it was never going to go that fast, no matter how much horsepower you put into it. True, the Typhoon was 400mph+ with a thick wing, but that was with that monster Sabre engine, and its wing, although thick, wasn't as thick as that block the Hurricane called a wing. The problem with the Hurricane is with that wing and that 1920's technology fuselage (steel-tube frame, with wooden formers and stringers covered in fabric), it didn't have the design stretch of the Spitfire or the Bf-109, which were among the first advanced monoplane fighters, yet remained competitive against much later piston-engined fighters because of continuous improvement. True, you could have put more power into the Hurricane, made the wing thinner, and made the rear fuselage an all-metal monococque, but by then you'd have a Typhoon, not a Hurricane. Even the Soviets, in 1941-42, while terribly desparate for fighters, didn't particularly like the Hurricane, and it was replaced in frontline units (as opposed to PVO local interceptor units) as quickly as possible. Its forgiving qualities, good takeoff and landing characteristics, and steadiness as a gun platform didn't account for much when it was so quickly blasted out of the air by superior German fighters. These characteristics are fine for a training aircraft, but not so useful for an air-to-air fighter if they're not combined with manueverability and speed, two areas where the Hurricane was lacking in comparison to the Spitfire and the Bf-109 and Fw-190.

Venganza


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## tomo pauk (Jun 7, 2009)

Now the Hurricane is un-maneuvreable!? Yeah, right 

The Hurricane could've used 2 British radials too, Taurus Hercules. Turning the plane to a better ground attack and/or CV machine. The speed gain would've been negligible though.


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## Stitch (Jun 7, 2009)

Very simply, I would've designed the P-38, only fitted it with Rolls-Royce engines, either Merlins or Griffons. THE major weak spot on the P-38, as most people will agree, were it's Allison V-1710's; good engines for their time, but not GREAT engines. Put a couple of Merlins in a P-38, and you have a world-beater (kind of like a Mosquito, only more maneuverable). Later in life, you probably could've shoe-horned a couple of 2,000 HP Griffons into the P-38 airframe.


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## Soren (Jun 7, 2009)

Again, if I was the head of the LW I would've done everything in my power to get the Jumo 004E in production as quick as possible and install it on the Me-262 as that alone could've decided the war in Europe. With a speed of 900 + km/h and the range to reach England and back the Allies could kiss their bomber offensive goodbye.

Fortunately that didn't happen however.


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## Burmese Bandit (Jun 7, 2009)

Regarding the thick wing of the Hurricane - that would be a problem ONLY as speeds went over the 350 mark and crept up towards 400. At the much lower speeds at which the Battle of Britain was fought, the thick wing was of fairly negligible importance. 

Remember, I am talking about the Battle of Britain scenario, where there most pressing need was not for small numbers of high speed aircraft, but large numbers of passable aircraft built as quickly as possible and being repaired rapidly...and capable of being flown by the thousands of new pilots being hurriedly commissioned. 

And let's not forget that many of the German aircraft, both bombers and fighters, attacked by Spits in 1940 lived to limp home to Occupied France to fight another day...because of the inadequate armament of eight rifle calibre machine guns. While the best solution was the 20 mm cannon, there just weren't enough of them in 1940 and they had reliability and ammunition supply problems as well. 

So the 12 browning solution was the best available at the time. And the Spit couldn't carry 12 brownings. 

The radial Hurricane would have been the perfect solution in 1940, and as the war went on and it was slowly replaced by (say) Tempests, it could have had a great secondary career as an advanced trainer and a ground attack aircraft!


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## Burmese Bandit (Jun 7, 2009)

And one final statistic...


Which Non-Russian aircraft type killed the most Axis aircraft 1939-45? Three guesses.


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## Venganza (Jun 7, 2009)

Burmese Bandit said:


> Regarding the thick wing of the Hurricane - that would be a problem ONLY as speeds went over the 350 mark and crept up towards 400. At the much lower speeds at which the Battle of Britain was fought, the thick wing was of fairly negligible importance.
> 
> Remember, I am talking about the Battle of Britain scenario, where there most pressing need was not for small numbers of high speed aircraft, but large numbers of passable aircraft built as quickly as possible and being repaired rapidly...and capable of being flown by the thousands of new pilots being hurriedly commissioned.
> 
> ...



As far as the Battle of Britain, I think you're right about the Hurricane. As it was, the Hurricane shot down more aircraft than the Spitfire anyway, and with your modifications it would have done even better. I guess I was looking more long-term. I definitely agree about it making for a good advanced trainer.

Venganza


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## Venganza (Jun 7, 2009)

tomo pauk said:


> Now the Hurricane is un-maneuvreable!? Yeah, right
> 
> The Hurricane could've used 2 British radials too, Taurus Hercules. Turning the plane to a better ground attack and/or CV machine. The speed gain would've been negligible though.



Wasn't the Hurricane tested with a Taurus? Anyone know anything about that? As far as the maneuverability, I didn't say is was unmanueverable, I said it wasn't as manueverable as the Spitfire, the Bf-109, and the Fw-190, and I stand by that statement.

Venganza


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## Venganza (Jun 7, 2009)

Burmese Bandit said:


> And one final statistic...
> 
> 
> Which Non-Russian aircraft type killed the most Axis aircraft 1939-45? Three guesses.



I assume you mean the Hurricane. More than the P-39 or even the P-40? All I can say is that the PVO units must have shot down a lot of bombers and reconnaissance aircraft. Admittedly the Hurricane was a good bomber destroyer, especially if armed with 4 20mm's or the Soviet modification of 2 .50's and 2 20mm's. Still I would like to see your data regarding this. I'm not disputing it, I would just like to see the figures, as I don't have a comprehensive list of kills by Lend-Lease aircraft.

Venganza


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## vanir (Jun 10, 2009)

I think the Mustang has the highest number of kills.

The Hurricane was pretty manoeuvrable, the combination of thick wing and limited engine power for the time period reduced its sustained manoeuvrability however. It could get in a turning fight with a Messerschmitt, but not for long as the bleed of airspeed was too great and the Messer could keep his energy up with good pilot management.

The main good thing about the Hurricane was construction techniques (used existing industrial infrastructure from the interwar period so larger numbers were available more readily than the Spit early on), and also excellent stability for the sacrifice of only a little outright high speed performance. Spits and Messers were real thoroughbreds, but this also meant they could be a little tricky to get the most out of. An average pilot could fly a Hurricane well from what I understand.

Also the Merlin 20-series could handle up to +18lbs on WEP with good fuel for a short period (about a minute) so later Hurricanes had a fair bit of grunt even among contemporaries.
That being said I think the P-40E/K was better again, I've got some documentation for +18 and even +20lbs being used in the field at WEP on the Allison (up to 1780hp at the deck). Sure this was impossible at any altitude without ram effect or engine overspeeding, but down low the Warhawk could be one mean little nasty if you were happy to chance blowing the engine.


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## Venganza (Jun 10, 2009)

Now that I re-read his original post, I think Burmese Bandit was not just referring to Soviet Lend-Lease aircraft when he implied the Hurricane shot down more aircraft during the war than any non-Soviet type, as I had assumed. Am I correct about this, Burmese Bandit? That's interesting, Vanir, about the P-40E/K. That may explain why the Soviets had reasonable success with it as a fighter as they often ran it with the engines going flatout. It also explains why at first they only got about 30%-40% of the advertised MTBF for their Allisons. The problem of burned-out Allisons got so bad at one point that they re-engined about 40 P-40E's with Klimov M-105's (I'm actually doing a model of one right now).

Venganza


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## delcyros (Jun 10, 2009)

I would have an idea for a dedicated ground attack plane. Interested?


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## Venganza (Jun 10, 2009)

delcyros said:


> I would have an idea for a dedicated ground attack plane. Interested?


Go for it, delcryos!

Venganza


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## Burmese Bandit (Jun 11, 2009)

Vengenza: Yes, you're right. I meant the Hurricane. Shot down more enemy aircraft than the Spit, Mustang, the P 40, the Jug, or the Lightning. 

Delcyros: GO FOR IT!!! I Shall be Cheering you on!!!!


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## renrich (Jun 11, 2009)

Always good to hear from Del. BB, are you sure that Hurricane shot down more enemy AC in the whole war than Spitfire or P51? I find that hard to believe.


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## Burmese Bandit (Jun 11, 2009)

I have read 4 books on Aircraft of WW II and everyone of them said that the Hurricane did so.


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## delcyros (Jun 12, 2009)

Some preliminary thoughts:

At first I want to stress that I use german design / engine and equipments not because I like them more than -say- french material but simply because I am more familar with the technology. Basically I very much like dutch and french along with US and british designs. I have my utmost respect for soviet aeroengineering as well but I suffer from a somehow limited knowledge with regard to these. 

Ok, the timeframe in question is the well known ground attack A/C competition hold in Germany out of which the Hs-129 finally evolved in 1940/41. Some of the requirements were quite interesting for a dedicated ground attack A/C:

A) only low priority engines (2nd class) with low grade fuels are to be used, 1 crew only.
B) The aircraft´s performance should put emphasize on close range low altitude mission profiles
C) It should have a measure of redundancy and very tough structural strength. Additionally, crew, ammo boxes, fuel and engines should be armoured to resist light AAA and machine gunfire.
D) The target size should be as small as possible
E) interchangable loads are essentially important. Particularely because the A/C has to deal with enemy tanks so it should be able to take a big gun.
F) speed and altitude performances are irrelevant. The A/C should have a good low speed handling.

I will base my entry on an artificial ARADO / HENSCHEL joint ground attack fighter. 

let me just prepare some graphs...


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## Burmese Bandit (Jun 13, 2009)

Go for it Delcyros! Earlier in this thread I made a proposal for a five Argus-Engined Aircraft. with four engines in a push-pull a la Dornier and one engine behind the gunner for driving the common supercharger and rear protection. 

The Airplane also had a 'Tanden Triplane' configuration and an offset nosewheel so that the belly pack gun could fire on the centerline. 

What's your solution??? I am very interested!


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## Venganza (Jun 13, 2009)

Delcryos, it'll be interesting to see how you handle the problem of low-power engines. I've always thought the fatal flaw in that aircraft specification was the insistence on the use of non-strategic (read - low-power) engines. Because of that, the Hs-129 was always underpowered, especially when carrying that huge 75mm cannon. By the way, Burmese Bandit, did you ever complete any drawings of your plane (remember I did a feeble attempt to present my interpretation)?

Venganza


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## Burmese Bandit (Jun 13, 2009)

No. 

I am going to, however...but there is just so much to do IRL.

Still, it's coming along!


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## delcyros (Jun 14, 2009)

*Part I*

General layout:


My basic design root to move away from is the Arado Ar-240. I very much like the high lift devices installed into the small wing. But indeed, the Ar-240 is way to large and heavy for the low powered engines in question, so I will have to make it smaller and ultimately much lighter, too.
Sincehigh speed is not a primary concern, I will adopt a very thick airfoil (22% root thickness and 20% wingtip thickness) with poor high speed handling and low crit Mach factors (who cares about a crit Mach of M=0.65 when the profile asks for low altitude missions? I could live with M=0.5, too) but great lift properties and very good structural strength. I do not want to improve lift by adding wing area, I want to improve lift by increasing the lift coefficients of the wing with thick airfoils and sophisticated high lift devices (compare attached picture below for a detail of the slotted fowler flaps from the Ar-240 wing section)!
This will in turn greatly add wingload but that´s not negatively for the profile of the A/C: A high wingload implies an aerodynamically mor eefficient design and more importantly, a highly loaded plane does not bounce around that heavily in low altitude (thermics). I will take this to be one factor to the steady gun platform necessary for a dedicated ground attack A/C.

The Arado company worked on quite some novel but untested features back in 1937/38. The Ar E.561 project f.e. had both engines mounted into the fuselage moving a shaft via gearbox drive to propel both leading wing edge propellers.



> _The engines were to be mounted in the wing root junction with the fuselage, and the four-bladed, variable-pitch propellers were driven by a shaft. The reason behind this design was that if one engine failed, then the other engine could drive both propellers at half speed. Another advantage was that the aircraft could have a sleeker design with the engines buried in the fusleage-wing junction._



Arado Ar E.561 Luft '46 entry

I personnally may add other advantages of this configuration:

A) the target area is reduced caused by the loss of engine nacelles
B) The engine and drive section close to the center of the fuselage is nice for cg issues
C) Moving the weight of the engines to the fuselage allows for better (faster) roll charackteristics
D) The compact placement of the engines into the center of the fuselage allows for effective engine protection by armour plates 
E) the propeller in a clean pull-configuration mounted on the leading edge of the wing does add prop washout effects to the wing, greatly improving the lift coefficients of the wing section affected by propstream

This is a comparison of the frontal appearence of an early version of my design based on the same engines with normal nacelles and center engines with driveshaft (scales in metres):





Such a layout was indeed investigated by the Arado-company on the base of the Ar-240.

Arado Ar E.654 Luft '46 entry

Actually with twin Db-627 engines for a multi purpose fighter bomber. But we need something different, which brings us to the question of the dimensions and weights but before we do so, I will prepare something to the powerplant used for my ground attack A/C.
Compared with the Ar-240 the dedicated ground attack A/C in the suggested configuration will have less wetted and frontal area but more induced drag (thick airfoils!). We will discuss performances later.


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## Burmese Bandit (Jun 14, 2009)

So far, excelllent DelCyros. 

Some quick questions.

Is the Technology you describe plausible to effect in 1942-42? Or evcen earlier, such as the 1937-38 time frame you mentioned? Or is it only plausible in 1943 with mass production in 1944, at which point the war was almost certainly lost? Regarding the shaft extensions to remote propellers, I believe that only one company has done that in nearly 90 years of plane design - Bell with their V-22 Osprey. And I believe that Lockheed was thinking of doing that when Kelly Johnson was tinkering with the preliminary design of the P-38 but abandoned it as being too difficult at the time. Am I correct? Please correct me if I am wrong. 

What about combining high-lift devices, such as the leading edge slats (I believe they are called Handley Page slots after the name of the first company to use them) with spoilers on the opposite wing acting differentially, as was done with the P-61 Black Widow? 

I suspect your cockpit will be in front of those two engines. That would definitely provide for a measure of rear attack safety. Good. 

I also suspect that you will need an armoured firewall between the two engines, so that one cannon shell could not destroy two engines at once. 

Keep posting! I am very interested!


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## Soren (Jun 14, 2009)

The technology as I see it very much existed. I really like the fact that the engines are kept in the fuselage while the props are located at the wing leading edge, most likely on an elongated propeller hub to keep the prop blades roughly 65 cm away from the leading edge. That would make sure that full span slats could be added and go right up behind the prop. 

The fact that the wing is kept virtually completely clean except for the small spot with the propeller hub, means that more lift AND thrust is added. The idea is infact so good that it could be used for twin engined fighter design.

The long connection between the engines and the propellers is the most complicated thing to work, but the Germans already had that figured out in their Fa-223 Drache, so this wouldn't have posed a problem.

I see only one problem at this point, and that is the landing gear, it will have to be very long as the propeller arc stretches a long way below the fuselage.


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## delcyros (Jun 14, 2009)

Junkers (G-planes) and Dornier had plenty of experience with shaft extensions, particularely well demonstrated in the Do-18 floatplane with a long shaft extension to drive the pusher prop.
What was unknown is the question whether or not right angle drive shafts could work. The idea was already put into use by large naval crafts (Vulcan gear drive couplings on pocket battleships) but not on small airplanes. Hydraulic gears would be simple, mechanically reliable with high efficiancy and not difficult to master but they are to heavy for our plane. Electric drive gears do have not such a high efficiency and they are quite vulnarable. Mechanical drive gears are the solution. I suspect something like 5% loss of power and a system requiring approximately 180 kg of weight, including shafting (conservative guess based on Blume´s specifications for such a system and a safety factor of 1.50).

*
Part II: Engine.*

We want a simple and light engine. Preferably air cooled. Actually we do have a reasonable candidate: The Argus As 411A engine, a more developed As-410 version, driving Si-204 transports, Fw-189 recon and several Arado trainers:





*layout:* inverted 12 cylinder V-engine
*cooling:* unforced air cooling, ejector nozzles
*fuel rating:* 80 octane 
*compression ratio:* 6.4
*output:* 600 ps / 594 hp / 441kw @ 3300rpm
*rated altitude:* 3000m with single stage supercharger ("Höhenlader").
*dry weight:* 375 kg with "Höhenlader"
*length:* 1.585m
*width:* 0.66m
*height:* 0.97m
*specific fuel consumption:* 200 g/ps @ 3250 rpm (540 ps and 3250 rpm)

The engine was provided with single lever controll (automatically adjusted fuel mixture) and reduction gear. The latter may be removed completely as this task will be performed already by the gearbox necessary to drive the remote propellers. The supercharger, too, may be spared, freeing 60kg of weight per engine. The following picture shows a transverse cut in order to explain the engine installation into the fuselage:





As we have two such engines and 5% gearbox losses we will have the aequivalent of 1140 ps aviable to drive the plane. This is very important as it allows us to define the max. weight of the plane.
For comparison reasons I will give power / max. weight figures for several planes (the higher that ratio, the better the acceleration):

*transports:*
Si-204 (with As-411): 0.222
*recon:*
Fw-189 (with As-410): 0.235
*ground attack:*
Ju-87D-5 (with Jumo-211J): 0.198
Hs-129B (with G&R 14M): 0.270
Hs-123 (with BMW-132Dc): 0.386
*fighter trainer:*
Ar-96 (with As-410): 0.274
*multi-purpose:*
Bf-110C4 (with Db-601A/B): 0.293
Fw-190A (with BMW-801D-2): 0.442
*fighter:*
Bf-109e (with Db-601A): 0.459

Judging from these numbers, I could live with a power / weight ratio of 0.275 for the dedicated ground attack A/C, while under very heavy loads this could drop down to 0.200 in the worst case. The max.permissable take off weight should then be in between 4.145 kg normal and 5.700 kg under overloaded conditions. 
For reasons of simplicity, I will continue with a max. take off weight of 4.750kg.

The weights defined so far are:
750 kg -engines
180 kg -gearbox and shafts
80kg - pilot

we now add the desired weight for fuel. As endurance is a second order importance, I am statisfied with no less than one hour endurance at max. continuos power. This requires a total of only 216 kg of 80 oct. fuel. Quite enough for close range requirements. Careful fuel management will significantly improve range and endurance. The following part will deal with the dimensions corresponding with our weight figures.


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## delcyros (Jun 14, 2009)

Part III: Dimensions

The Ar-240 had quite a high wingload (330 kg/m^2) and our dedicated ground attack A/C should preferably fall in the same or nearby range. I suggest a wingload of 306.6 kg/m^2 @ 4.750 kg. This implies a wing area of only 15.5 m^2, approximately half of the Hs-129´s wing area and together with 9.64m span a corresponding aspect ratio of 6.0.

The lift coefficient with propwash and extended high lift devices should be 2.8 with an average of the whole wing (netto) beeing very close to 2.5, suggesting a take off speed of 160 km/h at MTOW(=4.750 kg). This is lower than for Fw-190 / bf-109 derivates, altough the take off run is estimated to be higher due to the weaker acceleration (compare the power / weight ratios given above).


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## Soren (Jun 14, 2009)

Delcyros,

The overall max lift coefficient of the wing with all the high lift devices extended would be around 3.2, atleast that is assuming that you are using fowler flaps. Highest Clmax occuring in some areas will be in the range of 3.4.

Regarding the chosen engines, well considering they are aircooled are you sure they'd be the right choice ? Aircooled engines are normally only used on designs with externally mounted engines with direct exposure to the airflow. When the engines on your design are to be hidden away I believe maybe a single Ju-213 might be a better choice, would also mean you could narrow down the fuselage, and with a power of 2,100 PS for a weight of just 910 kg you'd have a decreased weight as-well  

And there's the landing gear, I was wondering what your solution for that would be. Is it to b wing mounted or fuselage mounted. A three point landing gear like that of the Ar-234 might work?


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## Venganza (Jun 14, 2009)

Burmese Bandit said:


> No.
> 
> I am going to, however...but there is just so much to do IRL.
> 
> Still, it's coming along!



Good; it'll be great to see when you're done!

Venganza


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## Burmese Bandit (Jun 15, 2009)

A point on engineering, DelCyros...

If I understand your ideas and your schematic correctly, the power output from your engines will have to make a 90 degree turn in the fuselage when exiting the engine, and another 90 degree turn in the wings when moving to power the propellers. That means two, not one gearboxes per engine. Or am I wrong?

Furthermore you said that in the case of failure of one engine, the other engine will drive both propellers. In my mind that implies another gearbox...to coordinate the two engines...

Isn't that just a teensy-weensy bit too complicated? HE 177 engines begin to spring to mind...and even if if would work, shouldn't you add a loss of 5% more at least to each engine, for the extra gearboxes? 

Remember, although I do know something about engineering, | am not one by profession. Do point out my errors if I have made a mistake!


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## tomo pauk (Jun 15, 2009)

Hi,

I'd prefer to locate the planes from BBandit delycros as a genuine German WWII: pieces of an over-engineering. Many good attack planes did a fine job being of a plain-vanilla 2 engine machines. Soren just beat me about the issue of cooling of an burried air-cooleed engine, and the 5-engine Hs-129 is an exagerration, to put it mildly. Plus, the hull-mounted engines from the proposals will either hamper the cannons ammo installation, fuel tankage, not to mention engine gearboxes' maintenance.

My proposal is based at Do-17 airframe, crew reduced to 2, armor for the crew, standard and non-strategic Bramo engines, the cannon armament* ammo in the bomb bay, hard points for bombs rockets. Defensive armament would've ranged from MG-81Z, across the MG-131 barbette from Me-410 to the 20mm barbette from a Ju-187 proposal.

*From MG-C30L, captured HS-404, through MK-101/103 and BK-3,7, up to 7,5cm.


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## delcyros (Jun 15, 2009)

Only one gearbox is needed. The shematic known from Blume´s work on remote powered props show four aspects:

Drucklager-
Kupplung-
Getriebe-
Antriebe-

The Drucklager transfers power from engine shaft into the gearbox via Kupplung. The gearbox controlls reduction ratio power. The Kupplung switches power to the gearbox from one engine, the other or both simultaneously. The Antriebe transfer shaft power to props. In a simplier form (without reduction gear) this schematic was used back in ww1 to power some Siemens Schuckert giant planes in a similar manner: The engines were buried into the fuselage and drove two remote wing props.
It could be argued whether 3, 5 or 8% power will be lost in the way but 5% seems to me the most reasonable guess.

The Argus AS411 engines -altough buried into the fuselage- are actually exposed to the air via airscoops. The same airscoops (altough smaller) are visible in As-411 engine nacelles. They have to cool the cylinder heads. The As-411 was not fully exposed to the air (unlike the As-410) but the engeneerer develeoped a tight engine cowling with three airscoops (called "Luftleitbleche"), which are visible on As-411 engine installations. I do not see a reason why this shouldn´t work with airscoops portruding from the fuselage.

Maintenance may be quite good. The gearbox assembly is readily accessable in the configuration shown below. The engines may be lowered through the armoured service doors for changeover or special maintenance. Cannon / ammo installation is placed in another section, shown below, too.





This section shows that the space defined by the engine installation may be used here to a great effect for either a bomb bay (2 x SC-500 or 3x SC-250 internally) or a gun section (in this case with 3x 30mm high velocity guns and their relative ammo boxes). A very big gun could be installed here, too:
Either 2x 37mm or 1x 50mm, slightly off center. A 75mm autocannon can be installed with a droppable podlike system. Since this section is closest to the cog, different weights are less important. The upper part is reserved for protected fuel tanks. 

I still have not decided on the landing gear configuration. Two reasonable options are under investigation. The main landing gear will be retractable into the wings under protection of the two enforced main spars. Since we have neither engines nor fuel tanks in the wing (but a powered shaft), we have a lot of space left over to deal with.


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## Burmese Bandit (Jun 15, 2009)

Thanks for the explanation DelCyros! 

Looking good so far...am reading...


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## tomo pauk (Jun 15, 2009)

The pics are very professional. To bad I can't do anything similar...

...at least for my next 'design', the Ju-87 with two radials mounted 'above' the wing , with retractable (or not!) undercarriage, fixed 30mm and/or 37mm cannon(s), decent armor and rear armament, dive brakes (of course)...


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## delcyros (Jun 15, 2009)

Part IV: The wing 





Airfoil:
I choosed the 22% thick Eppler E 858 airfoil. Altough having a very low crit Mach (M= 0,58 ), this airfoil does allow very high angles of attack without stalling and thus, it gives naturally high maximum lift coefficients, esspecially at the very high Reynolds numbers typical for this wing (8 to 10 mio.). Basically, I may even gonna go with a normal high lift device system. Simple 25% long flaps should be enough to ensure the required high lift coefficients. The outer wingtips are geometrically tapered and tilted down by 1.5 deg in order to improve stalling behavior. The stall should be very gentle for a wide range of cog-conditions. Flaps are only at the center wing. automatic LE-slats are only at the outer wing, respectively.

The tradeoff comes in form of increased induced drag. Altough I would still prefer this one for 
A) structurally stronger wing design
B) more space inside the wing 
C) better lift creator
D) gentle stall behavior
E) lighter wing structures (simplified high lift devices)

wing area: 15.5m^2 -note: substantially less wing area than other ground attack A/C and even less than a bf-109 -call it small target size!
wingload: 306 kg/m^2 @ 4.750 kg
aspect ratio: 6.0
average wing depth: 1.6278m
wing sweep: 0 deg.
wing drag coefficiant at 1 deg aoa: 0.0215
lift coefficiant at 10 deg aoa and flaps down 40 deg: 2.79


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## Soren (Jun 15, 2009)

Overall I really like you design Delcyros, I just think the engine choice could be better and I'm still worried about the landing gear.

I understand the reasoning behind an aircooled engine: Better resistance to damage. But considering the much higher amount of power available with an engine like the Jumo 213 or DB-605, I was wondering wether it wouldn't prove more beneficial to mount one of these instead and take advantage of the lighter weight and armour the engine bay to the point where it will withstand 20mm AP rounds. The benefits would be more than one as-well, as drag would be considerably descreased because of the much smaller space needed fo a single Jumo 213 or DB-605 engine, meaning you could narrow down the fuselage. You'd also reduce the weight pr. power ratio by more than 80%. 

Just a thought anyhow.


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## delcyros (Jun 16, 2009)

I have no problem with Db-605, Jumo-213 or Jumo-211 for that matter. But they are high performance engines, not allowed in the competition. The AS 411 is non strategic, air cooled, fuel efficient, inline and readily aviable in time. Altough less efficient -powerwise- as shown by Your numbers, the As-411 allows for a very light and compact design and the flattened out fuselage cross section makes for a roomy bomb bay / weapons bay. I will nevertheless consider the Jumo-option for a later replacement of this ground attack A/C.


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## Burmese Bandit (Jun 16, 2009)

A point on power, Delcyros. With less than 1200 effective hp in your machine you will be duplicating the historical Hs 129 with 1400 total hp on the two Bramos and the 1400 hp JU 87 D. 

Which means that when it comes to armour and weapons you will be limited to the 30/37 mm option max effective weaponry. Sure, you could overload the aircraft and put in a Mk 214 50mm or even the 75 mm but then you would have the same control and performance problems as the historical HS 129 - well at least as far as I know. 

How do you plan to arm your aircraft? And armour it?

It was for precisely these reasons that I went for a total of 1,900 - 2.000 total hp in my design.


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## Soren (Jun 16, 2009)

BB,

Remember that while Delcyros's design features the same engine power as the Hs-129 it will however utilize this power a lot more efficiently because of the propeller design. Delcyros's propeller design, with the engine mounted in the fuselage, means more thrust less drag all at the same time. So performance wise it should be a pretty improvement on the Hs-129.


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## delcyros (Jun 16, 2009)

The armour scheme and weapon options will be discussed below seperately.
In comparison with the historical Hs-129 the plane has the same power / weight figure (speak: acceleration) but a much higher powerload (aviable power / wing area). True, wingload is higher too but this is by a large margin compensated for by the higher lift coefficients produced by the wing in the first place. Controll responsiveness in the limits defined by the mission profile should be expected to be better than for the Hs-129 (all around except high speed, particularely superior in roll rates and flight conditions approaching the stall).
I am convinced that twin 37mm, centerline mounted guns would be perfect for tank hunting purposes. Even the 30mm MK 101 / 103 with APCR is adeaquate for all but the heaviest main battle tanks. The BK 7,5cm autocannon is a monstergun, which cuts down performance drastically, agreed.
I am not wanting to design a supergroundattack plane, I just want to demonstrate what could have been possible within the design limits of the historical competition in a plausible timeframe.
After reconsideration upon the wing, I decide against automatic leading edge slats and prefer fixed slots for the outer wings (compare identic Me-163 outer wing slots). They do add drag but have all other advantages of slats and are simpler in design and construction (no movable parts). A tradeoff between technical sophistication and service reliability.


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## Soren (Jun 16, 2009)

Delcyros said:


> I am not wanting to design a supergroundattack plane, I just want to demonstrate what could have been possible within the design limits of the historical competition in a plausible timeframe



Ah ok! Didn't know that. Now I better understand your engine choice. But remember that your engine propeller design will prove quite a strain on German industry as it will be a very complicated build. The slots are a good choice, simple efficient.


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## delcyros (Jun 17, 2009)

*Part V -weights.*

Now, after defining layout and general configuration we come back to the weights of the airframe.
We have already accounted 1.994kg for:

750kg: normal internal ordenance (droppable or fixed fwd. firing guns, interchangable)
80kg: one crew
216kg : fuel
18kg : oil 
180kg: gearbox and related equipment
750kg: engines

-airframe:
material: all metal

*wings:*
limit g-factor: 5.33 (service limit. failure limit would be 8.0)
limit airspeed at sea level: 400 kts / 460mph / 740 kmh
This requires either a main spar or a single torsion box, preferably a counterstressed design.
Spar box weight: 74 lbs
wing surface weight: 1400lbs
Total weight: 1474lbs / 669 kg.

*tail:*
relation to wing size: 0,4
weight: 552 lbs / 250kg


*fuselage:*
length: 9,8m
wetted surface: 381 ft^2
weight: 857 lbs / 389kg

*armour:*
wing leading edge: The fwd. main spar is protected by an armoured airfoil shaped profile (nose of airfoil, only). It is 4m long each and armoured with 4mm sheets of steel, weighting in 187kg total.

Tail: The tail section is lightly build from dural and steel. No armour at all.

center fuselage:
The armour is a closed section, 4,5m long, covering engines, gearbox fuel tank sections and in part is used as structural component with different thicknesses:
aft bulkhead: 6mm (64kg)
top: 3mm (30kg)
top sides: 4mm (210kg)
sides: 3mm (75kg)
bottom sides: 8mm (290kg)
bottom: 6mm (174kg)
center fuselage weight: 843kg

Cockpit section:
Fully closed cockpit armour.
nose bulkhead: 20mm (52kg)
seating bulkhead, including headrest: 8mm (65kg)
bottom plates: 10mm (104kg)
side plating: 8mm (82kg)
frontal armoured window (75mm): 42kg
side armoured windows (30mm): 48kg
upper armoured window (30mm): 22kg
cockpit armour weight: 415kg

total armour weight: *1445kg.*
Note: about 570kg of this weight does count as structural weight because it does replace structural load taking frames, bulkheads or surface weights of the fuselage.


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## Soren (Jun 17, 2009)

Delcyros,

Isn't 216 kg or roughly 270 Liters of fuel (Gas has 0.70 factor compared to water IIRC) abit on the low side? I've expect atleast 550 to 650 Liter capacity, so that's a 500 to 570 kg of weight for fuel.


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## delcyros (Jun 18, 2009)

Range and endurance are factors of secondary importance. Close range air support was the typical purpose of the Hs-129 / Hs-123. 
The As-411 was one of the most fuel efficient aeroengines of it´s time. 

216 kg fuel are normal internal fuel for one hour endurance at max. continous power:
power: 540 ps 
specific fuel consumption: 0,2 kg/ps/h
required fuel for one hour endurance: 216kg.

More economical cruise speed would yield in 1.8 hour endurance. The endurance is so far not very different from those figures of Bf-109 fighters (without drop tanks). The 500 ltr. fuel load of the Hs-129 were to big for te mission profile of this plane. But with a fuel consumption of 0.242 kg/ ps / h, the Gnome Rhone 14m required more fuel indeed (305 kg for one hour endurance at max. continous power =630ps) and in top of this, the airframe was aerodynamically less efficient. 
I therefore see only little differences in range but drastic differences in fuel efficiency (less quantity and quality fuels are required to operate the plane). The enduranc eof the Hs-129 is higher but who enjois staying in the cramped Hs-129 cockpit for longer than -say- three hours?
That beeing said, I think You certainly have pointed me to extend the bunkerage to allow for fuel used up normally for warming up the engines, taxiing, acceleration take off. New fuel buncerage will be 250kg


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## Soren (Jun 18, 2009)

Good points Delcyros, you're absolutely right about the better fuel efficiency and much reduced drag of your design vs the Hs-129, again improving the fuel vs range covered ratio if I may call it that  So maybe you're right that once in the air no more than ~250 Liters of fuel will be needed. I would however make provisions for the ability to carry up to 400 Liters of fuel internally, this might prove useful if the tide of war was to change. (One has to think positive some times  )

Anyway keep up the good work


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## Venganza (Jun 18, 2009)

Delcryos, I've been thinking about the problem of the landing gear on this bird. Given the mid-wing configuration I think the best solution might be to have the main gear retracting into pods on the fuselage sides, with the main wheels protruding, and with a fixed tail wheel. Having the main wheels protruding will protect the fuselage from damage in the event of a crash-landing, and the fixed tail wheel will protect the aft fuselage also (although a partially retractable tail wheel might also do the trick, depending on where it's located). I've seen many pictures of crash-landed IL-2's that were saved from further damage by having the main wheels protruding (the same reasoning went into the A-10). Below is your drawing with my additions. Tell me what you think. I’m also curious about the cockpit – is it going to be faired into the fuselage, like the Hs-129, or raised, like the single-seat IL-2? Both have their advantages and disadvantages. The advantage to the Hs-129 arrangement is more protection; the disadvantage is less visibility. It’s just the opposite with the IL-2 arrangement, although with the armor plating around the canopy and the armored glass, it may not have been that much less protected than the Hs-129. If you do adopt the Hs-129 arrangement, one way around the rear visibility problem would be to have a periscope, or more simply, just a good rear-view mirror, like on the Spitfire, etc. I also think it might be a good idea to keep the twin tails as on the Arado Ar-240, for the redundancy they offer in the event of damage. At any rate, just some ideas I had rattling around my head.

Venganza


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## Burmese Bandit (Jun 19, 2009)

Keep it up, Delcyros, I am waiting for the armament package.

Before I post drawings of my previous efforts, I have two ideas I am going to throw into this thread. They share the same theme - the 'minimal change theme'.

The idea is for something that is such a fairly minimal change to the existing design that it can be rapidly produced, and yet creates a definite advantage.

My first idea with be a new Ju 87 optimized for tank killing. This requires a new front fuselage, but will recycle the engine, the tail and all the fuselage from the second cockpit backwardsl, and the wing of the original 87, as well as the original control system

My next idea is a new 109, ditto. 

Will post after Delcyros finishes.


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## Burmese Bandit (Jun 19, 2009)

By the way, Vengenza, that track looks too narrow to be useful in the muddy forward airfield conditions of the eastern front 1941-44.


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## Soren (Jun 20, 2009)

I think the main landing gear will have to be in the wings, so there would need to be room for that. They will also need to be fully retractable so that the drag remains low.


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## Soren (Jun 20, 2009)

Could probably be arranged like so:


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## delcyros (Jun 20, 2009)

I added updated drawing of the dedicated ground attack A/C and completed armour weight calculations above.
Venganca made a good case for keeping the twin tail of the Ar-240 and a semi retractable tailwheel. I just deleted the tail dive break (I feel it´s to heavy that far aft and technically complicated).
The main wheel design is quite different from the podded gears as envisioned by Vengenza. Altough I see agree with the advantages.
I base my decision on the fact that the center fuselage section is already an armoured box and thus able to deal with the loads of crash landing events. The service doors may be bulged in and related damage may occur but that´s the most serious risk so far.
The track of the standart three point landing gear is based upon the Fw-190A landing gear, altough it will have a slightly wider track (Arado had experience with them. The company was a first hour license contractor of Focke Wulf). With such a gear, the plane will be able to negotiate rougher field conditions. Ground clearence of the propeller tips is 0.50m in starting condition. The wing with 22% thickness is spacy enough to retract the main wheel into the wings. The tail wheel is half retracting (better servicability).
The plane does look more like a Terrier in it´s actual state.





One last word to internal fuel buncerage.
There will be an option to interchange 300 ltr. drop tanks with SC-250 bombs internally. We just need a hydraulic pump to circle the fuel into the "normal" internal tanks. Up to 3x 300 ltr. drop tanks could be carried this way (internally under armour) but more typical would be one 300 ltr. drop tank and two SC-250 or one drop tank and 2x MK-103. The wingtips have stations for one SC-50 / SD-50 / AB-50 or SD-70 each, drop tanks or larger bombs cannot be carried there.

The overall general weights increased to 4.781kg:

-general weights:
airframe: 1878kg (570kg of those weights are armoured structure)
engines and equipment: 930kg
armour: 875 kg (+570kg armoured structures)

additional weights:
fuel: 250kg / 360 ltr
oil: 18kg
crew: 80kg

usable military loads:
normal internal: 750kg
max. internal: 1000kg (overloaded)

external loads: 200kg -allowed only at 500 kg internal loads (=normal), or 750 kg internal weights (overloaded)

normal take off weight: 4.781kg
maximum take off weight: 5.031kg (overloaded)


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## Lucky13 (Jun 20, 2009)

Great stuff delcyros!


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## Soren (Jun 20, 2009)

Looks like the landing gear needs to be abit further out, cause at the moment you can't retract it without hitting the fuselage.

Btw, I was wondering, why not add semi elliptical wing tips to increase lift lower induced drag?

Looking forward to seeing a side view


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## Venganza (Jun 20, 2009)

Delcryos and Soren, the wide-track landing gear you propose would certainly give this plane more ground stability. And Burmese Bandit, that was something that concerned me about my somewhat narrow-track podded gear. I proposed them partly because I was doubtful the wings would accomodate landing gear without them being inordinately long - apparently they can. Soren, your comment about drag is correct, of course. The podded gear would create more drag, but I didn't think speed was too much of a concern for this plane (although speed is always nice to have if you can get it). The only concern I have about your gear is how long they are - how well are they going to stand up to rough-field conditions? The FW-190 also had long, wide-track gear, and I suppose they did pretty well operating from rough strips on the Ostfront so that may not be a valid concern. On the subject of the FW-190, I always liked the way the semi-retractable tail wheel operated. No doors, no pneumatic, electric, or hydraulic retraction - it was pulled mechanically straight up into the fin by a pulley arrangment utilizing a wire attached to the main gear. Very simple, rugged, and very reliable - perfect for a tough, ground-attack plane. Your creation's starting to look very interesting, delcryos. I like the new pictures you've added, but I'm with Soren - do you have any sideviews you can show us?

Venganza


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## delcyros (Jun 20, 2009)

The gear mechanism appearently does not interfere with either the airscoops or the fuselage. The relevant detail wa snot visible in the graph above so please compare the attached picture below.





I avoided semi elliptical wingtips for two reasons:
A) building simplicity
B) wingtip stations

The latter was more important for me. Originally I intended the wingtip stations for SD-250 bombs but after doing some maths, this goal appeared to be unreasonable. To much structure weight was necessary and the stability was cast in question, too.
But two 50 or 70 kg bombs may be carried there. A nice addition to the offensive suite. 
Possibly, elliptical wingtip fairings are an option in case the wingtip ETC is not used for bomb carriers. But I take this to be some kind of "extra", rather than standart.
Unfortunately, I do not have a complete side picture yet. It takes some time for me to prepare them.


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## Soren (Jun 20, 2009)

Hi Delcyros,

On that picture they fit, but on the other one they don't, they're too long. I actually measured them with a ruler on the screen


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## delcyros (Jun 20, 2009)

hmmm, something seems to be wrong with my first drawing. Thanks for the pointer.
I reused an older version for frontal graphs and used to work with the cutaway drawing.
Some differences appeared. 





Note that the airscoops are in front of the wheel bay and turn back inwards so that they don´t interfere (it is depicted the other way in order to show how far the wheels extend wrt fuselage). At the gear bay, the thickness of the wing is avg. 35cm.

performance projections to follow soon.


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## Soren (Jun 20, 2009)

Roger, looks good now Delcyros 

Btw, the airscoops need to be rounded to match your previous sketch of them. I'd make them follow the curvature of the fuselage, to cut down drag.


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## delcyros (Jun 20, 2009)

That´s the way to do.

Here is a size comparison of some ww2 ground attack A/C. The designation Ar-137 is purely hypothetical.





It makes for a difficult target to hit -the whole frontal area is armoured to some extant.


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## Soren (Jun 20, 2009)

That is one small aircraft!


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## Venganza (Jun 20, 2009)

That is a small plane! Perhaps you've already covered this delcryos, but what kind of dive-bombing would it be capable of - I mean at what angle? One thing that helped the Shturmovik, quite a large plane as is evident from your frontal views, reduce its vulnerability was a change in tactic where it increased its dive angle towards the target (up to 40%, I believe). In addition to increasing the altitude at which the attack started, the additional speed reduced the time over the target, very useful for any attack plane. With a fairly steep dive angle, and such a small frontal area, your Ar-137 would be almost invisible in a dive. I realize you've discarded the Ar-240 type rear fuselage "petal" dive brakes, and for good reason, but how about split flaps for brakes?

Venganza


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## delcyros (Jun 21, 2009)

It is already enforced to undertake "schräganflüge" / shallow dives up to 30deg. Split flaps would allow near vertical dives only if the flap area get´s increased, which would require about 11.29m minimum span for 25% deep flaps (deeper flaps would be difficult in the choosen airfoil due to alteration of center of lift and weight). I would like to avoid the increase in wing area for reasons already outlined above. Split flaps would allow steeper dive angles in the given configuration, perhaps up to 45 deg -I might be wrong- and should be taken into consideration. Dive bombing isn´t the main purpose.

Here are some versions:

*recon / observation:*
wingtip stations: none
fuselage weapon bay:
1x Rb20/30, 2 x Rb 50/30, 2 x MG-151/20 with 100 rpg, 1x 300 ltr aux. tank (undroppable).
gross weight: 
4.500 kg
endurance:
ca. 3 hours at max. economical cruise
range: max. 1285km at 3000m

*short range attack 1:*
wingtip stations: 2 x SD-70 
fuselage weapon bay:
3x MK 101/30 or MK103/30 with 100rpg.
gross weight: 
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

*short range attack 2:*
wingtip stations: 2 x SC-50 / SD-50 
fuselage weapon bay:
2x MK 103/30 with 100rpg; 1 x SC-250 or 1x SD-250 or 1 x AB-250.
gross weight: 
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

*tank hunter 1:*
wingtip stations: 2 x SD-70
fuselage weapon bay:
1x BK 3,7, 37mm with 10 x 6 round clips each; 2 x MG 151/15 with 200 rpg each.
gross weight: 
4.750 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

*tank hunter 2:*
wingtip stations: none
fuselage weapon bay:
1 x BK-5, 50mm with 22 rpg and 2 x MG 151/15 with 100 rpg
gross weight: 
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 790 km at 3000m

*tank hunter 3 (overloaded):*
wingtip stations: none
fuselage weapon bay:
1 x BK-7,5 with 12 rpg 
gross weight: 
5.231 kg
endurance:
1.8 hours at max. economical cruise
range: max. 700 km at 3000m

*short range bomber 1:*
wingtip stations: 2 x SC-50/SD-50 to 2 x SD-70
fuselage weapon bay:
8 x SC-50/SD-50 to 8 x SD-70
gross weight: 
4.531 kg (with SC/SD-50) to 4731 kg (with SD-70)
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

*short range bomber 2:*
wingtip stations: none
fuselage weapon bay:
3 x SD-250 or 3x SC-250 or 3x AB-250
gross weight: 
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 790 km at 3000m

*short range bomber 3 (overloaded):*
wingtip stations: none
fuselage weapon bay:
2 x SC-500 or 2 x SD-500 or 2 x PC-500 or 2 x AB-500
gross weight: 
5.031 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m


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## Burmese Bandit (Jun 21, 2009)

Since Delcyros has finished his proposal for a new attack plane - and it looks wonderful, and certainly appears to be quite plausible as well - I will now write on my proposal for a minimum change Ju 87 Stuka optimized for tank hunting. 

A new forward fuselage for the 87 is to be designed. This will be deeper than the original 87, though not by much more. The deeper forward fuselage is designed so that a BK 37 will be mounted on TOP of the engine, not between the vee of the Engine as in other engine mounted gun designs. In addition a ranging MG 151/20 will be mounted on the cowling, for ranging. The BK will fire though a spinner that now is on top of the engine, not in front as in the original 87. 

An armoured airscoop with armoured venetian blinds is directly under the spinner, and is connected to the radiator which is directly under the pilot's and gunner's seats by a tunnel that runs under the V of the inverted engine. 

The whole underside of the forward fuselage is built as an armoured shell like the Stormovik, and the rear gunner is protected by armour as well. This will add 1,000 kg to the total weight, again like the Stormovik. The gun and ammunition will add about 200 kg. Since the historical 87 could carry up to a single 1800 kg bomb this is well within its load carrying limit.
50-70 rounds of 37 mm ammo could be carried. 

The rear fuselage, tail, wings, landing gear, cockpit, rear guns will be like the original 87. 

This tank hunter, with its centerline armament and heavy armour, would in my opinion have been a much more sucessful design than the historical 87 with two wing guns that were difficult to aim.


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## Venganza (Jun 22, 2009)

BB, that's a good point about the centerline armament being better than the wing guns. Not only do you not have to worry about converging fire to get the most firepower, but you also avoid synchronization problems. What sunk the Shturmovik with the two 37mm cannons was having them wing-mounted (hard to avoid with the single-engined arrangement, without major modifications - which were a no-go with the IL-2's production requirements). The Soviets had problems synchronizing the guns to fire at exactly the same time, so that every time they were fired, the plane yawed and the aim was ruined (which was compounded by recoil dissipation problems). I've been thinking about how to have a tank-killing gun on the centerline of an IL-2, with limited success, but it looks like you've been able to do it with the Stuka. (Although, now that I think about it more, the Soviets were able to mount guns as big as a 45mm in the tiny Yak fighters, so why not in an IL-2?) It'll be great to see the initial drawings of your design.

Venganza


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## Burmese Bandit (Jun 23, 2009)

The Russians tried 37s and 45s on the Yak. 

Result: cracked engines. crashed aircraft.

The Russians tried mounting the excellent NS-37 on the Stormovik (IMHO the best 37 of the entire war)

Results, as said above by Vengenza.

That was why the Russians suddenly demanded 40mm Hurricanes from Britain...to the intense embarrassment of the Brits, who had just discontinued that entire production line! Second hand Hurri Tankbusters were hurriedly rounded up and sent to the Russkies.


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## tomo pauk (Jun 23, 2009)

Hi, BB,

That Russian usage of Hurricane IID is very interesting to me. Any good info about that (timeline, where it was used, numbers etc)?


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## tomo pauk (Jun 23, 2009)

Venganza said:


> ....
> (Although, now that I think about it more, the Soviets were able to mount guns as big as a 45mm in the tiny Yak fighters, so why not in an IL-2?) .....
> Venganza



Mikulin engines (AM-35, -38) have had auxiliary stuff (pumps etc.) attached to the rear of the engine, so that was the thing hampering engine cannon mounting. The Mig-1 -3 were the 'users' of the -35, and were notably poor armed.
The Klimov 105 was derived by French HS-12 series, so the engine cannon was possible from day one.


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## Venganza (Jun 23, 2009)

tomo pauk said:


> Mikulin engines (AM-35, -38) have had auxiliary stuff (pumps etc.) attached to the rear of the engine, so that was the thing hampering engine cannon mounting. The Mig-1 -3 were the 'users' of the -35, and were notably poor armed.
> The Klimov 105 was derived by French HS-12 series, so the engine cannon was possible from day one.



I see, that explains it. I knew the Hispanos were designed to accommodate an engine cannon, but I'd forgetten the Klimov 105 was developed from them. And no point in putting a Klimov in a Shturmovik, unless you want it as underpowered as an Hs-129. Thank you for the information, tomo pauk! I learn something new every day about Soviet planes.

Venganza


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## delcyros (Jun 25, 2009)

Don´t want to interfere but I still have the performance figures left out.

The performance model is based on the Ar-240 but with modifications.OK, so for this plane with 2x DB-601A and a full pressure height of 4500m we have a max speed: 618 km/h or 384 mph @ 4700m (including ram effects) - I will use subscript "1" for this model in the analysis below.
Power delivered is Thrust x Velocity. This is the power after the losses due to the gearbox and propeller inefficiencies.
* P = T x V*
At equilibrium straight-and-level flight (such as when maximum level speed is attained), Thrust is equal to Drag. Thus, the power required from the engine/gearbox/propeller combination is:
*P(required) = D x V
*
Also, we know drag can be written as:
* D = 1/2 x rho x V^2 x S x CD*
where* rho* is local air density, *V* is true airspeed,* S* is wing area and *CD* is the aircraft drag coefficient.

With the power curves and the reported top speed of the Ar-240, it is possible to graphically extrapolate the speed / altitude curves:





Since the As-411 driven Ar-137 does only have a full pressure height of 3000m, we should take this into account as a reference altitude. At this altitude, the top speed of the Ar-240 was approx. 585 km/h or 363 mph and 2 x 995 hp were required from the Db-601A/B to achieve this speed. 
Further when we study th wing area, we will see that the Ar-137 is just half the size of the Ar-240:

S[1] = 31,3m^2 -Ar-240
S[2] = 15,5m^2 -Ar-137

Unfortunately, the drag coeffcient is larger. In fact, the Ar-240 -thanks to the adoption of a high speed airfoil- was exceptionally clean aerodynamically. I got a CD-figure from rds-student, basing on wetted surface, frontal area and form factors beeing almost double as high as that for my Ar-240 simulation!
Ground attackers are not really aerodynamically efficient when relying on a high lift airfoil. Even with geared drives and center engines...

Ok-so far. This allows us to simplify top speed projections a bit. We have twice the CD but only half the reference area so both effects cancel each other out in this case, unless some fairly large changes to the model are made or compressibility effects are involved.
V*[2]= V[1] * (sqrt^3(P[1]/P[2]))*
= 585 * (sqrt^3(570/990))
= 510 km/h or 317 mph

300 mp/h at Bodenlader altitude is a reasonable top speed for an attacker
Performancewise, this is not stellar nor outstanding but it allows for a very fast speed at or close to Sealevel with an inferior engine. Quite an accomplishment (Anyone around interested to build a Reno Airracer with these center engines?).
The backside of the coin may be seen in a rather low service ceiling (ca. 7000m, of secondary importance for the mission profile). The high drag figure in combination with a high weight probably does not make for a good turner, too and single engine performance would be difficult -at best.





As a matter of fact, the drag coefficient is better than that of the Hs-129 (primarely due to missing nacelles and more thrust delivered by the prop installation) but not by much. Had the Ar-137 the same wingarea as the Hs-129, it would have been only able to hit 432 km/h at 3000m. Only a slight improvement over the Hs-129. The big improvement is the reduction in area and associated general drag reduction.


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## Burmese Bandit (Jun 25, 2009)

Delcyros, what's the stall speed for your design? Especially at low levels?


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## delcyros (Jun 25, 2009)

At Sea level and with flaps down, power on, the stall speed is 86.6 mph or 140 km/h at 4.781 kg with normal flaps and 135 km/h with split flaps (translates to a slightly higher CA-max).
At about sealevel with flaps up and power on, the stall speed raises to 118 mph or 190 km/h.
Finally the glide stall speed (flaps up, no power) is just under 210 km/h at sea level, not taking into account allowances for the ground effect.


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## delcyros (Jun 25, 2009)

I owe You a side view. Here it is, with the BK 7,5cm gun in the heaviest version.





Compared to the normal plane several modifications are made:
A) removal of parts of the frontal armour
B) removal of the fuselage tank and bulkhead
C) Installation of the gun below the weapons bay and the loader in the weapons bay.
D) armoured bulkhead behind the engine section is enforced to 10mm (CoG -shift requirement)
E) installation of two smaller fuel tanks in the center section below and to the sides of the drive gear mechanism.

All these changes increase the gross weight to 5.250 kg (overload condition).
A good side effect is the larger drum for 75mm shells. Instead of 12 rounds, the loader contains now 16 rounds.

Top speed is significantly reduced, I consider a figure of about 450 km/h as reasonable, but it´s just a guess.


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## Venganza (Jun 25, 2009)

Nice work, delcryos! Great to see the plane in side view. The pilot has an excellent view forward, although the rear view suffers. Is the 75mm jettisonable, in case of crashlandings? Are you sure the CG adjustments are sufficient to counteract the weight of the cannon - it still looks like it might be nose-heavy, which could be a problem when landing on mushy Ostfront airfields. Still, looking good!

Venganza


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## delcyros (Jun 26, 2009)

It´s one good thing to have that much armour to deal with. Gives plenty of opportunity for CoG-changes. Do not forget that the engines are behind the CoG. Removing parts of the armour and fuel tanks fore and upgrading armour aft is the solution. Unfortunately, the gun cannot be dropped for the very same reasons. Removing almost 1000kg that far fore would drastically change the CoG to become tail heavy in combination with the measures outlined above. On the other hand, emptying the fuel tank or the ammo drum does not change the CoG. In this way, the Ar-137 is no different than the Hs-129B3.
The plane is in an overloaded condition and likely would require fine landing strips anyway.


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## Burmese Bandit (Jun 26, 2009)

Delcyros, I would like to see a picture of your plane configured for the BK 5, and your thoughts on its ammunition supply. Also your comments on its handling thereof. 

Furthermore, could you give us a top view?


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## delcyros (Jun 26, 2009)

The BK-5 configuration appears to me the most reasonable tank hunter design. Only a small bulge is necessary. The belt design is unchanged (22 round closed belt). This gun fires normal APCBC rounds, which could be augmented by HE. Two MG 151 (either /15 or /20, depending on mission requirement) are placed to the sides with 100 rpg each. No special changes to the model are required. Gross weight is just under 4.800kg, top speed at about 500 km/h at 3000m.
The 50mm barrel extends through the lower cockpit and protrudes slightly over the frontal fuselage. A long recoil mechanism will help to dampen the 2.4t. recoil force. 
Penetration performance exceeds any tank in service by 1940/41 to 1944.

The handling wouldn´t have been much affected as the reference weight and gross weight is pretty much the same. It´s just a bit slower, but not by much.


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## VG-33 (Jun 26, 2009)

> Burmese Bandit said:
> 
> 
> > The Russians tried 37s and 45s on the Yak.
> ...


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## Venganza (Jun 26, 2009)

Very good, delcryos. Would the 50mm version have been capable of use from unprepared strips?

Venganza


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## delcyros (Jun 26, 2009)

Definetely. It has enough performance and structural reserves for rough field service.


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## Venganza (Jun 26, 2009)

delcyros said:


> Definetely. It has enough performance and structural reserves for rough field service.



So only the specialized 75mm version needed the prepared strips. I agree that the 50mm version is more plausible and useful, because of not needing prepared strips, being lighter, having less drag, etc. Perhaps you've covered this, but do you know how much lift that rather small wing is going to get from the propwash of those large, close-mounted (to the wing) propellers? By the way, what software are using to generate your nice drawings? If I try my hand at a "What if?" plane, I'd like to know a good drawing or engineering software to compose it in.

Venganza


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## Burmese Bandit (Jun 26, 2009)

Excellent, Delcyros! 

We now have three views of your aircraft, armament, handling, power, landing gear characteristics...and a performance chart as well. A very professional attempt, much better than what I could have done, and very succintly written as well. 

My next proposal will be an HE-177 with five engines in a very high speed configuration, and a total all up weight comparable to the B-29.


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## Burmese Bandit (Jun 27, 2009)

The He-177 I am designing has two engines in each wing, in tandem push-pull configuration as done by Dornier in their planes (most notably in the Dornier 26) and one engine in the fuselage behind the pilots cockpit. A shaft extends from that engine over the roof of the cockpit and exits in front of the cockpit, driving a propeller. This means that there is no physical communication possible between the pilot, flight engineer, navigator, and front gunner in the cockpit and the mid gunner, belly gunner and the tail gunner in the mid and rear section. 

With five engines each driving one propeller the gearing problems, and oil fire problems of the historical HE 177 are instantly bypassed. Cooling wil be done by radiators in the wing leading edges, in the wing roots: there will be two radiators in all. They will be protected by a 12 mm armour plate top and bottom. The extra weight of armour will add about 4-6,000 lbs to the design, partly offset by losing the weight of two gearboxes. A total all up weight of 40,000kg or 90,000 lbs is envisaged. 

With 7500 hp at least driving this design and basic drag lower than the original HE 177 frame even an extra 20,000 extra weight over the historical 177 should not slow my design down. As one or two of the five engines could be shut down in flight to save fuel this design should be able to cruise economically at a much slower speed that the historical 177, which means much greater range. The low drag airframe combined with the heavier weight means that my 177 design should be able to better the shallow dive speed of the historical 177. 

The historical 177 was able to reach 420 mph in a full power shallow dive. My design should reach 450. This means that if my 177 is bounced from behind by fighters it has a good chance of escaping, and the rear gunner plenty of time to aim and kill the rear attackers.


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## delcyros (Jun 28, 2009)

I sourced the net for programs.

rds-student is a basic and cheap tool for design, sizing, drag and performance analysis of general aircraft design, which I found to be helpful. Unfortunately, it´s not easy to get used to use.
Some model builders have very, very good airfoil and wing design tools for free.
Finally, Rick Robinson´s planebuilder and my own tabulated weight lists derived from my 1941 edition of Arado: Kriegsflugzeugbau helped me in my weight calculations.

All graphics were edited and made with Coral Draw 12.0, an older version of the series. It has some powerful tools for scaling and is easy to work with.

BurmeseBandit. If You want higher performance from Your He-177, then I suggest to use the fuselage engine as a slave engine to supply the air for the superchargers of the other engines (alike Hs-130e and Do-217P layout). Using this method You greatly increase the critical altitude and thrust output and hence improve the bombers high altitude speed by a considerable margin.


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## Venganza (Jun 28, 2009)

Thank you for the info on the programs, delcryos! I'll take a look at them.

Venganza


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## Burmese Bandit (Jun 28, 2009)

Is it Freeware? Or if you have to buy it, where and how much?


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## Burmese Bandit (Dec 23, 2009)

Rereading the history of both aircraft design and air combat, I was struck by a sudden idea...

WHAT IF THE GERMANS HAD REVERSE ENGINEERED THE P-39 BUT WITH 3 30mm MK 108 INSTEAD OF A SINGLE 37mm M4 CANNON IN THE NOSE???

Let's see if this flies.

Since the Germans had access to captured P 39s from 1942 onwards and heard about and seen them from 1940 onwards the design would not be a problem.

In place of the Allison, mount a DB or Jumo engine. 

From a weight point of view, the P 39 had one 96 kg M4 cannon in the nose plus two 29 kg Browning 50 cal machine guns. Total weight, 154 kg.

Three Mk 108 will weigh 180 kg. A little heavier, but in my opinion quite doable. The additional weight to the front will actually make the German P 39 handle better. 

How will the guns be mounted? I would design two Mk 108 in a Zwilling configuration, and then put one 108 on top, staggered and back. Ammo feed would be top down for the top gun, set back, and standard left and right feed for the Zwilling. 

The hole in the middle of the prop would need to be larger, but quite doable - this is a simple engineering problem. 

Result? 

1. High speed, maneuverable Bomber killer in the West. A one-pass kill machine. Also I suspect anything lighter and with less armour than a Sherman could be killed by the concentrated power of the three Mk 108 in the nose. With enough hits even the top armour of a Sherman could be vulnerable. And as for trucks, and armoured cars, goodbye. Heck, with a good burst I think even a LCI or LCT would be vulnerable!

2. High speed, maneuverable Stormovik killer in the east. Ditto. One pass one kill per Stormovik. And perhaps a T 34 killer too, although anything heavier would not be vulnerable. As for trucks... ditto as in west. 

Opinions?


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## riacrato (Dec 23, 2009)

I don't get it, do you want to have all 3 guns firing through the prop shaft? I very much doubt that's possible.

Remember you can't synchronize the MK 108, so you can't have it in cowling or wing root installations. I think a single MK 108 and 2 MG 151/20 would be a better setup anyways and easily enough to shoot down IL-2s in droves.


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## Burmese Bandit (Dec 23, 2009)

And just why would that not be possible? I fail to see the slightest reason why. Mechanically, it is merely a matter of fitting a large, hollow fixed shaft through which the 3 barrels would shoot. 

The second question you asked is: why would we want 3 Mk 108s anway?

And the answer is..

It is all about weight, and gun efficiency. 

The P-39 was a wonderful aircraft, but there were three things wrong with it: it had poor high altitude performance, it had too little weight forward and too much weight back, and the rate of fire of its main gun was way, way too slow. 

With a DB or Jumo, three Mk 108s, we take care of all three problems at once. Turning a 'good but flawed' design into an 'excellent' design. 

Why three Mk 108s instead of a combination of other guns or one Mk 108 and some other gun combination?

Simple. If you look at Tony William's website, you will see that no gun designed and used in WW 2 comes even close to the gun weight/rate of fire/ammo power/ cost equation that shows how efficient the gun was. The MK 108 is the King of all guns. It has an efficiency factor of 9.7 on the Tony Williams Website. No other gun comes half as close.


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## riacrato (Dec 23, 2009)

Lots of colorful sentences but let's get back to reality. The spinner you are proposing would have hole with a huge diameter (probably 40-50 cm) and would be huge itself. The large hole would require large gears for making the prop rotate with all the bad that comes with it. Then to get even halfway you would need very long blades or a large chord. Then what does such a huge hole do to your aerodynamics. Then there is the space issue... Just check the real P-39 installation and you want to fit 3 MK 108s there without interfering with the shaft?






And there is no need to tell me about Tony Williams site. The fact remains with 1 MK108 and 2 MG151 you have plenty of firepower to shoot down IL-2s and you're much more versatile. There was no need for a dedicated anti-Sturmovik aircraft.

And this is about as close as you can keep two MK 108s together:


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## Burmese Bandit (Dec 23, 2009)

Not two MK 108s together - did you not read my post? A two barrel Mk 108 in a Zwillig configuration was what I said. And it seems you have not read the part of the German P 39 being a MULTIPURPOSE aircraft, able to kill heavy four engine bombers, vehicles up to tanks, and even small landing craft. 

Tsk, tsk. This new TV and internet generation is slowly becoming illiterate.


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## tomo pauk (Dec 23, 2009)

Bandit, post some stuff sources about MK 108 Zwilling, please.


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## riacrato (Dec 23, 2009)

Wtf you are calling me illiterate? totally uncalled for. You talk like you know anything about the guns in question or what it means to design a prop installation when it is pretty clear you are probably 16 years old with no experience on either.


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## Soren (Dec 23, 2009)

Wow, calm down guys.


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## davebender (Dec 23, 2009)

Germany needs twice as much aviation gasoline. They also need DB603 and/or Jumo 213 engines early and in quantity. Early production of the R4M folding fin rocket would be nice too. With these changes the historical German aircraft designs will work just fine. 

The USA needs a proper supercharger for the Allison engine. Alternately they need to scrap the Allison design early and put the Packard Merlin into mass production. The USA also needs a decent 20mm cannon ILO .50cal machinegun. With these changes both the P-38 and P-51 become war winners during 1942.

The British Spitfire works fine in the daytime. Unfortunately most of the British air war was at night. They need to work out a system where Mosquito night fighters can accompany the bomber stream without getting shot up by nervous bomber tail gunners.

Italy and Japan both need to license build the DB601 engine early and in quantity. They need to throw enough money at the problem to fix the technical glitches. Both Italy and Japan produced airframes that have good performance when powered by DB601 / DB605 engines.

Russian Yak fighters and Sturmovik attack aircraft are both pretty good. Unfortunately they are crippled by a national command and control system driven by Stalin's meglomania. I see no solution as long as Stalin remains in charge.


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## Shortround6 (Dec 23, 2009)

Burmese Bandit said:


> Not two MK 108s together - did you not read my post? A two barrel Mk 108 in a Zwillig configuration was what I said. And it seems you have not read the part of the German P 39 being a MULTIPURPOSE aircraft, able to kill heavy four engine bombers, vehicles up to tanks, and even small landing craft.
> 
> Tsk, tsk. This new TV and internet generation is slowly becoming illiterate.



take another look at the picture of two MK 108s. even if you redesign the MK 108 to feed from either side AND EJECT out the bottom ( and I wonder how long that will take) to make a Zwillig you still have the bulk of the receivers dictating the barrel spacing so maybe you can reduce the barrel spacing to half, and that is before you add the third barrel. Still a big hole in the front of the aircraft and a lot of complication in the gerar drive and propeller. 

The Idea of turning the P-39 into a multi-role aircraft is a joke. An anti-tank/ground strafer plane is going to need all kinds of extra armour that will only hurt the performance of the bomber interceptor and a bomber interceptor is going to need a supercharger set up that is so much dead weight and bulk on a ground attack plane.


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## Shortround6 (Dec 23, 2009)

davebender said:


> Germany needs twice as much aviation gasoline. They also need DB603 and/or Jumo 213 engines early and in quantity. Early production of the R4M folding fin rocket would be nice too. With these changes the historical German aircraft designs will work just fine.



Means coming up with a new plane to replace the 109 which actually might have been a good idea.


davebender said:


> The USA needs a proper supercharger for the Allison engine. Alternately they need to scrap the Allison design early and put the Packard Merlin into mass production. The USA also needs a decent 20mm cannon ILO .50cal machinegun. With these changes both the P-38 and P-51 become war winners during 1942.



Just when were these decisions supposed to be made? The Allison's supercharger wasn't any worse than anybody else's supercharger in service in 1939. The Packard Merlin that was put into mass production in 1941 in America was a two-speed version not two stage and had niether the power or the altitude performance of the two stage engines that helped make the Mustangs reputation. As far as a 2 speed engine replacing the Turbo supercharged Allison's in the P-38, they may have been a bit more reliable but the with speed, climb and range all going to pot I am not sure the result would have been a war winner even if the US had sorted out the 20mm problem.



davebender said:


> Italy and Japan both need to license build the DB601 engine early and in quantity. They need to throw enough money at the problem to fix the technical glitches. Both Italy and Japan produced airframes that have good performance when powered by DB601 / DB605 engines.



Or throw enough money at the available radial engines to solve their problems and skip the DB601/605 all together. Replacing an 840hp radial with an 1100hp V-12 doesn't really prove how good V-12s are.

Japan actually needed to cut out the multiple different engines and try producing a smaller number of different types.


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## davebender (Dec 24, 2009)

> throw enough money at the available radial engines to solve their problems and skip the DB601/605 all together.


I could envision Japan taking this approach as shipping machine tools and Daimler-Benz engineers from Germany are rather difficult. 

But what was Italy's excuse for DB601 / DB605 engine production problems? The production machinery and Daimler engineers were only a short train ride away. Specific engine components like those troublesome crankshaft bearings can be imported directly from Germany. Copy or purchase the MG151/20 cannon also. A Macchi C.202 fighter powered by a reliable engine and armed with a pair of MG151/20 cannon would be a world class fighter aircraft.


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## Clay_Allison (Dec 24, 2009)

davebender said:


> I could envision Japan taking this approach as shipping machine tools and Daimler-Benz engineers from Germany are rather difficult.
> 
> But what was Italy's excuse for DB601 / DB605 engine production problems? The production machinery and Daimler engineers were only a short train ride away. Specific engine components like those troublesome crankshaft bearings can be imported directly from Germany. Copy or purchase the MG151/20 cannon also. A Macchi C.202 fighter powered by a reliable engine and armed with a pair of MG151/20 cannon would be a world class fighter aircraft.


Italy lacked mass production capability, they were really not industrial enough to pull their weight.


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## davebender (Dec 24, 2009)

Most of the German military-industrial capability was built from scratch after 1934. Why can't Italy do the same thing with help from German engineers and German machine tools?


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## Burmese Bandit (Dec 25, 2009)

Here is another idea, this time for a dedicated ground attack aircraft for the Luftwaffe.

*THE PROBLEM*

Starting from 1942 onwards the T-34 problem begins to loom larger and larger on the Eastern Front. While other tanks pose a problem, Intelligence tells the Germans that for the forseeable future, the mass-produced T-34 will be the biggest danger on the Eastern front. 

The Greatest Danger for German ON THE GROUND is in the East.
The Greatest Danger in the East lies in the NUMBER of Russian Tanks.
The Greatest Percentage of those Russian Tanks is the T-34 model.

Ergo: solve the T-34 Problem, solve the danger in the East. 

But German does not have the time to develop a perfect solution to the problem. It does have some resources, but they are being stretched thin. 

So what is needed is something that can be put into production very fast, and uses limited resources. 

Historically, the Germans answered that question by putting two 37 mm cannon under a Stuka (The only plane in their inventory that had the wings with the strength to handle the recoil of that gun) and building the ground attack version of the FW 190, with armour. 

These designs were capable of being put into production fast, and they did not use a large amount of resources. 

But the weakness of these designs has been discussed in this forum and many others, notably in Tony Williams' 'Flying guns'. The best solution to the problem was a centerline mounted heavy gun of at least 37 mm in a fairly cheap, rugged, Russian field condition tolerant plane of fairly small size. 

The plane needed to be cheap to be able to counter the large numbers of Russian Tanks and to survive battlefield attrition. It needed to be rugged to take the punishment dished out to it by the Russian anti aircraft guns and Russian Fighters. It needed to be able to fly in the Russian Winter and the mud of the Russian Spring. 

And while the 30 x 184 of the Mk 103 with Tungsten Ammunition was adequate, Tungsten was scarce. As Tony Williams said

"...The lighter, more compact and faster-firing MK 103 used a hybrid gas+recoil system and was belt-fed. Various AP rounds were used, but the most effective was the _Hartkernmunition_, which had a penetrating core of tungsten carbide sheathed in a light-alloy shell with a sharply-pointed profile. This could penetrate 75-90 mm / 300 m / 90 degrees (depending on the type of armour), dropping to 42-52 mm when impacting at 60 degrees..."

But without the tungsten, the penetrative power dropped sharply. Thus with the tungsten ammuniton, the 103 was just capable of penentrating the top armour of the T 34 at high angles, but without, it was not. 

Therefore what was needed was a gun capable of penentration using vanilla steel cored ammo. Of all the guns the germans had in that category, only the BK 3.7 was ready and available in significant numbers in 1943. The BK 5 was not ready yet, and the BK 7.5 was a technological marvel...but it was way too heavy, the recoil way too much, and the muzzle blast almost as dangerous to the aircraft carrying it as ground fire!

Now the Germans did have a fairly cheap aircraft, adequately armoured, that could carry a centerline mounted gun. This was the Hs 129.

Unfortunately its French Grnome Rhome engines were not only unreliable and sensitive to battle damage, they were underpowered. 

In an earlier part of this thread I proposed a solution for a four AS 410 engined aircraft in a dornier tandem configuration with a supercharger powered by a fifth 410 in the fuselage. 

My new solution is almost as powerful, and much more simpler to design and produce. 

(to be continued)


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## davebender (Dec 25, 2009)

*Fw-190F3/R3.* Based on the Fw-190A6 airframe. This was a dedicated tank buster.
WW2 Warbirds: the Focke-Wulf Fw 190 Wrger (Shrike) - Frans Bonn
2 x 3cm Mk103 cannons.

*Mk103 cannon.*
MK 103 cannon - Wikipedia, the free encyclopedia
Armour penetration: AP-T(WC) 70 mm /60°/300 m or 100 mm /90°/300 m 
Rate of fire: 380 (HE/M) to 420 (AP) rounds/min

*T-34 Tank.*
T-34 - Wikipedia, the free encyclopedia
Armor 52 mm

A Fw-190F armed with Mk103 cannons will turn a T-34 tank into Swiss cheese. It's superior in almost every way to both the Ju-87G and Hs-129. It was possibly the best all around CAS aircraft produced by anyone during WWII. Germany just needs more of them plus an adequate supply of aviation gasoline.


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## Clay_Allison (Dec 25, 2009)

davebender said:


> *Fw-190F3/R3.* Based on the Fw-190A6 airframe. This was a dedicated tank buster.
> WW2 Warbirds: the Focke-Wulf Fw 190 Wrger (Shrike) - Frans Bonn
> 2 x 3cm Mk103 cannons.
> 
> ...



Besides AVGas you'll need more tungten for the ammo.


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## Burmese Bandit (Dec 26, 2009)

From "Flying guns" by Tony Williams:

There were various possible locations for heavy cannon, but they all boiled down to two basic types - wing or fuselage mountings. Wing mountings had several disadvantages. First, they suffered the usual problems with this location of harmonisation; that is, the guns had to be angled inwards to coincide with the sight line, and this could only be for a specified distance. At much shorter or longer distances, the projectiles would not strike where the sights were aimed.

Incidentally, it is worth mentioning that with all guns, wherever mounted, there was also a vertical harmonisation issue, in that projectiles followed a curved trajectory so at much shorter or longer distances they would strike above or below the aiming point. However, this would be much less of a problem with a high muzzle velocity. Other disadvantages of wing mounting peculiar to heavy cannon were, obviously, that the weight and drag penalties were much greater than with one fuselage-mounted gun, the wings were more flexible not just in flight but also under recoil (which affected accuracy) and the plane could be moved from side-to-side by the recoil if the guns fired at different instants, further affecting accuracy. 
The guns were also mounted under the plane's centre of gravity, which meant that recoil pushed the nose down on firing. 

All of this added up to less accuracy and lower aircraft performance with wing-mounted cannon. This is significant because most single-engined aircraft fitted with large cannon had no option but to fit them under the wings, as few vee-engines, and no radials, were compatible with the engine-mounting of the gun. In theory, a gun could be mounted under the belly of the plane and synchronised to fire through the propeller disk, but in practice this became more problematic as the size of the cartridge case increased because of the variations in the burning time of the propellant *(the Luftwaffe considered but rejected such an installation of the MK 103 in the Fw 190 for this reason).*
Of course, none of these problems bothered twin-engined aircraft, which were able to employ a rigid central mounting in or under the fuselage, directly under the sights, to the great benefit of accuracy. They also usually had a much better forwards and downwards view (important for a ground attack plane), although blocked to the side by the engines. 


From Wikipedia:

Il-2 with NS-37 
Referred in west as "Il-2 Type 3M". Based on two seat Il-2, armed with Nudelman-Suranov NS-37 instead of 20/23 mm cannons, this version is an approach to anti-tank airplane, prepared for the Battle of Kursk. *However, combat effectiveness was quite low and production of version was limited to about 3,500.* Moreover, bomb load decreased from 600 kg to 200 kg. It was replaced by conventional Il-2 attackers armed with cassettes with cumulative bomblets. 


That's why your idea wouldn't work, Dave. It was tried IRL by both the Germans and the Soviets, and both found out through bitter battlefield experience that wing mounted heavy guns simply were not effective because they shot all over the place.

So how did Rudel kill hundreds of tanks? He fired single shots. And corrected his aim after every shot - not that he needed to do that often, since he had the nerve to get down to point blank range before shooting. 

And apart from that...look at the critical shortage of tungsten and molybedenum in the late years of the war. No, the way to go is vanilla hard steel armour piercing bullets. 

(to be continued)


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## Clay_Allison (Dec 26, 2009)

Could a Bf 110 carry the BK 3.7?


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## tomo pauk (Dec 26, 2009)

No reason why not - Beaufighter was tried (successfully) with 2 x 40mm Bofors. So the single 3,7 would've worked without trouble. There was a twin 30mm (MK 103) instalation that Bf-110 carried under belly too.


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## riacrato (Dec 26, 2009)

It could, but the installation was not considered very successful iirc.


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## davebender (Dec 26, 2009)

Then use R4M rockets with HEAT warheads. No critical resources are required. Even a Me-109G6 can kill tanks (and heavy bombers too!) using this weapons system.


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## Burmese Bandit (Dec 27, 2009)

And now, my idea for a ground attack aircraft of the Luftwaffe. 

It is the FW 189...*but instead of the 3 man central gondola of the 189, it has a slightly enlarged version of the Hs 129 armoured cabin, and a third Argus As Engine in a pusher confguration behind the pilot. I will call it the " FW 289 ". *
Why would this design be perfect for tank killing in 1943?

1. The base design for the FW 289, the 189, was already flying in July 1938, which was a full 12 months ahead of the historical Hs 129. This meant that if our 289 with a third engine was designed at the same time, it could have been in service a full 12 months sooner.

2. There was already a production line for the 189. Many components - the twin booms, the wings - would have been common to it and our 289.

3. The weight of the armour made the historical 129 underpowered in the beginning. It was only when the two 700 hp Gnome Rhone engines were fitted for a total of 1400 hp that adequate performance was achieved. Three As 410s in early part of war = 465 x 3, = 1395hp. Later in the war 600 hp As 411s can be fitted for a total of 1800 hp.

4. Unlike the Gnone Rhone, which gained a battlefield reputation for being sensitive to dust and bullets, the Argus As series gained nothing but praise in both areas during WW II.

5. The rear pusher engine protects the pilot from rear attack. Not even 20mm armour piercing bullets will go through an engine AND rear armour. 

6. The twin boom installation makes for an extremely robust aircraft. During WWII the Fw 189 was one of the most survivable planes on the battlefield. Even Ramming attacks by Desperate Russian aircraft were survived!

7. There is a free centerline position for guns and bombs...historically, the Mk 103 in a pod was carried by the Hs 129. In the early part of 1943 I propose this for the armament. Later in 1943 when the 600 hp As 411 becomes available, I propose the BK 3.7 be mounted. If no centerline gun pod, 500 kg of bombs can be carried there, increasing to 1,000 kg in late models. 

8. Note that with three engines, we have the possibility of a 'loiter capability' where one or two of the three engines can be switched off and the airplane cruise around slowly over the battlefield. And three engines means that even if enemy fire knocks out two of the three engines, and the plane is at low level, still the plane can still stagger back about 5-15 kilometers back towards the safety of its own lines before it falls to the ground. 

For production, I propose first flight in December 1938, and from mid 1940 onwards production to Ground attack planes to be split equally between the Stuka and the 289. From 1943 onwards all ground attack planes to be 289s only.


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## Clay_Allison (Dec 27, 2009)

davebender said:


> Then use R4M rockets with HEAT warheads. No critical resources are required. Even a Me-109G6 can kill tanks (and heavy bombers too!) using this weapons system.


You have to have a real pair of balls to hold your fire down to breath-smelling range, which is what you'd have to do to hit with bloody unguided rockets.


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## davebender (Dec 27, 2009)

R4M rocket - Wikipedia, the free encyclopedia
The R4M was the world's first effective folding fin rocket. It's not like the previous clunkers used by Britain, Germany and the USA.


> R4Ms were usually fired in four salvos of six missiles at intervals of 0.07 seconds from a range of 600 m. Two warheads were available for the R4M, the common PB-3 with a 0.4 kg charge for anti-aircraft use and the larger shaped charge, similar in construction to the Panzerschreck, the Panzerblitz II (PB-2), for anti-tank use



So....
You approach the target and fire all 24 rockets in less then 5 seconds from a range of 600 meters. The law of averages suggest you are going to hit something.

A crazy man like Bronc will then charge in to finish the job with cannon fire. As for me, I firewall the throttle and head back to the airfield for another load of rockets. 8)


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## Vraciu (Dec 3, 2010)

Hi guys,
an idea came to me today to make a fighter for the Japanese which would combine best abilities of such aircraft like Ki-61/Ki-100, Ki-84, J2M and N1K2-J. Main fuselage of three sections like Ki-84 in order to simplify production process. I want to adopt engine cowling from Raiden for Homare engine (it would lead to make some changes in NK9A, but I think that it's worth it - aerodynamics). Then, center section from Shiden-kai, canopy from Hayate. Third section of fuselage: combined Ki-84 and Ki-61 (just bottom from the latter). Wings from Shiden-kai, maybe a bit longer. Armament of 4x20 mm Ho-5 cannons (2 per each wing) or 2x20 mm Ho-5 and 2x30 mm Ho-155 cannons. Engine, as said before - NK9 Homare, maybe version for J2M's cowling would be called Model 32. I hope, if engineers would do their job properly, it will produce 2,200-2,300 hp. It would be good to equip it with supercharger but to be honest I don't know if there was such possibility for Homare or even for any engine in Japan AD 1944/45. Propeller with design from Raiden but adjusted for Homare performance. Cockpit with center from N1K2-J and sides from Hien (design of course, controls adjusted for other kind of aircraft and other kind of engine), seat from Hien. Radio equipment - Type 4 Hi Model 3, as I know it's the best Japanese aircraft radio of WW2. Type 4 gunsight (God, I would like to have an AceMaker Japanese equivalent, but...). Undercarriage from Ki-61/Ki-100 (u/c of remaining trio caused problems for non-experienced pilots). Ability to get one droppable fuel tank under fuselage (for 300 l of fuel) and two under wings (one per wing, 200 l each). With three additional tanks and, I hope, ca. 700 l in internal tanks, the maximum range would be even about 3,000 km. Instead of fuel tanks ability to get some bombs, of course (2x250 or 3x100 I think). So, and that's it. Any ideas to improve the project? I will start making some drawing soon.

Regards from Poland,
Chris


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## Vraciu (Dec 5, 2010)

Well, I'm thinking now about changing the engine to NK11 or MK10 (about 2,500 hp each one). And about A7M3-J. 

Regards


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## Vraciu (Jan 8, 2011)

Here it is, some changes made:
powerplant is MK9D, undercarriage is from A7M3-J, tailwheel from Ki-84, behind tailwheel is tailhook for carrier landings, wings are combined N1K2-J's and Ki-100's and folded like F6F's ones (Japanese had one F6F so they could copy it).

Length is 11,78 m, 
Wingspan - 15,12 m.







Regards from Poland,
Chris


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## davebender (Jan 8, 2011)

Japan, Germany and Italy all made great fighter airframes. Give them adequate quantities of good aircraft engines (plus fuel!) and they have everything necessary for a superior aircraft.

In the case of Japan they need a reliable copy of the 1,350hp DB601E V12 in mass production NLT January 1942 to power the Ki-61 IJA fighter. That would give 1942 Japan the best fighter aircraft in the Pacific and one of the finest in the world.


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## Vraciu (Jan 8, 2011)

Yes, but servicing liquid-cooled engines in jungle was a serious problem for Japanese. Allied mechanics were accustomed for them and Japanese were not. That's why Japanese preferred radial, air-cooled engines.


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## davebender (Jan 8, 2011)

> servicing liquid-cooled engines in jungle was a serious problem for Japanese.


If Japan produces enough DB601 aircraft engines then it's not an issue. Worn out engines get replaced and shipped back to the factory for rebuild rather then trying to overhaul engines at front line airfields. That's what the WWII era Luftwaffe did and I think most air forces operate that way in the modern world.


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## Shortround6 (Jan 8, 2011)

davebender said:


> If Japan produces enough DB601 aircraft engines then it's not an issue. Worn out engines get replaced and shipped back to the factory for rebuild rather then trying to overhaul engines at front line airfields. That's what the WWII era Luftwaffe did and I think most air forces operate that way in the modern world.



It is one thing in the modern world and another thing in WW II.
While the engines may not have been overhauled at front line fields the allies certainly used regional depots to over haul engines. Engine repair shops in Cairo overhauled engines for the Mediterranean theater. I am sure that the 8th and 9th Air forces over hauled engines in England rather than ship them back and forth to the US. Pacific theater probably also had overhaul facilities.
The Japanese may have established regional depots/shops also. It is not like they can drive the engines in a truck to a local rail line and get get them to the factory in a couple of days and get replacement engines the same way like a Continental power could. It is either fly the engines 1,2, or 3 at time using scarce transport aircraft or use ships taking weeks to get back and forth. while there are replacement engines available engines sitting in freighter holds don't do anybody any good. 
Shipping bearing, ring and gasket sets is a whole lot easier than shipping complete engines. Throw in a few connecting rod/piston sets, some valves and valve springs and few other parts and you can cover a fair amount of over haul needs. 
The British gave the US 600 Merlins as both complete engines and for breaking down for parts for engine replacement-parts for repair and overhaul for Merlin powered P-40s in North Africa. I doubt that they sent the 600 engines to the United States to be Broken down.
Even in the 1950-60s the US and Nato were working to to overhaul engines in Europe. German and Italian companies were contracted to repair/overhaul jet engines rather than ship them back to the US for overhaul. I believe at least one Japanese company got similar contracts. In some cases this repair/overhaul work lead to licence manufacture of parts if not complete engines. 

Sometimes licence manufacture is not all that easy. A country has to have all the parts suppliers in line and up to spec for it to work. Some engine companies did not make their own bearings but bought them from specialty companies (Allison's profitable part of the business during the 1930s).
Bristol was actually dependent on Swedish roller bearings for the Hercules engine for much of WW II.


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## renrich (Jan 9, 2011)

Here is a simple and easily done way to come up with a great fighter design for WW2. You take what is arguably the best all around fighter of the war anyway, the F4U. You redesign the structure so that the wing and fuselage section does not have to carry the loads of a carrier landing. Likewise the landing gear. The aft fuselage is lightened because it does not have the carry through of the shock of the tail hook catching the wire. All of this saves weight. You delete the anti corrosion treatments necessary for duty at sea. You leave in the two internal wing tanks which gives you an internal fuel capacity of 361 gallons. You delete the right wing leading edge spoiler that evens the stall characteristics and the plane can turn tighter. That spoiler is not needed for land based duty. You use automatic blower controls instead of manual to lighten the pilot load. If you want more armament you go with the two 20mms and four 50 cals like some of the Hellcats had.

You wind up with a long range, even better maneuvering, heavily armed, fast and fast climbing, rugged fighter that can do almost any job.


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## johnbr (Jan 9, 2011)

What the Ki 61 need was 605 with a two stage supercharger.


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## cocky pilot (Jan 9, 2011)

I dont know the technical details yet but I have an anglo american design team called the hindsight committe working on it and we have already come up with the names.

Production would be carried out by Supermarine Westland and Vickers in UK and Curtiss Douglas and Northrop in the US

Naming is as follows for all planes

Supermarine shudabin
Westland wudabin
Vickers Virtually
Curtiss Couldabin
Mitchell Mightabin
Northrop Neighon


Fighters will have the suffix Unbeatable and Bombers suffixed Unstoppable

At present my favourites are the Supermarine Shudabin Unbeatable Mk 4 (jet powered to mach .9 with six cannon)and the Northrop Neighon Unstoppable Mk2 cruising at 60,000ft with 10 ton bomb load.


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## koivis (Jan 9, 2011)

Vraciu said:


> It would be good to equip it with supercharger but to be honest I don't know if there was such possibility for Homare or even for any engine in Japan AD 1944/45.



Every single aircraft engine producing over 1000 hp had a supercharger in WW2. Every one of them. What you are probably meaning is a _turbo_supercharger.



johnbr said:


> What the Ki 61 need was 605 with a two stage supercharger.



What the DB 605 did not need was a two stage supercharger. It already had a _variable-speed_ supercharger, driven through a barometrically controlled clutch.


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## Vraciu (Jan 9, 2011)

koivis said:


> What you are probably meaning is a turbosupercharger.



You're probably right. Sorry for my English. In Polish turbosupercharger is in fact "turbosprezarka" but I thought that "sprezarka" is simply charger.

BTW I have another idea of never-were aircraft - medium bomber for RAF, a slightly bigger Canberra with 2 Centauruses.

Regards


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## cocky pilot (Jan 9, 2011)

Vraciu said:


> You're probably right. Sorry for my English. In Polish turbosupercharger is in fact "turbosprezarka" but I thought that "sprezarka" is simply charger.
> BTW I have another idea of never-were aircraft - medium bomber for RAF, a slightly bigger Canberra with 2 Centauruses.
> Regards



In the UK a supercharger is driven from the engine and a Turbocharger driven from the exhaust. As with all things it is easy to say and not so easy to do.

There is a difference between two stage and two speed, heres some wiki info on the merlin.
__________________________________________________________________________________________________________________________
Central to the success of the Merlin was the supercharger. A.C. Lovesey, an engineer who was a key figure in the design of the Merlin, delivered a lecture on the development of the Merlin in 1946; in this extract he explained the importance of the supercharger:

"Coming now to specific development items we can ... divide them into three general classes:

Improvement of the supercharger. 
Improved fuels. 
Development of mechanical features to take care of the improvements afforded by (1) and (2). 
Dealing with (1) it can be said that the supercharger determines the capacity, or ... the output, of the engine. The impression still prevails that the static capacity known as the swept volume is the basis of comparison of the possible power output for different types of engine, but this is not the case because the output of the engine depends solely on the mass of air it can be made to consume efficiently, and in this respect the supercharger plays the most important role ... the engine has to be capable of dealing with the greater mass flows with respect to cooling, freedom from detonation and capable of withstanding high gas and inertia loads ... During the course of research and development on superchargers it became apparent to us that any further increase in the altitude performance of the Merlin engine necessitated the employment of a two-stage supercharger."[26]
As the Merlin evolved so too did the supercharger; the latter fitting into three broad categories:[27]

Single-stage, single-speed gearbox: Merlin I to III, XII, 30, 40, and 50 series (1937–1942).[nb 3] 
Single-stage, two-speed gearbox: experimental Merlin X (1938), production Merlin XX (1940–1945). 
Two-stage, two-speed gearbox with intercooler: mainly Merlin 60, 70, and 80 series (1942–1946). 
The Merlin supercharger was originally designed to allow the engine to generate maximum power at an altitude of about 16,000 feet (5,000 m). In 1938 Stanley Hooker, an Oxford graduate in applied mathematics, explained "... I soon became very familiar with the construction of the Merlin supercharger and carburettor ... Since the supercharger was at the rear of the engine it had come in for pretty severe design treatment, and the air intake duct to the impeller looked very squashed ..." Tests conducted by Hooker showed the original intake design was inefficient, limiting the performance of the supercharger.[28][nb 4] Hooker subsequently designed a new air intake duct with improved flow characteristics which increased maximum power at a higher altitude of over 19,000 feet (5,800 m); and also improved the design of both the impeller, and the diffuser which controlled the airflow to it. These modifications led to the development of the single-stage Merlin XX and 45 series.[29]

A significant advance in supercharger design was the incorporation in 1938 of a two-speed drive (designed by the French company Farman) to the impeller of the Merlin X.[30][nb 5] The later Merlin XX incorporated the two-speed drive as well as several improvements that enabled the production rate of Merlins to be increased.[32] The low-ratio gear, which operated from take-off to an altitude of 10,000 feet (3,050 m), drove the impeller at 21,597 rpm and developed 1,240 horsepower (925 kW) at that height; while the high gear's (25,148 rpm) power rating was 1,175 horsepower (876 kW) at 18,000 feet (5,490 m). These figures were achieved at 2,850 rpm engine speed using +9 pounds per square inch (1.66 atm) boost.[33]

In 1940 Rolls-Royce considered adapting the Merlin to use an exhaust-driven turbocharger to increase the power of the Merlin. Although a lower fuel consumption was an advantage, the turbocharger was rejected in favour of a two-stage supercharger.[34] The basic design, first tested in September 1941, used a modified Vulture supercharger for the first stage while a Merlin 46 supercharger was used for the second.[35] A liquid-cooled intercooler on top of the supercharger casing was used to prevent the compressed air/fuel mixture from becoming too hot.[nb 6] Fitted with the two-stage two-speed supercharger, the Merlin 60 series gained 300 horsepower (224 kW) at 30,000 feet (9,144 m) over the Merlin 45 series,[35] at which altitude a Spitfire IX was nearly 70 miles per hour (113 km/h) faster than a Spitfire V.[36]


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## Shortround6 (Jan 9, 2011)

koivis said:


> What the DB 605 did not need was a two stage supercharger. It already had a _variable-speed_ supercharger, driven through a barometrically controlled clutch.



This seems to be one of the more common/persistent myths.

The _variable-speed_ supercharger drive replaced the 2 speed drive used on a number of other engines but the _variable-speed_ supercharger drive could do _nothing_ to improve/change the actual pressure ratio of the supercharger itself. 

DB 605's used a higher compression ratio than allied engines and so could not use as much boost as allied engines without detonation. DB 605's, with their larger displacement didn't need as much boost to make their rated power. 

The DB 605A was compressing the surrounding air just under 3 times at 5700meters for it's 1.42 ata rating. Power fell off above this height.

The Merlin 61 at 23,500ft was compressing the surrounding air just over 5 times to make its rated power at 15lbs of boost which is close enough to 2.0 ata to make no real difference to this discussion. At the time no single stage compressor could get anywere near a 5:1 pressure ratio no matter how it was driven.


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## davebender (Jan 10, 2011)

I agree. 

If Japan wants the Ki-61 program to be successful they must sink some serious money into facilities for manufacture of the DB601 engine and it's sub-components. Otherwise they are wasting their time. The same goes for Italy if they want the DB601 / DB605 engine for their Macchi C.202 fighter aircraft.


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## billswagger (Jan 11, 2011)

I'm not sure how outrageous this concept would be, but how about a variable gear ratio for the reduction gearing. 
Perhaps something that works like an actual transmission?
I'm not sure of the benefits of such a concept anyhow.

Other than that, i would expand on a more stream line 109, removing the wing radiators and developing a rear section similar to the mustang's.


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## tomo pauk (Jan 11, 2011)

Bf-109G-2 "a better warbird": 
Bf-109F-4 hull, MGs deleted, plugs between wings and hull containing cannons (added benefit would've been better undercarriage layout), wings without rounded wingtips so span would almost the same, but the wing area slightly increased, new fuel tank instead of hull MGs and their ammo.


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## Vraciu (Jan 11, 2011)

I made somewhat similar project about two years ago, but I have taken Bf 109G-14 as basic structure. Here you go:




Powered by DB 605ASM, armed with 1 MK108 and two or four MG151/20s, it has normal undercarriage (assembled inwards like Fw 190's, unlike Spitfire's or original 109's) and canopy which provides better visibility (it comes from Fw 190). Lenght is 9,55 m.

And here is our "Ultimate Axis Fighter" which I made today. 




Powered by DB603, armed with 5 MG151/20s, fuselage is combined Bf 109G-14/G.55/Ki-61/Ki-84/my A8K/N1K2-J, wings are my original project (they have combat flaps), undercarriage comes from G.55, canopy from Ki-84, as cockpit is, but I equipped it with Kommandogerat. German radio equipment and gunsight. 
Lenght is 10,22 m.

And here are plans I reffered to during work:
Ki-61




G.55




N1K2-J (from Z.J. Krala book "Kampanie powietrzne II wojny światowej. Daleki Wschód cz. VIII")




Bf 109G-14 (from K. Janowicz book "Bf 109G/K vol. II")




Ki-84 (from K. Zalewski book "Samolot myśliwski Nakajima Ki-84 Hayate Frank")





Regards


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## cherry blossom (Jan 11, 2011)

davebender said:


> I agree.
> 
> If Japan wants the Ki-61 program to be successful they must sink some serious money into facilities for manufacture of the DB601 engine and it's sub-components. ...


There were several major problems for the Japanese in building an engine based on the DB 601. 
Firstly, they had not previously used an aero-engine with roller bearings. The roller bearings came from DB's history of designing engines for motor racing and are better for going suddenly to full power from idle at a race start. However, late DB 605s went to shell bearings for ease of manufacture. The problem was that Japanese crankshaft pins could not survive the distortions caused by the roller bearings as they rotated. There is a photograph (Photo 38-3) of the wear in "The Romance of Engines" by Takashi Suzuki. He notes “On the otherhand, when observing the structure of the carburized area, the German Benz crankshaft has a neat Martensite structure (indicating satisfactory quenching). The Japanese engine crankshaft shows precipitation of troostite, which indicates inadequate quenching (Photo A38-2).”
Secondly, although the Japanese had obtained two licences to build the DB 601 (Army and Navy separately), Bosch had refused to supply tools to build the fuel injectors. Thus Japanese fuel systems were either frequently defective (from Kawasaki for the Army Ha 40) or hand built and rare (from Mitsubishi for the Navy).
Thirdly, as noted by Dave, the design of the DB 601Aa was copied rather than the redesigned DB 601E with repositioned plugs and changed valve timing to allow 2800 rpm.
Finally, what if the Japanese had copied a Mustang radiator for the Ki-61 (assuming skilled espionage)?


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## davebender (Jan 11, 2011)

> several major problems for the Japanese in building an engine based on the DB 601.


I agree. So Japan must count the cost before choosing this option. Building a poor copy of the DB601 engine is simply a waste of money.

On the other hand....
The DB601 / DB605 was an excellent WWII era aircraft engine. If Japan spends the money to produce a reliable copy it could power more aircraft models then just the Ki-61.


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## Zeke_Freak (Jan 13, 2011)

Interesting thread. There's obviously some very knowledgable people here, well versed in aircraft specifications and performance. I doubt I could design a 'better' aircraft (in quotes because 'better' could be defined different ways). But I do like the canard style designs that appeared later on, like the Kyūshū J7W1 Shinden.

But I would challenge the idea that having a better performing aircraft was all that was important. Yes, aircraft design certainly was important. But personally, I think some of the biggest factors in any WWII aircraft design weren't about the performance of the aircraft alone, but the overall cost, component availability, build time, and the tactical philosophy behind the design. It wasn't always about having the best aircraft, but more that the aircraft was easily produced, reasonably protected the crew, and met a critical need. A great example being the Hawker Hurricane. In my opinion, many could easily design a better performing aircraft, but I doubt very few could have designed an aircraft that better met the needs of the RAF at that time.

The Japanese had some wonderful aircraft, that met their tactical philosphy. But their philosophy was inferior. They didn't protect their pilots well. They fought in a 'lone warrior' style reminiscent of samurai, instead of emphasizing team work. They used their most skilled pilots in action instead of pulling them back to use their expertise in training new pilots. The Americans did exact the opposite, and the difference showed.

Leif


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## cherry blossom (Jan 13, 2011)

davebender said:


> I agree. So Japan must count the cost before choosing this option. Building a poor copy of the DB601 engine is simply a waste of money.
> 
> On the other hand....
> The DB601 / DB605 was an excellent WWII era aircraft engine. If Japan spends the money to produce a reliable copy it could power more aircraft models then just the Ki-61.


I hope that we are not hijacking this thread and turning it into a history of Axis failure to cooperate. Searching the internet seems to find many versions of “In March 1938, Kawasaki signed an agreement with Daimler-Benz of Germany for obtain manufacturing rights to the liquid-cooled inline engines then under development by the German firm. In April 1940, a Kawasaki engineering team visited Daimler-Benz in Stuttgart to obtain plans and samples of the DB 601A engine, then being used in the Me-109” which is taken from Kawasaki Ki 61 Tony. The question is why did they waste two years? I suspect that one problem would have been how the Japanese were going to pay the Germans. Japan had little foreign currency and neither had fully convertible currencies. Thus they probably had to negotiate a barter deal possibly involving soy beans from Manchuria. The other issue would have been futile negotiations over the fuel injection system and perhaps also the electrical equipment. All the prototypes of the Ki-60 were powered by imported DB-601 engines and those of the Navy's D4Y by imported DB-600 engines. The prototype of the Ki-61 in December 1941 may have been the first real use of a Japanese built engine. There would have been two consequences from the delay in producing the engines. Firstly, without engines there was little pressure to rush aircraft development. This did have some good consequences as three He-100s arrived in Japan and some ideas were incorporated in the Ki-61's structure. Secondly, without running Japanese built engines, it was impossible to find the problems such as those involving the crankshaft pin. Had a Ha-40 been available for a prototype in December 1939, it seems likely that testing would have led to a design with shell bearings for 1941 production which would have been much more reliable.

Clearly other German developments could have been incorporated. I am not sure when the DB 601E influenced the development of Japanese engines. As a DB 605 was delivered to Japan, it should have influenced the Ha-140 at least. The Ki-61's radiator design could have been improved if Günther Bock's lecture boundary layer | transition point | drag coefficient | 1942 | 0665 | Flight Archive had been passed to Kawasaki. Perhaps, it was necessary to combine the oil and coolant radiators to actually generate useful thrust?


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## davebender (Jan 13, 2011)

I think this is the crux of the problem.

Prior to the start of WWII in Europe Japan could import production tooling and technical experts from Germany. That must happen before September 1939 if Japan is to have a reliable copy of the DB601 engine. Otherwise Japan should forget the entire project.


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## Shortround6 (Jan 13, 2011)

Does some one want to tell us WHEN the DB601 was demonstrated to be a RELIABLE mass production engine?
As a known quantity rather than predictions or promises.
How many months do the Japanese have to make up their minds and considering their options ( how many PROVEN liquid cooled V-12s were there in the world in 1938/39?) I think it was more a case of take what they could get and hope it worked out. 
Considering the trouble with early Merlins, Vultures, Peregrines, Griffions, Bristol sleeve valve engines, the Napair Sabre, it took a lot of faith in many cases to sign onto a new engine. Sometimes it worked and sometimes it didn't.
If the Japanese could see into the future well enough to predict that they couldn't build the DB 601 then they should be able to see that they couldn't win the war either.


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## Vraciu (Jan 15, 2011)

I made some changes in Me 155E:






And I made a fighter-bomber/recce/night fighter a/c for the Axis:




It's powered by 2 DB603's, radiator air intake is like in Mosquito (in the wing):




Armament is 6xMG 151/20s




and 4 SC500 bombs.




Canopy is based on He 219:




Tail section and aerodynamical concept comes from Ki-83:










Regards


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## drgondog (Jan 15, 2011)

In every case of airframe design, the proposals that ended up as production fighters served a purpose aligned to the national 'mission' and belief systems regarding tactics and applications of airpower.

Had the design criteria for Germany been for an air superiority fighter capable of escort to say 400 mile radius in 1935, the Me 109 would not have been the choice, nor would such capability of performance and range been considered practical with a single engine fighter with the aerodynamics and engines of the day. The Fw 189 may have had a different historical perspective

Had the Japanese doctrine been built around strategic bombing in daylight at high altitude, the design of the Zero would have been compromised to achieve high altitude performance with an engine not yet on their drawing boards... or relegated entirely to the naval version to support air superiority and escort at medium altitudes for both land based and carrier based aircraft.

Was the Mustang a lucky accident, a combination of the excellent aerodynamics of both airframe and wing, along with a predisposition for placing ALL of its fuel in the wings? But even if it had been originally designed with the Merlin instead of Allison, would the USAAF been overwhelmed with its capability given the belief by Arnold, Eaker, Spaatz, etc that the B-17 and B-24 did not need long range escort?

The DB601-605 and the Merlin were the only two in-line designs available in 1938-1943 with both the foundation and growth potential to surround with a high performance, light weight, airframe for a single engine fighter... capable of 0-35K high performance.

The wonderful radials required turbo-supercharging and the fuel and materials to match the above two in-lines above 20K - at a consequential penalty in drag and weight - to mate the engine and supercharger to the airframe, until the very late dash numbers of the R-2800 and BMW801s became available.

So every discussion regarding 'improvement' usually focus on some engine swap for an existing airframe. The discussions I have seen that venture to airframe mods with same basic engine packages (like a 'twin' Me 109) usually ignore the delicate trade offs between additional airframe weights and increased drag to a potential performance gain without specifying why the modification is made? 

If you re-arrange a wing to take more fuel, you basically redesign a wing from scratch, increase the structural weight to accomodate the fuel cells, decrease performance for same power.

If you add fuel to the fuselage you frequently must change the dimensions (and weight) and re-arrange relationships between epennage and wing to account for stability issues.

If you dramatically increase horsepower, re: existing structure - particularly the rudder size and aft fuselage carry through structure needs to be beefed up - or manuever limits imposed (a la Mustang P-51B/D) 

Everytime you add metal to the solution, you increase drag. Everytime you add fuel you lose certain intrinsic manuever performance. One of the great airframes (the Mustang) did Not improve handling qualities as it morphed - until it was basically re-designed from the ground up to lengthen the tail to aero center of lift, shift fuel tank capacitites, and lighten the airframe back to nearly the P-51A weights.


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## cherry blossom (Jan 15, 2011)

Shortround6 said:


> Does some one want to tell us WHEN the DB601 was demonstrated to be a RELIABLE mass production engine?
> As a known quantity rather than predictions or promises.
> How many months do the Japanese have to make up their minds and considering their options ( how many PROVEN liquid cooled V-12s were there in the world in 1938/39?) I think it was more a case of take what they could get and hope it worked out.
> Considering the trouble with early Merlins, Vultures, Peregrines, Griffions, Bristol sleeve valve engines, the Napair Sabre, it took a lot of faith in many cases to sign onto a new engine. Sometimes it worked and sometimes it didn't.
> If the Japanese could see into the future well enough to predict that they couldn't build the DB 601 then they should be able to see that they couldn't win the war either.


Good question!! According to Wikipedia, the DB 601 was first run in 1935, 150 were ordered in February 1937 and production began in November 1937. The source given was in Russian, so that trail went cold for me. Two Bf 109s powered by DB 600s had taken part in an international meeting at Zurich in July 1937 but the Bf 109D in production in 1938 were still powered by Jumo 210s (AFAIK as sources differ). Thus even the DB 600 may not have been available in quantity in 1938 although there seem to have been enough DB 601s to power a range of prototypes (Bf 109s, Bf 110s, Bf-162s and He 111Gs with the last in airline service). However, according to “Aeronautical research in Germany: from Lilienthal until today”, Volume 147, Ernst-Heinrich Hirschel, Horst Prem Gero Madelung (Springer, 2004, ISBN 354040645X) page 212, the DB 601 Re III was supplied to both Messerschmidt and Heinkel in Spring 1938 and gave 1660 hp. Thus, although production of the DB 601 was not exactly racing when Kawasaki signed the initial agreement, it may have been clear that the basic design could survive for 5 minutes under higher load and at faster rpm. It is also quite clear that by early 1939, reliable engines were being mass produced for the Bf 109E. Thus there was at least one wasted year.


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## cherry blossom (Jan 15, 2011)

Shortround6 said:


> ....
> If the Japanese could see into the future well enough to predict that they couldn't build the DB 601 then they should be able to see that they couldn't win the war either.


They should have been able to see that it would be much easier with blueprints and tools for the Bosch components (i.e. the fuel injection and electrical systems).


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## davebender (Jan 15, 2011)

> WHEN the DB601 was demonstrated to be a RELIABLE mass production engine?


During August 1938 DB601 production at Genshagen reached 200 engines per month. So I think the Japanese knew what they were getting when they signed the license agreement.


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## tomo pauk (Jan 20, 2011)

P-51 got accolades for it's merits, with only shortcoming being it was initially powered with engine ill suited for higher altitudes. Let's say that during the talk between Brits and NAA someone proposes installation of Merlin XX 'stead of V-1710 (so P-40 remains Allison-only plane), and the deal is on.
So the RAF tests the Mustang prototype during winter 1940/41, and the brass is stunned that new fighter is considerably faster then beloved Spitfire, even faster than the brand new Mk.V. And that is with pretty low boost settings (10% less power than Mk.V), 20% greater weight and provision for huge fuel load.
As they boosted engine like the one in Hurricane II, another 20 mph were achieved, and climb rate also went up. Sure enough, RAF orders 500 Mustangs, with increased boost, of course. Those started to arrive in late 1941, to be used in mid 1942. Reign of Fw-190s and Bf-109Gs is stopped cold before it started.

But, everybody is not excited that RAF uses 420 mph plane, not even on allied side...


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## tomo pauk (Jan 20, 2011)

The 1st one's are at UK.
People at Supermarine will not allow that easy their bird is out-flown by an imported one, so they decide to take a look at the features of Mustang. After a while, the engineers agree to design a new wing, with enough space for fuel tanks, inward retracting U/C and a pair of cannons. The resulting Spit Mk.VIII really doubles the combat range vs. Mk.V, and it's performance is almost same as of Mustang. 
In order to go one better than the American, they start to test the new two-stage supercharged Merlin with the new airframe. The plane clocks 440 mph, combat ready. Called Mk.IX, it's produced along the Mk.VIII.


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## tomo pauk (Jan 20, 2011)

Sidney Camm looks carefully onto Mustang too. The thing is better performer then his Typhoon. So he too takes a second look at Tiffie, whose prototype is only as fast as Mustang, despite 50% more power. He is angry at himself for going with tick wings for the plane, while beard radiator doesn't look that clean either, so it's back to the drawing board. 
Finally, the new Typhoon prototype is flown in late 1941. It has thinner wings now (but of greater area, so the fuel and ammo are not reduced), and, leading-edge radiators for the powerful Sabre. When Sabre performs as advertised, new Typhoon outperforms the American. When thrown in combat in late 1942, the only thing that can kill Tiffie pilot is his own plane...


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## tomo pauk (Jan 20, 2011)

Some folks back in the USA are not happy either. At Curtiss, for example. Their P-40 is looked as a better Hurricane, not as the competitor in class of Spitfire, 109, or the new plane from NAA. And now, in 1941, that new plane steals their orders. So they set to improve the -40.
Since the Packard Merlin was no available, ditto R-2800, they opted for next one that was - their own R-2600. Armament was 4 HMGs in wings, and dorsal fin was added for increased stability. The resulting plane 1st flies on Dec 6th, 1941. The usage of 'bomber engine' hampers performance above 15K. RAF acquires the plane, using is as a bomber. OTOH, Russians equip their fighter squadrons with it. Australians too.
Curtiss now pushes for true 2-speed supercharged R-2600, so, in late 1942, things improve. With 390 mph at 15K, disadvantage vs. competition is thin, as noted during the Battle of Kursk.


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## Shortround6 (Jan 20, 2011)

tomo pauk said:


> Curtiss now pushes for true 2-speed supercharged R-2600, so, in late 1942, things improve. With 390 mph at 15K, disadvantage vs. competition is thin, as noted during the Battle of Kursk.



2 speed or two stage?

those A-20 and B-25 engines were 2 speed. 

low gear peaked at around 4500ft and high gear at around 12,000ft.


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## tomo pauk (Jan 21, 2011)

Indeed, I was thinking about 2-stage 

Now, let the man with too much spare time continues 

Though not very keen on the new fighter from NAA (since they have two world beaters in the pipeline - P-38 P-47), USAAC did not pass on the opportunity to test the Mustang in fall 1941. While new fighter was slightly slower then P-47 P-38 prototypes (while outclassing the similar-sized P-39 -40), it's rate of climb was better than of those two. 
The best thing for the new fighter was the affordability - almost 2 per each P-38 could be bought, and 3 for each 2 of P-47s. So, after much discussion, USAAC orders Mustang (called now P-51), but it will wait 'till production ramps up. The 1st US squadrons go to combat in early 1943 in MTO, and in summer '43 in ETO. With drop tanks.

Not so fast, say people at Allison, when their product gets expelled from Curtiss. They set to the task of developing a two-speed supercharger set for the V-1710. Engine develops 1400 HP, and it's useful at high altitudes. Taking advantage the Packard Merlins are still in short supply (plus RR gets royalities for each produced), they manage to have it installed in P-51. The new version, P-51B, is in usage from summer 1943.


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## gjs238 (Jan 21, 2011)

Can you put together a similar what-if chain of events for the P-38?
British order initial batch with Merlins as you suggest for P-51.

Go for it!


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## tomo pauk (Jan 21, 2011)

(I'll bite... or not)

Don't think Brits were eager to buy half of fighters with money they had. Plus, having Merlins in quantity in 1941 was not as easy as in, say, 1943 or 44.


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## Shortround6 (Jan 21, 2011)

gjs238 said:


> Can you put together a similar what-if chain of events for the P-38?
> British order initial batch with Merlins as you suggest for P-51.
> 
> Go for it!



For what ever perceived faults the Allison had it got better fuel economy than the Merlin. 
Plus the two stage supercharged Merlin 61 ( or V-1650-3) doesn't show up until mid 1942 and then only handfuls. In fact the 10th two stage V-1650-3 doesn't leave the factory until May of 1943. 
There were three different paper studies of Merlin engined P-38s. In no case was it estimated that the Merlin Version would have a significant performance difference than the turbo Allison. And in some cases whatever speed or climb benefit there was was balanced by an 8-30% loss of range depending on which Merlin was being compared to which Allison.


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## tomo pauk (Jan 22, 2011)

Me thinks the only real problem P-38 had was availability in the time it was located in top 3 fighters of the world, ie. prior 1944. 

Now about alternative engines for P-38...
There is (was) no need for it to wait two-stage Merlins. Single-stage, US-made Merlins were available in some numbers in late 1941, providing 1300-1450 HP, depending on boost applied. So we could expect a performance in late 1942 (squadrons in combat) to be as good as that of historical P-38J (late 1943).
Adding Merlins to the P-38 would've:
- avoided problems caused by British fuel to the turboed Allisons, 
- the absence of turbo intercooler would've enabled more fuel to be carried,
- installation of the engine as a power egg (just like Beaufighter, for example) would've make the cooling system lighter more compact (= less likely to be punctured) and with another gain in space for fuel tanks. 
Perhaps 3 cannon armament for RAF; 5 HMGs for the ones USAAF got?

Another engine that might have been installed in P-38 was Twin Wasp, either as mech-supercharged, or turboed. With turbo, my take is that performance would be as good as of pre-P-38J models - for slightly more drag we cut the weight of cooling system. Again, zero issues with Brittish fuel.
The two-speed two-stage Twin Wasp would offer more simplicity (lower price, more planes...), less weight - if additional fuel tanks are not added in lieu of turbo it's accessories. Above 15K it would be not as good as turboed versions though.
Attack/bomber version (mech Twin Wasp, 2-3 HMGs, in the place of now-deleted turbo, intercooler, coolant system guns ammo we mount fuel tanks) would've been nice - armed Mosquito...


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## davebender (Jan 22, 2011)

Not much point to using that large / heavy / expensive P-38 twin boom airframe unless you need the space for turbochargers. With mechanical superchargers you could employ a lighter and more compact airframe similiar to the Westland Whirlwind.







Speaking of which....
I wonder if the somewhat similiar Fw-187 airframe could have been powered by a pair of 950 hp BMW132 radial engines? Power to weight ratio would be pretty good even with such small engines.


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## Shortround6 (Jan 22, 2011)

tomo pauk said:


> Now about alternative engines for P-38...
> There is (was) no need for it to wait two-stage Merlins. Single-stage, US-made Merlins were available in some numbers in late 1941, providing 1300-1450 HP, depending on boost applied. So we could expect a performance in late 1942 (squadrons in combat) to be as good as that of historical P-38J (late 1943).



That doesn't follow at all. 
1. First P-38F is delivered in March of 1942, First P-38G is delivered in June of 1942.

2. P-38Fs used V-1710-49/53 engines rated for 1325hp for take-off AND at 25,000ft. P-38Gs used V-1710-51/55 engines with the same nominal ratings.

3. The single stage US Merlins were rated at 1300hp for take-off, 1240hp at 11,500ft in low gear and 1120hp at 18,500ft in high gear. Any 'over' boosting that might raise the power only raises the power BELOW those altitudes.

4. Historically, " Merlins were available in some numbers in late 1941" was 45 engines total US production by the end of 1941. Granted production was ramping up fast with 109, 149, 333 and 505 engines built in Jan, Feb, Mar and April respectively. This compares to 6402 Allison's delivered by the end of 1941 and deliveries of 1,101, 1,179, 1,151 and 1,203 for the same four months. 

5. While there were problems with the Allisons in the P-38Fs it had to do with the under sized intercoolers, the engines were down rated for a number of months and WER was never authorized for them (although units like the 8th fighter command used their own limits, 1325hp up to 20,000ft). The engines in the "G" had larger carburetors and other modifications and may never had had restrictions placed on them and may have had a WER rating of 1450hp at sea level. . 

6. The bit about the singe stage Merlin (V-1650-1) powered P-38 offering the Performance of a P-38J is really off the mark. The engines in the P-38J had a take-off and military rating of 1425hp to 24,900ft or better and also had a WER rating of 1600hp up to at least 10,000ft. 




tomo pauk said:


> Another engine that might have been installed in P-38 was Twin Wasp, either as mech-supercharged, or turboed. With turbo, my take is that performance would be as good as of pre-P-38J models - for slightly more drag we cut the weight of cooling system. Again, zero issues with Brittish fuel.
> The two-speed two-stage Twin Wasp would offer more simplicity (lower price, more planes...), less weight - if additional fuel tanks are not added in lieu of turbo it's accessories. Above 15K it would be not as good as turboed versions though.



It is not slightly more drag, it is a lot more drag unless you can move forward the knowledge of engine cooling and cowling by by 1-2 years. 
After the first P-40 was built and flying they figured it had 30%less drag than the P&W powered P-36 by measured flight tests. While Radials git a lot better it wasn't until mid-late 1942 that ALLIED EXPERIMENTAL installations got to where they were about equal to liquid cooled engines. Add in 3-6 months (minimum) to get these designs into production and to the combat units. 
While the aircooled engine does ditch the cooling system (300lbs per engine?) the R-1830 is about 100lbs heavier than the V-1710 so the weight savings is only 200lbs per engine not counting slightly larger cowling and such. Being down anywhere from 0 to 250hp per engine depending on which model of each each you are comparing isn't going to do much for performance when you count in the higher drag. 
Known two stage R-1830 engines seem to be limited to 1200hp for take off and 1040hp/18,400ft or 1000hp /19,000ft depending on source. At any rate it seems it took 150-200hp to run the auxiliary supercharger so even a best case where you get a 1350hp take off R-1350 you are gong to down to 1150hp at just under 20,000ft. The 1350HP R-1830s were about 100lbs heavier than the 1200hp versions though. 1550-1575lbs? for single stage superchargers. Add 100lbs plus for the two stage supercharger. 
I am not seeing any real advantage for the R-1830 here. 

British fuel in P-38s. A throughly bad rap. The components of the fuel were known ahead of time and Allison was working an an improved intake manifold ( the gypsy queen) for ALL Allison engines, not just the turbo ones to solve mixture distribution problems. Eighth Air Force would have had a lot fewer problems if they had flown the P-38s as both Allison and Lockheed wanted them to. Low rpm and high boost would have helped keep intake manifold temperatures up in cruising conditions and prevented fuel puddling in the manifolds and poor mixture distribution. "Hanger talk" had the pilots flying at high rpm and low boost because they thought they could get to military power quicker if bounced. They also would have gotten more range on the same amount of fuel.


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## Shortround6 (Jan 22, 2011)

davebender said:


> Not much point to using that large / heavy / expensive P-38 twin boom airframe unless you need the space for turbochargers. With mechanical superchargers you could employ a lighter and more compact airframe similiar to the Westland Whirlwind.



Only if you use smaller, lighter and less powerful engines.
Don't get me wrong, I really like the Whirlwind but 1100lb/885hp (765hp for take off) engines are not 1450lb/1200hp engines, especially after you fit the bigger propellers and other assorted bits the bigger engine needs. 




davebender said:


> Speaking of which....
> I wonder if the somewhat similiar Fw-187 airframe could have been powered by a pair of 950 hp BMW132 radial engines? Power to weight ratio would be pretty good even with such small engines.



But the drag would have been horrendous. Frontal Area of the BMW 132 was 16 sq ft compared to the Jumo 210's 4.9 sq ft or the DB 601's 5.4. Granted cowling and radiators make up a bit of the difference but the 132 was actually several inches larger in diameter than the 801. 

See Grumman Skyrocket with similar sized engines.


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## davebender (Jan 23, 2011)

XF5F Skyrocket
Grumman XF5F Skyrocket - Wikipedia, the free encyclopedia
2 x R1820 radial engines.
3,677 kg Empty weight. similiar to Fw-187
4,600 kg Loaded weight. once again, similiar to Fw-187
383 mph max speed
4,000 ft / min. rate of climb.

If RLM had provided funding the Fw-187 would have been in mass production by 1940. An aircraft with the above performance plus exceptional endurance (1,100 liters of internal fuel) would have been a world beater during 1940 and would remain competitive through 1942. What's wrong with that?


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## Shortround6 (Jan 23, 2011)

davebender said:


> If RLM had provided funding the Fw-187 would have been in mass production by 1940. An aircraft with the above performance plus exceptional endurance (1,100 liters of internal fuel) would have been a world beater during 1940 and would remain competitive through 1942. What's wrong with that?



Nothing is wrong with that if actually could have been achieved in service.
The F5F had 1200hp engines not 950hp engines, They are similar in size not power. The F5F was plagued with cooling problems which means that performance, if it was actually achieved and not an estimate might not be available in service. The plane was flown in both the short nosed, short nacelle,no spinner form without guns and in the long nose, long nacelle, spinner form with four .50s. I haven't seen yet which form the performance figures are for. 
you also have to believe that this plane with it's 'streamlining' was over 40mph faster than a P-38 at sea level with the P-38 having another 125hp per engine.


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## tomo pauk (Jan 23, 2011)

Glad you do not have any objections vs. idea of P-38 with turboed Twin Wasps 


Shortround6 said:


> That doesn't follow at all.
> 1. First P-38F is delivered in March of 1942, First P-38G is delivered in June of 1942.
> 
> 2. P-38Fs used V-1710-49/53 engines rated for 1325hp for take-off AND at 25,000ft. P-38Gs used V-1710-51/55 engines with the same nominal ratings.



Sorry, the source I've looked (book "P-38 in detail scale") states engine powers at just above 1100 HP for pre-P-38H 



> 3. The single stage US Merlins were rated at 1300hp for take-off, 1240hp at 11,500ft in low gear and 1120hp at 18,500ft in high gear. Any 'over' boosting that might raise the power only raises the power BELOW those altitudes.


 
Of course - some 10% extra power (WER?) at still decent heights.



> 4. Historically, " Merlins were available in some numbers in late 1941" was 45 engines total US production by the end of 1941. Granted production was ramping up fast with 109, 149, 333 and 505 engines built in Jan, Feb, Mar and April respectively. This compares to 6402 Allison's delivered by the end of 1941 and deliveries of 1,101, 1,179, 1,151 and 1,203 for the same four months.



Yep, that's why I don't trumpet very much about Merlined P-38 (contrary to P-51 Merlin): while superb plane on paper, numbers would've been modest compared with Allison engined one. Hence idea for Twin Wasp as alternative: very much feasible in 1941, all-American. 



> 5. While there were problems with the Allisons in the P-38Fs it had to do with the under sized intercoolers, the engines were down rated for a number of months and WER was never authorized for them (although units like the 8th fighter command used their own limits, 1325hp up to 20,000ft). The engines in the "G" had larger carburetors and other modifications and may never had had restrictions placed on them and may have had a WER rating of 1450hp at sea level.



Again, I have nothing against P-38s performance, even more so for pre-J versions 



> 6. The bit about the singe stage Merlin (V-1650-1) powered P-38 offering the Performance of a P-38J is really off the mark. The engines in the P-38J had a take-off and military rating of 1425hp to 24,900ft or better and also had a WER rating of 1600hp up to at least 10,000ft.



Nope - we can take a WER of Merlin XX and then compare it with values of P-38J.




> It is not slightly more drag, it is a lot more drag unless you can move forward the knowledge of engine cooling and cowling by by 1-2 years.
> After the first P-40 was built and flying they figured it had 30%less drag than the P&W powered P-36 by measured flight tests. While Radials git a lot better it wasn't until mid-late 1942 that ALLIED EXPERIMENTAL installations got to where they were about equal to liquid cooled engines. Add in 3-6 months (minimum) to get these designs into production and to the combat units.
> While the aircooled engine does ditch the cooling system (300lbs per engine?) the R-1830 is about 100lbs heavier than the V-1710 so the weight savings is only 200lbs per engine not counting slightly larger cowling and such. Being down anywhere from 0 to 250hp per engine depending on which model of each each you are comparing isn't going to do much for performance when you count in the higher drag.
> Known two stage R-1830 engines seem to be limited to 1200hp for take off and 1040hp/18,400ft or 1000hp /19,000ft depending on source. At any rate it seems it took 150-200hp to run the auxiliary supercharger so even a best case where you get a 1350hp take off R-1350 you are gong to down to 1150hp at just under 20,000ft. The 1350HP R-1830s were about 100lbs heavier than the 1200hp versions though. 1550-1575lbs? for single stage superchargers. Add 100lbs plus for the two stage supercharger.
> I am not seeing any real advantage for the R-1830 here.



The advantage is availability lower cost, as I've stated in prior posting. If we loose 15 mph @ 20K vs. P-38s of 1942, so what. We can have 500 more planes in time allies were hard pressed, balancing out speed loss by a huge margin.



> British fuel in P-38s. A throughly bad rap. The components of the fuel were known ahead of time and Allison was working an an improved intake manifold ( the gypsy queen) for ALL Allison engines, not just the turbo ones to solve mixture distribution problems. Eighth Air Force would have had a lot fewer problems if they had flown the P-38s as both Allison and Lockheed wanted them to. Low rpm and high boost would have helped keep intake manifold temperatures up in cruising conditions and prevented fuel puddling in the manifolds and poor mixture distribution. "Hanger talk" had the pilots flying at high rpm and low boost because they thought they could get to military power quicker if bounced. They also would have gotten more range on the same amount of fuel.



I've read that in a book I've stated above in the post - seems like authoritative


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## davebender (Jan 23, 2011)

4,600kg XF5F loaded weight.
7,000kg P-38 loaded weight (early models).

The P-38 weighs about 50% more while having about 10% more engine power. It could probably beat the F5F in a sustained dive. Otherwise I suspect the F5F would have superior aerial performance.


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## Shortround6 (Jan 23, 2011)

tomo pauk said:


> Sorry, the source I've looked (book "P-38 in detail scale") states engine powers at just above 1100 HP for pre-P-38H



Seems to conflict with "America's Hundred Thousand", "The American Fighter" by Angelucci and Bowers and most importantly "Vee's For Victory" by Danial Whitney, the story of the Allison engine.




tomo pauk said:


> Of course - some 10% extra power (WER?) at still decent heights.



Define decent heights. It took the American's longer to get into the WER thing than the British. But even using British ratings from one book the XX engine gets to 1480hp, quite nice at first glance but that is at 6,000ft in low gear declining to the above mentioned 1240hp at 11,500ft after which the gear change can be made the power goes back up to 1480hp at 12,500ft but declines once again back to the standard 1120hp at 18,500ft. WER only works when the supercharger has 'extra' capacity. It NEVER works above the rated altitude or critical (full throttle hight) height of the engine. 




tomo pauk said:


> Yep, that's why I don't trumpet very much about Merlined P-38 (contrary to P-51 Merlin): while superb plane on paper, numbers would've been modest compared with Allison engined one. Hence idea for Twin Wasp as alternative: very much feasible in 1941, all-American.



It wasn't a superb plane on paper, and numbers would have been even more modest. Of those production numbers I gave 2/3 of the engines went to the British. As far as the win Wasp alternative goes, Something like 96 Two stage Wasps were delivered in 1941. Production per month didn't exceed 20 until June of 1942. Of the 324 F4Fs delivered in 1941 65 were F4F-3As with single stage engines, About 130 Were British Martlet IIs &IIIs, also with single stage engines and there may have been few left over Martlet I with Wright engines. Pratt Whitney was having trouble developing and Building the two stage engine despite the fact that they were cranking out 400-500 single stage engines a month. 



tomo pauk said:


> Nope - we can take a WER of Merlin XX and then compare it with values of P-38J.



See above, 1480hp at 12,500ft doesn't quite equal 1425hp at 25,000ft. 





tomo pauk said:


> The advantage is availability lower cost, as I've stated in prior posting. If we loose 15 mph @ 20K vs. P-38s of 1942, so what. We can have 500 more planes in time allies were hard pressed, balancing out speed loss by a huge margin.



I think the speed loss would be even greater and I don't think it was an engine shortage that held down P-38 production, There is more to aircraft production and tooling up factories than cost per airplane. The US already had a crapload of fighters that could do 360-370mph at 15,000ft, what it didn't have was a fighter that could do 370-400mph at 20-25,000ft. THAT is were the P-38 came in. 




tomo pauk said:


> I've read that in a book I've stated above in the post - seems like authoritative



I could be wrong but I am going by a 11 page article in Volume 1, issue 2 of the 'Torque meter" by Daniel Whitney titled "The Allison Time Bomb" which seems to be a thorough examination of the problem. The 'Torque meter' is/was the journal of the AEHS whose website is here.

AEHS Home


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## Shortround6 (Jan 23, 2011)

davebender said:


> 4,600kg XF5F loaded weight.
> 7,000kg P-38 loaded weight (early models).
> 
> The P-38 weighs about 50% more while having about 10% more engine power. It could probably beat the F5F in a sustained dive. Otherwise I suspect the F5F would have superior aerial performance.



Why would you suspect that?

We can look at the P-36/Curtiss 75 and the early P-40s and see a parallel. 

Curtiss 75A-4 2608Kg loaded 
Curtiss P-40C 3323kg loaded 
27% more weight.

Curtiss 75A-4 1200hp at take off, 1000hp at 14,200ft
Curtiss P-40C 1040hp at take off, 1090hp at 13,200ft. 1040hp at 15,000ft ?
4% more power?

Curtiss 75A-4 323mph at 15,100ft.
Curtiss P-40C 345mph at 15,000ft. 
6% more speed.

Curtiss 75A-4 2820ft/min initial climb.
Curtiss P-40C 2690ft/min initial climb.
4.6% less climb but then the engine in the 75A-4 was rated at 1200hp for 15% more power. 

Not seeing a big improvement here just because of lighter weight. 
I wonder the extra drag of the radial has something to do with it.


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## tomo pauk (Jan 24, 2011)

Shortround6 said:


> Seems to conflict with "America's Hundred Thousand", "The American Fighter" by Angelucci and Bowers and most importantly "Vee's For Victory" by Danial Whitney, the story of the Allison engine.
> 
> Define decent heights. It took the American's longer to get into the WER thing than the British. But even using British ratings from one book the XX engine gets to 1480hp, quite nice at first glance but that is at 6,000ft in low gear declining to the above mentioned 1240hp at 11,500ft after which the gear change can be made the power goes back up to 1480hp at 12,500ft but declines once again back to the standard 1120hp at 18,500ft. WER only works when the supercharger has 'extra' capacity. It NEVER works above the rated altitude or critical (full throttle hight) height of the engine.


 
What power was practically extracted from V-1710s in F G models of P-38, according to those books?




> It wasn't a superb plane on paper, and numbers would have been even more modest. Of those production numbers I gave 2/3 of the engines went to the British. As far as the win Wasp alternative goes, Something like 96 Two stage Wasps were delivered in 1941. Production per month didn't exceed 20 until June of 1942. Of the 324 F4Fs delivered in 1941 65 were F4F-3As with single stage engines, About 130 Were British Martlet IIs &IIIs, also with single stage engines and there may have been few left over Martlet I with Wright engines. Pratt Whitney was having trouble developing and Building the two stage engine despite the fact that they were cranking out 400-500 single stage engines a month.
> 
> See above, 1480hp at 12,500ft doesn't quite equal 1425hp at 25,000ft.



Indeed, they do not equal, so I'd reduce my estimates of Merlinized P-38 to achieve performances somewhere between H and J models, achieveble in late 1942




> I think the speed loss would be even greater and I don't think it was an engine shortage that held down P-38 production, There is more to aircraft production and tooling up factories than cost per airplane. The US already had a crapload of fighters that could do 360-370mph at 15,000ft, what it didn't have was a fighter that could do 370-400mph at 20-25,000ft. THAT is were the P-38 came in.



The mech-supercharged Twin Wasp would've been less complicated to build then turboed one, or turboed Allison version, thereby speeding up preparations for alternative production line. And even if I agree that such a plane would do only 370mph @ 15K, that's still plenty of performance for Japanese fighers to deal with until Hayate or Raiden show in - in 1944. Now before people cut in to say that P-39 and/or P-40 were able to fly as fast, we calculate in range, sturdiness and multi-role capability such P-38 would've possessed, and then draw conclusions. We can take a look at other Allied (and Axis) planes, and have trouble to find a plane that would be better in range-speed-firepower-durability combo such a P-38 would've offer. Spitfire Mk.VIII as only contender, from late 1942 - really shame it wasn't produced in more examples.




> I could be wrong but I am going by a 11 page article in Volume 1, issue 2 of the 'Torque meter" by Daniel Whitney titled "The Allison Time Bomb" which seems to be a thorough examination of the problem. The 'Torque meter' is/was the journal of the AEHS whose website is here.
> 
> AEHS Home



Hmm, so choosing alternative engine configurations would've made such pilot-induced engines less likely to happen. I stand corrected re. Brittish fuel issue


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## Shortround6 (Jan 24, 2011)

tomo pauk said:


> What power was practically extracted from V-1710s in F G models of P-38, according to those books?


There is a bit of conflict so, in the interest of learning with you, I found 'specific engine flight charts' from the flying manuals for the planes in the manual section of this website. This what the Army said the pilots could do.

P-38D-E
1150hp take-off rating could be used at from sea level to 25,000ft. It was also the military power. 5 min time limit. 
1000hp max continuous to 28,000ft. No time limit, could be used until the fuel ran out temperatures permitting but you got short range. 
NO WER

P-38F
1240HP take-off to 21,000ft 5min limit.
1325hp military to 15,000ft 5 min limit.
1000hp max continuous to 28,000ft. 
NO WER 

P-38G
1240hp take off to 21,000ft 5min limit.
1425hp military to 15,000ft 5 min limit
1100hp max continuous to 24,000ft. 
NO WER

When taking off with heavy loads on short runways the pilots were allowed to use the military rating as a WER take off rating. 

The P-38H showed a major improvement.
1425hp take off to 22,000ft 15min limit.
1600HP WER to 10,000ft 5min limit.
1425hp Military rating to 24,900ft 15 min limit.
1100hp max continuous to 34,000ft no limit.

fitting the 'chin' intercoolers to the same engines on the "J"s changed things to:
1425hp take off to 26,600ft 15 min limit.
1600hp WER to 28,700ft 5 min limit.
1425 Military power to 29,000ft 15min limit
1100hp Max continous to 22,800ft no limit.



tomo pauk said:


> Indeed, they do not equal, so I'd reduce my estimates of Merlinized P-38 to achieve performances somewhere between H and J models, achieveble in late 1942


See above, not counting the weight reduction, a Merlin XX powered plane may beat the P-38F at certain altitudes but somewhere above 15,000ft it looses whatever advantage it had. As for equaling a P-38G, that doesn't look likely and any version after the "G" it is no contest. 





tomo pauk said:


> The mech-supercharged Twin Wasp would've been less complicated to build then turboed one, or turboed Allison version, thereby speeding up preparations for alternative production line. And even if I agree that such a plane would do only 370mph @ 15K, that's still plenty of performance for Japanese fighers to deal with until Hayate or Raiden show in - in 1944. Now before people cut in to say that P-39 and/or P-40 were able to fly as fast, we calculate in range, sturdiness and multi-role capability such P-38 would've possessed, and then draw conclusions. We can take a look at other Allied (and Axis) planes, and have trouble to find a plane that would be better in range-speed-firepower-durability combo such a P-38 would've offer. Spitfire Mk.VIII as only contender, from late 1942 - really shame it wasn't produced in more examples.



All you have simplified is the booms, or you have changed problems and gotten rid of the radiators, the two stage Wasps still need intercoolers of some sort. installing heavier engines forward of the CG while pulling radiators from behind the CG is going to take a bit of working on. It is doable but this is not fast or easy with engineers and draftsmen in short supply. And you still need all the tooling, jigs, fixtures and work force for the second production line. 
Allison got about 10% better fuel economy than the Merlin, not sure how the wasp compares but higher drag at cruising speeds isn't going to help either. Yes you may be able to cram enough fuel into the plane to get the range you want. 
Two stage Wasps at the time you want them (lets assume you can get them) have: 
1200hp for take off at 2700rpm
1200hp military at 1800ft at 2700ft
1040hp military at 18400ft at 2550 rpm
1100hp max continous at 3300ft at 2550rpm
1040hp max continous at 13,000ft at 2550rpm
NO WER.
2 stage Wasp weighed about 200lbs more than an Allison so weight savings from losing the radiators and turbos, while there, is not so much as at first glance.
You can trade fuel for turbo weight but you have less power to lift weight from runway once you get to the 'G" model. 

Add you still don't have a plane that could fly "top cover" to prevent enemy planes from diving on your formations from above. 





tomo pauk said:


> Hmm, so choosing alternative engine configurations would've made such pilot-induced engines less likely to happen. I stand corrected re. Brittish fuel issue



That or just better training to begin with


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## tomo pauk (Jan 24, 2011)

I sure can learn from people that have your way of sharing stuff. Thanks 

The main reason I've gotten in thinkering about re-engined P-38 was premise that such a version would've increased availability of the plane, not that it's original performances were lacking - as stated in 1st post re. such P-38.


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## davebender (Jan 24, 2011)

> main reason I've gotten in thinkering about re-engined P-38 was premise that such a version would've increased availability of the plane


If engines are in short supply then the USA should build a new engine plant, which takes about 2 years to become fully operational. The USA had the money and the time.


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## tomo pauk (Jan 24, 2011)

Having hundreds of new planes (with good performance) in 1942 means as much as thousands of new planes in 1944, for Allied cause - hence my turboed mech-supercharged proposals for Twin Wasp in P-38. Very much feasible in 1941/42.


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## Shortround6 (Jan 24, 2011)

tomo pauk said:


> Having hundreds of new planes (with good performance) in 1942 means as much as thousands of new planes in 1944, for Allied cause - hence my turboed mech-supercharged proposals for Twin Wasp in P-38. Very much feasible in 1941/42.



If turbos (actually the turbo controls) are giving problems on the V-1710 engine why do you think the very same turbo from the same company (GE) using the very same turbo control units is going to be trouble free on the R-1830?
The Turbos and turbo controls were NOT quite ready in 1941/42 on any engine.


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## davebender (Jan 24, 2011)

> Turbos and turbo controls were NOT quite ready in 1941/42 on any engine.


I agree. Otherwise the P-40E would be an excellent candidate for a turbocharger.


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## Shortround6 (Jan 24, 2011)

davebender said:


> If engines are in short supply then the USA should build a new engine plant, which takes about 2 years to become fully operational. The USA had the money and the time.



What Money and what time?

in 1938 you had TWO US plants that made large aircraft engines. They were joined by Allison in 1939, if you can call 46 engines large production. Allison went on to build 1178 engines in 1940.

Allison's proposed Plant 3 was 390,000sq ft at it's ground breaking in 1939. It was over 3 million square feet by June of 1943. And a number of General Motors plants were doing major subcontracting. 

P&W quadrupled the size of their factory between 1938 and 1940.
Wright also had massive expansions of floor space. 
The Government gave Ford over 14 million dollars in 1940 to build a new factory to make R-2800s, Packard go the deal to make Merlins in 1940.
neither produced any engines to really speak of until 1942. 
Wright by the middle of 1941 had completed their Cincinnati Plat, the largest aircraft engine plant in the west.
In the spring of 1942 Studebaker, Buick and Chevrolet all started delivering engines from either new factories or from extensively retooled ones. Work on them had started months if before if not in late 1940/early 1941. 
Nash Joined in by the end of 1942. 
All these factories were either under construction or being planed before Pearl Harbor. 
This does not take into account the enormous amount of sub-contracting that went on. For instance that Huge Cincinnati plant was being fed by, the Ohio Crankshaft company (crankshafts), Otis elevator (crankcases), Hudson Motor Car Company ( Pistons and rocker arms), Eaton manufacturing company (propeller shafts) and the Graham-Paige Motors Corporation (Master and articulated connecting rods). 

Many of these aircraft engine factories doubled or tripled their sizes by the time they hit peak production in 1944. For example that Ford factory for the R2800 went from 890,000sq ft planned sq ft for 300 engines per month in the fall of 1940 to a 536,000sq ft addition completed Feb 1 1942 to June 1942 plan of 2,618,000sq ft and planned out put of 1800 engines a month to a Jan 1943 plan of a total of 3,852,000sq ft and a planned 3400 engines a month, this was later scaled back to 3100 engines per month but the factory set a peak production record of 186 engines in one day in July of 1944. 

If you want more engines at the start of 1942 you had better go back to the summer of 1939 to make any real changes. 

Every war related industry was competing for factory space, machine tools, trained workers (or training them themselves) and even raw materials. 
Allison at one point in 1940 when strategic materials were getting hard to come by found a stock of 2,000tons of steel bars of an unusual shape that were considered unusable. Allison bought the bars sent to steel mills to re-rolled and heat treated. This was done before the government froze vital materials and instituted a priority system. This stock of material lasted them into 1942 by which time the Government priority system was working well. 

America was still coming out of the depression. Even if the money spigot opened up there was only so much you could buy because the mines and factories that made the raw materials and machine tools needed time to gear up to the new demands.


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## Shortround6 (Jan 24, 2011)

davebender said:


> I agree. Otherwise the P-40E would be an excellent candidate for a turbocharger.



were would you put it? 

you need somewhere between 10 to 15 cu ft of space for the turbo, the intercooler and ducting. Throw in a few CG problems and the fact that the ducts need to be certain sizes and can't be squashed down to fit some existing space and you might wind up with a rather different aircraft.

Like the XP-60A;


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## tomo pauk (Jan 25, 2011)

Shortround6 said:


> If turbos (actually the turbo controls) are giving problems on the V-1710 engine why do you think the very same turbo from the same company (GE) using the very same turbo control units is going to be trouble free on the R-1830?
> The Turbos and turbo controls were NOT quite ready in 1941/42 on any engine.



I've thought it was Allison/turbo combo that needed to be treated in a certain way, while turboed 1830 was void of such an issue?
Were the P-43 experiencing any issues with their powerplants?


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## Shortround6 (Jan 25, 2011)

tomo pauk said:


> I've thought it was Allison/turbo combo that needed to be treated in a certain way, while turboed 1830 was void of such an issue?
> Were the P-43 experiencing any issues with their powerplants?



The P-43 and early B-17s (Bs, Cs, and Ds for sure) had issues along with the early P-38s, different issues than the later ones but still issues. Add what works on a slow climbing, slow diving B-24 with a flight engineer to monitor the engines may not work on a fighter with rapid altitude changes and a busy pilot. 
Early turbo controls measured the exhaust back pressure (pressure in the exhaust manifold) and tried to keep it at a value near an open exhaust near sea level. This pressure device opened/closed the waste gate to control the pressure and thus the speed of the turbine and thus the intake pressure to the carburetor. It was actually not very precise leading to rich or lean conditions and with the moisture in the exhaust it was prone to freezing in the sensor line, which could lead to runaway (exploding) turbines. Later turbo controls just measured the pressure coming out of the turbo compressor before the carburetor and offered better pressure control and less chance of freezing. These controls (at least the early ones) were part of the Army designed or specified turbo package and not really up to the airframe manufacturer. A lot of problems were caused over the years because certain items, like guns, radios, some instruments and even engines/propellers were "government furnished equipment" to the airframe manufacturer. The Government wrote separate contracts to the suppliers of those items and then supplied them to the airframe manufacturer who then installed them.
This lead to a lot of finger pointing when things went wrong. 
One reason for R-R success was back in the thirties they established their own flight center to test engine installations and were able to make modifications and test them themselves rather than waiting for third parties to do the testing. With small contract before the US got in the war airframe manufactures could not afford to build, equip and test 'extra' aircraft over what the government ordered in order to catch problems the the Army or Navy weren't catching or rating high on the list of problems to take care of.


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## tomo pauk (Jan 25, 2011)

Many thanks for the detailed info


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## drgondog (Jan 27, 2011)

I have occasionally considered a deeper chord wing with reduced t/c (but same 'actual depth), same wingspan, with more taper to achieve a similar AR/Oswald efficiency. 

Greater wing area, etc - for a P-51, would result in more possible fuel capacity eliminating most of the fuselage tank requirements. It would also result in lower lift loading making it more manueverable in turn and climb, and slow transonic drag rise due to the thinner wing.

Assuming the knowledge of today was available to re-think the P-51 wing, boundary layer control might be improved with no weight penalty - resulting in better drag and lift and improving pre-stall characteristics as well as theoretically raising the CLmax..

I would apply that to the P-51H concepts which lightened the airframe back to P-51B levels, which also improved yaw stability by extending fuselage 13 inches.


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## tomo pauk (Jan 30, 2011)

Okay, lets continue with my what-if 

FAA was also interested in having a fighter of great performance, since their Hurricanes, Martlets and Fulmars were lacking performance in late 1941. The new fighter in pipeline, was about to be flown just prior 1942, and the prototype was notably slower then both Spitfire Mk.VIII prototype and Mustang. Not just that, FAA was fearing that advent of new high performance Allied fighters would've spurred Axis forces to introduce even better planes for themselves, threatening FAA. 
So they decided to go for each-way bet - to navalize Spit and to bolt the most powerful engine onto Firefly airframe. 
The navalized Spit VIII offered better U/C layout than 'hooked Spitfire' FAA was experimenting so far, but it's wing (optimized for high speed) was regarded as a liability for a naval plane. The part of the wing outboard of hinges was of broader chord, resembling of a dog tooth (with tooth being at trail edge), so the wing area was increased 10%. The resulting Seafire III have had performance somewhere in between of RAF's Spit V and VIII, with an useful combat range. The 1st squadrons receive their planes early in 1943, and use it to a great success during invasions of Sicily Italy.
As for the Firefly, FAA was thinkering about Sabre even erlier, but now they decided to use it really. In order to avoid issues with engine, FAA chooses to go with 2100 HP - enough for 360 mph. The 1st squadrons receive their mounts in mid 1943, using them in early 1944.


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## Rick65 (Jan 30, 2011)

Not sure that I would have liked to be in a single Sabre engined naval aircraft even in 1944. The reliabilty of the Sabre was greatly improved by then, but still not so good that the Centaurus powered Tempest II didn't rapidly supersede the Sabre Tempest V post war.


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## tomo pauk (Jan 30, 2011)

Perhaps Centaurus was chosen because it was perceived as more rugged, being air-cooled? 
As for Sabre, toss some informations about reliability of it, for 1944.


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## tomo pauk (Jan 30, 2011)

About the early German response, when encountering new Allied fighters:
The main adversaries Allied planes were facing in late 1942 were a good match for Spit VIII and Mustang, but Spit IX and Typhoon induced more worries for the Jagdwaffe. Luftwaffe also enjoyed (so far) better quality of pilots, but the numbers were not on their side. Therefore, they set to find the cure both in short- and long-terrm. 
The short term solution was making DB 605 to run reliably at 1,42 ata, while BMW 801 are to receive MW system. Both systems were introduced in summer of 1943.
On long-term basis, Luftwaffe was to receive jet fighters. That approach have had few drawbacks, though. Jet engines were still at prototype stage, ditto for fighters that were to use them. Plus, it took two engines per fighter, if existing planes are to be produced only. So RLM demands a single-engined plane to be flown within half a year, and mass production to start before 1944. As a back-up, both 109 190 are to receive engines that would be 30% more powerful than existing ones, to be introduced early in 1944.
Unaware of all of that, Allied high commands decide to put pressure on Luftwaffe...


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## tomo pauk (Jan 30, 2011)

...and that started on Aprils Fools Day, 1943.
USAAF mustered 150-odd P-47s and 100 P-38s, while RAF used 250 Mustangs, 200 Spits VIII and 300 Spits IX, plus 200 Typhoons; all equipped with drop tanks. As a bomber force, at disposal were 400 medium bombers and 150 B-17s. RAF will fly night bomber sorties vs. aircraft factories that were regarded as too dangerous for daylight force. The aim was to go 'beyond Ruhr', and all Luftwaffe-owned property was regarded as fair game. 

At the end of the week, Luftwaffe in the west was only a pale shade of itself, despite relocating fighters from East and South.


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## drgondog (Jan 30, 2011)

tomo pauk said:


> ...and that started on Aprils Fools Day, 1943.
> USAAF mustered 150-odd P-47s and 100 P-38s, while RAF used 250 Mustangs, 200 Spits VIII and 300 Spits IX, plus 200 Typhoons; all equipped with drop tanks. As a bomber force, at disposal were 400 medium bombers and 150 B-17s. RAF will fly night bomber sorties vs. aircraft factories that were regarded as too dangerous for daylight force. The aim was to go 'beyond Ruhr', and all Luftwaffe-owned property was regarded as fair game.
> 
> At the end of the week, Luftwaffe in the west was only a pale shade of itself, despite relocating fighters from East and South.



On April 1, 1943 only the 4th FG equipped with SpitV was operational. Neither the 56th nor the 78th FG were quite ready w/P-47C..55th FG P-38s didn't become operational until October 1943.

The first time the 8th AF FC could put up ~ 150 P-47s equipped to go to German border was after August, 1943 when the 353rd FG became operational and even then they weren't quite equipped to penetrate German airspace with enough fuel - and Spits were barely able to cross the Holland border.

On 1 April 1943 the entire 8th AF was only putting an average of 80+ B-17s (no B-24s yet). It wasn't until May that both B-24s and B-26 BGs became operational . The B-24s were assigned to Ploesti effort and did not return (significantly 'whittled down') until late August.

The B-26 in 3 CBW didn't put up a force exceeding 48 until August 19.

So, in mid-May 1943 was the threshold for the Entire 8th AF BC ability to put up 150+ B-17s, 12 B-26 (322BG) and ~ 40 B-24s. With 120 total effective P-47's...

Simply stated the LW was stronger than the 8th AF when considering the ability to fly west from Frankfurt through Hannover... and the only a/c capable of penetrating the German border in daylight was the 8th AF.. the 9th was just beginning to go operational.


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## tomo pauk (Jan 30, 2011)

You're right all the way, Bill, but this is merely a what-if that starts with premise Merlins were on board P-51s from day 1, thus accelerating development of Spitfire Typhoon, and encouraging a more offensive attitude vs. Luftwaffe. I've started it with post #332 of this thread


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## davebender (Jan 30, 2011)

You need about two years to put the Merlin into U.S. production. Meeting your timeline requires Packard to sign a license agreement with RR during 1939.


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## tomo pauk (Jan 30, 2011)

Not really, Merlin was provided by RAF here, so Mustang prototype can go airborne in second half of 1940


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## drgondog (Jan 30, 2011)

tomo pauk said:


> Not really, Merlin was provided by RAF here, so Mustang prototype can go airborne in second half of 1940



TP - If the merlin engine mounts, cooling system revisons to radiator core, etc were in the original design, and if the engines were available to be installed in US at NAA or upon arrival in UK, then it would have a shock to the LW on early and often fighter sweeps deep into Germany in early 1942

Had that happened you might also contemplate how the RAF might have invested in daylight bombing more with escort available. I also perceive a reduction in Spitfire and Hurricane production with licenses granted to England to start making the P-51 in the UK in 1941. 

You could project that a reduction in Hurricane production would fill some of the potential merlin bottlenecks


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## tomo pauk (Jan 30, 2011)

Hmm, Mustang produced by Blackburn Boulton Paul perhaps? Boy, Luftwaffe would've been given good run for their money  Guess cancellation of Hurricane mass production (mid 1942?) would've make easier for Hawker to ramp up production of Typhoon too, while locating/curing the airframe issues earlier?
As for LR fighter sweeps, I'm all for usage of overwhelming power if possible, that's why I've contemplated spring of '43 as start of offensive. That way Mustang would've been backed by other designs from my posts, too.


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## davebender (Jan 30, 2011)

*Historical P51 production.*
US Warplanes
618 Mustang Mk I. 1941.
150 P51. 1942.
500 A36 dive bombers. 1942.

Nothing like optimism! 

U.S. production of the P-51 didn't shift into high gear until 1943. How many are you planning to build in England during 1941?


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## drgondog (Jan 30, 2011)

davebender said:


> *Historical P51 production.*
> US Warplanes
> 618 Mustang Mk I. 1941.
> 150 P51. 1942.
> ...



With a Merlin design profile for the XP-51 all of those could have been P-51B and production tooling in place in early 1942 in the UK.

The A-36 most likely would have been killed due to higher priority and the P-38 production probably would have been killed in late 1943 in the US with the P-51B replacing it.


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## The Basket (Jan 31, 2011)

The reason NAA were given the contract was because the UK couldn't build enough aircraft.

And there was certainly no idea that the P-51 was any good.

It would have been the P-40 that the British would have produced in the early 1940s timeframe.


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## drgondog (Jan 31, 2011)

The Basket said:


> The reason NAA were given the contract was because the UK couldn't build enough aircraft.
> 
> And there was certainly no idea that the P-51 was any good.
> 
> It would have been the P-40 that the British would have produced in the early 1940s timeframe.



The reason NAA was given the contract was that Curtis couldn't produce enough P-40s and NAA convinced the Brits that they could design and produce a Better fighter.

The point that TP was making is that a 'better aircraft' would have been the P-51B in 1940 instead of 1943 with no reason why not. The bottleneck was lack of USAAF support and a steady production allocation from Rolls until Packard could replace them.

As to British 'not being able to build enough aircraft' - it all depends on priorities doesn't it? Would the Brits rather build and deploy P-51B/Mustang III in 1941 or Hurricanes? - and I realize that switching aircraft in production and then deploying them is not so simple... BUT mechanics and logistics for the most crucial component was the engine and Hurricane crews would be maintaining the same engine.


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## davebender (Jan 31, 2011)

I'll buy that. UK production of the Mustang starts during 1942 (with Merlin engine) and achieves large scale production during 1943. 

Of course you also need to massively increase Merlin engine production. Historically Britain didn't produce enough for the Lancaster Bomber program. Building P51s in Britain makes the engine shortage even worse.


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## tomo pauk (Jan 31, 2011)

Cancellation of Hurricanes solves that problem in mid/late 1942.


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## Shortround6 (Jan 31, 2011)

drgondog said:


> Would the Brits rather build and deploy P-51B/Mustang III in 1941 or Hurricanes? ........ BUT mechanics and logistics for the most crucial component was the engine and Hurricane crews would be maintaining the same engine.



Would it really be a "P-51B/Mustang III in 1941" or would it be a P-51A with a Merlin XX and not a Merlin 61 in 1941?

Still better (much better) than a Hurricane but not quite a P-51B either?


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## drgondog (Jan 31, 2011)

Shortround6 said:


> Would it really be a "P-51B/Mustang III in 1941" or would it be a P-51A with a Merlin XX and not a Merlin 61 in 1941?
> 
> Still better (much better) than a Hurricane but not quite a P-51B either?



It would have to be the P-51 'Merlin XX' whatever that is but the engine mount, carb relocation, new cowl, new wing drop to enable faired cowl and new radiator would have to accompany it. I can't think of a reason why the Merlin 61 couldn't be accomodated as soon as it became prioritized for the Mustang.

One interesting question is whether the fudelage would be extended during this design cycle instead of waiting for the P-51H?


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## tomo pauk (Feb 1, 2011)

Continuation follows  :

During the April '43 offensive, some things were made more clear to the Allies, too. From technical side, P-43 was lacking range (when equipped with same drop tanks as other planes - so no 'beyond Ruhr' for him yet), and the performance needed some boost in order for plane to be competitive under 20K. The ability to take punishment was the best plus. 
Engineers at Republic redesigned the inner part of wing, making it more simple, with each wing receiving 40 gal tank, plus provision was made for 3 drop tanks to be carried. Until more power becomes available, a pair of HMGs was removed, to cancel out the increase of weight of the new tanks. The -D version entered combat in March '44, and mostly featuring water injection for 2300 HP in WER, and paddle blade props.
The more substantial version to become produced was one with fan-cooled R-2800, with 2800 HP and all 8 HMGs. The -M enters combat in June '44, just in time for invasion.


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## davebender (Feb 1, 2011)

> whether the fudelage would be extended during this design cycle instead of waiting for the P-51H?


What triggered the historical design change?


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## drgondog (Feb 1, 2011)

davebender said:


> What triggered the historical design change?



Major reasons were the fuselage fuel tank cg issue and the issues associated with roll and yaw that cropped up with added horsepower going from A to B without making any changes to the tail. 

They reduced the capacity to 50 gallons, increased the length to restore 'original' yaw handling of the P-51A as well as improve take off characteristics and effectiveness of the rudder without adding stress to fuselage. The reduced the weight back to the B but still retained the 6x50 and larger ammo capacity of the D.


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## davebender (Feb 2, 2011)

> Major reasons were the fuselage fuel tank cg issue and the issues associated with roll and yaw that cropped up with added horsepower going from A to B without making any changes to the tail.


I expect Britain would have the same learning curve if they produced the Mustang.


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## Milosh (Feb 2, 2011)

davebender said:


> I'll buy that. UK production of the Mustang starts during 1942 (with Merlin engine) and achieves large scale production during 1943.
> 
> Of course you also need to massively increase Merlin engine production. Historically Britain didn't produce enough for the Lancaster Bomber program. Building P51s in Britain makes the engine shortage even worse.



Great Britain produced half again as many Merlins as what the USA did.


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## drgondog (Feb 3, 2011)

davebender said:


> I expect Britain would have the same learning curve if they produced the Mustang.



But this is a 'better design' so of course the US/UK collaborate perfectly.

Having said this only a 'future seeing' design team could predict the merlin would increase Hp by nearly 2x from 1940 to 1945 and THAT knowledge would have to be anticipated to further strengthen the aft fuselage but the added fuel tank would suggest extending the fuselage.


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## gjs238 (Feb 3, 2011)

Perhaps higher output engines were anticipated, such as Continental I-1430, Pratt Whitney X-1800, etc.
We know these didn't work out, but at the time there was "optimism."


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## gjs238 (Feb 3, 2011)

davebender said:


> Not much point to using that large / heavy / expensive P-38 twin boom airframe unless you need the space for turbochargers. With mechanical superchargers you could employ a lighter and more compact airframe similiar to the Westland Whirlwind.



Fokker G.I used twin boom design.


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## tomo pauk (Feb 4, 2011)

The introduction of Anglo-American high performance fighters served as incentive for Soviets, too. The two types they evaluated in mid 1942 - Mustang and Spitfire VIII - were found to have almost 100 km/h speed advantage vs. current Soviet types, with double the range firepower (Spit only). So they too decided to try out the laminar-flow wing for next generation of their fighters.

The 1st type going to production was from Yakovlyev OKB. Their latest Yak-7D was offering good range, but performance was lacking vs. German opposition. The new wing was almost the same as Mustang's, but cropped, with wing area of mere 200 ft^2. The resulting Yak-7DI (later named Yak-9) have had the same range as the predecessor, while being only slightly slower than German fighters. 1st combats occurred in late 1943.
Yakovlyev engineers took the advantage of designing 'new' wing and have made also the undercarriage legs slightly longer, so Ash-82 engine with regular prop could've been mounted. The Ash-82F on a Yak provided finally a level of performance Soviet needed, starting in 1944.


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## davebender (Feb 4, 2011)

> Great Britain produced half again as many Merlins as what the USA did.


Still not nearly enough to meet British requirements due to the high priority Lancaster Bomber program.


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## drgondog (Feb 4, 2011)

davebender said:


> Still not nearly enough to meet British requirements due to the high priority Lancaster Bomber program.



Given the long range and high performance of the P-51B type, the RAF may well ahve re-allocated 500+ engines to get them into the MTO and ETO.


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## Milosh (Mar 2, 2011)

davebender said:


> Still not nearly enough to meet British requirements due to the high priority Lancaster Bomber program.



There was 7377 Lancasters produced requiring 29508 engines. Double that for spares.

Be sure, there was enough for the high priority Lancaster Bomber program.

Britain - 112000
USA - 37000


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