# Bf 109 F series



## silence (Jul 30, 2013)

Since the F series is often regarded as the pinnacle of 109 development, are there ways in which it could have been improved?

It seems the early Gs were basically up-engined Fs; could the 601E have been further developed?

How would it have fared against the late war allied fighters?


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## davebender (Jul 30, 2013)

Heinkel and Focke Wulf fighter aircraft had bubbly canopy by late 1930s. IMO RLM should have insisted on an improved canopy for Me-109F. Even Erla style canopy would be a big improvement over historical Me-109F canopy.

Me-109F was designed for a level speed of about 400mph. Might be a good time to introduce Flettner tabs to improve high speed handling rather then waiting until Me-109G series.


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## silence (Jul 30, 2013)

Is that the same as a servo tab?

And how about a bubble canopy like the Spit V and IX? I would think such a change would not interrupt production and be an easy in-field modification.


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## davebender (Jul 30, 2013)

If Me-109 adopts a bubble canopy it would be like He-112B and/or Fw-190 as those aircraft were familiar to Messerschmitt by late 1930s.


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## GregP (Jul 30, 2013)

Improvements to the Bf 109F:

1) Bubble canopy and a windscreen with much more narrow posts or no posts. No big deal, DO it.
2) Landing gear. Move the gear outward to widen the track. Easy but would mean a production interruption.
3) Add a rudder trim tab. No real issue and not much weight.
4) Increase mechanical advantage for the control stick. Easy and NO extra weight.
5) Reduce flap span by about 1 foot per side and add aileron span. Increase aileron travel and add tabs to reduce roll forces at high speed. The 109 already had a very low stall speed and short takeoff and landing distances. These steps wouldn't affect them much.
6) I'd leave the engine alone and try a wider-chord propeller. They worked well on the Fw 190's. Why not the 109's?
7) Add ore fuel. Put in another 20 gallons at least.
8) Finally, the biggest headache for many units all during the war ... add a damned electric starter! The scrambles would be MUCH quicker!
9) Once these are done, quit messing with it and get on with the successor while producing the new Bf 109F as rapidly as possible.
10) Steal as much 130-grade fuel as you can get and make that DB hum!


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## beitou (Jul 30, 2013)

Where does the battery go for the electric starter, or do you mean a externaly powered starter? If external and each aircraft needs a power cart how much quicker would mass scrambles be? Is it worth carting round the honging big battery needed to start the beast?


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## Tante Ju (Jul 30, 2013)

GregP said:


> Improvements to the Bf 109F:
> 
> 1) Bubble canopy and a windscreen with much more narrow posts or no posts. No big deal, DO it.
> 2) Landing gear. Move the gear outward to widen the track. Easy but would mean a production interruption.
> ...


 
1) It would require a serious redesign of the fuselage and may pose stability problems. An unnceccesary risk, maybe, as the rear view was fairly good with the armored glass headrest. Introduce those immidiately. Its not hard to cut a hole in a piece of steel and insert some glass into it... also heatable panels for freezing. Thats actually useful for winter/high altitude work.
2) Negative. The landing gear track isn't a problem, its geometry is. Introduce different angle tire mountings and long tailwheels sooner to solve problems, as on 109K.
3) Probably should be done, not many seems to be complaining, but hey, it costs next to nothing to add a knob. CC that to Herr Prof. Tank, too.
4) Probably useful too, though not vital. Decreasing physical loads on the pilot may be useful on one hand (getit?), but OTOH may also impose overstressing risks and good low speed control harmony. Maybe introduce non-linear control, if thats possible?
5) Partially disagree, tabs should be added - but the aileron control and travel was just fine already.
6) Already done. Propellers got wider in chord and tailored to the needs of every new engine, until they got really very noticeable by 1944 with late war those high altitude engines..
7) Probably unneccesary. The Fw 190 was fine, the Bf 109 had the same capabilities, so, what for? But it should be an easy fix, the fuel tank could be enlarged to the rear without any problem. Maybe ask the RLM if they want it. 70-10 kg of extra weight shouldnt be an issue. Or is it.
8) No space for that, sorry, we overlooked that in 1934. But you already signed a contract for 12 000 of them. Marketing departments addendum: doesn't seem to be that much of a problem in practice. 
9) That would be the Me 262, the rest simply did not have a worthwhile improvement, or even were a step back in some areas, to be produced.
10) Why steal 130-grade fuel when you already have 150 grade fuel..?

+11 but could be point Zero as well: Fire the guy at the head of the Undercarriage Aerodynamic Cover Deperatment. He was doing nothing useful between 1936 - 1944. Already the 109E (or before) was supposed to have faired-over undercarriage and a retractable tailwheel. What went wrong until the 109K?! He cost the plane already some 20 mph in top speed (and range).


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## l'Omnivore Sobriquet (Jul 30, 2013)

The Russians designers were ordered systematically to take the Me-109 G2 as their goal to better, in their famous long work to raffinate existing production types.
There has to be a reason !


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## Civettone (Jul 30, 2013)

I agree. If these improvements were that easy, I am sure the guys at Mtt would have introduced them.

I think we should stay humble with our all-knowing wisdom toward the Bf 109. I do not think we know the full story behind each component and aspect of this aircraft. For instance, the reason why they did not introduce a bubble canopy was because it was more difficult to produce and because it would reduce max speed (like on the P-51D vs B/C)

Kris


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## silence (Jul 30, 2013)

I just read *somewhere* that even when LW craft did have landing gear doors these doors were often removed in the field.

What would be the reason for this?

As another improvement, could the supercharger be enlarged?


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## GregP (Jul 30, 2013)

Hi Tante Ju, 

Let's just say that if we were running the Bf 109 program, we'd make wildly different decisions. We already know what happened, but I'm trying to make it BETTER, not let it flounder along as it did. I do NOT think a serious redesign was necessary to greatly improve the canopy. The radial-powered Bf 109 prototype had such a canopy and it wasn't a major issue. The improvements I suggested would have been lighter than the Bf 109G at least.

I don't think the Germans had plently of wonderful fuel widely available or the power in the DB engines would have been better per the displacement. The octane or performance numbers cited for their fuels weren't all that damned good. Don't tell me how the fuel was better than rated. I've seen the reports in great detail and have them in pdf format.

We had a group of former Luftwaffe Bf 109 pilots at Chino when the Russell Bf 109E was initially restored. To a man (13 of them) they were adamant that having the electric starter, as was fitted at Chino, would have made their lives MUCH easier. One even said if they had electric starters, they would have won the war! I, for one, believe them that it would at least have been of great benefit. 

If you don't, that's OK. They all might be wrong. Me, too. I have cranked an intertia starter and didn't like it much when pressing a button was SO much easier, especially on a cold day. The weight penalty is almost meaningless compared with the gross weight and there's plenty of room in the fuselage. I can even climb into it myself behind the ccokpit, and have ... well ... into an Hispano Ha.1112 Buchon anyway.

So, what is YOUR list of suggested improvements to make the Bf 109F better and more competitive into the late war?

The main issues to me were canopy, landing gear, short range, and high control forces when going fast. Those are the primary faults I want to correct, without leaving out any single item.


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## pattle (Jul 30, 2013)

I tend to think the F model was as good as they could make the Me109 at the time. I have read that at first there were concerns in the Luftwaffe that it was under armed, but that when it went into combat it's other qualities more than compensated for it's lack of guns. I think it was certainly the perfect plane for going up against P40's and Hurricanes in, and wasn't it the F model that gave the B24's such a rotten time over Ploesti?


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## GregP (Jul 30, 2013)

The Bf 109F was a good figher. Minor changes would have made it MUCH better and maybe even competitive well into the future.

The G-series was a step backward, what with the weight increase. It needed more wing and more power to handle the weight, but never got it, and they left all the basic faults in the plane!

It had potential and was pretty good as it was, but some relatively minor changes would have made it much better ... I think.


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## Aozora (Jul 30, 2013)

I'm wondering how JG 26 (or was it a rear echelon conversion unit?) managed to replace the MG 17s in the upper cowling of one of Galland's "special" F-2s with MG 131s without needing the large blisters used by the G-5 series on? Did this conversion see any combat? If it could have been done on the production line the MG 131s would have been a useful modification.


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## Civettone (Jul 30, 2013)

Oh boy, this is going to be thread #673 about all the things which people (wrongly) believe were bad about the Bf 109. The same outdated stories about frozen controls, narrow landing gears, light armament, short range, ...  



Kris


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## Shortround6 (Jul 30, 2013)

silence said:


> As another improvement, could the supercharger be enlarged?



Possibly, the supercharger did not stay the same through all models of the engine. The later DB 605s actually got a DB 603 supercharger, I believe but could be wrong, it may have been _based_ on the 603 supercharger. 

However a bigger supercharger not only weighs a bit more it takes more power to run, meaning you have a bit less power from sea level to near critical altitude on the same grade of fuel. The gain comes higher up. 

Perhaps the slightly larger supercharger fitted to the 605 could have been used. An increase of just under 6mm in diameter but I don't know if their was a change in thickness. In any case the DB 605A had a Critical altitude 700meters or less higher than a 601E and a good part of that came from the higher rpm. 200 rpm on the crankshaft is worth just over 2000 rpm on supercharger impeller. 

Picking supercharger performance is always a trade-off. High altitude performance is _always_ bought with a low altitude penalty of some sort.


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## GregP (Jul 30, 2013)

Hi Civettone,

You won’t get that from me. I thought the intent of the thread was to suggest improvements for the Bf 109F, not to trash it.

The controls did NOT freeze. Above 330 mph they were objectionably heavy and there was a remedy that was never implemented. Stop living with the weaknesses and FIX it. That way, the Bf 109 would not be so unmaneuverable at higher speeds.

The landing gear WAS narrow and the geometry was wrong. The intent is to fix it. By all means try the geometry fix first. If that did the trick, go with it. If it was still dicey, MOVE THE DAMNED GEAR OUTWARD AND FIX IT. Doesn’t mean the 109F was bad, it wasn’t. It means there was room for improvement.

I never mentioned the armament but could. It was light but effective. To avoid a heavy “solution” simply supply more ammunition for the existing armament and FIX IT.

The range WAS too short. If anyone doesn’t see that as a major fault, then you would have lost just as many Bf 109’s to fuel exhaustion as happened in real life. It was a crime that was preventable. FIX IT.

The Bf 109F was the pinnacle of the 109’s in the eyes of many of its former pilots and was a very good fighter. My suggestions do NOT insinuate it wasn’t … they are suggestions to make it better than it was in real life since that was the subject of this thread.

If you think it was as good as it could be, then you simply have no suggestions for improvement to the Bf 109F. I do have suggestions and all would have been welcomed by the WWII Luftwaffe Bf 109 pilots.

No suggestion that the Bf 109 was a poor representative of German fighters, it wasn't. It was VERY good but, like many fighers, could have been better with a few relatively minor changes that were desired by the pilots ... who never seem to get listened to by the people in command.


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## Shortround6 (Jul 30, 2013)

Civettone said:


> Oh boy, this is going to be thread #673 about all the things which people (wrongly) believe were bad about the Bf 109. The same outdated stories about frozen controls, narrow landing gears, light armament, short range, ...



Except they are mostly true 

The controls were not as "frozen" as many people like to believe but there were problems, and the 109 wasn't the only plane to suffer this way. 
Narrow landing gear, yes, but so did a few other planes (not just the Spitfire, the Wildcat had it's share of landing gear/taxiing problems).
Light armament? if we are talking about the majority of the "F" model then it WAS light. Heavy compared to a Japanese KI-43 or Italian planes with two 12.7mm guns but compared to the vast majority of western allied planes in 1941/early 1942? 
Please do not point to the poorly armed Russian aircraft as justification. The had both engine power and quite possibly CG problems in trying to increase armament. They certainly trialed enough heavier combinations to show they were not happy with the armament they were using. 

Range?
You can fly a P-47 (with the small fuel tank) over 800 miles on internal fuel, you just can't do it at an altitude and speed that will allow it to survive in enemy airspace. What counts is the 'practical' range/radius a plane can fly at speeds/altitudes that allow it to be effective. The P-47s 835 mile "book" range turned into a 125 mile radius when figured for "standard" mission conditions. 

The 109 was short ranged. So were a number of other fighters (P-39) What really hurt is there wasn't anything to take it's place, the Fw 190 wasn't enough different to say so and the Bf 110 was??? The Americans had the P-38 in the early years (1943) to make up/cover the P-47s lack of range. BUT the P-47 had the size/bulk to enlarge the internal fuel to 370 gallons and the extra 65 gallons was worth another 100 miles radius even without drop tanks. 

Sticking with the "F" it was a major improvement over the "E". There are few, if any, negatives about the "F" compared to the "E" except possibly the armament. The real problems with the 109 come with the "G" and even then it is the later ones. 

Lots of WW II fighters could have been improved with very minor changes (in some cases just rearranging some of the cockpit controls).


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## silence (Jul 31, 2013)

Aozora said:


> I'm wondering how JG 26 (or was it a rear echelon conversion unit?) managed to replace the MG 17s in the upper cowling of one of Galland's "special" F-2s with MG 131s without needing the large blisters used by the G-5 series on? Did this conversion see any combat? If it could have been done on the production line the MG 131s would have been a useful modification.



Good point. How would the small bump 13mm cowl - or adding the outer wing 20mm - affect performance? Could MG 151/20s or 151/15s have been fit in lieu of MG FFs?


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## Tante Ju (Jul 31, 2013)

silence said:


> Good point. How would the small bump 13mm cowl - or adding the outer wing 20mm - affect performance?



The 13mm bumps decreased top speed by 9 kph at SL, ironically the wing 20mm gondolas - only by 8 kph. The gondolas (with ammo) also added some 215 kg weight (the HMGs only + 40 kg), which meant about -2 m/sec decrease in climb rate and ca. + 2 sec slower turns.

Kurfürst - Leistungzusammenstellung Me 109 G.

The 13mm bulges were far from ideal, the later revised cowling decreased the loss to only 3 km/h. Its amusing why they were designed so badly. The question why the solution on Gallands personal ride was not adopted is interesting, but it might have not been so ideal for feeding/aerodynamics perhaps. The reason for the cowl bulges was that the guns were not fed from outwards on the serial planes, so perhaps Gallands mod was not feeding reliably enough.

Here is a picture of Gallands modded 109F(-2/U). Note the teardrop shaped bulges for the HMG. 







Another of Galland 109F he has modded with wing MG FFs and the "Galland Panzer", named after him, which placed a transparent armor glass into the standard and bulky armored headrest.








> Could MG 151/20s or 151/15s have been fit in lieu of MG FFs?


 
There are drawings of that being proposed for 109K wings, so at least physically they would fit (with 100 rpg). They could also fit the bulkier MK 108, with 45 rpg.


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## silence (Jul 31, 2013)

So the G-6 to G-14 style bumps cost 9kmh in level speed, while the revised cowling of the G-10 and K-4 dropped that penalty to 3kmh. Is that correct?

If the "Galland cowling" is used, the speed penalty would - I expect - be minor enough to be acceptable for the increased firepower. Even MG 131s in the outer wings would be a nice increase and far less of a weight penalty than 151s. (For example, two cowling MG 131s, two outer wing 131s, and the MG 151/20 motor cannon. I dunno - just throwing out ideas...)


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## GregP (Jul 31, 2013)

Tante Ju,

You amaze me. Where do you FIND this stuff? Great pics of the modified Bf 109F! The rear portion of the bump needs to taper to eliminate turbulence (drag). It isn't all that difficult.

I appreciate the close up. Great pic of Galland in his mount, too. I always THOUGHT the parachute would put your head into the top of the canopy once I sat in one. Now I know.

Keep it up! 

I still think the F was the best of the series from a pilot's perspective, given the opinions I've seen from the people who flew them all. Truly a great plane if ever there was one. My suggestions above do not detract from its greatness at all. They are merely suggestions for improvement, and it is very possible that one or more would not be possible without an excessive weight gain. In that case, I'd forego the mod for lightness ... except for the battery for the electric starter. I'm thinking it would fit just fine right behind and to the bottom of the fuel cell. Not far from the CG and plenty of room there since I can sit right there inside a 109 fuselage in a pinch.

It might have been a good thing if the Germans used the Hispano wing, too. It had two guns internally and was just as strong. But ... that would also add weight and the real question is how heavy is too heavy? Certianly the G-model was. Maybe leave the armament alone ... and let it go with fixing the primary weaknesses, such as they were. It probably would have tipped from teh Spitfire the balance back to the Bf 109 side. They DID tend to trade being "the best" back and forth.

A German redesign of the Reggiane Re.2005, Macchi C.205, or Fiat G.55 might wasily have been a good replacement. The Germans would have simplfied them and made them lighter, smoother, and faster ... in my vision ... maybe. Or a totlally new design. But the Bf 109 wasn't necessarily done as a design with the F model. The problem with the G was the weight. There is surely SOME subset of the mods that would result in a plane better than the F and lighter than the G ... WITH some of the fixes proposed. If the K could go in the mid 400 mph range, then so could a cleaner F model. I KNOW the radiators weren't all that great. Maybe a new radiator along the lines of the P-51 unit that eliminated a lot of cooling drag. By that time they had info on it.

Or, as a last resort, increase the wing area so the wing loading for the G was the same as for the F. It might have taken only a small increase in chord or span, but it could be done without a major weight penalty.

I reaching here, so I'll stop. Cheers.


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## OldSkeptic (Jul 31, 2013)

It was the pinnacle of the basic design and a superb fighter aircraft, if not the absolute best it definitely shared 1st place at the time and place it became operational.

But, and here is the but, the fundamental weakness of the 109 was it's size. It was the smallest package that you could build around a good engine and decent guns.
That meant there was little left to grow and if you added something there, you lost something elsewhere.
As operational requirements grew it simply couldn't be altered enough to meet them.
Therefore the superb F became the much poorer G. 

Everyone compares it with the Spit, but I'd rather compare it with that other superb design the 190 and, more importantly, the design and manufacturing team.

While Willy had basically washed his hands of the 109 (and the 209, et al were failures). Tank (as did his counterpart at Supermarine Smith) kept developing the 190 with more and more power and then, when the engine became available (after much prodding) he stretched to 190 into the excellent 190D.

Willy was a purest, he wanted perfect designs, he ran things like an autocrat, made many mistakes but played his political cards well. He had some great successes, the 109, the 110 (though not for the original purpose), the 262. His failures he, by and large, managed to avoid any criticism of (the 210, the 410, et al).
His biggest failure, unlike the great Kurt Tank, Mitchell, Smith, (etc) was he never wanted to get into the hard business of continual development (or even just delegate it, that autocrat in him got in the way, teamwork was not his style).

So with all that background , improve the 109F? Impossible. As I said it was the pinnacle of the superb basic design with the engines available at the time (though note even then the rot was starting, with ever more vague promises of 'better' engines, 'if only' the Govt would do something).

The 109G .. now that is another story entirely.... that is when it all turned to custard.


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## CobberKane (Jul 31, 2013)

I've always thought that the 109F was a significant plane in that it was the last model that could really be said to be every bit as good as the contemporary version of its arch-foe, the Spitfire. From all accounts there was really nothing between the 109F and the Spit V. By the time the Spit IX came along, the 109 was no longer the most feared German fighter in the sky. The G models remained dangerous opponents, particularly for the earlier American fighters, but from 1943 on every German pilot who met a Spit IX or XIV was, at least to some degree, at a disadvantage. The German pilots who had flown the 109 from right back to the Spanish Civil war through to the 109F could be confident they were in a machine could best almost any other fighter in the world, and equal the one it couldn't. In that respect the 109F really was the nadir.


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## pattle (Jul 31, 2013)

Just to leave the topic slightly, can anyone tell me what generally happened to older models of the Me109 when newer ones came along? I know that some were used for second line duties or sent to less competitive fronts but were for instance F's modified into G's and were the F's kept in front line service until they were just either worn out or destroyed? I think the D model was upgraded into the E?


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## Aozora (Jul 31, 2013)

Tante Ju said:


> The 13mm bumps decreased top speed by 9 kph at SL, ironically the wing 20mm gondolas - only by 8 kph. The gondolas (with ammo) also added some 215 kg weight (the HMGs only + 40 kg), which meant about -2 m/sec decrease in climb rate and ca. + 2 sec slower turns.
> 
> Kurfürst - Leistungzusammenstellung Me 109 G.
> 
> ...


 
Ah Ha! There's the reason for the smaller bulges - Galland's F-2 had ejector chutes for the cases and links on the sides of the cowlings, whereas the Gs had ejector chutes directing them below the forward fuselage; chances are the ejected casings could potentially damage the airframe, particularly the tailplanes and rudder on Galland's aircraft.









Tante Ju said:


> Another of Galland 109F he has modded with wing MG FFs and the "Galland Panzer", named after him, which placed a transparent armor glass into the standard and bulky armored headrest.



Interesting photo - now we can see why it was named after him...



pattle said:


> Just to leave the topic slightly, can anyone tell me what generally happened to older models of the Me109 when newer ones came along? I know that some were used for second line duties or sent to less competitive fronts but were for instance F's modified into G's and were the F's kept in front line service until they were just either worn out or destroyed? I think the D model was upgraded into the E?



Most of the above - for instance, the Luftwaffe kept their 109Ts (carrier versions of the 109E with extended wings etc) operational until August 1944; at least three B-17s were shot down over Norway by 109T's of 11./JG11 on February 22 1944. The last operational T flew its last op in August.


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## silence (Aug 1, 2013)

davebender said:


> Me-109F was designed for a level speed of about 400mph. Might be a good time to introduce Flettner tabs to improve high speed handling rather then waiting until Me-109G series.



Could this have been done in the field? (I would think not, but mechanics can be pretty ingenious.)


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## Shortround6 (Aug 1, 2013)

That is about the _last thing_ an Air Force would want to happen.

While some mechanics ARE pretty ingenious they don't all do things the same way so Pilot Adolf who is used to flying plane #7 in Squadron A with tab designed and installed by mechanic Hans gets transferred to squadron B and draws plane #6 with tab designed and installed by mechanic Otto? 
What happens then? each different Tab set up is going to require a different amount of control force (input) to get the same result. And who gets to test fly the 'new' tabs to see if the mechanic got it right and didn't over do it so the plane over controls?

Existing aircraft could have been refitted in the field with a standardized kit.


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## GregP (Aug 1, 2013)

Many planes were field fitted. An example would be the paper drop tanks made in England and used by P-51's and P-47's. They said at the factories it could not be done even they were being used on missions.

Modifications to the airframe might well have been tried in the field. But, if they had come up with a possible improvement, it would have been shared almost immediately if it had worked well. The planes were placed right next to each other and you could not "hide" airframe or sheet metal work very easily. If a control surface suddenly sprouted a tab, the next guys in line would have seen it almost as soon as it was fitted.


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## Shortround6 (Aug 1, 2013)

Somebody at the factories had short memories.


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## Civettone (Aug 1, 2013)

GregP said:


> Hi Civettone,
> 
> You won’t get that from me. I thought the intent of the thread was to suggest improvements for the Bf 109F, not to trash it.
> 
> ...


I reject all your claims. These 'problems' are mainly based on Western reports. Most German pilot accounts do not mention these. For instance, the track was not too narrow, it was similar to the Spitfire. There was a tendency to ground loop and this was fixed with the lengthened tail wheel of the G-10/-14. The Bf 109 was a handful for untrained pilots, but this can hardly be the fault of the Bf 109. Until 1943, training was good. There were no more landing/take off accidents with the Bf 109 than with the Fw 190. 
Also, the controls, heavy but not a major problem. If you are sure it was easy to fix, then why did Mtt not see a reason to change it? The only logical explanation is that it was not a major problem. 
Similar story with the cockpit. Western accounts will tell you the cockpit was too small. Maybe Luftwaffe pilots were midgets??
The Bf 109 range was good enough. We had a discussion about the Bf 109 range just last month. Western reports even showed that it had better range that the British fighters of its time.
Armament? The Bf 109F-4 had 1 MK and 2 MGs, which was effective for what it was hunting: lightly armoured fighter planes. The heavies only became a problem in 1943/1944.
The Bf 109F is considered to be the perfect Bf 109, while the Bf 109G suddenly becomes sluggish and slow... Check the facts. The Bf 109F-4 weighed around 2,400 kg while the Bf 109G-1 was around 2,550 kg with 100 hp extra combat power. (Of course Notleistung was not available on the Bf 109G until 1943).

Until we find clear data from Messerschmitt itself that improvements for the Bf 109F/G were required, I think we should be very careful about trying to fix what is not broken.
Kris


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## silence (Aug 1, 2013)

on the topic of cockpit size, I saw a modern documentary comparing the 109 to another fighter.

When the "comparer" climbed in to the 109, he closed the canopy and commented on how little room there was.

When he climbed into the other plane, he never closed the canopy and proceeded to comment on how much less restrictive that plane's cockpit was.

As far as the size of Luftwaffe pilots, maybe they were smaller. I can't imagine Germany's between-war economic woes could have led to a healthy diet for kids growing up (kinda like N Korea today - bunch of twerps from poor nutrition).


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## Juha (Aug 1, 2013)

Civettone said:


> I reject all your claims. These 'problems' are mainly based on Western reports. Most German pilot accounts do not mention these. For instance, the track was not too narrow, it was similar to the Spitfire. There was a tendency to ground loop and this was fixed with the lengthened tail wheel of the G-10/-14. The Bf 109 was a handful for untrained pilots, but this can hardly be the fault of the Bf 109. Until 1943, training was good. There were no more landing/take off accidents with the Bf 109 than with the Fw 190.
> Also, the controls, heavy but not a major problem. If you are sure it was easy to fix, then why did Mtt not see a reason to change it? The only logical explanation is that it was not a major problem.
> Similar story with the cockpit. Western accounts will tell you the cockpit was too small. Maybe Luftwaffe pilots were midgets??
> The Bf 109 range was good enough. We had a discussion about the Bf 109 range just last month. Western reports even showed that it had better range that the British fighters of its time.
> ...



IMHO Finnish pilots agree with most of so called 'problems'
The main reason with the u/c was that it was rather weak and because the CG was rather far behind the main u/c there was a tendency to ground loop, a good point was that one could brake rather hard without fear of a nose-over. In Spit it was opposite, it was easy to land but it was also easier to get the propeller blades hit to ground by harsh braking. And 109 landing accidents happened also to good, experienced pilots.
Finns thought that the stiff controls at high speed were intentional, the purpose being to protect the structure from overstressing at high speed manoeuvres at low altitude.
Small cockpit made it more difficult to look behind, maybe one reason that didn't went to bulged canopy in 109, and made it more difficult to put max muscle to the stick in sideway movement, making still worse the high speed rollrate at lower altitudels.
The range might be better than that of Spit IX, which was a short range plane, but less than that of Tempest V or even Spit Mk VII and VIII
Notleistung was permanently accepted in Oct 43 and the t/o weight of 109G-6 was 3100 - 3196kg (depending the docu one looks)

Juha


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## GregP (Aug 1, 2013)

Well Civetone,

I suppose we'd make different decisions if we were running the Bf 109 program, wouldn't we? That's OK since neither of us will ever get to run it. So, we're probably stuck with what was historically flown.

And if I had one, it would be restored to stock condition, without and modifications.


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## MikeGazdik (Aug 2, 2013)

Minor- install some sort of bubble canopy, such a Malcom type hood. Major- complete redesign of wing structure. Much like the Mustang. Two spars, fuel carried between, inward retracting gear, 2 machine guns outboard of fuel tanks. You can keep the basic shape of the wing, just internally vastly different...and stronger...and more useful.


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## Juha (Aug 2, 2013)

MikeGazdik said:


> Minor- install some sort of bubble canopy, such a Malcom type hood. Major- complete redesign of wing structure. Much like the Mustang. Two spars, fuel carried between, inward retracting gear, 2 machine guns outboard of fuel tanks. You can keep the basic shape of the wing, just internally vastly different...and stronger...and more useful.



But also heavier and one of the strong points of 109 was its excellent roc, more weight, lower roc. There is always trade-offs.


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## silence (Aug 2, 2013)

"roc"? What is that?


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## GregP (Aug 2, 2013)

Rate of Climb ...


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## Juha (Aug 2, 2013)

Roc roll, 2 very important characteristics for a fighter


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## GregP (Aug 2, 2013)

Good one, Juha!

Maybe rot, roc, and roll ...

Turn is also quite important ... but you came up with a GOOD one!


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## Denniss (Aug 2, 2013)

F-4 had a t/o weight of ~2850 kg, G-6 trop of 3154. Don't know how much the trop eqipment added to weight but I assume in the range of 50kg.
Basic airframe weight is 2083 vs 2300kg. G-6 trop weights may include the external rack as standard equipment, an F-4 trop load plan has 2150kg as basic airframe weight but it only contains weight with bombs (3254kg with 250kg bomb, requires strengthened tires).


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## Civettone (Aug 2, 2013)

Juha said:


> IMHO Finnish pilots agree with most of so called 'problems'
> 
> ...
> 
> ...


Well, that kinda knocked me off my feet. Because I distinctly remember this well known website about Finnish experiences with the Bf 109:
virtualpilots.fi: 109myths

And I am talking about empty weight, based on official German test report sheets. Of course the G-6 gained more weigth.

Kris


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## GregP (Aug 2, 2013)

Hope you didn't hurt your bum when you were knocked off your feet ...


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## stona (Aug 2, 2013)

Widening the undercarriage track is a non-starter on the Bf 109. 

The undercarriage attached to a cast steel truss (forged in later models) which was part of the fuselage, not the wing. This truss also served as an attachment for the lower strut of the engine bearer and the front attachment for the wing. No copy of the original technical requirements survives but several of the Bf 109s co-designers remembered that the wings had to be removable and the resultant parts be transportable on a standard German railway truck. The fuselage could also be simply towed. This feature had time saving benefits during construction and in the field eased maintenance. For example a wing could be changed without any specialised lifting equipment.

To widen the track would involve a major design change, unlike fitting a different canopy (which was done) or other relatively minor fixes. This is why even the BF 109 T still retained the original undercarriage track.

Cheers

Steve


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## GregP (Aug 2, 2013)

That's EASY. Change the requirements so the landing gear track was wider.


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## jim (Aug 2, 2013)

The question of a better 109 is not a stricly technical one.
The questions are 1) could the germans accept a reduction of the production in order to introduce major improvements? The answer was NO. Actually were unable to introduce even small improvements
2) Had the mother company interest and intention to push hard and fast the aircraft s evolution? NO. It appears Messerschmitt wanted to sell new types. Their main concern was the profit.

Anyway, if the answers to the above questions were YES
The logical next step after the F4 would be the aerodynamic airframe of the K4, even with DB605A. Could be available middle /late 43 . Would be 25-30 km/h faster than G6 on same engine. 
A new ,under fuselage radiator could give some additional speed . The freed space at wings perhaps could accept small fuel tanks
Or introduce some type of combat flaps.
Standart main wheels , not the enlarged of the K4. Long tail wheel
Accept the fact that it was a small air superiority fighter. Not use it as multi purpose fighter, with heavy equipment. Its structure and landing gear should be only strong enough to support the standart configuration (with the 605 engine) and a 300lt drop tank. No 30mm cannons,no rockets ,no bombs , no presurized cocpits, no fancy radios . All these required additional structural strength (=additional weight)
Improve its armament by introducing better guns I have read about the proposals and studies of a faster firing and lighter 20mm gun, and more powerful but little heavier 13mm HMG
Introduce flettner tabs IF the wing can handle the forces
Study the possibility for a sliding canopy similar to that of Ania S199. It seems to offer even better visibility than Erla canopy
Study the possibility to replace the under nose oil cooler with a cooler similar to that of D9
Study the usefulnes of a different attachement of the wing for higher speeds
Ensure good building quality
Use slipper fuel tanks to boost range
Introduce as soon as possinle MW50 ,wide propellers and 603 supercharger

OR
Simply replace it with an easier to produce version of the Fiat G55


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## Juha (Aug 2, 2013)

Hello Jim
I agree with the first part and the need for a better canopy, the more aerodynamical fuselage, Flettner tabs if possible and better quality control. And if easily possible the movement of GC somewhat nearer to the main u/c legs and some more fuel. But because of the reasons you gave in the first part of your message, that's all.


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## Juha (Aug 2, 2013)

Civettone said:


> Well, that kinda knocked me off my feet. Because I distinctly remember this well known website about Finnish experiences with the Bf 109:
> virtualpilots.fi: 109myths
> 
> And I am talking about empty weight, based on official German test report sheets. Of course the G-6 gained more weigth.
> ...



Hello, if you read the comments of the most experienced, you see what I meant, for. ex Karhunen never flew 109 in combat, all his kills were achieved while flying Fokker and B-239.

Juha


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## Tante Ju (Aug 2, 2013)

I do not get why the wing needs to be redesigned with two spars... for one the current one was plenty strong with a box spar and good torsion resistance, and had some space in it for fuel if one really wanted that... one could place tanks in the gondola bay for example. 

But why would anyone want that btw? The main L-shaped fuel tank was in the rear of the fuselage, right behind the pilot, and could be easily enlarged backwards a bit for a larger capacity one - as was done before, the original Bf 109 had a much smaller tank, something like 250 liters - the was both space and it would be close to the CoG. In fact they could slam a 100-110 kg MW 50 tank, GM 1 tank with no problem much further back in the fuselage.

So why tinker with the wing when you have space in the fuselage I wonder. The Mustang held fuel in the wings, because the fuselage space was already occupied by the radiator. The Spitfire could not enlarge the fuselage tank without some difficulty and redesign of the fuselage, since the volume around it was already non-existent, being slammed between the pilot and the engine.


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## Tante Ju (Aug 2, 2013)

jim said:


> Anyway, if the answers to the above questions were YES
> The logical next step after the F4 would be the aerodynamic airframe of the K4, even with DB605A. Could be available middle /late 43 . Would be 25-30 km/h faster than G6 on same engine.



I agree. Even better, introduce those fixes like wheel well cover on the first 109G, as was originally intended (did anyone notice the straight sides wheel wells vs the rounded ones on the 109F?) And why those bulky HMG bulges were used when it must have been quite obvious to anyone that a elongated, streamlined cowling (as on the 109K proto) could be much better is beyond me.



> A new ,under fuselage radiator could give some additional speed . The freed space at wings perhaps could accept small fuel tanks



Possibly doable, but would need a major redesign of the aircraft, since the fuel tank was already where a Mustang-style ducting would be. The Italian design had such, but the Germans criticized those for a) being too small capacity b) making it impossible to mount heavier bombs under the fuselage hardpoint. Note the size of italian wing bombs.. and droptanks.



> Or introduce some type of combat flaps.



Already present, just manual.



> Standart main wheels , not the enlarged of the K4. Long tail wheel. Accept the fact that it was a small air superiority fighter. Not use it as multi purpose fighter, with heavy equipment. Its structure and landing gear should be only strong enough to support the standart configuration (with the 605 engine) and a 300lt drop tank. No 30mm cannons,no rockets ,no bombs , no presurized cocpits, no fancy radios . All these required additional structural strength (=additional weight)



But tactically all these were very very useful. Also the larger main wheels were needed to cope with increased weight and added stability. BTW the larger main wheels were not a problem, but they were mounted in more right angles, which more or less fixed the looping tendency.



> Improve its armament by introducing better guns I have read about the proposals and studies of a faster firing and lighter 20mm gun, and more powerful but little heavier 13mm HMG



IMHO the guns were all fine. The 13mm weak HMGs were light, fast firing and could penetrate any aircraft armor. That was all asked for.



> Introduce flettner tabs IF the wing can handle the forces



Agree. It was a mistake that these were only introduced on certain batches.



> Study the possibility for a sliding canopy similar to that of Ania S199. It seems to offer even better visibility than Erla canopy
> Study the possibility to replace the under nose oil cooler with a cooler similar to that of D9
> Study the usefulnes of a different attachement of the wing for higher speeds



Probably studied though and though not worth it.. I doubt the sliding canopy would have been any better, but one interesting (and unexplainable) thing was that the 109K proto featured a bulged-top canopy. The 109 canopy was fine, except for tall people. A small bulge would have easily fixed that, and ti was only one plexi panel to be changed. Perhaps they worried about canopy distortions.



> Ensure good building quality
> Use slipper fuel tanks to boost range



That would probably add a few km range and kph speed with a droptank - and would also mean that 109s would need a special droptank and could not use the standard droptank used by all other aircraft from fw190 through ju 87 to destoyers. A simply aerodynamic fairing between the tank and the fuselage was tried and was very effective in reducing drag, but probably not worth it. Increasing speed for cruise by 20 km/h in a four hour cruise adds what, 80 km to range?



> Introduce as soon as possinle MW50 ,wide propellers and 603 supercharger



The problem is that the engine bearings/lubrication can't even handle 1500 HP until the autumn of 1943, much less 1800-1900.. though a 603 supercharger could be probably still used.



> Simply replace it with an easier to produce version of the Fiat G55



They would end up with much fewer fighters with different set of problems.. the G55 was a good fighter, but costly and far from perfect IMHO. The Germans considered it seriously, even tested it, but declined in the end.


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## Milosh (Aug 2, 2013)

Both the P-51 and Spitfire got fuselage fuel tanks mounted behind the pilot Tante Ju.


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## Tante Ju (Aug 2, 2013)

As far as volume went, its possible on any plane, but the original placement of the tanks will limit its practicality. 

both spit/109 of them had stability problems until the tanks were emptied (as exhaustively discussed in the another threard), for a simply result, CoG is usually located near the main tanks for obvious reasons, and placing aux. tanks far from the CoG (forward in case of the Spit, I am not sure about the 51).


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## OldSkeptic (Aug 2, 2013)

Forgotten which one said it, but a famous German fighter ace said, "it just needed a bigger wing'. 

Basically needed a 190D or Tempest like conversion. Stretch the fuselage, bigger wing, bubble cockpit, bit more fuel, some more guns.
Crash program, start (say) mid 41, production in late 42.


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## GregP (Aug 2, 2013)

Agree OldSkeptic, wholeheartedly.

Thye 109F was very good. Later models could have been better but weren't.


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## stona (Aug 3, 2013)

GregP said:


> That's EASY. Change the requirements so the landing gear track was wider.



I thought we were talking about improvements to the extant Bf 109, not starting with a completely different aeroplane 
Cheers
Steve


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## Dogwalker (Aug 3, 2013)

Tante Ju said:


> Possibly doable, but would need a major redesign of the aircraft, since the fuel tank was already where a Mustang-style ducting would be. The Italian design had such, but the Germans criticized those for a) being too small capacity b) making it impossible to mount heavier bombs under the fuselage hardpoint. Note the size of italian wing bombs.. and droptanks.


And the solution was...





You need more than a (or two, with two hardpoints, you have only to have enough power to lift it) 640 kg bomb? The Re.2005 made several tests with the asymmetrical hardpoint, with good results (even the landing of the MM495 prototype with a 640kg bomb still attached to the rack due to a failure in the hydraulic system can be considered a success), and it still had the wing hardpoints.
Note thet this solution was possible only with the outward retracting wheels.


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## Civettone (Aug 3, 2013)

Juha said:


> Hello, if you read the comments of the most experienced, you see what I meant, for. ex Karhunen never flew 109 in combat, all his kills were achieved while flying Fokker and B-239.
> 
> Juha


True, but he was the commander of a Bf 109 unit. I am sure he knew what he was talking about.



Tante Ju said:


> Agree. It was a mistake that these were only introduced on certain batches.


Interesting. On which batches is that? And why was it not generally introduced? My gut feeling tells me there was no need for it. 



> They would end up with much fewer fighters with different set of problems.. the G55 was a good fighter, but costly and far from perfect IMHO. The Germans considered it seriously, even tested it, but declined in the end.


Declined? I believe the Italian surrender came in between. Would you happen to have a source which states that the Germans declined? 
Also, I am very curious and sceptical about the Kurt Tank link. I do not see why he would be interested in the licence production. In fact, he would be least likely candidate, as he had the Dora lined up.



OldSkeptic said:


> Basically needed a 190D or Tempest like conversion. Stretch the fuselage, bigger wing, bubble cockpit, bit more fuel, some more guns.
> Crash program, start (say) mid 41, production in late 42.


They already tried modifying an existing Bf 109. Every change led to another required change, eventually becoming the Me 209, a totally different ship.

Kris


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## silence (Aug 3, 2013)

Dogwalker said:


> And the solution was...
> 
> 
> 
> ...



But you could have several 109s produced for every 2005. Can one 2005 make up for, say, three 109s? Even switching to the G55 you'd only get one of G55 for every two 109s. I think Germany needed numbers and the 109 was at least more than good enough considering its production advantages.


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## Dogwalker (Aug 3, 2013)

I'm not saying that Germans had to produce Re.2005s. I'm saying that's possible to carry a bomb, or two, or even a torpedo (the Re.2005 had the same loading capability of the Re.2001/2002, that included a W125/450/3.63 600kg torpedo), under the fuselage with a ventral radiator, and incidentally it requires the same undercarriage disposition the Bf109 already had.









silence said:


> Even switching to the G55 you'd only get one of G55 for every two 109s.


That's producing it in Italy. Even producing a Bf109 in Italy would require much more hour of work than producing it in Germany. Were the industrial conditions more than the projects that made the difference.
However, to switch production from the Bf109 to another rather similar piston engined aircraft sometimes in 1944 was simply not convenient for Germans.


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## stona (Aug 3, 2013)

Civettone said:


> Also, I am very curious and sceptical about the Kurt Tank link. I do not see why he would be interested in the licence production. In fact, he would be least likely candidate, as he had the Dora lined up.



Any license agreement would have gone through the RLM, neither Tank/Focke-Wulf nor any other manufacturer had freedom to make such deals. This would make it even less likely. The RLM was more interested in licensing German aircraft technology for production abroad. I too would be very sceptical.

Oh, I think you meant that Focke-Wulf had the Ta 152 lined up. The "Dora" was just a stop gap 

Cheers

Steve


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## Civettone (Aug 3, 2013)

Dogwalker said:


> I'm not saying that Germans had to produce Re.2005s. I'm saying that's possible to carry a bomb, or two, or even a torpedo (the Re.2005 had the same loading capability of the Re.2001/2002, that included a W125/450/3.63 600kg torpedo), under the fuselage with a ventral radiator, and incidentally it requires the same undercarriage disposition the Bf109 already had.


The G.55S would also work. Easier to produce. 




> That's producing it in Italy. Even producing a Bf109 in Italy would require much more hour of work than producing it in Germany. Were the industrial conditions more than the projects that made the difference.


The real problem here is that we simply do not know ! We have all read that the Fiat G.55 took 15,000 man hours to build and that it could be brought down to 9,000 through rationalisation and mass production techniques. BUT who came up with these figures? Can we really rely on them? 
I believe they are estimates. I guess they were based on the technological level and modernity of the factories of Fiat and Reggiane. Fiat probably had the advantage here? I also read that the Reggiane factory was very modern. For sure, the German factories were much more advanced. Even so, I do not believe anyone in the 1930s would have thought the Bf 109 could be produced in just 2,000 manhours but that is what happened. The Fiat G.55 but also the other 5-series could probably have been produced even faster. However, this would require a lot of investments in specialized machinery and continuously training your work force. If you just invest enough, who knows where you will end up? 

Kris


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## DerAdlerIstGelandet (Aug 3, 2013)

Keep it civil guys...


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## GregP (Aug 4, 2013)

Hi Stona,

Better landing gear geometry would have been an improvement to the Bf 109. I believe we already know the landing gear was badly implemented. It has been suggested to try fixing the geometry first ... good suggestion. 

If it works go with it. If it doesn't, move the gear outward and redesign to fix it. Ergo, improvement.

Th entire intent is to fix things, whether it take slight geometry corection or majot redesign. Eliminate the faults to the maximum extent to make it better. Trying to taxi, take off, and land a Bf 109 must be like trying to drive a car that badly needs an alignment.

The redesign amount is entirely dependent on how the proposed "fixes" work. Once they work right, stop improving and move on.

Or at least that was the intent of my suggestions.


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## stona (Aug 4, 2013)

GregP said:


> Hi Stona,
> 
> Better landing gear geometry would have been an improvement to the Bf 109. I believe we already know the landing gear was badly implemented. It has been suggested to try fixing the geometry first ... good suggestion.



Agreed. Other aircraft with similar narrow track undercarriages do not seem to attract the same approbation as the Bf 109. Look at the Spitfire or even the F4F as examples. It is the geometry that is different, not simply the distance between the wheels. 

Cheers

Steve


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## tomo pauk (Aug 4, 2013)

I've posted this many times, a Bf-109 with small wing 'plugs' (but with cut wing tips, so the wing would be still not that big), that would've contained the additional cannons each, while the wheel struts would be aligned more vertically, without the toe-out appearance. No cowl MGs.


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## OldSkeptic (Aug 4, 2013)

GregP said:


> Agree OldSkeptic, wholeheartedly.
> 
> Thye 109F was very good. Later models could have been better but weren't.



Thanks, the size thing is key, there just wasn't enough room to cram everything in that it needed to remain competitive and maintain good aerodynamics, hence the nickname of the 'G" as the 'bulge'.
And the operational requirements had changed significantly from what was envisaged when it was originally designed.

That's why I see the "F" as the epitome of the design. And in good hands a very, very dangerous opponent.

Conceptionally (though the devil is always in the details) I don't see any major issues with the 'extended' 109 design. The longer fuselage gives you more room for fuel, MW50, NO2, etc and allows a bubble canopy. The larger wing improves high altitude performance, agility and gives more room for guns and ammo, bombs and so on. And it should be possible to clean up some other issues like the undercarriage as well, control issues and so on.

It doesn't have to be perfect by any means, just overall better than the G, basically a quick compromise upgrade like the Dora.


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## stona (Aug 5, 2013)

tomo pauk said:


> I've posted this many times, a Bf-109 with small wing 'plugs' (but with cut wing tips, so the wing would be still not that big), that would've contained the additional cannons each, while the wheel struts would be aligned more vertically, without the toe-out appearance. No cowl MGs.



And what do the landing gear legs attach to? The attachment to the truss was to "direct the landing impact loads to a statically favourable point in the fuselage". These things are not as simple to alter as a drawing might suggest.
Is the attachment now to the main wing spar? It ran behind the wheel well IIRC. I'm not an engineer but attaching an undercarriage to a major structural component that was never designed for this might need some careful consideration. Otherwise we are back to a major redesign 

I don't know whether simpler changes in geometry might have been made. As far as I can tell they were never attempted.

Cheers
Steve


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## razor1uk (Aug 5, 2013)

If the main spar and the wing attatchment points had never been designed for the inclusion of landing gear, then it would require a major redesign assuming a suitable alternative redesign wasn't already waiting 'the go'.
If done in a modification of the existing structural way, then the new gears or their mountings would be much weaker than the normal ones, and then you'd severely risk loosing your wings on landings that weren't the most gradual in sink rate and on flater ground.


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## GregP (Aug 5, 2013)

You know, it occurs to me that maybe I’m misunderstanding the geometry thing when it comes to the Bf 109’s landing gear.

We are in the middle of repairing our Hispano Ha.1112 right now and the landing gear is one of the things that had to be fixed. When we hung the gear and tried to retract it, one leg wouldn’t go into the gear well. We were a bit perplexed until we stopped and looked at the gear system. The gear attach points are bolted right to the firewall-fuselage joint. The gear projects forward from the firewall and is tied to the firewall with a turnbuckle-type brace. Simply turning the turnbuckle adjuster changes the gear geometry and it was quite simple to line up the gear with the wheel well in the end.

Since we have been talking about incorrect geometry, I surmise the issue is that when the gear is adjusted so it will retract and hit the center of the wheel well, the tires are not aligned properly for good ground handling. The solution, to me, would be to design a different wheel pivot point setup so the retraction and tracking of the wheel had separate adjustments. That is the wheel tracking should be able to be adjusted separately from the retraction plane. That way, if the tracking is indeed at fault, it could be adjusted without making the gear impossible to retract.


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## stona (Aug 5, 2013)

That, Greg, is a very interesting point!
I was so focussed on the geometry that I completely ignored that the gear still had to retract into the well. Maybe that's why it was never substantially changed. Redesigning the pivot/attachment point under the pressure of war time production may have been considered impractical.
Cheers
Steve


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## razor1uk (Aug 5, 2013)

Interesting info Greg, I wonder how easy it might have been to perhaps have altered/adjusted/redesigned the stub axles angle to the oleo and if that might have helped if they would've got around to it. hindsight sometimes makes things appear to simple and easy/logical than then.
It would seem that Willy once the design was final draughted for producting, he almost ignored any attempt to redress any remaining issues unless forced to by the party/command, - I suppose some of that could be because he likely understood the mass production difficulties within Germany and those vast resources manufacturing manpowers facing them.


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## tyrodtom (Aug 5, 2013)

Were the wheels toed out ?
That's seems to me would be what you'd want. If you came down on one wheel, and it was toed out, it would tend to steer the aircraft outward, bringing the other wing down and the other wheel in contact with the ground, it's toe out would then cancel out the other wheel's, and the aircraft would steer straight.
I think maybe they didn't align the wheels straight because of the fear that the wheels could go into toe in, which would have the opposite effect when you got up on one wheel. 
Toe in would steer the aircraft inward, making it tip ever farther.


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## GregP (Aug 5, 2013)

Just for completeness, on most oleo gear, the wheel can turn on the hydraulic damper shaft and there is a strut that is fixed to the non-rotatable part of the gear lag and one that is attached to the rotatable strut as well as the rotating part. It is called a drag link. You can see it on most oleo struts as two straight link that move when the strut is compressed. You can see the drag link below:






Of course, thesea re not Bf 109 gear legs. It is just to show the drag link and the idea,

Changing the geometry would have been as simple as changing the angle of the fixed part of the drag link. Since that is NOT a major effort (landing gear are designed for all aircraft with retractable gear anyway), I fail to see why it wasn’t addressed … unless the designers were not aware of the geometry issue or unless there was some reason why expending a small bit of time fixing it was simply not considered important. Or maybe Willy Messerschmitt simply refused to consider that it was wrong to start with.


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## stona (Aug 5, 2013)

tyrodtom said:


> Were the wheels toed out ?



I think they were not toed either way. They have a rather odd geometry nonetheless.






Cheers

Steve


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## GregP (Aug 5, 2013)

Most conventional gear aircraft have a small bit of toe-in. Toe-out is what casuses dangerous instability. If you land one wing low, toe-in keeps the plane going with that wing still low. If you had toe-out, the other gear would slam down without pilot control and you could easily have an out-of-control situation.

That is, of course, a general rule for which exceptions can probably be found.

I do NOT know if the Bf 109 was designed with toe-out, but will try to find out. I do NOT like the angle of the axle on the landing gear. It could have been angled so the tire was much more vertical. It probably wasn't because the wing is barely thick enough to accommodate the wheel when it is relatively flat relative to the wing when retracted. In other words, the wing probably dictated the landing gear tire angle rather than ground handling concerns.


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## tyrodtom (Aug 5, 2013)

GregP said:


> Most conventional gear aircraft have a small bit of toe-in. Toe-out is what casuses dangerous instability. If you land one wing low, toe-in keeps the plane going with that wing still low. If you had toe-out, the other gear would slam down without pilot control and you could easily have an out-of-control situation.
> 
> That is, of course, a general rule for which exceptions can probably be found.
> 
> I do NOT know if the Bf 109 was designed with toe-out, but will try to find out. I do NOT like the angle of the axle on the landing gear. It could have been angled so the tire was much more vertical. It probably wasn't because the wing is barely thick enough to accommodate the wheel when it is relatively flat relative to the wing when retracted. In other words, the wing probably dictated the landing gear tire angle rather than ground handling concerns.



If toe out would bring the other wing and wheel down, wouldn't then toe in tend to make the other wing get ever higher?

Maybe i'm overthinking it for aircraft, we use toe out in racecars to make the car turn in better, you don't want a aircraft to be easy to turn on the ground.


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## GregP (Aug 5, 2013)

The toe-in we're talking about is minor. The intent is to set the toe-in so that even at maximum compression, toe-out will not develop. That is for fixed gear, spring steel legs. For oleo struts, they woiuld set slight toe-in or zero toe, depending on the designer's preference.

I am very curious about the toe for the Bf 109. but do not know where to find any information on it. Setting the gear legs so they are centered in the wheel well sets the toe on the Hispano (basically a Bf 109G from the firewall back) and also sets the gear leg so a simple sheet metal lock will engage. There are no other toe adjustments of which I am aware at this time. I can check the Hispano manual and will do so. 

It simply never occurred to me to check it before. However, since it is non-adjustable, it is possible there is no spec for it in the manual. Manuals tend to give you specs on the basic airframe, torques, etc. and settings for adjustable things, not a design analysis.


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## Juha (Aug 5, 2013)

Civettone said:


> True, but he was the commander of a Bf 109 unit. I am sure he knew what he was talking about...



Yes he knew but the question is what he told. Karhunen was excellent lentueenpäällikkö/Staffelkapitän, I have not an oppinion how good he was as laivueenkomentaja/Gruppenkommandeur. After retirement he was very profilient writer, he wrote probably 30+ books, mostly on the FiAF during the war. In those there were 3 infallible men, Magnusson (his immediate superior), Lorentz and himself and 2 hopeless officers, one of his collagues and the C-in-C FiAF. So ef there was some problems in his unit he didn't necessarily reveal that in his books and interviews. Even some ex FiAF officers joked on that. I don't know how it was on Bf 109G training but at least the way he told the initial career of B-239 in FiAF, and he knew that very well because he commanded the detachment which went to Sweden to accept the first B-239s to FiAF and then flew them to Finland, and how it looks after reading the official reports doesn't always meet.

Juha


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## stona (Aug 6, 2013)

Not conclusive, but I've been through a couple of Bf 109 hand books and no angles for toe on the main U/C are given. They give angles for just about every other conceivable part of the airframe so I'm leaning towards a toe of big fat 0.
Cheers
Steve


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## tomo pauk (Aug 6, 2013)

stona said:


> And what do the landing gear legs attach to? The attachment to the truss was to "direct the landing impact loads to a statically favourable point in the fuselage". These things are not as simple to alter as a drawing might suggest.
> Is the attachment now to the main wing spar? It ran behind the wheel well IIRC. I'm not an engineer but attaching an undercarriage to a major structural component that was never designed for this might need some careful consideration. Otherwise we are back to a major redesign
> 
> I don't know whether simpler changes in geometry might have been made. As far as I can tell they were never attempted.
> ...


 


razor1uk said:


> If the main spar and the wing attatchment points had never been designed for the inclusion of landing gear, then it would require a major redesign assuming a suitable alternative redesign wasn't already waiting 'the go'.
> If done in a modification of the existing structural way, then the new gears or their mountings would be much weaker than the normal ones, and then you'd severely risk loosing your wings on landings that weren't the most gradual in sink rate and on flater ground.


 
Fair points, people. 
My proposal is less 'radical' than the Bf-109H, featuring smaller plugs and removed rounded wingtips. The 109H was featuring landing gear attached to the plugs.
File:Bf109H 3Seiten neu.jpg - Wikimedia Commons


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## cimmex (Aug 6, 2013)

stona said:


> Not conclusive, but I've been through a couple of Bf 109 hand books and no angles for toe on the main U/C are given. They give angles for just about every other conceivable part of the airframe so I'm leaning towards a toe of big fat 0.
> Cheers
> Steve


I may be wrong but my understanding of physics tells me that the angle of the wheel axis works the same as a conventional toe in would do.
cimmex


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## GregP (Aug 6, 2013)

The fuselage joins to the firewall in a sort of 90° oval ... not quite an oval actually. Along the lower portion is a sort of straight section.

Inside the fuselage there are two 90° L-shaped extrusions bolted into the fuselage-firewall joint in the mostly straight section. The landing gear attach pivots are bolted to these two shaped extrusions and stick straight out from the firewall. Since they are somewhat wide, relatively speaking, the front of the pivot is triangulated to the center of the firewall with a sort of turnbuckle affair. 

If you twist one way, the front is forced outward. If you twist the ohter way, the front is forced inward. In this manner, you twist until each gear leg retracts into the center of the wheel well and then safety the turnbuckles so ithey can't move. That sets the retraction plane of the gear leg and the alignment of the wheel is cast into the upper gear leg drag link point with no adjustment possible other than setting the gear to retract into the wheel well. I suppose you COULD offer several lower drag link pivots that would slightly alter the alignment. I am not aware that this was ever done, but it COULD be the most simple "fix."

If there were a separate alignment for the drag link alignment, it would be simple to set the tracking of the gear. It would have been a minor redesign. But it never happened.

There is no possibility to move the wheel well since it is right up against the spar. So you'd have to either re-align the drag link (wheel alignment) or make it adjustable in the field. Of the two, I'd opt for an adjustable alignment with a screw or bolt head with threaded alignment movement and a tabbed lock washer that is set and then bent into a locking recess. There are several of these type locking washers in most engines of the time. You set them, bend the lock into place, and it never needs to be touched again until disassembly.

End of the issue. If that didn't fix the tracking, it would be time for redesign.


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## silence (Aug 6, 2013)

Out of curiosity, how would a F-4 stack up against a G-10 and K-4?

Also, can someone please clarify what "toe-in" is?


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## Shortround6 (Aug 6, 2013)

The tires are NOT aligned in line with the fuselage or direction of travel. Same with cars,


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## GregP (Aug 6, 2013)

No toe at all or very slight toe-in is quite stable. Too much toe-in is bad, too.

Toe out makes the vehicle very "twichy" ... it seems to want to dart one way or the other at all times.


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## drgondog (Aug 7, 2013)

GregP said:


> Improvements to the Bf 109F:
> 
> 1) Bubble canopy and a windscreen with much more narrow posts or no posts. No big deal, DO it.
> 2) Landing gear. Move the gear outward to widen the track. Easy but would mean a production interruption.
> ...



Uncle Willy must have been pretty stupid to not figure out how 'easy' such design changes would be..


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## Tante Ju (Aug 7, 2013)

drgondog said:


> 7) Add ore fuel. Put in another 20 gallons at least.
> Where?


 
Should be pretty easy - there is plenty of room in the back of the fuselage, and the 109 versions progressively added more fuel.

See: 

Bf 109 B - 235 liter in L-shaped tank
Bf 109 C - 337 liter in enlarged L-shaped tank
Bf 109 E-G - 400 liter in enlarged L-shaped tank
Bf 109 K - 400 liter in enlarged L-shaped tank plus optionally the MW tank could be used as an extra 115 liter fuel tank.

If the drawings are somewhat accurate, you can see they played with the positioning of the tank, too. The second version (C) seems to also have moved back the tank, the third version (E-K) kept its place but extended it forwards.

The late Gs also had this same tank, they just did not have the valves to use it as fuel tank, but this should be an easy fix. If more fuel is needed, I do not see much problem with a further enlargement of the L shaped main tank. At worst, ballast in the nose or a front fuselage extension ring (a la D9) could solve any possible CoG problem.


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## Milosh (Aug 7, 2013)

Cutaway drawing of a G-14 but should be useful.


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## drgondog (Aug 7, 2013)

Tante Ju - where put 130 pounds and 20 gallons of fuel volume aft of main fuel tank? What would effect to CG be?


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## Milosh (Aug 7, 2013)

> 10) Steal as much 130-grade fuel as you can get and make that DB hum!



The Germans were using C3 fuel during the BoB in the DB601.


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## jim (Aug 7, 2013)

drgondog said:


> Uncle Willy must have been pretty stupid to not figure out how 'easy' such design changes would be..



Mr drgondog
Uncle Willy ,may have not been stupid but
a) it took him 3 years to introduce elementary aerodynamic improvements( tail wheel,streamlined nose, wheel covers)
b) It took him 2 years to introduce the tall rudder and erla canopy
c) never standarised improvements like the fletner tabs, the radiators isolation valves,rudder tabs, and others
d) actually the radiators of the last 109s were simpler than those of -F
I imagine that you would agree that these are not terribly dificult improvements.
Obviously the company had other interests and intentions thatn to improve the 109


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## drgondog (Aug 7, 2013)

jim said:


> Mr drgondog
> Uncle Willy ,may have not been stupid but
> a) it took him 3 years to introduce elementary aerodynamic improvements( tail wheel,streamlined nose, wheel covers)
> *Trade off between drag and weight*
> ...



Willy was an absolute fanatic regarding weight but after he lost control of the Bf 109 manufacturing I don't think he was involved much in production/production design decisions.


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## GregP (Aug 7, 2013)

Well, in answer to some of the questions, I never said moving the gear would be simple. I said it should have been done. I like the stub wing idea brought out earlier in the thread. Simple and easy to implement.

The slight extra aileron size would no doubt add a bit of torsion, but that is why you have designers ... to handle things like required changes to correct problems.

Where to add the fuel? Well, we have a Bf 109G-6 and an Hispano Ga.1112 Buchon. In both of them, the fuel cell could be extrnded backward a bit. If I can fit into the space, surely some fuel could ... and I have been in that space when we were working in that area. The room is there.

I never meant to say Willy was stupid, but he was notoriously stubborn. He may well have thought the Bf 109 to be beneath his dignity to re-address, I can't say. However, of the major fighters, how many did NOT have rudder trim? How many had a canopy with so much framing around it? How many got so solid above 350 mph as the Bf 109?

Name one that suffered more takeoff and landing accidents.

Reading quite a few combat comparisons I note that almost all say the way to handle a Bf 109 was to stay fast. When everyone knows that, it's time to change something.

Sorry, I don't get the objections to improvements but it's becomming increaslngly clear why the improvements were not to come. Here it is 65+ years later. We KNOW the weaknesses and I'm still hearing excuses for not fixing the Bf 109. No wonder it never got fixed in real life. When the war ended the windcsreen was still the worst in service anywhere in a front line fighter. It was still a short-legged bird that was prone to running out of fuel just when the battle was being fought. The controls were still very heavy at speed, and the landing gear was still not fixed.

I'm not saying the Bf 109 didn't make a significant contribution to the Luftwaffe's war effort, it did. I am saying it could have been better almost immediately, but never was. With so much attention to the quality of their weapons, the Germans left the Bf 109 with major weaknesses that could easily have been corrected.

It almost smacks of conspiracy, but there is no real reason to suspect anything more than indifference on the part of the Luftwaffe to the Bf 109's shortcomings except for the obvious point that the weaknesses were never corrected and could so easily have been.


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## drgondog (Aug 7, 2013)

Greg - could be that pilots very familiar with the 109 were solicited. If so, the discussion is always "if we do that, the other thing won't be quite as good" or "production re-tooling to change wing design is XX months" or "add this and your climb rate will be yy less"

BTW - if you move the gear - it has to re-located to main spar or create a major carry through Structure just aft of the leading edge "d' box is.. last - to do so means a major re-design for fuselage carry through structure if wings are to be made 'removable' as before.

MAJOR re-design and significant weight increase - look to Milosh's post 88 for closer inspection.


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## GregP (Aug 7, 2013)

Actually Drgondog, it is quite possible that operational Bf 109 pilots WERE consulted and had no suggestions for improvement. If that is the only fighter they flew, then maybe they never thought of the Bf 109 weaknesses AS weaknesses since that's the way it was from when they first flew it.

I've heard maybe 2 dozen P-51 pilots say it was the best fighter of the war ... but it was the ONLY fighter they ever flew. So how good is their opinion? Depends on the listener I suppose. I like their war stories but have little respect for their opinions of other fighters they never flew and never flew against either.

Adding a stub wing would greatly simplify the gear structure since it doesn't have to support for any long distance. I'd probably opt for that if I were doing the job. Since it never happened, it's a "what if" that means doing a redesign and estimating the weight change. I'm interested, but not THAT interested. I'd probably add a stub spar only as long as the stub wings were wide, and attach it across the bottom of the firewall, right where the gear is attached in real life. I'd move the pivots outward by about a foot and half on each side, and correct the geometry by changing the toe-in setting ... assuming it seemed to still be needed after moving the gear.

Let's just say that if the weaknesses had been corrected early on, things might have gone better for the Bf 109 drivers, though I doubt the eventual outcome would have changed regardless of Bf 109 changes unless production could have been substantially increased.


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## pinsog (Aug 7, 2013)

Sounds a bit like the US Sherman tank to me. Some glaring weaknesses that could/should have been addressed, but weren't because 1. top brass didn't see a problem (because they weren't fighting/dieing in it) 2. they couldn't afford/didn't want to slow down production to make the changes 3. cost/money issues


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## GregP (Aug 7, 2013)

Sounds exactly like that to me, too.

Love the Sherman (we have one and run it ... ours has a Continental radial engine) but, if I were going into a tank battle, I can think of places I'd rather be than in a Sherman ... unless there were a lot of hedgerows around to hide in.


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## pinsog (Aug 7, 2013)

GregP said:


> Sounds exactly like that to me, too.
> 
> Love the Sherman (we have one and run it ... ours has a Continental radial engine) but, if I were going into a tank battle, I can think of places I'd rather be than in a Sherman ... unless there were a lot of hedgerows around to hide in.



Agree 100%

There were fighters I would rather be in instead of a 109 also. But with a few changes it would have really helped it, just like a Sherman Firefly or a Sherman with a different turret and a 90mm gun would have been a whole different animal.


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## Gixxerman (Aug 8, 2013)

In the end tho tens of thousands of (on a one on one basis) 'inferior' Shermans ( T 34's for that matter) were exactly the correct choice verses a few hundred Tigers and a few thousand Panthers.
Dreadful for those poor guys that suffered the Tiger/Panther etc but in the scheme of things it was the winning strategy.

It took another 40yrs or so for tech quality to get so good that quantity really didn't matter so much.


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## Denniss (Aug 8, 2013)

Only in some aircraft


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## Civettone (Aug 8, 2013)

drgondog said:


> Greg - could be that pilots very familiar with the 109 were solicited. If so, the discussion is always "if we do that, the other thing won't be quite as good" or "production re-tooling to change wing design is XX months" or "add this and your climb rate will be yy less"
> 
> BTW - if you move the gear - it has to re-located to main spar or create a major carry through Structure just aft of the leading edge "d' box is.. last - to do so means a major re-design for fuselage carry through structure if wings are to be made 'removable' as before.
> 
> MAJOR re-design and significant weight increase - look to Milosh's post 88 for closer inspection.


I completely agree! I think it is very easy for us to assume the role of the all-knowing-aeronautical-engineer, but we have to assume the designers/engineers knew what they were doing. If they would be with us, they could probably come up with a dozen objections to the things we propose. I think we should be very careful and above all, modest about what we think should have been done.


Kris


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## jim (Aug 8, 2013)

Often even engineers disagree between them about what s good. 
I have read somewhere that when some german enginners saw the spanish 109s with the internal wing cannons critisized the choise for weakening the wing.. Who was correct? Who knows...
Mr Greqp
Do you believe that there was space for improvement in the wind screen section of the 109? Impropvement that would bring speed benefit?


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## GregP (Aug 8, 2013)

There certainly IS space and it would certainly improve the view. Whether or not it would result in any speed increase depends on the entire cockpit canopy, not just the windscreen. 

For best streamlining, the height of the canopy above the fuselage should be about 1/3 or less of the horizontal length of the windscreen and the sliding (or swining as the case my be) part of the canopy enclosure needs to be at least 3 times the horizontal length of the windscreen. Any shorter and drag starts to increase. What that tells me is that there SHOULD be a slight decrease in windscreen drag with a new canopy.

How much speed difference it would make is dubious and would have to be determined in a wind tunnel or on an aircraft. If there was an increase, it would be slight ... on the order of a few knots, maybe even 1 or 2 knots.

My chief concern would be to make the canopy frames as small as possible and to fit a bubble-type canopy enclosure ... for the purpose of improved visibility, not for any speed increase which, though small, would be welcome I'm sure ... if it was noticed at all by the fliers.

When I go into the Museum Saturday, I'll make sure to charge my camera and get some landing gear shots and some canopy shots. I'll post them in here Saturday or Sunday.


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## silence (Aug 8, 2013)

How about going back to a canopy with rounded rather than angled edges, a la the Emil? I read somewhere that sharp angles produce a lot more drag (this was an issue with the old Lamborghini Countach, as I remember). Or a Erla canopy with rounded edges and the armored glass headrest thingy. At least then you'd get some improved vision without having to redesign the fuselage, too.

Not sure if the drag saved is significant, though. But, yeah, gotta get rid of those prison bar frames.


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## GregP (Aug 8, 2013)

The windscreen was awful. The canopy, while not my favorite by any means, isn't bad except for rearward visibility.

I have sat in Bf 109 / Ha.1112 cockpits for some time while working on them. The visibility forward and I mean directly forward is OK. Anything to the side, even slightly, is almost blind. Terrible except directly forward.

That's what I would change before anything else. I'd also put in a curved windscreen bow, meaning a new tilting or sliding canopy, too ... as a result of the curved windscreen bow. Don't even tell me they couldn't do it. Go look at an Me 163B or an He 100 or even an Me 262, which has a decent windscreen with small frames and is very close to a P-51 windscreen.


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## stona (Aug 9, 2013)

The problem with visibility is not just the canopy design, framework etc. The cockpit is very narrow. It is so narrow at shoulder height that it is almost impossible for an man of average build to turn to look behind (assuming the view is going to be anything but armour plate), unless his neck operates like the girl in "The Exorcist" . Behind is where the most immediate danger is likely to come from. I know because I've tried. That is not an easy fix.

There is an old joke that evasive action in a P-47 meant running around in the cockpit, not an option in a Bf 109 

Cheers
Steve


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## GregP (Aug 9, 2013)

True ... it IS narrow, but not so much unless you're sitting on a parachute as in combat. If you are, it IS narrow. If you aren't it is ... OK. If you are face down with your feet sticking out trying to bolt in the landing gear brackets on the inside of the firewall, it is absolutely insane. Been there, done that ... no thanks again.

I don't really see the narrowness as an issue, but I was sitting in it without a parachute on the ground ... not in the air WITH a parachute at 5+ g. In that situation, I can see the issue. The solution is a slightly shorter stick with more mechanical advantage and relocated tabs for the control cables. VERY possible ... might need thicker elevator and aileron skin or at least doublers.

I have also sat in a replica Caurdon C.460. The cockpit is as narrow as your head ... without a helmet. Very claustrophobic and very likely to kill you if ANY impact happens. But ... a decent-flying aircraft to hear Mark Lightsey tell it (the builder and pilot).

I have an offer to get into the cockpit of a flying de Havilland Comet replica and will DO it when I get the chance.


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## drgondog (Aug 9, 2013)

Greg - you're designing in a 'no amateur' zone and making suggestions based on your observations - not facts or design approach based on facts and choices based on facts. The 109K was a derivative of the original 109 with few external/internal changes regarding layout of critical components such as cockpit dimensions, control surfaces, control links, seat arrangements, etc. 

Your assumptions of "VERY possible" are based on your limited knowledge of the specs, the data, and the reasons for the design questions and ultimate design decisions. In essence you have declared victory based on your opinions versus some of the finest airframe design engineers in the world. 

Good luck with that.


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## GregP (Aug 9, 2013)

Thanks Drgondog for the "good luck" encouragement.

You are pontificating based on no design work on improvements to the Bf 109 at all. Doing no redesign is easy. Coming up with "fixes" isn't quite as simple but is way more fun. None of my suggestions for the Bf 109 were taken to final design stage, they were suggestions on a way to go to help fix some shortcomings back in the day, not complete redesign plans and drawings complete with stress analyses. If I had a Bf 109F today, it would have a modern panel, but the rest would be as stock as possible.

I have participated in the redesign of several items on our YP-59A Airacomet including design and fabrication of a completely new sliding canopy that is now on the plane and helping with changing the trim tabs into boost tabs on the ailerons. I am now working on adding an external canopy crank that doesn't protrude into the airstream. I also designed and fabricated the sheet metal to keep water out of the cockpit when we wash it and was half of the team that made a new windscreen bow when the old one was shown to be insufficient. 

So far, all of the projects I have worked on as "fixes" are on planes that are flying (includes a Vought Corsair and a Northrop N9M-B Flying Wing) or still in restoration to fly in the future (includes a Bell YP-59A, a North American O-47, a Yokosuka D4Y Judy (static on purpose), an Aichi D3A Val, and modifications to one of our AT-6's). I've also done several mods to a freind's RV-7 at his request. It flies frequently.

I was one of three guys who restored a WW2 pulsejet to running condition. You can see it if youi Google "Chino Pulsejet." The gray Nissan Titan being pushed down the runway is my truck. That was an entire exercise in "fixes" and there was no manual. Took 2 years but was worth it.

Sorry you have such a low opinion of my general suggestions. Glad other people don't or I wouldn't have so much fun doing it every weekend. Some of my Bf 109 suggestions would be fun to put on our Hispano Ha.1112, but the objective is to make it back into a stock Hispano, not modify it into something that never flew operationally. We're well along with it now. Most of the Hispano mods have consisted of going to SAE hardware where practical but I did rebuild one wood structure for a radiator by simply duplicating the shape of the deteriorated unit.

Good luck to you, too, guy.


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## drgondog (Aug 9, 2013)

Greg - have you given any thought to the enormous leap to go from piddling around with restoration of an existing airframe to analyzing the implications of making major re-design decisions affecting tooling, spares, production efficiency?

Sometimes good ideas for incremental improvements are discarded primarily for one or more of the factors above.

As to being 'sorry', you shouldn't care for my opinion one way or another..


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## drgondog (Aug 9, 2013)

GregP said:


> Thanks Drgondog for the "good luck" encouragement.
> 
> You are pontificating based on no design work on improvements to the Bf 109 at all. Doing no redesign is easy. Coming up with "fixes" isn't quite as simple but is way more fun. None of my suggestions for the Bf 109 were taken to final design stage, they were suggestions on a way to go to help fix some shortcomings back in the day, not complete redesign plans and drawings complete with stress analyses. If I had a Bf 109F today, it would have a modern panel, but the rest would be as stock as possible.
> 
> Good luck to you, too, guy.



I forgot to comment on this pearl of wisdom.

You also seem to struggle a little bit with how design mods work.
1.) Customer requests the change.
2.) Airframe group analyzes and proposes changes to a.) airframe, b.) effectivity, c.) non-recurring costs to make and implement the change, d.) unit price change for new version (which includes tooling, space on the line, re-training, communication and on-going support)

It usually Doesn't originate from a bored engineer flipping paper clips into the ceiling, and in times of war - always originates and receives approval (funded) from the customer after being blessed by Company management team including the Chief Designer, the Chief Manufacturing, the CFO and CEO.

I'm happy for your experience and skills as a restorer. While my experience at Lockheed and Bell as design, preliminary design, airframe structures and manufacturing Liaison engineering and project management may not qualify in your mind as one to comment on your vocalized thoughts...? 

Oh, well I can live with that.


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## GregP (Aug 9, 2013)

Not being in the design end of an aircraft production staff, I don't care one way or the other myself. The thread went toward suggesting improvements for the Bf 109F and I went with it. This forum, for me anyway, is for exchanging information and for fun ... not for completed redesign plans. All my suggestions would have been run through the Messerschmitt design staff had I been there, not done on a one-or-two basis. Some were simple, like adding a rudder trim tab. That's almost a no brainer and should have been there from the start. Brain fart on Willy's part. 

Others would have taken some time, like moving the landing gear. I think they should have done so and early on, even before they were sent to Spain. Obviously you think the Bf 109 was fine the way it was. In the end, so did Willy since the changes were never done. That doesn't leave much room for discussion about changes, does it?

Viva la difference.

I have regard for your opinion, but not so much when it is cached in sarcasm or insult ... much more so when it is given objectively and constructively.

Cheers.


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## GregP (Aug 9, 2013)

I was primarily in the electronics industry (electrical engineer) after changing from aeronautical engineering in my junior year. We had procedures, too, for changes that ran about as you describe above.

But when WE were the design agency (like Messerschmitt was) and had suggested improvements, we suggested them together with NRE and all costs. Sometimes they were accepted and sometimes not. If the product was ours, we suggested to an internal staff and the suggestions were either accepted or rejected based on incremental cost and break-even time. I believe we have already touched on whether or not the Nazis would approve any Bf 109 changes. It appears they might not have approved any changes.

So don't go thinking that you were alone in management or engineering. There are LOTS of us out there. I'd bet a good deal that we have 25 or more managers or former managers in here who can write out a change process easily and can do a cost breakdown. As far as that goes, the cost would be minimal if done while the planes were in production, but would be more expensive if retrofitted.

I'd have gone with the changes in the production phase and lived with the existing aircraft.

Enough about us and the change process, let's get back to the Bf 109F, OK?

Great plane with some flaws ...


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## drgondog (Aug 9, 2013)

Yawn


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## razor1uk (Aug 9, 2013)

I think their is some kawasaki green-ness building to a fire risk soon here...


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## GregP (Aug 9, 2013)

Back to the Bf 109 after a brief stopover in the "who can piss farther into the wind" zone. I have to let that go or it escalates and somebody gets wet. I seem to recall a warning before on it, so I give. 

I went to the Museum today and got some pics so we can see what we are talking about. Below is a pic of the firewall and gear brackets. You can see the bottom of the fuselage oval has a more or less straight piece in it and the gear bracket is attached to both the fuselage and the firewall at a 90° angle and is bolted from both directions. There are also bracket backings inside the cockpit.












You can see there's room along the bottom of the firewall for a stub spar across the botttom to extend the gear to the end of a stub wing. The gear alignment adjusters are easily adjusted and locked in place but they can’t be adjusted for alignment except to make the gear leg fit into the wheel well. The drag links set the wheel alignment and are are cast into the upper gear leg.






As you can probably tell, these aren't Bf 109 tires. While we are working on it we have MiG-15 tires fitted since we have them and they fit.

I thought the pics would make it more clear.

Here is some eye candy. While I was there they were rolling out Race 232 for the first pre-Reno 2013 test flight. We filled the boil-off oil cooler with ADI (water-methanol) and fueled it. The test fight will probably take place tomorrow or Monday.






Race 232 finished second at Reno last year in the Unlimited Gold class, but Rare Bear is back WITH sufficient cooling, Strega is back and Voodoo is back, so poor old 232, with a quite stock R-3350 of about 3,600 HP, will be lucky to be fourth unless someone breaks. Of course, I'm pulling for Stevo Hinton Jr, in Voodoo. Go Stevo!

Here's a clip of Race 232 when it was September Pops:


_View: https://www.youtube.com/watch?v=wMPdV6xA8X0_

In case anyone is wondering, the R-3350 is an 18-cylinder engine and there are 9 exhaust pipes on each side.


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## GregP (Aug 9, 2013)

Here is the rear access hatch. Believe it or not, I've been in there myself! Tight fit for me. The second pic down is looking forward inside the access hatch. As you can see, there is plenty of room for slightly more fuel right there.











The bottom curved parts of the bulkhead are where the Oxygen tank would go, but there IS enough room for extra fuel to a point.


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## Tante Ju (Aug 10, 2013)

GregP, thank you for posting these wonderful detail pictures!


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## GregP (Aug 10, 2013)

You're welcome. 

If you have any requests, I can take pics. Look at the Planes of Fame website. Many of the planes are at Chino while some are in Arizona. I can get any detailed pics of the Chino planes easily and will post if asked specifics. For some, I can get cockpit pics ... but not for all. Some of the planes are owned by private owners and we can't get on them to get cockpit shots.

Here's a shot of the bottom front right of the cockpit of the Ha.1112. Everything has been removed or you'd see the rudder pedals near the landing gear backing brackets. The nuts you see at the bottom are actually at the top of the landing gear mounting brackets, so the stresses are carried by about half of the firewall-fuselage joint.






You can probably see the bolt pattern matches the upper landing gear mounting bracket in the second bracket pic 2 posts above. The entire cockpit has been cleaned out and we are starting on the new instrument panel now. We have SOME original instruments, but also have some USA-required instruments that have to be there to get an airworthiness certificate in all practicality. 

Altimeter and airspeed come to mind. They need to be in feet and knots to fit in with air traffic control and avoid overspeeds below 10,000 feet, which the Ha.1112 is easily capable of.


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## GregP (Aug 10, 2013)

I mentioned in my rant above with Drgondog that I had made a new canopy for the Bell YP-59A. Here is a pic of it sitting backwards on the starboard wing:






The people involved were me, Greg Pascal, Bob Velker (the defacto leader), and Fran Pieri (former B-47 pilot and American Airlines Captain). Below is the method we came up with to hold the canoy on the plane in flight. I'll get a shot of it when the emergency release handles are in place the next time we put the entire canopy together. Yo0u can see the sheet metral doesn't exactly fit the windscreen near the top ... but it WILL when we're done. Just a bit more ""persuasion" is required.






We made the emergency release mechanism from a milled-down Grumman F8F Tigercat emergency release mechanism. It was about .025 inch too wide so we milled it down so it would pass the structure. Seems to work just fine.

I also said we made a new canopy bow. Here is a pic.






We modeled it out of balsa wood, went and got a 6-inch cylinder of 7075 Amuminum, cut it in half on a BIG bandsaw, sculpted the bow on a mill, and sanded it to exactly conform to what we needed. Solid and not too heavy. Besides which, we'll need about 1,000 pounds of lead in the nose anyway to make up for the lack of guns, so 4 pounds or less isn't excessive.

Nothing to do with a BF 109F but seemed relevant to thread development so I don't come across as a bullsh*tter. I am one of about 300 volunteers who get it done for the Planes of Fame.


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## GregP (Aug 10, 2013)

Here is a pic of where the Hispano engineers put the cannon port. We have covered it with sheet metal to save weight since the USA frowns on civilians flying armed aircraft AND the intent is to mimick a Bf 109, not an Ha.1112 Buchon.







You can see the slat just outboard of the cannon port. It is retracted in the pic, but air pressure extends it when the plane nears a stall angle of attack. I can get a slat-extended pic if anybody wants to see it.


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## GregP (Aug 10, 2013)

I also said we restored and ran a WWII pulsejet. Here is a clip of it pushing my truck down the runway at Chino. I am the guy behind the driver seat in the truck bed. I started the pulsejet and the primary restorer, Robin Scott, is the guy who steps up and puts the engine into high thrust mode from the idle mode start, and then sits on the trailer.

Robin was the primary force behind the resotration and I helped along the way. He flies a red Yak-52 in airshows when he isn't bored and plays jazz guitar for a hobby away from flying and restoration. AND has cold beer. What more can you ask?


_View: https://www.youtube.com/watch?v=KTv7dfs_Mlc_


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## stona (Aug 10, 2013)

Very nice images.

Here's a drawing of the main gear attachment on a Bf 109 E, from the parts list, to compare with the first image.






Very similar (as you'd expect).

Cheers

Steve


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## jim (Aug 10, 2013)

Mr GreqP
Nice photos. Thank you for posting them
I would like to ask you this. What internal changes has the wing in order to fit the 20mm cannon? Have the spaniash holed the wing s main spar?


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## cimmex (Aug 10, 2013)

The Spanish 109 had a complete new wing with two spars to hold the cannon. This pic is from meiermotors who is currently restoring a Buchon.
cimmex


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## GregP (Aug 11, 2013)

Checked the manual today and the landing gear toe-in is not specifed, as I expected. Since the drag drag link is cast into the gear leg and is not adjustable, I suppose there is no point in specifying it.

When we repaired the wing damage after the groundloop, we removed the outer wing fuel tanks and the pic above is accurate ... the spar has a hole in it but is strongly reinforced as you can see.


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## GregP (Aug 11, 2013)

Hey Civetone,

In case you liked the pulsejet, here is a short video looking down the throat of the engine while it is running, You can hear this thing for about 10 miles and we scared the crap out of the poor woman in the Cessna 152. The main thing I like about it is you can see the reed valves working ... sort of. The frequency is about 43 Hz, so the sound really carries.


_View: https://www.youtube.com/watch?v=U-xlttsfWn4_

And here is one of a short evening run:


_View: https://www.youtube.com/watch?v=j4hBwCDRwK0_

We only have two sets of reed valves and so we don't run it for more than about 1 minute and 20 - 25 seconds. We stop when the pipe temperature reaches 1,100°F or so. When it does, the reed valves are not really all that hot. So with maybe 40 runs on it we have about 25 hours on the reed valves and they are in good shape since we don't run them until the melt.

Unfortunately the unit is down right now for something as mundane as the fuel pump. We need to take it out and get it rebuilt, but the museum doesn't want to fund it ... and we already have enough of our own money in the engine as it is. The cowling you see is home-made and we spent several thousand dollars reproducing the rubber diaphragm for the fuel controller (had to make a mold at a machine shop ... the original had turned into rubber dust).

So ... when they want to run it again, they'll have to rebuild the fuel pump ... it started grinding and leaking and raw gasoline around a hot pulesjet is a formula for an explosion that nobody wants to be around.

Interestingly we can run it on 87 octane or 100 Low Lead but the needle valve settings are different. It seems to prefer 87 octane which it what was used in them in WWII. When we have correct fuel pressure, it strats and runs very reliably.

This is what it looked like before we restored it:






This is what it looked like when we first got it to run:






And this is it when we finished. Same trailer .. .we restored that, too.






The little wire-like thing coming out of the bottom of the cowling running back for a foot and half or so is the thermocouple we use to monitor pipe temperature. That's Steve Hinton's P-51 in the background.

OK, back to the Bf 109F!


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## wheelsup_cavu (Aug 11, 2013)

I had never seen those before restoration pictures. 
After seeing them it makes the accomplishment of getting it running all the more impressive.


Wheels


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## Civettone (Aug 11, 2013)

GregP said:


> It seems to prefer 87 octane which it what was used in them in WWII. When we have correct fuel pressure, it strats and runs very reliably.


Greg, I always read that the pulsejet was loved because it was able to run on much inferior fuel quality.

Also, how do you assess the vibrations? It is said that the vibrations were too much for the Me 328. But, maybe that's an unlucky matter of oscillations??


Kris


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## Milosh (Aug 11, 2013)

Is that an Argus engine Greg or the American copy as used on the Loon?


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## Shortround6 (Aug 11, 2013)

Thank you for all the pictures. They do help in understanding the layout and construction.


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## GregP (Aug 11, 2013)

The engine is a US engine, not an esact copy of the Argus, and was used on the Loon. The US pulsejet is smaller and produces good thrust. We were amazed that the addition of the cowling increased the thrust by 30% or so and we all figure it was the shaping of the cowling that helped direct better airflow into the intake.

Interestingly, forward speed seems to have an effect since we only got to some 15 - 20 mph and the thrust went up another 15% or os even with that slow forward speed. We have a force transducer on the test stand and we get a direct thrust readout, which we calibrated with a canbrated spring. We used a spring with 70 pounds per inch of force (±1%), compressed the spring two inches and adjusted the transducer to get 140 pounds of readout thrust.

We'd love to restore an actual Argus and get it running, but we don't HAVE one. The hardware would be essentially the same. You can see two fuel nozzle lines in the video and the Argus has three. So we MIGHT need 1/3 or slightly greater fuel pressure and flow, but it runs the same as the US pulsejet. We have carefully compared the Argus diagramns with what we see in our pulsejet, and everything is similar. 

There IS a real Argus at Chino, but it is in the Yanks Air Museum. not in the Planes of Fame. They have great displays and some really interesting aircraft, but don't fly their planes or operate their display engines. So, we're left with our pulsejet ... when someone wants to pay to overhaul the fuel pump, we can run it agains easily. We KNOW how it works by now and how it starts and transitions between idle and working thrust.

The vibrations are a bit brutal. It goes from full thrust to almost zero thrust about 43 times oper second and you can really feek the vibration ... but not for too long. The heat generated, bot radiant and infrared, is intrense. When you stand right next to it to set the fuel controller, it gets painful rather quickly just from heat.

The German Argus was about 1/3 or maybe a bit less large and the frequency should be a small bit less, say 2 - 5 Hz or that ballpark, but the vibrations would be slightly larger in amplitude and slightly longer in duration. We designed a small aircraft to be powered by the pulsejet we have, but is was a paper design using Lanxair wings and new fuselage. We did the basic desgn, but did NOT do any vibration investigation bevause the Museum would not sell us the pulsetjet or let us try to fly it. Ergo, it would have been a waste of time on our part when beer was available and calling. However, if we manage to get it or one like it, the design could be revived easily and the analysis could be continued.

There were two of us working on the design, me and the primary restorer. The design was basically his and I looked into stress and weight. We KNOW already what a completed Lancair wing weighs since we have a friend who made one and we weighed the wings, complete with control linkages. The fuselage would have been aluminum with a fiberglass nose cone with streamlined fixed landing gear. It would have looked like a miniature He 162 sort of (with the twin tails) only with low-mounted Lancair wings. The intent was to keep it as light as possible while being able to handle 6 - 7 g's in a 5 minute show routine.


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## bobbysocks (Aug 11, 2013)

Civettone said:


> Well, that kinda knocked me off my feet. Because I distinctly remember this well known website about Finnish experiences with the Bf 109:
> virtualpilots.fi: 109myths
> 
> And I am talking about empty weight, based on official German test report sheets. Of course the G-6 gained more weigth.
> ...



check this site out... WW II ACE STORIES


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## bobbysocks (Aug 11, 2013)

just remember when you are modding a plane you are still at the mercy of the other technology of that specific time. so if you move the gear outward or put a second spar you will add significant weight to the same aircraft with the same engine. you will most likely lose performance just like they did with the G model. so what are you really gaining? nothing. also, yes, you can probably stick a fuel cell aft of the pilot but what happened when they did that to the 51s?? you had to limit your maneuvers until it was emptied down to ~25 gallons. this they could do while heading to the RV. if jumped right away with a full center tank....would be no fun. the same thing would happen to the 109 if you did that. it would have to be a small enough tank to be emptied when they reach alt. you would be way better off with drop tanks. you can burn all the fuel you want but when the fit hits the shan you can dump them and maneuver like you need to.


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## GregP (Aug 11, 2013)

Hi Bobbysocks,

I get the fact that many out there are strongly resistant to changes to the Bf 109. In real life it didn't change much except to get heavier.

It WOULD have had I been in charge, which I wasn't. Since it is a "what if," I think my suggested changes would have resulted in a better airplane. 

Anyone and everyone is free to feel otherwise. But if I couldn't improve the Bf 109, I wouldn't be much of a designer what with the poor sideward and downward visibility, stupid langing gear, extremely short range, poor control feel at higher speeds, and limited stick leverage. I think Willy could have easily improved it, too, but simply didn't for one reason or another, We are unlikely to find out why not at this late date and the few left are certainly better off staying stock in msueums and the few flightworthy examples remaining.


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## silence (Aug 11, 2013)

So, then, since Willy wasn't going to make changes, what could be done in the field? I like the Galland special with the 13mm MGs and little bumps. I also understand that the 601E used 87 fuel; why not tune it up for C3 and increase the boost pressure (I think that's what the change would be useful for - please correct me if I'm wrong!)

And which was the last unit to use the F? How long into the war did it soldier on?


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## bobbysocks (Aug 11, 2013)

greg, i am not resistant to change or improvement. i am sure there are things that could have been done to the F series to get the most out of that airframe / engine combo. like others have said its rob peter to pay paul for the most part. whats it going to gain you vs is it really worth it. a retractable tail wheel and cleaning up of the air frame....removing any possible bump ( with the exception of a rear view mirror), seam, high standing rivit, etc. ...having gear doors that completely cover the retracted gear....no fabric used at all.... could have netted you a little more speed. rudder trim and some way ( possibly a more complex or compound system of pulleys ) to boost flight controls at high speeds IF *the airframe could take that degree of stress*. experimenting with vortex generators and ways to lower the stall speed...many turning battles were fought in the edge of stalls. ways to boost and cool the engine with existing space restrictions. better vis with a better designed hood. drop tank / bomb rack. experiment with different size wings and styles of wing tips....experiment with manually operated standard flaps instead of slats...which would require moving the radiators <<<< so that would be in the mix if it could be done in a more aerodynamic way. some of these may be impossible to impliment but i would have a go at it. 

as for the design of the u/c...yeah its not ideal but get over it. if you're a pilot you learn to fly it. i dont see any data...other than the mythical rantings quoting ungodly high numbers that no one can prove... that the LW suffered significantly more accidents during landing DUE TO AIRPLANE DESIGN or PILOT ERROR than the allies or other axis contries. i have a bunch of pictures of 51s with that wide gear ....cracked up on a field without battle damage....it is what it is and they were all about the same. und das ist meine zwei Pfennige wert....


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## GregP (Aug 11, 2013)

We already know the airframe can take a good deal of stress. Speed doesn't change the ultimate strength of the structure. If it can take, say, 7 g, then it can take it at any speed that is under the flutter speed. Since Bf 109's were involved in many, many diving attacks, I feel pretty safe in saying the flutter speed was high. The Bf 109K could hit 450 mph and possibly slightly faster. To have a safe margin, the flutter speed should be higher than 500 mph, so it isn't an issue.

I don't believe they were about the same and I do believe the Bf 109 had more than its fair share of ground accidents due to the gear. The stall speed was low and the takeoff run was short. They operated out of farmer's fields.

I don't have to get over anything, I like the Bf 109. The thread evolved along the path of what could be done to improve it and I went with it. Nothing more. One change I'd definitely make after watching some combat film is to change from 3 wing mounting points to four. That way, if ONE failed for some reason, the wing woudn't fall off as it was otherwise prone to do. I'd also change the windscreen as a minimum into something MUCH better. 

That's two changes I'd make for sure, even if it interrupted production for a short time in addition to adding rudder trim. Of course, I'm also not running Messerschmitt ...

As for what could be done in the field, the answer is almost anything. They had the normal tools for repair and such, but also had fabrication tools for repair of battle damage. That being said, they did NOT have metal casting facilities, so major changes would be tough but doable on a one by one basis ... if there was ample proof of need for the changes. Apparently there wasn't as I haven't seen a lot of pics of field-modified Bf 109's.

We had and have to do fabrication to restore our Hispano, the YP-59A, and the pulsejet, but we also have sent some things out to local shops who specialize. Maybe those jobs could be done in the field and maybe not. Most field mods are done for the sake of necessity, such as fitting more fuel for a special mission. They don't usually engage in field redesign whout getting into some trouble with the powers that be.

So, I'd lean toward most field mods being of the repair and special fitting for specific mission type of mods in the real world.

So possible changes are one thing and likely changes are another ...


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## OldSkeptic (Aug 12, 2013)

Greg I think the 109 (at least the E anyway) had very good positive G limits but poor lateral ones. From memory I remember reading that pilots (again in the E so not sure this applies to the F) were warned to not get any yaw or side slip in a dive otherwise they could overstress the airframe.

As for field modifications it is amazing what they could do at times. The great story of the RAF's ME Command modifying a Spit V to get the high altitude performance to take out JU-86Ps is a classic of its kind.

But back to the F (as I have said that I think was the epitome of the basic design) , the problem is that when they need more engine power and firepower the airframe was just too small to encapsulate them, hence the G 'Bulge', which meant the originally excellent aerodynamics were severely compromised so that the G never really delivered the performance the basic design potentially had.

Though the German engine manufacturers can take some blame for going towards 'make it bigger, rather than more boost' route.

Hence the 'lengthen it' argument for a post F model. Longer nose for the later larger engines, but a longer fuselage to maintain balance (plus the added advantage of some more room for extra fuel, power boosting stuff, etc). Naturally the weight goes up (and the 109 was always the lightest in its class in the European theatre) hence the 'bigger wing' as well.


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## GregP (Aug 12, 2013)

I pretty muich agree, Oldskeptic.

It would not have hurt to be a bit bigger and could easily have helped a LOT. But ... the basic F airframe could have had several things fixed without much weight gain or much effort. Among those would be windscreen and canopy (might actually be lighter), gear toe-in (NO weight gain to fix the wheel alignment), rudder trim, and a bit of exra fuel.

It also would not have taken much to change to 4 wing-mopunt points from 3. They already had the design from the main spar. They only had to make another one and the weight gain would be quite small ... probably no more than 40 - 50 pounds total for both fuselage and wings. Many more pilots would have gotten home.


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## OldSkeptic (Aug 12, 2013)

Greg agree totally.

I just take the case of Supermarine (and for others reading this this is not a 'Spit vs 109' rant' and what was better), this is evolutionary production engineering stuff. And the endless fixes and changes they made throughout the Spit's life. And North American and the Mustang .. and the Mosquito .. and the 190 ... like all the 'greats'.

Feedback from operations, work out a fix and then include it into the next production batch sort of stuff. It doesn't have to be perfect, just good enough and better than what went before.

Again, my great admiration of Kurt Tank and his team (in my opinion Germany's Mitchell, not just a great engineer in himself, as he was, but a great leader of a technical team). You contrast the 190 development vs the 109 and you see good teamwork, where R&D worked closely with requirements and production. Continually improving the plane and producing much needed variants as needed, without the chaos and 'perfectionism' that crippled so much of Germany's efforts (in all areas not just planes). Sadly, again let down by the German engine manufacturers far too often.

The UK and the US has a lot to thank Rolls Royce for, for never deviating from, despite much political pressure at times, from the 'main game'. Plus without RR creating and pushing it the Merlin Mustang would never have happened (the US was not interested, the British Air Ministry was against it ... and Portal was very against it).

Hives, that very great man. a very 'unsung' hero and the architect of why RR was the antithesis of (say) Daimler Benz. As he would say, in his own inimitable way, "a good engine NOW is worth far more than a 200% better engines THEN'.

So even if Willy had been interested (which he wasn't in the least) in future 109 development he would still have been up against DB and the like (oh the games they played, DB promising the earth about the 603 as a political play to do down Jumo, got a whole factory allocated .. then did nothing, in their minds they had won by crippling the opposition ...hmm sounds familiar as Mark Twain said "history rhymes").


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## Kryten (Aug 12, 2013)

Was there any growth potential left in the 109 though?

It was designed as a small, lightly built aircraft, was there any realistic development left, the late G and K were basically tinkered adjustments rather than evolutionary steps, should the 109 have been made obsolete earlier, replaced by the newer 190 designs?


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## CobberKane (Aug 12, 2013)

Kryten said:


> Was there any growth potential left in the 109 though?
> 
> It was designed as a small, lightly built aircraft, was there any realistic development left, the late G and K were basically tinkered adjustments rather than evolutionary steps, should the 109 have been made obsolete earlier, replaced by the newer 190 designs?


 
As I mentioned in an earlier post, I think the 109 F was the nadir of the type, in that it was the last 109 model that was the equal of anything the allies had, and in 1941 'anything' was the Spitfire. That said, through to 1943 it could be argued that the later marks of the 109 were still as good as anything EXEPT the Spitfire IX, and not hopelessly outclassed then. And over most of Europe it wasn't going up against Spitfires anyway, it was dealing with mid war models of the P-47 and P-38 which were still struggling to achieve parity at that stage.
Then came the P-51 and improved models of the Thunderbolt and, to a lesser extent, the Lightning. I think by this time the pattern of sticking more and more powerful engines into that small 109 airframe really began to run into the law of diminishing returns. The Messeschmitt got faster and faster climbing, but it got more much more unforgiving too. No surprise there. I'm an averagely good driver, but give me a five hundred horsepower Mini and tell me to drive it fast around a racetrack and pretty soon I'd be a hole in the scenery. Give me a five hundred horsepower Corvette and I might not set any records, but I'd at least survive the experience. If the Germans hoped to maintain parity with the new allied fighters, the Fw190 was the way to go.
Still, hot rod versions of the 109 like the G-10 and K still made sense. They might not have been quite the equal of the latest Allied fighters, but they were still in the ball park. They were also cheap and fast to produce. Looks good on paper, but I suspect there wasn't another late war fighter that asked so much of its pilots when they had less and less to give.


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## Civettone (Aug 12, 2013)

How was the Bf 109K not as good as the latest Spitfires or Mustangs??

Its controls were rather heavy, other than that, an excellent machine with a superior flight performance, speed/climb rate as well as manoeuvrability. 

I think this _intuitive_ idea of too much horsepower for such a small frame is terribly misleading. There is nothing which indicates this. Did it suffer from excessive vibrations? Mechanical defects due to the too much power? I have never heard of any such thing. 

Kris


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## bobbysocks (Aug 12, 2013)

i agree they should have probably made the 109 a little bigger all the way around. it should have morphed like the 51. the H model looks like a 51 but as i understand shares none or very few parts of a D model. its a completely different ac. in order to keep the sleek lines of the 109 and accomidate a larger engine or the supercharger unit it should have had a major overhaul/redesign....only problem was did germany have the resources to run 2 simultaneous productions lines? one to keep the older version replacements flowing while the newer version was being built and ramped up?


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## GregP (Aug 12, 2013)

I like the Bf 109K except for the intrinsic weaknesses that I have touched on already.

1) I covered the windscreen / canopy thing. It might be lighter than the existing unit.
2) Fix the toe-in. No weight gain.
3) Add rudder trim. Very small weight gain.
4) Have to make the plane handle better in aerobatics and at speed. Not for the sake of aerobatics, but for combat maneuvers. Most test reports I have seen state the 109 was difficult to fly in aerobatic maneuvers, even combat maneuvers. This might be due to relatively small tail surfaces or something else, but I'm SURE it could be corrected. This is from reading maybe 10 flight reports, probably 7 of them of British origin.
5) I've never been sure the slats were needed. Might be able to eliminate them and add some washout ... might not. I'm also sure Willy put them there for a reason. This might or might not make the plane better but, before I hear it, it has NOTHING to do with CL max at combat speeds. If you were above 250 mph the slats, almost regardless of g-load, were closed. They were primarily for the lower-speed regime, where combat seldom took place. So, I'm not sure they were needed ... but maybe so. A simple, easy experiment would settle the question in a test flight or two at alomst no cost. Just wire them shut and see what changes in flight characteristics. If low-speed handling suffers. add some washout to one set of wings and repeat the test. Easy and a quick answer would be forthcoming.
6) I've always wondered why complete gear doors were not used. Had to cause drag. Add them and see what effect it has.
7) I'd experiment witrh 4-bladed props.

So, basically, I'd go back to the F model from the K and incorporate some changes. If nothing else, al LEAST make one as a test mule and try the changes out to see what the result would be. That shouldn't interrupt production. Just take one off the line and start on the mods. 1 or 2 guys could do some of them all by themselves except for changing the wing mounts to 4 points. That would need an engineer and a small bit of effort to accomplish. 

The reason I'd go back to the F model is to save weight.

With better visibility from the new canopy, rudder trim to ease pilot fatigue, better control surface leverage for more agility at speed, slightly larger tail surfaces, fully enclosed gear, fixed toe-in, and maybe 20 more gallons of fuel, the F could solider on for quite awhile. The better handling at speed would make it into a new threat. Some of the changes might add a few percent to the speed, and a better propeller might help both climb and speed, while maybe slightly dropping the weight of fire per second.

This is not to denigrate the Bf 109F or K which were good flighters. It is all in response to the question of how the Bf 109F could have been changed to make it better and maybe add some development potential.

The main issue would be to make the changes with minimum weight inpact, or even to make the changes while simultaneously making it lighter. 

One last time for clarification, make the changes to a test muile and let the operational pilots fly it against their own mounts. If they like it, maybe the changes are worth incorporating. If they don't, keep making what you are already making. So none of this had to be a big effort ... it could involve one (or two or three) new F model airframe(s) only ... until such time as the changes are proven or shown to be not worth the effort. Either way, you have NOT crippled the Bf 109 line or used a great deal of resources. 

That's a far cry from 60+ prototypes for the Ju 88's trials at modifications to suit all tasks in the entire Luftwaffe.


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## Milosh (Aug 12, 2013)

> That's a far cry from 60+ prototypes for the Ju 88's trials at modifications to suit all tasks in the entire Luftwaffe.



What is this suppose to mean?


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## CobberKane (Aug 12, 2013)

Civettone said:


> How was the Bf 109K not as good as the latest Spitfires or Mustangs??
> 
> Its controls were rather heavy, other than that, an excellent machine with a superior flight performance, speed/climb rate as well as manoeuvrability.
> 
> ...


 I suspect the 109K is something of the great white hope of the 109 enthusiasts. This site gives some information comparing it to the Spit XIV. The site notes that the performance figures for the K are estimated, assuming several factors that seldom if ever occurred in actuality, and should be accepted with caution.

Spitfire Mk XIV versus Me 109 G/K

It would seem the 109k matches the spit up to 25000 ft, then falls behind. The Spit out climbs the 109 almost everywhere.

1. Out turn the 109. I Know there is a body of opinion that holds an excellent pilot in a 109 could turn with a Spit, but in the real world the great majority of pilots on both sides accepted the Spitfires superiority in this respect across all marks
2. Had much better visibility. The Galland hood might have helped, but the 109k had worse visibility by far than any allied fighter of its time. Visibility is vital
3. Handled better at speed. Unless something major was done to the 109k in this respect it would have been much like the later G variants. Allied testing of these used somewhat harsher terms than 'a little heavy' at high speed.
4. Had better armament. The 109 was limited to a centreline arangement. It's 30mm was ill suited to fighter v fighter combat. Sure there was the option of going back to a 20 mm, but that would have left it at a real firepower disadvantage against the allied fighters of the time in the ETO.
5. The spit was much better built. The poor quality control of the Germans was not a fault of the 109 per se, but it was a fact of life. To disregard it when considering the 109k moves us from the real world that existed into a 'what if' scenario.

The 109 was a great fighter and effective to the end. but by 1944 it was no longer top of the heap.


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## GregP (Aug 12, 2013)

Hi Milosh,

It means that I have seen it written that there were 104 prototypes built to support 60 different versions of the Ju 88 as they kept trying to adapt it for different roles. That might or might not be accurate, but it DOES show a LOT of prototypes for that aircraft. There is amlost no air force task they didn't try out the Ju 88 for except troop transport and they DID try towing troop gliders with it, so maybe they DID try it out as a troop transport, in essence.

For the Bf 109F thread above, I am proposing 1 - 3 airframes, each modified the same or almost the same. Perhpas some mod could be tried on 1 airframe and, if not liked, could be removed. The reason for having up to 3 is so they could be flown by more pilots for assessment when the mods were completed.


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## jim (Aug 13, 2013)

CobberKane said:


> I suspect the 109K is something of the great white hope of the 109 enthusiasts. This site gives some information comparing it to the Spit XIV. The site notes that the performance figures for the K are estimated, assuming several factors that seldom if ever occurred in actuality, and should be accepted with caution.
> 
> Spitfire Mk XIV versus Me 109 G/K
> 
> ...


 
THIS ARTICLE IS FULL OF LIES. iTS WORTHLESS
Mr Kurfust has written an article that presents all the lies and manipulations of evidence of the known person that wrote the article that you mention. 
Mr Kurfust proves that K4 was better than Spit XIV. Find his response on the net to the articles that you mentioned.
Your article ,and the site were is posted , are more than unreliable sources.


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## Aozora (Aug 13, 2013)

jim said:


> THIS ARTICLE IS FULL OF LIES. iTS WORTHLESS
> Mr Kurfust has written an article that presents all the lies and manipulations of evidence of the known person that wrote the article that you mention.
> Mr Kurfust proves that K4 was better than Spit XIV. Find his response on the net to the articles that you mentioned.
> Your article ,and the site were is posted , are more than unreliable sources.


 
WE ARE NOT GETTING INTO THIS CRAP, thank you very much - if you want to be partisan so be it, but don't make accusations about other forum members without good evidence - Mike Williams has long been a valuable contributor to this forum, while your Mr Kurfurst was banned long ago and for very good reasons. OVER AND OUT!


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## FLYBOYJ (Aug 13, 2013)

Folks, several of you have been warned to keep this thread civil, if I see any more BS I'm shutting it down and banning those behaving like idiots WITH NO WARNING!

My one and only warning!!!!!!


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## stona (Aug 13, 2013)

It's not got a whole lot to do with the Bf 109 F series either 
Cheers
Steve


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## Tante Ju (Aug 13, 2013)

OldSkeptic said:


> Again, my great admiration of Kurt Tank and his team (in my opinion Germany's Mitchell, not just a great engineer in himself, as he was, but a great leader of a technical team). You contrast the 190 development vs the 109 and you see good teamwork, where R&D worked closely with requirements and production. Continually improving the plane and producing much needed variants as needed, without the chaos and 'perfectionism' that crippled so much of Germany's efforts (in all areas not just planes). Sadly, again let down by the German engine manufacturers far too often.



I am very curious on this. 190 development, what was that? The 190 airframe was barely changed at all between the A-1 and the A-9, it only got aerodynamically worse.. contrast the performance of the early A-5 vs that of the A-8 and you will see. Of course it was improved in capabilities - better guns, more fuel, but weight crept up and performance went down... Even the D-9 was little more than sticking a new engine in the same airframe and adding an extra ring of metal sheet to the fuselage. The Ta 152 series was the only serious development of that aiframe. The Bf 109 was upgraded at least three times (A-D to E, E to F/G, G to K) in the same time period...


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## Civettone (Aug 13, 2013)

I completely agree with that. In fact, the Ta 152 was chosen over the Ta 153, because it was not a new design, but based on the Fw 190. I have read that the Ta 152 was a completely new aircraft, yet the prototypes were rebuilt Fw 190s. 

Also, I have often ranted about Tank's unexplainable lack of progress on the Fw 190C/D. The C flew already in 1942. How you could need two more years (til late 1944) before coming up with the Fw 190D is quite beyond me. Even the celebrated annular radiator does not impress me: is it that different from the Jumo 211 naceless of the Ju 88?


Kris


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## CobberKane (Aug 13, 2013)

Good grief, if I'd known that questioning the 109K as an uber-fighter was going to get such a vitriolic response I would have stayed quiet. On the other hand, I go all weak at the knees when Flyboy get all alpha male, so I guess it was worth it... 
Re relevance to the 109F, I see the 109K as about as far as you can get from the 109F's ideal compromise between the designs strengths - ease of production and maintenance, performance - and it's potential weaknesses - armament limitations, deteriorating flight characteristics etc.
When I think of the 109F I invariably also think of it's great rival, the Spit V. My understanding is that the 109 out-performed the Spit at lower altitude but as most combat took place at higher altitude the Spit was able to hold its own. But it occurs to me that there was one other RAF fighter of the time that might have outperformed the 109F when they met. That's my teaser - off to post another thread.


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## DonL (Aug 13, 2013)

Tante Ju said:


> I am very curious on this. 190 development, what was that? The 190 airframe was barely changed at all between the A-1 and the A-9, it only got aerodynamically worse.. contrast the performance of the early A-5 vs that of the A-8 and you will see. Of course it was improved in capabilities - better guns, more fuel, but weight crept up and performance went down... Even the D-9 was little more than sticking a new engine in the same airframe and adding an extra ring of metal sheet to the fuselage. The Ta 152 series was the only serious development of that aiframe. The Bf 109 was upgraded at least three times (A-D to E, E to F/G, G to K) in the same time period...



Ever thought about the FACT, that the base of the FW 190 was very much better then that of the first Bf 109 series and later of the Bf 109G series, so is wasn't necessary to change anything on the aerodynamic. The FW 190 was in all it's life much much easier to fly as any Bf 109 series and it was much much better to the sticks from the beginning till the end at high speed maneuvers. This can you easily see at flight school report and many statements from LW experts.



> Also, I have often ranted about Tank's unexplainable lack of progress on the Fw 190C/D. The C flew already in 1942. How you could need two more years (til late 1944) before coming up with the Fw 190D is quite beyond me. Even the celebrated annular radiator does not impress me: is it that different from the Jumo 211 naceless of the Ju 88?



Very very easy no engines were available! Alone this statement shows me how minor is your knowledge about the development and production of the LW engines.

Neither any DB 603 was produced in numbers till end 1943, beginning 1944 nor the Jumo 213 was entering mass production before end of 1943.
The DB 603 engine was strictly for the Me 410 and Do 217 at the beginning and only with the mass produced Jumo 213 was an engine available.
You should look at the produced engines and the timeline, the production of 1942 (DB 603, Jumo 213), was a blow in the wind and at 1943 the production and tooling was changed, but the produced numbers were very smal!

______________________________________________________________________________________________________________

Even if I get a bann for this statement, 
Mark Williams reports about german aircrafts were often disproved from primary german sources, not only from Kurfüst, but also from delcyros and other members. So personally I think it should be allowed to point out, that Mr. Williams reports about german aircrafts should be taken with a grain of salt.


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## OldSkeptic (Aug 14, 2013)

Aozora said:


> WE ARE NOT GETTING INTO THIS CRAP, thank you very much - if you want to be partisan so be it, but don't make accusations about other forum members without good evidence - Mike Williams has long been a valuable contributor to this forum, while your Mr Kurfurst was banned long ago and for very good reasons. OVER AND OUT!



Mike puts all the data on his website. By definition he cannot be a liar... a real liar would not make all the stuff available to anyone
I've said it before, he shows *real intellectual honesty* by putting all the data up for everyone else to see and use (and pays for it himself). 

Now it is ok to disagree with his analysis and conclusions (heck I do about somethings), but you have to do your own analysis and write it up based on the facts.
And be polite. Now Mike is perfectly capable of dealing with 'rigorous debate' as anyone (we can all get hot under the collar but we are adults), but outrageous and completely untrue claims about him are simply not acceptable.

If you find any further information from original sources, pass it on to Mike, I'm sure he'll put it up on his website (after the usual checking of course). 

And a bit of thanks and recognition from people here would be nice about the immense amount of work he (and his collaborators) have done in collecting, converting and loading all the data.

Take the kind of person he is, not forgetting he actually has a life and other commitments, when on another thread some comments came up about the DH Hornet he posted lots of data on it .. and then onto his website. 
He didn't have to do that, he is not being paid to do it, he does it because he has a great love of all this.


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## Mike Williams (Aug 14, 2013)

Thanks for the support gentlemen; it’s much appreciated.


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## Aozora (Aug 14, 2013)

DonL said:


> Even if I get a bann for this statement,
> Mark Williams reports about german aircrafts were often disproved from primary german sources, not only from Kurfüst, but also from delcyros and other members. So personally I think it should be allowed to point out, that Mr. Williams reports about german aircrafts should be taken with a grain of salt.


 
This constant, partisan, über-109 disparagement of decent people who go to the time, trouble and _considerable expense_ of providing information that would otherwise stay hidden is just pathetic. Like I say, we don't need this crap!


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## Tante Ju (Aug 14, 2013)

We are getting very far from Bf 109F subject. Obviously Mr William work developed very controversial reputation over years between fan of axis and allied aircraft, result of his debated articles that are seen by many to strongly favour allied aircraft and are perhaps inaccurate. It is not important question here and I do not think either side will convince the other, so any criticism of this controversy should not be further in this thread as moderator noted very clear already..

So, lets all get back to far more interesting subject while mod allows!


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## Tante Ju (Aug 14, 2013)

DonL said:


> Ever thought about the FACT, that the base of the FW 190 was very much better then that of the first Bf 109 series and later of the Bf 109G series, so is wasn't necessary to change anything on the aerodynamic. The FW 190 was in all it's life much much easier to fly as any Bf 109 series and it was much much better to the sticks from the beginning till the end at high speed maneuvers. This can you easily see at flight school report and many statements from LW experts.



Hi DonL,

I do not think its so black and white. The LW considered the advantages of the Fw 190 handling over the Bf 109 (mostly: lower stick forces at high speed, higher roll and more robust construction), but they were not homogenous. Stall characteristics of the Fw 190 were very poor in comparison, showing tendency of unexpected flick rolls while the 109 was benign in this regard. The 190 pilot on the landing pattern to deal with higher approach speeds and unexpected sink rate, though it was free of the ground looping tendencies of the 109. So I would not describe the 190 much easier to fly, but rather just having different quirks.

There is statement on this from german experts. Kurfürst - Vergleichsfliegen Bf 109 E, Bf 110 C, Spitfire, Hurricane und Curtiss.

Also the story of Fw 190A was somewhat similar to the story of the bulgy 109G-6, the 190 lost some 20-25 km/h speed due to increased drag of airframe between A-5 and A-8.


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## Juha (Aug 14, 2013)

CobberKane said:


> ... Re relevance to the 109F, I see the 109K as about as far as you can get from the 109F's ideal compromise between the designs strengths - ease of production and maintenance, performance - and it's potential weaknesses - armament limitations, deteriorating flight characteristics etc.
> When I think of the 109F I invariably also think of it's great rival, the Spit V. My understanding is that the 109 out-performed the Spit at lower altitude but as most combat took place at higher altitude the Spit was able to hold its own. But it occurs to me that there was one other RAF fighter of the time that might have outperformed the 109F when they met. That's my teaser - off to post another thread.



IMHO 109F-4 was faster than a normal Mk V across the altitude bands and especially at higher altitudes. Not a big surprise because Merlin 45 and 46 had one-stage supercharger.

Juha


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## Shortround6 (Aug 14, 2013)

What are the actual differences between a "F" airframe and and early "G" without pressurized cockpit?

Not just a different contour to the engine cowl but actual differences besides the DB 605 engine? AS in could you stick a DB605 (with proper cowl and and oil coolers and such) on a "F" and turn it into a "G"or a DB 601 installation on a "G" and turn it into an "F"?

Few "F"s had the GM-1 Installation, not all "G"s had it. Could the weight and position of the GM-1 installation affect flying "qualities"?


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## Juha (Aug 14, 2013)

Hello SR6
IIRC G-2 had a bit stronger wing than F-4, being covered by a bit thicker sheets, at least at roots. Internal wiring allowing the use of wing armaments (gunpods, rockets) as standard etc.

Juha


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## Njaco (Aug 14, 2013)

and CobberKane just got a week's vacation for that comment at FlyboyJ. Joe warned everyone and the Mods agree - no more nonsense!


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## FLYBOYJ (Aug 14, 2013)

CobberKane said:


> Good grief, if I'd known that questioning the 109K as an uber-fighter was going to get such a vitriolic response I would have stayed quiet. On the other hand, I go all weak at the knees when Flyboy get all alpha male, so I guess it was worth it...



I just caught this. NJACO gave you a week, I'm giving you a month. One more incident and you're gone.


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## Tante Ju (Aug 14, 2013)

Shortround6 said:


> What are the actual differences between a "F" airframe and and early "G" without pressurized cockpit?



Very little. In fact the 109G replacement part list booklet refers back the 109F part list booklet for those items not listed. New welded canopy, reinforced wings, the G got laminar fuel tank armor and front bullet proof glass as standard (Fs were retrofitted) and the radiator boundary layer was deleted on the G. There was a squared wheel well on the G - it was intended to have wheel well covers. The G was probably even a bit better since it had an internal armored glass as opposed to the external ones retrofitted to 109F.



> Not just a different contour to the engine cowl but actual differences besides the DB 605 engine? AS in could you stick a DB605 (with proper cowl and and oil coolers and such) on a "F" and turn it into a "G"or a DB 601 installation on a "G" and turn it into an "F"?



In fact the famous Black Six started out as a late production 109F according to its history, but finished as a G. There was very little difference between the 605A and the 601E, external dimensions were identical, the 605 for all practical purposes was just an up-bored 601E with minor improvements.



> Few "F"s had the GM-1 Installation, not all "G"s had it. Could the weight and position of the GM-1 installation affect flying "qualities"?



Russian trials returned practically identical turn times for F4 and G2, so I doubt there was much difference in flying qualities... GM 1 added some weight, but apart from that.

All in all I consider the 109G the very subject of this thread, an improved 109F - with wheel well covers and a 605A with full potential. An easy 700 km/h plane... in 1942.


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## GregP (Aug 14, 2013)

I thought the only real differences between the DB601 and DB605 were the 605 had 4 mm greater bore, turned slightly higher revolutions, has a hiogher compression ratio, and a more powerful supercharger. And that was it. The DB605 used the same case and mounting holes and was designed from the outset to run on B4 (87 Octane) fuel. Later, in 1944, they came up with a version allowing C3 (100 Octane) and boosting systems like MW 50 and GM-1.

They did have a different propeller reduction gear for the twin engine fighters and also came up with a projected 2-stage supercharged unit (DB621), built a 3-stage unit (DB628 ) but abandoned it in 1944, and also built a turbocharged unit (DN625). They even tried a pair of coupled DB628's called the DB620. None of these went anywhere, but developmental work continued on the DB 605.

The DB605 with all the improvements was about 330 pounds heavier than a DB 601.

I'd really like to be able to stop the editor from replacing my "eight-)" with a smiley face.


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## razor1uk (Aug 14, 2013)

Until the emote codings (if ever) are redone Greg, just remember to put a space before the end bracket - I too find it annoying, but not as much as the di-sgusting emote even more annoying when you type it as one word and get ing.


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## Shortround6 (Aug 14, 2013)

Thank you for the information. On book I have says that the GM-1 system in the F was in the wing ( two different systems actually) and good for 10 minutes maximum. either eight small bottles or two circular tanks, weight of fluid was either 34 or 42 KG and weight of the whole system 46 or 75KG. 

I haven't been able to find the weight/s of the system in the G series aircraft. We do have this from the Kurfurst web site from the short manual/ instructions on the GM-1 system. 

"Beware the Start! Plane is tail heavy by the GM-1 system and 
therefore to trim nose down to 1 1/2."

Now the GM-1 is not used on every flight and while the weight of the system may not affect the ultimate turning times or turning ability it may affect low speed handling? Perhaps like flying a Cessna or Beechcraft at the full aft limit? 

I am not trying to run down the 109 here but trying to find out why/what the differences are between the "F" and "G" that _might_ explain the the _alleged_ reputation the later "G"s had. Why they needed bigger landing gear , and so on.

The P-51s were NOT supposed to be landed with the rear tank full or near full. The GM 1 system may not be anywhere near as a bad as a P-51 with a full rear tank but something may have been going on that affected elevator response at slow speed/landing configuration. 

Understanding that might give us some idea what might (or might not) have been done to the 109F. 

From the


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## Shortround6 (Aug 14, 2013)

GregP said:


> The DB605 with all the improvements was about 330 pounds heavier than a DB 601..



The last 601 (E) may have been a bit heavier than the early ones and the first 605s a bit lighter than the later ones, and that is the change from the "F" to the first "G"s. 

This is what gets a bit confusing ( at least to me) is that there were at least two 601s used in the "F"s and several different 605s used in the "G"s (not counting experimentals) and the landing gear was changed twice (?) on the G's so which change/weight increase was responsible for which landing gear change ?


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## GregP (Aug 14, 2013)

Hi Shortround,

I think there is a lot of informaiton available in English about the P-51 and other American and British planes. Conversely there is much information NOT available in English on the Bf 109 and there is also quite a bit of either misinformation or outright disinformation on the Bf 109 out there. Some is probably a holdover from early mistakes. 

I have seen people take William Green to task for this, but his later works seemingly corrected much of that. I've head a lot of folks who liked Martin Caiden, but he also tried to "fill in the gaps" when he was missing some information and, in some cases, seems to have just made things up in order to finish a book.

The little nuances of Bf 109 information are mostly probably still in German for the most part, but that doesn't account for the great disparity in performance attributed to it. I can find flight test by different organizations out there in which the speed and rate of climb for a single model are so different as to almost be ludicrous. Naturally the Bf 109 fans take the highest number and the detractors like to take the lowest number, leaving us in an argument with little resolution.

I've seen some data not labeled as to whether it was IAS or TAS, also an issue with US and British tests, though not too widespread.

Too bad there aren't more tests where the roll rate at different speeds is show along with the time to complete a 360° turn at various heights and speeds. These might BE available but, if they are in German and it is scanned and not copyable text, it is tough to get a translation from BabbelFish or other online translator. Many of the very excellent USAAF and US Navy post-WWII documents are that way ... sanned and not copyable.

What I'd really like to see is a single place where primary source data are translated and kept together. Personally, I trust the German data as I trust the British and American data. If the Americans or British wanted to show a better domestic product, they simply limited the manifold pressure for the foreign plane, but at least the manifold pressure is usually noted in the data, so we can tell when this type of stuff is being done.

As for the German data, I can read the charts and numbers, but am unaware of any special circmstances or limitations since I don't read German. But I'm sure the data are accurate and reliable. Of course, I'd prefer to see Luftwaffe tests over, say, Messerschmitt, Junkers, Arado, etc. data. The Luftwaffe would have no reason to lie to itself while a manufacturer might want some data to help sales along, just as in Allied countries. Still, primary source data would be very welcome.

In restoring our Hispano Ha.1112 Buchon, we have come across many needs. For instance, we spent a year looking for the landing gear uplocks. We have the manuals but the drawings are simple illustrations, not fabrication drawings. So, we couldn't just have one made at a machine shop since we didn't HAVE a suitable drawing. We had to locate an existing pair of uplocks and obtain them.

This lack of good data carries over into restoration.

Right now we are making a new instrument panel in which our chosen instruments will fit. We will save the original, but nobody rxcept a museum (like us ... we HAVE a display of original WWII instrument panels complete with instruments) is going to set up an original 1960's Ha.1112 panel these days, what with so many new great instruments out there. We stole the wingtips from our Bf 109G-6 in Arizona and when the Ha.1112 is flying again and we have time, we need to fabricate new ones and return the originals to the Messerschmitt. We already made new wheels from Aluminum instead of magnesium, so the Messerschmitt still has its original wheels. Again, we had no fabrication drawings, so we took an original wheel and had a machine shop duplicate it in Aluminum.


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## razor1uk (Aug 14, 2013)

Sounds like you need someone with AutoCAD to jury rig a draught/design or the uplocks - that and micrometric verniers, calipers and radius gauges to supply them with info...


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## Aozora (Aug 14, 2013)

Juha said:


> IMHO 109F-4 was faster than a normal Mk V across the altitude bands and especially at higher altitudes. Not a big surprise because Merlin 45 and 46 had one-stage supercharger.
> 
> Juha



The Malta campaign showed that given the right tactics the Spitfire Vs, even with the Vokes tropical filters, could hold their own against F-4s, albeit the F-4 was definitely faster. Over France it was a different story, although it was the 190 that really exposed the performance deficiencies of the single-stage Merlin.


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## GregP (Aug 14, 2013)

AutoCAD isn't going to help much. It will if you can borrow a part, but without the part, the landing gear must be assembled to the landing gear bracket in order to get a meaurement, and the access room is just not there. It is very tight and you'd not be able to get good meaurements. You could try and I wish anyone luck. Really, it is tight.

We COULD have borrowed some parts, had them measured and then created a fab drawing ... but once we found the parts it wasn't necessary. When the plane is groundlooped (last time was due to right brake failure, not pilot error), the locks aren't usually damaged ... it snaps off the gear on the most forward side and damages the gear but not the downlock on the other side.

All we did was to misplace the parts. If we had not FOUND parts, we would have gone through the fab drawing stage, but there was plenty to keep us busy until we found the downlocks. First we had to repair the landing gear with new brackets. The we had to repair the damaged wings and landing gear items. Since none are available, we had to fabricate all the repairs and make new pieces. That took awhile and required custom wood fab molds be made. Meanwhile we found the downlocks. No problem.

Here is a shot of the old panel from back in June 2007. Since the airframe is basically that of a Bf 109G with a Merlin on the front, the former owner had the small placard made and he installed it there. We didn't.







You can see we have a knots airspeed indicator, rate of climb in feet per minute, attimeter in feet and manifold pressure in inches of Mercury absolute, just like all our other warbirds. Really, the numbers aren't much different from familiar US or British numbers when you convert them all to the same units. They are, in fact, amazingly similar

Here is a shot that shows a small bit of damage to the starboard wing root, but doesn't convey the extent of the damage, The bracket in the wheel well goes on the 4 bolts at the top center ... but the enire tab is bent and there is some missing reinforcement where the root rib was broken, plus a LOT of generally bent stuff:







Today it is all repaired and the wing and gear are back on the fuselage and the panel is out of the aircraft having a new one made. It will not have a placard mis-identifying the aircraft when we are finished.


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## Civettone (Aug 16, 2013)

DonL said:


> Very very easy no engines were available! Alone this statement shows me how minor is your knowledge about the development and production of the LW engines.
> 
> Neither any DB 603 was produced in numbers till end 1943, beginning 1944 nor the Jumo 213 was entering mass production before end of 1943.
> The DB 603 engine was strictly for the Me 410 and Do 217 at the beginning and only with the mass produced Jumo 213 was an engine available.
> You should look at the produced engines and the timeline, the production of 1942 (DB 603, Jumo 213), was a blow in the wind and at 1943 the production and tooling was changed, but the produced numbers were very smal!


I do not think my knowledge is that minor. I have the figures for DB 603 production - I have shared them here before - and it clearly shows that it was mass produced in 1943. By the end of 1943, over 350 engines were being produced monthly. That is not _very small_. Production would have been increased if there was a need for it, just like happened with Dora's Jumo 213 in the second half of 1944.


Kris


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## Juha (Aug 16, 2013)

Hello Kris
but there were many Do 217Ms standing engineless while waiting for their DB 603s.

Juha


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## Civettone (Aug 16, 2013)

Okay, but when was that? 1943 or 1944? 
Also, during 1943, there were some reliability issues concerning the DB 603. Only fixed toward the end of 1943 (IIRC)

Production picked up at the end of 1943 and increased throughout 1944.

Kris


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## Juha (Aug 16, 2013)

Hello Kris
I would like to give a better answer but Griehl's Do 217-317-417 book isn't the easiest one to find a specific info and I'm in the hurry. B ut 10 Feb 44, 270 Do 217s, lacking engines, were cancelled.

Juha


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## jim (Aug 18, 2013)

Aozora said:


> WE ARE NOT GETTING INTO THIS CRAP, thank you very much - if you want to be partisan so be it, but don't make accusations about other forum members without good evidence - Mike Williams has long been a valuable contributor to this forum, while your Mr Kurfurst was banned long ago and for very good reasons. OVER AND OUT!



Mr Aozora
The fact that Mr Kurfust has been banned from this forum cancels his great knowledge? His great research?
You claim that the author of the article K4vs XIV has done very good work at his site and for free. So has Mr Kurfust at his own site. And never was accused for inaccurancies.
You ask good evidence. Go read Mr Kurfust s response to the article K4 vs XIV . ITS FULL OF EVIDENCE. Evidences and arguments that have never been answered by the other side.WHY? (eg Is it fair to take datas of gondolas equiped K4 to compare them to XIV s ?)
You know , the problem with the site in question, is not that is "accused by partisans" like me, a worthless amateur. The problem is that serious reserchers of german aviation have proved it of questionable reliability , at least as far as german aircrafts are concerned

And somethimg ...irrelevant...
I asked my motorbike enginneer , with vast experience in engine tunings . I asked car enginneers. I asked race engineers. I asked greek air forces mechanics
Is it possible to increase an piston engine s output 30% by SIMPLY provide higher octane fuel? They ALL laughed . Not me. The proffetionals


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## jim (Aug 18, 2013)

OldSkeptic said:


> Mike puts all the data on his website. By definition he cannot be a liar... a real liar would not make all the stuff available to anyone
> I've said it before, he shows *real intellectual honesty* by putting all the data up for everyone else to see and use (and pays for it himself).
> 
> Now it is ok to disagree with his analysis and conclusions (heck I do about somethings), but you have to do your own analysis and write it up based on the facts.
> ...



Mr Oldsceptic
I may have been rude and should have avoided this. But the analysis that you ask has been made by Mr Kurfust with evidences
In my opinion it is clear that there are more than human mistakes at that text. I find clear manipulation of evidences, and biased judgement from the author. Especially , if you consider that the author is very experienced , some mistakes are unexplained


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## OldSkeptic (Aug 18, 2013)

> Is it possible to increase an piston engine s output 30% by SIMPLY provide higher octane fuel? They ALL laughed . Not me. The proffetionals



You can if you are super or turbo charging the engine. Because it will allow higher boost without pre-detonation. Naturally the engine has to mechanically and thermally capable of it.

So, looking at the Rolls Royce chart 87 octane (all values are British ones of the time and not entirely directly comparable to German ones) was limited to about 9lb boost. 100 octane could go to 20lb, 25lb with water injection. 150 octane about 35lb.

Putting it in very simple terms (and not allowing at all for power used for the supercharger, etc), the 27 ltr Merlin was equivalent to a 43ltr non-supercharged one at 9lb boost. 60 ltr at 18lb boost and a whopping 73ltr one at 25lbs boost. Of course diminishing returns set in. So instead of a theoretical 2,700 bhp engine at 25lbs boost it was only 2,050bhp for the Merlin 66 (and about 2,150 for the more efficient RM17SM).

The RM17SM engine got even higher, with about 2,300bhp at 30lb boost and a whopping 2,600bhp at 35lb boost.


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## OldSkeptic (Aug 18, 2013)

Jim, I never said I agree with all of Mike's analyses. So I do my own and come to my own conclusions. The data is all there provided by him for anyone to do that, which is what I mean by intellectual honesty.

I have never seen any sign, in any way, of 'manipulation' etc as some have claimed. Anything but in fact.

Analysis and interpretation is not an exact science, Mike is perfectly free (as is everyone else) to come to his conclusions based on the evidence.

But I'd much rather see someone do a comparable analysis (and as well written, Mike is a good writer) that comes to other conclusions than just name calling. 
I'm happy to read it, and of course come to my own personal conclusions .... which can be different from anyone else's of course.

But I think the key thing is some respect and politeness when you are intellectually disagreeing with someone, especially with someone who has gone to great lengths and a heck of a lot of hard work to provide us all with so much good data.

There is no absolute right or wrong here, only 'rightish' and 'wrongish' sort of stuff with a lot of wriggle room between those limits, heck even today it is hard to compare modern plane's performance right across their whole flight envelope to determine what is overall 'better' or 'worse'. Have a look at the recent stoush between Boeing and Airbus over various claims for the 747F and the 380.......


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## Shortround6 (Aug 18, 2013)

If they all laughed then you asked the wrong question. 

IF you run an engine on 87 octane fuel and set it up correctly and then switch to 100 octane and do _NOTHING_ to the engine you will get a ZERO PERCENT increase in power. ALL these men are quite correct. 

HOWEVER, 100 octane fuel allows you to change either the compression ratio or, on a supercharged engine, the amount of boost used. Or some combination of both. 

But that is *NOT* _SIMPLY providing higher octane fuel_. To change compression ratio usually requires new pistons. To change boost requires a new supercharger or new supercharger gears or at the least changing the supercharger boost controls. 

The best ( or easiest) example is the Merlin. The Merlin III was good for 1030hp at 16,250ft at 6lbs boost with 87 octane fuel. 100 octane fuel is good for a _potential_ 30% increase over 87 octane ( argue with Sam Heron, not me). When the British ran them on 100 octane ( actually 115-120 performance number) There was absolutely NO CHANGE in power ABOVE 16,250ft. The supercharger was maxed out and could supply no extra air above that altitude. Below that altitude the supercharger could supply extra air and the higher octane fuel allowed higher pressure without detonation. Max power was 1310hp at 9,000ft at 12 lbs boost. The increase from 6lbs boost to 12lbs boost is about a 28.5% increase in manifold pressure. A few other things are going on like different intake temperatures and pumping losses than can affect things by a few %. 
Please note that further increases in power _required_ new superchargers (Merlin XX and 45) different supercharger gears and finally the two stage supercharger. Also note that the British fuel changed twice AFTER the first 100 octane as used in the BoB. 
G0 back and ask the professionals what happens when you increase the manifold pressure by 25-30%. It should increase the amount of fuel and air going though the engine in any given time period by 25-30%. 

The performance number scale is much more linear than the octane rating scale. 87 octane is 68.5 on the Performance number scale. 100 octane is 100PN. Going from 100PN to 130PN should give another 30% ( if the supercharger can supply 30% more air the engine doesn't break/bend). Going from 130 to 150 should give about another 15%


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## silence (Aug 18, 2013)

What does this do to the rate of fuel consumption?


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## Aozora (Aug 18, 2013)

jim said:


> Mr Aozora
> The fact that Mr Kurfust has been banned from this forum cancels his great knowledge? His great research?
> You claim that the author of the article K4vs XIV has done very good work at his site and for free. So has Mr Kurfust at his own site. And never was accused for inaccurancies.
> You ask good evidence. Go read Mr Kurfust s response to the article K4 vs XIV . ITS FULL OF EVIDENCE. Evidences and arguments that have never been answered by the other side.WHY? (eg Is it fair to take datas of gondolas equiped K4 to compare them to XIV s ?)
> ...


 
No Mr jin this is just adding to your crap. The reason why no-one finds fault with Mr Kurfurst, and why Mr Williams hasn't bothered to answer is because Mr Kurfurst's response to anyone trying to debate his facts and figures is usually so unpleasant/nasty/full of distortions and half truths that ANY "discussion" isn't worth the trouble. You are indeed a "worthless amateur" that you can take Mr Kurfurst so seriously. 

As it is you don't even have the decency to call Mr Williams a liar to his face, using your real name, via PM, so your opinion isn't worth a whole lot.


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## DonL (Aug 18, 2013)

Mr. Kurfürst's site is basing on primary german sources and documents, there is not much room to discredit him or his site about the Bf 109.
Or perhaps you want to claim that primary german sources are lies?


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## Aozora (Aug 18, 2013)

silence said:


> What does this do to the rate of fuel consumption?



According to the Spitfire II PNs fuel consumption was: 

Maximum Cruising (weak mixture, 2,650 rpm) = 55.5 gall/hour at 13,000 ft

Maximum Cruising (Normal mixture, 2,650 rpm) 77.5 gall/hour at 13,000 ft

All-out level at 3,000 rpm = 98 Gall per hour at 14,500 ft


Modifications to Merlin II/III series to enable +12 lbs boost:


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## Aozora (Aug 18, 2013)

DonL said:


> Mr. Kurfürst's site is basing on primary german sources and documents, there is not much room to discredit him or his site about the Bf 109.
> Or perhaps you want to claim that primary german sources are lies?



Mr Kurfurst has been banned from enough websites to have discredited himself and his site, except to his most dedicated fans. Enough said on the subject.


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## DonL (Aug 18, 2013)

You will be confronted with his research and his site every time the issue is the Bf 109, simply there is no other site at the web, which provide more german primary sources and documents about this a/c.
This is simply a fact.
To discredit him, because of his behaviour (to your opinion) and also try to discredit his site, research and provided primary sources will not function!
You will be also chanllenged in the future with his provided primary sources about the Bf 109, if you deny this sources or discredit his site, you automaticly discredit primary german sources.


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## Greyman (Aug 18, 2013)

silence said:


> What does this do to the rate of fuel consumption?


Rolls Royce Merlin II/III
+ 6.25 boost, 3000 rpm = 89 gal/hr
+ 12 boost, 3000 rpm = 125 gal/hr


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## silence (Aug 18, 2013)

Just to clarify, the boost rating is the max that a given engine will hit in flight: there might be no boost at a normal cruise, half boost at max cruise, and full boost at emergency power (just as a general "for example" statement)?


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## Greyman (Aug 18, 2013)

Yeah by 'boost' I mean full manifold pressure at full throttle. + 6.25 being the max you can hit with 87 octane, + 12 with 100 octane.


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## GregP (Aug 18, 2013)

I see Kurfurst post the absoute highest numbers that can be found on his site as known fact, not the average numbers. I belong to another forum dedicated to WWII aviation, too, as well as this one. Most members over there know Kurfurst simply isn't a reliable souce for factual data on the Bf 109. I am not sure how the majority feels in here yet but won't argue about it much either way. People believe or don't.

His data don't agree with the surviving operating examples (E and G) of the type while the P-51B/D, Spitfires, Sea Furies, P-47's, P-40's, etc., meet book values from when they were produced. In fact, we fly (at the museum) more than 30 WWII types and they ALL meet book specs when pushed. We have a Bf 109E ready for restoration, so I'm sure than in a couple of years, we'll see if a second Bf 109E also meets book spec like the one originally restored at Chino now flyingas the Russel Bf 109E. We already KNOW the Paul Allen Bf 109E meets book specs. They didn;t try top speed but it makes book rate of climb, book cruise, and book takeoff distane from grass. Of course, it might depend on whether or not the owner elects to have an authentic prop made in Germany, which he well might. That would be nice to see.

Were German factory books wrong or is Kurfurst a bit optomistic?

The US and British tests of the type mostly DO nearly agree with one another and the surviving operating examples of the type (E and G), while there are few tests that were run at lower boost when the proper boost levels weren't known.

Wish we had an operating F model with the proper fit out flying. I'm sure it would be welcome anywhere at an airshow, whether or not they had authentic props or not. 

Sorry to hear about the recent forced landing. Hope it is repaired to flight status again amd not turned into a static unit.


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## Greyman (Aug 19, 2013)

GregP said:


> Were German factory books wrong or is Kurfurst a bit optomistic?



Not necessarily wrong, but different calculations used. For example, over at wwiiaircraftperformance there is this explanation in a British P47 trial:

'_Since the P-47C has not been through the hands of the Performance Testing Flight of the Aeroplane and Armament Experimental Establishment, some careful check flights were made at this Unit to obtain an approximate idea of its performance. ... In an independent trial the U.S.A.A.F. obtained slightly higher figures, possibly owing to the ... different methods of reduction. At this Unit the British Performance Reduction Methods for Modern Aircraft (A. &A.E.E./Res/170) were used._'

I've seen things like this come up a few times when looking in on aircraft performance. Not every establishment used the exact same math when calculating aircraft performance.


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## Denniss (Aug 19, 2013)

Kuffie/MW site: Both are known for their more or less existing bias towards their favorite a/c. As always with data posted on the net, take it with a grain of salt and cross-check it with other sources (if available).


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## GregP (Aug 19, 2013)

Yeah, I know what you mean about the grain of salt, Denniss.

I am of the opinion that the Bf 109 was one of the finest fighters in existence when WWII started, right there with the Spifire and the Zero, and it maintained rough parity for the duration of the war in the ETO. That doesn't mean the Bf 109 could not have been improved and also doesn't mean the Spitfire could not have been improved as well. Both could have used some improvement but were VERY good on an as-is basis when compared with the state of the art everywhere else.

As for the performance claims, they are the subject of some scrutiny. I tend to take the reports from established flight test agencies rather than combat reports. Many combat fliers only flew ONE fighter and their opinions are next to useless when other planes are concerned. The opinions of people whose job to was to fly and evaluate fighters is much more reliable when coupled with performance data from such tests. German flight test were no less thorough than Brittsh (or US, Japanese or French test). I tend to suspect some Soviet tests since meeting the spec could mean somone's life or relative freedom.

The Bf 109 had major weaknesses that didn't come into play if the pilot had YOU in his sights. The short range affected the usefulness of it and the relatively light armament made for a tougher time for the Bf 109 pilots. But they learned to adjust and were able to set a high standard with it. I am relatively sure, though obviously not positive, that had they swapped their mouints for the British mounts and the numbers had been the same, with neither the Luftwaffe nor the RAF getting any more or less planes, that the outcome would have been the same. That is, the RAF fliers would adapt to the Bf 109 / Fw 190 and the German fliers would adapt to the Spitfire / Hurricane with about equal success as they achieved in the war. I could easily be wrong there, but it will be hard to prove, won't it?

That's relatively high praise for both planes and I personally rate them as nearly equal with the winner being determined by the pilot and the situation when they entered combat. Saying the Bf 109 was flawed to the point of being useless is to go against all the real and achieved evidence to the contrary. Saying the Spitfire was not as good as the Bf 109 does almost the same from the other direction.

Two greats if ever there were two. We need more Bf 109's flying ... off GRASS. Someone neeeds to make some new-build DB 601 / 605's ... and some props! Od course, some new Allied engine would be a welcome sight, too, but the German engines are just too scare. 

Who here besides ME had heard a running Jumo 213? 

I heard the former Doug Champlin Fw 109D start up once. It now rests in Seattle at the Museum of Flight, but sounded wonderful when started in the mid-1980's and probably still COULD. When it started, I was surprised that the prop only turned 3 - 4 blades before it kicked off just fine. Probably means they ran it earlier to be sure, but nontheless it was a neat sight and sound.


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## nuuumannn (Aug 19, 2013)

Very pertinent and timely observation, Denniss.


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## silence (Aug 19, 2013)

Is this the one you are talking about, GregP?


_View: https://www.youtube.com/watch?v=4Y5LBUVS1T8_


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## OldSkeptic (Aug 19, 2013)

Shortround6 said:


> If they all laughed then you asked the wrong question.
> 
> IF you run an engine on 87 octane fuel and set it up correctly and then switch to 100 octane and do _NOTHING_ to the engine you will get a ZERO PERCENT increase in power. ALL these men are quite correct.



Good one. 

I used to have a Subaru WRX (great car) and the engine control computer would adjust the power depending on the fuel. Rated for 98 octane you could (in an emergency) run it on 95 octane. Plus here in Australia there are some significant variations between the different 98 octane suppliers, one in particular was renowned for being a bit dodgy while BP's was excellent. And yes you could feel the difference between them.
The best I found was actually one of the cheapest with 10% ethanol, trouble was your fuel consumption suffered, very noticeable if you pushed it hard. Once ran through nearly a third of a tank on a (very) fast run up Mount Buffalo.

One advantage, not often mentioned, was how easy it was for RR to alter the carburettor to provide higher fuel flows for the higher boost. A much harder task on the mechanical fuel injection systems that the Germans used.


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## OldSkeptic (Aug 19, 2013)

The other thing that has to be remembered is that all the planes of that era aged very quickly and their performance deteriorated quite quickly.
Dings in the leading edges (or even just cracked or badly applied paint), engine aging, etc.

I can easily see someone in a well used Mustang with a lot of hours under its belt and close to a major service having a real hard time against a brand new late model 109G or a K.

Mike Williams has some stuff on the Crossbow (anti V1) efforts, where they were trying to get as much speed out of their fighters as possible. AFDU would get a stock service plane, clean it up and add anything like 10-20mph to it.

Just like a bug splat would destroy a 'laminar' wing's airflow, even little dents, bad paint, panels on the wing or fuselage not quite matching (after being opened and closed many times), replaced rivets or screws poking out a bit ... all could take a lot of speed off a plane. Then there was the engine aging.

Plus you could just get a bad brand new one, the British suffered more from this than did the Germans (at the beginning of the war, towards the end their quality was shocking, starving slave labourers are not exactly motivated to produce good quality stuff) or the Americans given their overall poorer quality control (the endemic British issue).

Even RR had issues and it was good (at least as good as anyone else, certainly better than most, reasonably arguably amongst the best), again there is some figures on Mike's site about variances in FTH between different engines (of the same type of course).

The British standard was +- 3% in performance. That means of you had a (say) Spit LF IX, book speed of 404mph, and it was a bad one your max was only 392mph (and 416 on a good one, smart senior pilots made sure they got the good ones ... and looked after their service crews) and then it would age quite rapidly getting steadily slower as time went on in a sort of downward 'saw tooth' way (decline until service, then a rise, then a decline again, with each peak being slightly less than the previous one).

Modern warbirds are lovingly looked after and kept right up to spec so their performance is probably closer to ideal than anything that was operational during the war. (thanks to a lot of great people like GregP here)


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## GregP (Aug 19, 2013)

Poorer quality control? At least our Merlins has interchangeable part! The British Merlins surely didn't.

Go work on one. I have. Custom-fit parts for EACH engine. Weird but it works when all the parts fit.


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## Kryten (Aug 19, 2013)

This is why I am always sceptical when people chime in with the "the figures are not relative as the plane was in bad shape" argument, I would argue that was the condition of a front line aircraft, not a factory fresh one!


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## OldSkeptic (Aug 19, 2013)

GregP said:


> Poorer quality control? At least our Merlins has interchangeable part! The British Merlins surely didn't.
> 
> Go work on one. I have. Custom-fit parts for EACH engine. Weird but it works when all the parts fit.



Well the British ones were supposed to a well, and the rebuilding organisations (often forgotten) broke down Merlins and rebuilt them from scavenged parts all the time.

Depends on the era I suppose, Ford UK made a tremendous contribution by having all the plans re-drawn to higher tolerances to make sure of interchangability (as Stanley Hooker notes in his book). The early ones I suppose were were more 'hand built' than the later mass production ones (when Packard, Ford, Glasgow, etc got up to speed.) 

Overall US quality control was vastly better than the UK at that time, only later did the US decline (relatively at first, then absolutely as the accountants took over) in that regard. Germany started off as the best, but all that forced and slave labour does not a happy workforce make, so they went down the tubes as time went on. Bit like modern Volkswagons, get an older German made one and it is superb, get one (and we have this issue here in Australia right now) from one of their 'other plants elsewhere' and they are rubbish.


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## Shortround6 (Aug 19, 2013)

OldSkeptic said:


> Good one.
> 
> I used to have a Subaru WRX (great car) and the engine control computer would adjust the power depending on the fuel. Rated for 98 octane you could (in an emergency) run it on 95 octane. Plus here in Australia there are some significant variations between the different 98 octane suppliers, one in particular was renowned for being a bit dodgy while BP's was excellent. And yes you could feel the difference between them.
> The best I found was actually one of the cheapest with 10% ethanol, trouble was your fuel consumption suffered, very noticeable if you pushed it hard. Once ran through nearly a third of a tank on a (very) fast run up Mount Buffalo.



Not sure if you are agreeing or not.
A modern "engine control computer" does do something to the engine, it changes the ignition timing at the very least, it may or may not alter fuel flow. Put in poor fuel and the engine control computer detects the engine "knock" and retards the timing until it goes away. Power is reduced. Old aircraft engines used fixed timing (for the most part). If the engine was set for 20 degrees BTDC then that is what you had had idle or at max RPM. 
Allisons used for training in the US and run on 91 0ctane fuel had their timing retarded and the boost control modified to limit total boost. A few of these engines would up in Europe _without_ being reset and there was quite a flap (investigation) when these engines failed to give proper performance with 100/130 fuel.


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## Aozora (Aug 19, 2013)

DonL said:


> You will be confronted with his research and his site every time the issue is the Bf 109, simply there is no other site at the web, which provide more german primary sources and documents about this a/c.
> This is simply a fact.
> To discredit him, because of his behaviour (to your opinion) and also try to discredit his site, research and provided primary sources will not function!
> You will be also chanllenged in the future with his provided primary sources about the Bf 109, if you deny this sources or discredit his site, you automaticly discredit primary german sources.


 
I have no problem with using primary German sources, which is why I have in my library books by the likes of Prien Rodeike, Pethrick, Smith and Creek etc - credible aviation historians with a record of solid research; I do not need to refer to kuffie's selective "research", nor do I ever bother. As for Kuffie's lamentable, mendacious behaviour - that is not my _opinion_, it is on the internet for all to see...


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## FLYBOYJ (Aug 19, 2013)

jim said:


> I asked greek air forces mechanics


When was the last time any of them worked on a recip using 100 octane? An in-line recip?


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## jim (Aug 19, 2013)

FLYBOYJ said:


> When was the last time any of them worked on a recip using 100 octane? An in-line recip?


 
Mr Flyboy J

For the history, Hellenic Air force used 3 C-47s until a few years ago
But the mechanics i asked were veterans of HAF and members of my aero clumb. They had experience on Harvands, Noratlas, Alpatros, Canadairs( both with the original engines and with the turboprop engines) etc.
Moreover all of them had off duty experience with general aviation small aircrafts. Plus extensive theoritical internal combustion engine education.


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## jim (Aug 19, 2013)

Shortround6 said:


> If they all laughed then you asked the wrong question.
> 
> IF you run an engine on 87 octane fuel and set it up correctly and then switch to 100 octane and do _NOTHING_ to the engine you will get a ZERO PERCENT increase in power. ALL these men are quite correct.
> 
> ...



Mr Shortround6
I dont understand.... Where do we disagree?? 
I agree that better fuel leads to better output. But it requires major engine changes
When i up tuned my FZS 1000Fazer , i turned to 100 octane gasoline. But in order to take advantage from that fuel
1)Changed the pistons and the gaskets
2) Rejetted the carburators( not that simple procedure)
3)Used a new exaust system
4) The engine had by its mother company large strength reserves
5)) New bigger cooling radiator ( and that for an naturally breathing engine. A supercharged one would require even more cooling)
6) I improved the internal engine surfaces for better flows
7) Modified the engine ignition
8) Used improved lubricant parts
Plus a number of small detail improvements(plugs etc). With all these i got 17% more power( okay it was a conservative choise)
Plus many hours to fine tune the improved engine. And now the engine can run only on 100 octane fuel ( a bad idea during economic crisis)
How they got 30% more power from merlin III without major component improvements? How they used additional supercharging without cooling the air? I dont accept the claim that they simply put in the majic new fuel( asterix majic filter?) and they got 1300hp. And thats i have read on that site

to answer your final question , if you increase the in flow mixture by 30% (HOW???) and the engine is not prepared to take the machanical load , you destroy the engine. As simple as that


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## Kryten (Aug 19, 2013)

Going to 100oct allowed a higher boost to be used, nothing more and as pointed out above that only worked under 17k ft alt as the supercharger could not provide enough air at higher alt's.

This was limited to 5 mins at a time to keep temps under control.

no need to replace internal components in this case.


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## jim (Aug 19, 2013)

Aozora said:


> No Mr jin this is just adding to your crap. The reason why no-one finds fault with Mr Kurfurst, and why Mr Williams hasn't bothered to answer is because Mr Kurfurst's response to anyone trying to debate his facts and figures is usually so unpleasant/nasty/full of distortions and half truths that ANY "discussion" isn't worth the trouble. You are indeed a "worthless amateur" that you can take Mr Kurfurst so seriously.
> 
> As it is you don't even have the decency to call Mr Williams a liar to his face, using your real name, via PM, so your opinion isn't worth a whole lot.



Mr Aozora
1)I dont call him liar because i try to follow the forum rules. Plus ,as Lw fan, i must be extra cautious
2) My name is known to the moderators, but what s the point?
3)Did you have the decency to read Mr Kurfust respond article? FULL of evidences
4)So, you and your author, dont answer Mr Kurfust arguments because he "isnt worth the trouble" . Excellent ,democratic habits.... for 8 years old children. What about answering his arguments and let each reader reach his own conclusion? Or ,simply, your author can not answer Mr Kurfust s arguments
5) I would like to remind you that a worthless amateur (according to the scientists of its era) discovered America


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## bobbysocks (Aug 19, 2013)

i am skepitcal of most reported data. its not that cut and dry. manufacturers were in competition so they put their best foot forward...the best stats they could provide. i accept more info that puts the findings in a range that will give you a good average. there are so many variables it can be difficult to nail down exact figures. temp, air density, humidty, are never consistant but all will affect flight characteristics. the same plane flown on 3 different days could give you 3 very different readings. most tests are subjective or looking for a specific issue. sometimes mechanics will give the plane some help..lessening weight....tuning it up...etc. i am a fan of all the ww2 ac...so as to which one was best....depended on the day and the pilot and...and..and.


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## Shortround6 (Aug 19, 2013)

jim said:


> Mr Shortround6
> I dont understand.... Where do we disagree??
> I agree that better fuel leads to better output. But it requires major engine changes
> When i up tuned my FZS 1000Fazer , i turned to 100 octane gasoline. But in order to take advantage from that fuel
> ...



WHich shows that you _cannot_ just pour the new fuel in the tank.




jim said:


> How they got 30% more power from merlin III without major component improvements? How they used additional supercharging without cooling the air?



That is a difference between aircraft engines and ground (car, motorcycle, boat) engines. ALL major (over 500hp or so) aircraft engines used superchargers and just about _every ONE_ was set up for a full throttle (throttle plate all the way open) from 1500 to 4000 meters above sea level. If they opened the throttle fully at sea level they could destroy the engine. They had _extra_ supercharger capacity they couldn't use at low altitude with the lower grade fuels. The _ability_ to flow more air at low altitudes is already there. Wither the engine is strong enough to withstand the power is another question. However 'a' Merlin had been run at 1600hp for 15 hours on a test stand when preparing the "speed Spitfire" and even high power settings for short periods of time. The strength was there. In 1939 Rolls was _claiming_ an max time between overhauls of 240 hours for fighters and 300 hours for bombers. That does not mean the engine was guaranteed to last that long but if the engine made it that far it should be pulled for overhaul. This engine "life" was around twice what some other engines were offering so you could trade higher output for shorter engine life and that is what was done. EVERY use of over boost had to be noted in log books and engineering officers decided when to pull engines for over haul. Also please note that that at altitude the air is usually cooler than at sea level. 










jim said:


> I dont accept the claim that they simply put in the majic new fuel( asterix majic filter?) and they got 1300hp. And thats i have read on that site



You are free to believe as you wish but since those figures and modifications are listed in several books put out by Rolls-Royce and have nothing to do with Mr. Williams site I am not sure how you figure that Mr. Williams is lying or making things up unless Rolls-Royce is also lying/ making things up and doing so in books published 35 years after the war ended. They adjusted the boost limiting device and changed to a different spark plug and that was it. 



jim said:


> to answer your final question , if you increase the in flow mixture by 30% (HOW???) and the engine is not prepared to take the machanical load , you destroy the engine. As simple as that




In order for the supercharger to deliver 6-6 1/4 lbs of _boost_ at 16,250ft it had to compress the outside air at over a 2:1 ratio, perhaps 2.3:1. When you drop down to 9,000ft from 16,250 ft and compress the air 2.3 times you get 30% more air flow in pounds per minute than at 16,250 ft. with that particular supercharger.


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## Shortround6 (Aug 19, 2013)

bobbysocks said:


> i am skepitcal of most reported data. its not that cut and dry. manufacturers were in competition so they put their best foot forward...the best stats they could provide. i accept more info that puts the findings in a range that will give you a good average. there are so many variables it can be difficult to nail down exact figures. temp, air density, humidty, are never consistant but all will affect flight characteristics. the same plane flown on 3 different days could give you 3 very different readings. most tests are subjective or looking for a specific issue. sometimes mechanics will give the plane some help..lessening weight....tuning it up...etc. i am a fan of all the ww2 ac...so as to which one was best....depended on the day and the pilot and...and..and.



A lot depends on how the contracts are written. Most US contracts had an allowable tolerance on weight and performance of around 3%. EVERY production aircraft was weighed and EVERY plane was test flown before acceptance. Manufacturers were penalized (not paid the full contract price) if the planes were overweight ( and some times penalized per pound once the agreed tolerance was exceeded) and inspectors could either reject low performing planes to be reworked at company expense or invoke performance penalties in the contract. 
It took a mighty brave company to oversell a plane and then sign a contract guaranteeing that level of performance. Curtiss lost over 14,000 dollars on the second prototype XP-46 because it wouldn't hit promised performance levels. 
Screw up the estimates/promises on a production batch of 500 aircraft and the company could go bankrupt.


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## Matt308 (Aug 19, 2013)

Any more insults and you all will be banned. Thread closed.

jim and aozora, don't even sneeze.


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## DerAdlerIstGelandet (Aug 23, 2013)

The Usual Suspects...


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