Re-engined planes

[Shortround6]

P-40F (6 MGs) was 6300 lbs empty equipped. We delete 2 MGs and their ammo (-180 lbs for guns only), and substitute the engines (+400 lbs, if even so). Result is circa 6500 lbs for P-40 with R-2600.

The 6300lb figure is without guns.

Of course, but we do not need such firepower - no heavy bombers to take down.

You can guarantee that in 1940? that the Germans or Japanese will not develop a 4 engine bomber in the next 3-4 years. You weight comparison is done much good by using the weight of the particularly heavily armed A-8 model.

Yep, think those figures are pretty accurate - the A8 paid the price for it's heavy punch. OTOH, the engine of A3 not as reliable as later BMWs, nor as many contemporary Allied Axis engines in wide use, and the plane would be still some 600 lbs heavier then a 4-gun P-40 with R-2600.

What has reliability of the early engine got to do with weight of the entire airplane. ?

Please re-check your figures. Down is the table with weight for P-40N variant that reinforce my figures.

you may want to recheck your own figures, you picked the lightest P-40 built since the C model. How did they achieve this? one trick was using aluminum radiators, another was using just 4 guns (you not only save the weight of the guns but the mounts, charging equipment ammo boxes etc), another trick was leaving out the forward fuel tank (and self sealing) reducing internal fuel capacity to 120 US gallons. reductions in landing gear weight and armor may have also helped.
Later versions of the "N" model with the forward fuel tank replaced and provisions for 6 guns went up to 6200lbs empty. of course reducing the weight of the radiators just increases the difference of the weight installation when you switch to the aircooled engine. The Allison also weighed around 180lbs less than the Merlin in the "F".

Comparing a heavily armed A-8 model FW to a special "stripper" model of the P-40 (only 400 built) doesn't seem a fair weight comparison.

The difference in engine diameters is 4in, so the cowl would've been that much wider.

The 52in diameter for the BMW engine includes the cowl. The BMW engine was noted for how tight the cowl was in relation to other radial engines. I have seen one dimension of 60in for the diameter of an A-20 cowl so I figured 58in wasn't a bad compromise. Unless of course your alternative time line has the US beating the Germans to the punch with the whole tight cowl fan cooling thing. Incorporating the oil cooler into the cowling leading edge was another low drag trick the Germans used on the Fw 190 which no WW II US plane copied. How much lower in drag than a standard oil cooler I don't know but you rarely get something for nothing.

Sure, but it has to pull a 1000 lbs heavier plane

want to recheck that in light of the above.

Of course it received the development, but never received ADI, nor it was tasked to qualify for military rating.

You have been quoting military ratings for R-2600.
Military is not WEP.
Please note the changes I gave you before and add to them a change in master rod bearing material and increased strength rods and crankshaft.
ADI is not magic. It does several things to help an engine develop power.
One thing it cannot do is increase the airflow of a supercharger. ADI systems only increase the power of an engine below it's rated or critical altitude.
It helps cool the incoming charge, this allows more boost to be used before detonation(assuming the supercharger can supply more boost). More boost means more pressure in the cylinders and acting on the crankshaft, rods and crankcase. While ADI can help in making more power it does nothing in helping an engine stand up to the extra stress.
ADI also acts as an internal engine coolant, it helps cool the inside of the cylinders, piston tops, head areas etc. while this may allow for some increase in power without additional fins or liquid circulation the question maybe how much on a particular engine. Please note the P&W smaller cylinders on the R-2800 meant that they were a bit easier to cool in theory.
Another thing that ADI allowed was that it traded ADI fluid for fuel. Many engines in high boost conditions used extra fuel as an internal coolant, detonation suppressant. As a for instance, one version of the BMW 801 D could inject from 14.3 to 39 gallons an hour (depending on which part of the source you believe) into the supercharger allowing a 3.3lb increase in boost good for 140hp at sea level.
ADI allowed for the increase in power at the lower fuel consumption and the ADI tank didn't have to have the heavy self sealing liner/coatings.
How much ADI can be used depends on the capacity of the supercharger to begin with, the strength of the engine and the ability of the engine to stay in temperature operating limits even with the ADI.

You are no longer talking about swapping one existing engine for another but coming up with new lines of development for engines that they may not have been able to support. Again please note the considerable upgrades and re-tooling of the factories (changing from thousands of cast cylinder heads per week to thousands of forged heads,etc) needed to go from 1600hp to 1900hp. The R-2600 may not have been able to meet the military's requirements for WEP (7.5 hours at WEP on a test stand in, I believe, 5 minute spurts with cool down periods between.)

I may not be the only person who thinks the R-2600 was too wide. Wright developed and tested a short stroke version, the R-2170 with the stroke reduced to 5.25 in but with a much reduced diameter of 47in. It did not go into production however. Sorry, but I have no power figures available.

 

[tomo pauk]

Uh, pushing a plane to take advantage of a greater angle of attack how?

Plane accelerates down the strip, tail comes up and angle of attack on the wing falls to near zero, Or for trike gear aircraft angle of attack stays low until nose wheel comes of the ground.

The idea is that pilot would've pull the stick when he reaches last 80% of runaway. That way he'd increase AoA ( as much as tail allows) lift.

Trying to pull the plane up too soon means it stalls and crashes back on the runway or you force the tail back down and increase drag while partially blocking the tail surfaces.

It wouldn't crash since the deployed slats would allow 'better' airflow and therefore prevent the stall.

The idea is to get to flying speed as soon as possible. I still can't see how trying to taxi/accelerate down the runway/carrier deck with the wing tilted at 12 degrees or better is really going to work.

The stronger engine would've allowed for better acceleration.

 

[tomo pauk]

The 6300lb figure is without guns.

You might be right (I was mistaken many times ), but please post some table or something like that

You can guarantee that in 1940? that the Germans or Japanese will not develop a 4 engine bomber in the next 3-4 years.

The P-40B was produced with 2 HMGs 4 LMGs - the 4 HMGs are at least on par with that, more so since the HMGs rate of fire would have not been notably reduced by prop rotation. Not to mention P-40B (of 1940) was lacking the engine power to compete vs. those (anticipated) targets.
The US have had P-38 ready for production, just aiming at those bombers.

You weight comparison is done much good by using the weight of the particularly heavily armed A-8 model.

I've agreed with your figures for the A-3 (lightest?) version, and that one too would be in hardly any advantage vs. the opposite number (7100 lbs vs 6500 lbs for 'P-40N' with R-2600) if we talk about power-to-weight ratio.

What has reliability of the early engine got to do with weight of the entire airplane. ?

Pushing a not-so-reliable engine to extract some extra mph from a hefty plane is not very viable, more so if done time again.

you may want to recheck your own figures, you picked the lightest P-40 built since the C model. How did they achieve this? one trick was using aluminum radiators, another was using just 4 guns (you not only save the weight of the guns but the mounts, charging equipment ammo boxes etc), another trick was leaving out the forward fuel tank (and self sealing) reducing internal fuel capacity to 120 US gallons. reductions in landing gear weight and armor may have also helped.
Later versions of the "N" model with the forward fuel tank replaced and provisions for 6 guns went up to 6200lbs empty. of course reducing the weight of the radiators just increases the difference of the weight installation when you switch to the aircooled engine. The Allison also weighed around 180lbs less than the Merlin in the "F".

Well, what ever they did to save weight is indeed applicable to 'my' P-40 (minus the reduction of glycol radiator); we can add 50-100 lbs and be done with that
That's 6600 lbs at most, again favorably vs. any Fw-190.

Comparing a heavily armed A-8 model FW to a special "stripper" model of the P-40 (only 400 built) doesn't seem a fair weight comparison.

Answered above

The 52in diameter for the BMW engine includes the cowl. The BMW engine was noted for how tight the cowl was in relation to other radial engines. I have seen one dimension of 60in for the diameter of an A-20 cowl so I figured 58in wasn't a bad compromise. Unless of course your alternative time line has the US beating the Germans to the punch with the whole tight cowl fan cooling thing. Incorporating the oil cooler into the cowling leading edge was another low drag trick the Germans used on the Fw 190 which no WW II US plane copied. How much lower in drag than a standard oil cooler I don't know but you rarely get something for nothing.

Im 'my' time line, the P-40 would receive the R-2600 ('stead of V-1710) in 1940. My guess is that they would do something about the cowl in years after that. And I've already proposed clipping the wings, canceling a lot of added drag of R-2600, and some added weight.

want to recheck that in light of the above.

Think I did that (not that I claim I know everything).

You have been quoting military ratings for R-2600.
Military is not WEP.

Sorry fo the typo; I've ment WEP was not developed, not military rating.

Please note the changes I gave you before and add to them a change in master rod bearing material and increased strength rods and crankshaft.
ADI is not magic. It does several things to help an engine develop power.
One thing it cannot do is increase the airflow of a supercharger. ADI systems only increase the power of an engine below it's rated or critical altitude.
It helps cool the incoming charge, this allows more boost to be used before detonation(assuming the supercharger can supply more boost). More boost means more pressure in the cylinders and acting on the crankshaft, rods and crankcase. While ADI can help in making more power it does nothing in helping an engine stand up to the extra stress.
ADI also acts as an internal engine coolant, it helps cool the inside of the cylinders, piston tops, head areas etc. while this may allow for some increase in power without additional fins or liquid circulation the question maybe how much on a particular engine. Please note the P&W smaller cylinders on the R-2800 meant that they were a bit easier to cool in theory.
Another thing that ADI allowed was that it traded ADI fluid for fuel. Many engines in high boost conditions used extra fuel as an internal coolant, detonation suppressant. As a for instance, one version of the BMW 801 D could inject from 14.3 to 39 gallons an hour (depending on which part of the source you believe) into the supercharger allowing a 3.3lb increase in boost good for 140hp at sea level.
ADI allowed for the increase in power at the lower fuel consumption and the ADI tank didn't have to have the heavy self sealing liner/coatings.
How much ADI can be used depends on the capacity of the supercharger to begin with, the strength of the engine and the ability of the engine to stay in temperature operating limits even with the ADI.

Informative as always

You are no longer talking about swapping one existing engine for another but coming up with new lines of development for engines that they may not have been able to support. Again please note the considerable upgrades and re-tooling of the factories (changing from thousands of cast cylinder heads per week to thousands of forged heads,etc) needed to go from 1600hp to 1900hp. The R-2600 may not have been able to meet the military's requirements for WEP (7.5 hours at WEP on a test stand in, I believe, 5 minute spurts with cool down periods between.)

I was giving the figures for off-the-shelf engines, available as in original time line all the times.
The ADI and WEP were never developed because nobody was requesting them - no fighter design ever used R-2600 in the 1st place.

I may not be the only person who thinks the R-2600 was too wide. Wright developed and tested a short stroke version, the R-2170 with the stroke reduced to 5.25 in but with a much reduced diameter of 47in. It did not go into production however. Sorry, but I have no power figures available.

Since R-2170 never went into production, perhaps they were wrong about that


Have you notice that original P-40 was never talked as able to take at any Fw-190

 

[Shortround6]

The idea is that pilot would've pull the stick when he reaches last 80% of runaway. That way he'd increase AoA ( as much as tail allows) lift.

He also increases drag. Please note that this trick would work with a normal wing if it worked at all because the normal wing has a much higher coefficient of lift at 10 degrees than it does at 0-5 degrees that wing may be operating at in a normal take-off.

It wouldn't crash since the deployed slats would allow 'better' airflow and therefore prevent the stall.

slats don't create ANY lift. the allow the wing to operate at a higher angle of attack than normal and it is the higher angle of attack that creates the lift. For the slats to work at all (even a few percent) the AoA has to exceed 12-13 degrees, for them to really work the AoA is more like 16-22 degrees.

this trick might work for changing the distance to clear an obstacle at the end of the runway. Once the plane is flying at 10-20 ft and with a little extra speed pulling back might help the climb out. But I would certainly want to check with an experienced pilot before trying it.

See:http://lets-go-fly.com/Lift and Drag curves for the Wing.pdf

 

[Shortround6]

You might be right (I was mistaken many times ), but please post some table or something like that

Weight figures are from "America's Hundred-Thousand" by by Francis Dean, Schiffer Military History.
With your interest in aircraft I would strongly recommend getting this book as it has weight break downs for eleven Major US fighters (sometimes for a number of models of each) along with many other details. It may have a few errors (what large book doesn't) but as a one volume resource for US fighters it is hard to beat it's value.

The P-40B was produced with 2 HMGs 4 LMGs - the 4 HMGs are at least on par with that, more so since the HMGs rate of fire would have not been notably reduced by prop rotation. Not to mention P-40B (of 1940) was lacking the engine power to compete vs. those (anticipated) targets.
The US have had P-38 ready for production, just aiming at those bombers.

Being on a par with less than adequate is not a good recommendation.
The US, rightly or wrongly was looking for heavy armament in 1940. Saying the US should have adopted a 4 gun fighter in 1940 because they historical didn't need to shoot down 4 engine bombers 2-4 years later seems a poor argument when one looks at the designs they were considering and which ones they adopted. 733 P-47Bs with R-2800s and 8 guns are ordered in Sept of 1940. This is after the meeting in June (before the BoB) when Republic is told that both the P-44 (a P-43 with an R-2180 engine) and Allison powered XP-47 are to be dropped and a plane using the R-2800 is wanted.

I've agreed with your figures for the A-3 (lightest?) version, and that one too would be in hardly any advantage vs. the opposite number (7100 lbs vs 6500 lbs for 'P-40N' with R-2600) if we talk about power-to-weight ratio.

I am not agreeing with your 6500lb R-2600 powered P-40. Even taking a P-40C at 6143lbs and yanking 1649lb worth of engine and cooling system and adding 1950lbs worth of R-2600 is going to push you to 6444lbs, changing from 4 .30 cal guns to 2 .50s is going to add another 50lbs for 6494lbs.

Right on the money you say!!

Of course your 1700hp , 2600cu in engine still has the same oil system as the 1090hp, 1701 cu in engine, the same propeller, the same starter, exhaust system weight, engine mount weight and so on......right?

Pushing a not-so-reliable engine to extract some extra mph from a hefty plane is not very viable, more so if done time again.

Still has nothing to with estimating performance on a power to weight ratio does it.

Well, what ever they did to save weight is indeed applicable to 'my' P-40 (minus the reduction of glycol radiator); we can add 50-100 lbs and be done with that
That's 6600 lbs at most, again favorably vs. any Fw-190.

Reducing the fuel capacity for a larger, thirstier engine doesn't seem like a good idea. First P40N-1 is delivered in March of 1943.

Answered above

Really

Im 'my' time line, the P-40 would receive the R-2600 ('stead of V-1710) in 1940. My guess is that they would do something about the cowl in years after that. And I've already proposed clipping the wings, canceling a lot of added drag of R-2600, and some added weight.

Well, that leaves you with the high drag cowl in 1940-41-42, and I rather doubt clipping the wing is really going to do that much. The Fw 190 was first built with about a 160sq ft wing and changing to the 196sq ft wing only cost them 6mph. As far as weight goes I gave you 172lbs max, that is from dividing the weigh of the wing of a late model P-40 (see book listed above) by the wing area and then multiplying the weight per sq ft by your 36 sq ft reduction. of course this assumes that the weight of the wing is constant per sq ft which it is not. outer sections of wing using smaller, lighter ribs and thinner lighter spar sections.

I was giving the figures for off-the-shelf engines, available as in original time line all the times.
The ADI and WEP were never developed because nobody was requesting them - no fighter design ever used R-2600 in the 1st place.

Some of those Avengers and Helldivers might have wanted a bit more power getting off those flight decks, what do you know......they got it!!! when Wright could supply it.
Same with A-20s and B-25s.
Martin Mariner flying boats even got fan cooled engines to help cure chronic overheating, next model just shifted to R-2800s
Trying to haul a 55,000lb plane out of the water is not easy for one pair of engines
One problem that Wright had was that the father of the R-2600 was sent home and placed in virtual isolation because he was German. A majority of the rest of the engineering staff was trying to turn the R-3360 into a working engine. Just adding 2 cylinders per row to the R-2600 wouldn't seem like a big deal but it turned into a nightmare for Wright and took years (work started in 1936).
More or faster work on R-2600 may mean the R-3360 is even later in development.

Since R-2170 never went into production, perhaps they were wrong about that

Well, you might look at the two P&W R-2180s for hints.

Here is a hint for you though. The lead sentence in the wiki entry "The Pratt Whitney R-2180-A Twin Hornet and R-2180-E Twin Wasp E were closely-related radial engines developed in the United States by Pratt Whitney." is wrong.

Have you notice that original P-40 was never talked as able to take at any Fw-190

I have noticed that
Since I don't believe that your R-2600 powered version is going to show any large advantage over the P-40F it does bring us back to the question of why bother.

 

[tomo pauk]

Weight figures are from "America's Hundred-Thousand" by by Francis Dean, Schiffer Military History.
With your interest in aircraft I would strongly recommend getting this book as it has weight break downs for eleven Major US fighters (sometimes for a number of models of each) along with many other details. It may have a few errors (what large book doesn't) but as a one volume resource for US fighters it is hard to beat it's value.

Yep, some 35-45 USD +p&p - quite a bargain when comparing what they require for not as good books in Croatian book stores.

Being on a par with less than adequate is not a good recommendation.
The US, rightly or wrongly was looking for heavy armament in 1940. Saying the US should have adopted a 4 gun fighter in 1940 because they historical didn't need to shoot down 4 engine bombers 2-4 years later seems a poor argument when one looks at the designs they were considering and which ones they adopted. 733 P-47Bs with R-2800s and 8 guns are ordered in Sept of 1940. This is after the meeting in June (before the BoB) when Republic is told that both the P-44 (a P-43 with an R-2180 engine) and Allison powered XP-47 are to be dropped and a plane using the R-2800 is wanted.

Even better - the USAAC have had 2 world beater designs then
'My' P-40s/P-43s would've provided numbers required at 'low' part of high-low mix, like P-40 originally did.

I am not agreeing with your 6500lb R-2600 powered P-40. Even taking a P-40C at 6143lbs and yanking 1649lb worth of engine and cooling system and adding 1950lbs worth of R-2600 is going to push you to 6444lbs, changing from 4 .30 cal guns to 2 .50s is going to add another 50lbs for 6494lbs.

Right on the money you say!!

Of course your 1700hp , 2600cu in engine still has the same oil system as the 1090hp, 1701 cu in engine, the same propeller, the same starter, exhaust system weight, engine mount weight and so on......right?

Still has nothing to with estimating performance on a power to weight ratio does it.

Okay, than we'd add some 300 lbs for beefed-up stuff (exhaust, prop, starter, engine mount), but also remove at least 100 lbs from reduced wing. 'My' P-40C would've been 8% heavier then, but engine power would be 40-50% greater. Comparable with achievements of Spit IX-> Spit XIV, or LaGG-3 -> La5.

Reducing the fuel capacity for a larger, thirstier engine doesn't seem like a good idea. First P40N-1 is delivered in March of 1943.

We'd trade off some of range to achieve much greater performance.

Really

Yep

Well, that leaves you with the high drag cowl in 1940-41-42, and I rather doubt clipping the wing is really going to do that much. The Fw 190 was first built with about a 160sq ft wing and changing to the 196sq ft wing only cost them 6mph. As far as weight goes I gave you 172lbs max, that is from dividing the weigh of the wing of a late model P-40 (see book listed above) by the wing area and then multiplying the weight per sq ft by your 36 sq ft reduction. of course this assumes that the weight of the wing is constant per sq ft which it is not. outer sections of wing using smaller, lighter ribs and thinner lighter spar sections.

While we'd never know just how much the smaller wing would've canceled the enlarged engine, I've acknowledged the higher drag of it, and suggested the clipped wing as the most obvious/the easiest way of reducing wing's drag. Granted, if the R-2600 was ever mounted on a such streamlined design, like Spit, Bf-109, or P-51, the influence of draggier engine would've been more pronounced than with not-so-sleek P-40 hull.

Some of those Avengers and Helldivers might have wanted a bit more power getting off those flight decks, what do you know......they got it!!! when Wright could supply it.
Same with A-20s and B-25s.
Martin Mariner flying boats even got fan cooled engines to help cure chronic overheating, next model just shifted to R-2800s
Trying to haul a 55,000lb plane out of the water is not easy for one pair of engines

Never said that R-2600 received no development, but that it never received fighter-plane accessories (ADI, WEP qualification, perhaps a supercharger set for hi-alt work?). I so speak affirmatively about it - hence 'my' P-40

One problem that Wright had was that the father of the R-2600 was sent home and placed in virtual isolation because he was German.

Granted, you're very knowledgable man

A majority of the rest of the engineering staff was trying to turn the R-3360 into a working engine. Just adding 2 cylinders per row to the R-2600 wouldn't seem like a big deal but it turned into a nightmare for Wright and took years (work started in 1936).
More or faster work on R-2600 may mean the R-3360 is even later in development.

Perhaps some of stuff developed for R-2600 would've ease the R-3360 development?

Well, you might look at the two P&W R-2180s for hints.

I could ( will, provided I have time), but I've never had love for those 'intermediate' engines. No niche for those, you know...

Here is a hint for you though. The lead sentence in the wiki entry "The Pratt Whitney R-2180-A Twin Hornet and R-2180-E Twin Wasp E were closely-related radial engines developed in the United States by Pratt Whitney." is wrong.

I take Wiki as reference only when lacking something better

I have noticed that
Since I don't believe that your R-2600 powered version is going to show any large advantage over the P-40F it does bring us back to the question of why bother.

The difference vs. the P-40N would be indeed small, but the -F presented only 10% of P-40s produced. 'My' P-40 would've been vastly better than Allison-engined planes, and that is it's main quality

 

[Shortround6]

.
Okay, than we'd add some 300 lbs for beefed-up stuff (exhaust, prop, starter, engine mount), but also remove at least 100 lbs from reduced wing. 'My' P-40C would've been 8% heavier then, but engine power would be 40-50% greater. Comparable with achievements of Spit IX-> Spit XIV, or LaGG-3 -> La5.

For now lets stick to 1940. The R-2600 available at this time is the 1600hp for take-off version, the "A" series. It has the Aluminum crankcase. It is good for 1600hp at take-off, 1600hp at 3000ft military power in low gear and 1400hp at11,500ft in high gear.
For an idea of performance lets look at the P-40 in 1940, two, 50cal guns no armor or self sealing tanks and an Allison engine of 1040 for take off and 1030hp at 14300ft or 1090hp at 13,200ft depending on source (although with 60hp less at 900ft higher they aren't that far apart) at a weight of 6,787lbs gross it manages 357mph at 15,000ft.
Now for an Idea of what the V-12 engine got for it's 'streamlining' we have the numbers for a Curtiss Hawk 75A-4. Poweerd by a 9 cylinder Wright cyclone of 1200hp for take off and Military ratings of 1200hp at 1800ft and 1000hp at 13,600ft. Speed is 323mph at 15,100ft and 272mph at sea level at a weight of 5,750lbs. again no armor, self sealing tanks but with 4 wing guns crating a bit of drag.

V-12 engined plane with 45-50 more HP is about 10% faster while weighing 1,000lbs more.

The 1940 R-2600 doesn't have 40-50% more power at altitude (13-15,000ft) but 30% or under. At sea level it has 33% more power than the cyclone 9.
The R-2600 weighs 600lbs more than the Cyclone for a dry, bare engine. Over 40% more.
Using the Hawk 75 as a basis and since drag goes up with the square of the speed you need 21% more power for a 10% increase in speed if everything stays the same. Since it didn't (heavier engine, heavier armament etc) you need even more power for a 10% increase in speed.
Would your R-2600 powered plane be faster than a P-40?
quite possibly but is 5-10mph faster going to be enough to change the tactical situation for the "NEW" P-40 in air combat? Oh yeah, you get an extra 3-5 mph for clipping the wing.

.
We'd trade off some of range to achieve much greater performance.

a couple of hundred pounds isn't going to give you Much greater performance, a little bit yes. This change was thought so valuable by the USAAF that most later versions than the N-1 series had the fuel tank put back in.

.
Never said that R-2600 received no development, but that it never received fighter-plane accessories (ADI, WEP qualification, perhaps a supercharger set for hi-alt work?). I so speak affirmatively about it - hence 'my' P-40

ADI doesn't show up until 1943. Why Wright didn't use it I have no idea, it might have been a god send to B-29 pilots trying to take off with overheating engines form those Pacific Islands. getting event the same take-off power at lower temperatures would have been an advantage. But it does mean greater strain on an engine if used to get more power, I doubt it could be added to much advantage to an "A" series engine.

WEP only was awarded if the engine proved it could stand up to the power. Given some of the improvements Wright made between the Early engines and the later ones there may be some doubt as the ability of the early engines to use a WEP setting. It is not just a matter of shorter times between overhauls. Breaking a connecting rod or launching a cylinder head through the cowling tends to end a mission pretty quick.
There were a few experimental supercharger set ups and a few very short production runs of turboed early R-2600's. It seems not to have been repeated. Given the troubles with the turboed B-29 engines it might have been a good idea NOT to turbo the R-2600.

.
Perhaps some of stuff developed for R-2600 would've ease the R-3360 development?

It might work the other way, I am not sure how much stuff developed for the R-3360 found it's way into later R-2600s.

 

[tomo pauk]

For now lets stick to 1940. The R-2600 available at this time is the 1600hp for take-off version, the "A" series. It has the Aluminum crankcase. It is good for 1600hp at take-off, 1600hp at 3000ft military power in low gear and 1400hp at11,500ft in high gear.
For an idea of performance lets look at the P-40 in 1940, two, 50cal guns no armor or self sealing tanks and an Allison engine of 1040 for take off and 1030hp at 14300ft or 1090hp at 13,200ft depending on source (although with 60hp less at 900ft higher they aren't that far apart) at a weight of 6,787lbs gross it manages 357mph at 15,000ft.
Now for an Idea of what the V-12 engine got for it's 'streamlining' we have the numbers for a Curtiss Hawk 75A-4. Poweerd by a 9 cylinder Wright cyclone of 1200hp for take off and Military ratings of 1200hp at 1800ft and 1000hp at 13,600ft. Speed is 323mph at 15,100ft and 272mph at sea level at a weight of 5,750lbs. again no armor, self sealing tanks but with 4 wing guns crating a bit of drag.

V-12 engined plane with 45-50 more HP is about 10% faster while weighing 1,000lbs more.

The 1940 R-2600 doesn't have 40-50% more power at altitude (13-15,000ft) but 30% or under. At sea level it has 33% more power than the cyclone 9.

The R-2600 weighs 600lbs more than the Cyclone for a dry, bare engine. Over 40% more.
Using the Hawk 75 as a basis and since drag goes up with the square of the speed you need 21% more power for a 10% increase in speed if everything stays the same. Since it didn't (heavier engine, heavier armament etc) you need even more power for a 10% increase in speed.
Would your R-2600 powered plane be faster than a P-40?
quite possibly but is 5-10mph faster going to be enough to change the tactical situation for the "NEW" P-40 in air combat? Oh yeah, you get an extra 3-5 mph for clipping the wing.

That would make 8-15 extra mph, making P-40 (from 1940) faster than Spit II Bf-109E-7, the fastest planes in service in second half of 1940. Also much more durable.

a couple of hundred pounds isn't going to give you Much greater performance, a little bit yes. This change was thought so valuable by the USAAF that most later versions than the N-1 series had the fuel tank put back in.

Okay, the R-2600 was better able to pull it in 1943 with 1750 HP for take off, than Allison with 400 HP less

ADI doesn't show up until 1943. Why Wright didn't use it I have no idea, it might have been a god send to B-29 pilots trying to take off with overheating engines form those Pacific Islands. getting event the same take-off power at lower temperatures would have been an advantage. But it does mean greater strain on an engine if used to get more power, I doubt it could be added to much advantage to an "A" series engine.

The more I read about engines, i like ADI more more

WEP only was awarded if the engine proved it could stand up to the power. Given some of the improvements Wright made between the Early engines and the later ones there may be some doubt as the ability of the early engines to use a WEP setting. It is not just a matter of shorter times between overhauls. Breaking a connecting rod or launching a cylinder head through the cowling tends to end a mission pretty quick.

Agreed

There were a few experimental supercharger set ups and a few very short production runs of turboed early R-2600's. It seems not to have been repeated. Given the troubles with the turboed B-29 engines it might have been a good idea NOT to turbo the R-2600.

No need for turbo here (more so if it was that plagued); USAAC have had two fighter designs with excellent turbo-supercharged engines early enough.

It might work the other way, I am not sure how much stuff developed for the R-3360 found it's way into later R-2600s.

Yep

 

[tomo pauk]

The FAA planes are my eternal inspiration
Here is Fulmar again, this time with R-2600 (with 1600 HP, almost 50% more HP for T/O at low level than with Merlin III of Fulmar Mk.I). Sure enough, it would've take a lots of foresight to make it, but it's certainly at my liking.
On another pic is comparison with Helldiver.

 

[tomo pauk]

A more radical proposal, the Merlin is here supercharged with auxiliary engine of some 300 HP, mounted alt the radiator. Surely, Fairey Battle would've make a good use of it (hopefully).

 

[tomo pauk]

A radical proposal (the Do-355 fans would be thrilled), two Merlins in push-pull layout. It could use some tweaking (we're just added a full ton of metal aft the CoG), like moving the front engine perhaps a foot forward, with some fuel located in the newly acquired sapce, 'thinner' main fuel tank (so the 2nd crew member could move forward to allow 2nd engine being located more towards the CoG), or perhaps an inverted Airacobra layout (engine between main fuel tank navigator, with shaft located under navigator)...
Anyway, here it is (the thin horizontal vertical lines are for 'computing' the aft prop/low fin clearance):

 

[tomo pauk]

Here is how the Fairey Barracuda might have looked like, with a proper engine. R-2800, never the less

 

[Marcel]

G.1 with merlins:

 

[tomo pauk]

Lovely plane indeed

 

[tomo pauk]

The P-51 with a well-streamlined radial; the scale fits to R-2800 Ash-82 (depicted).

 

[tomo pauk]

Fairey Battle in push-pull variant. Mosquito-catcher?
2nd engine is above the place where bomb-aimer originally way in prone position, aux fuel tank and/or bombs would've been there now. Prop shaft under the second crew member (observer/bomb-aimer now, or radar operator in night fighter version), reduction gear afer him.

 

[tomo pauk]

Willy's tandem plane - Bf-110 in push-pull configuration - might have looked this way:

 

[hawkeye2an]

Keep 'em coming Tomo. I look foreward to your new posts. Always something fun to consider.

 

[tomo pauk]

Here are some planes that would've used some extra HP, in master-slave flavor.
Fw-200, with one slave engine per 2 engines (one per wing), to give it more altitude speed. Note the elongated 'gondola', for better structural integrity.
Second one - Ju-188, with one slave engine per one master engine (BMW-801), only one HMG defensive weapon.

 

[tomo pauk]

Fulmar with 2 Merlins, Beaufighter is for comparison. Hull fuel tank loses lower half (now occupied by guns ammo), new fuel tanks in wings.