# If no P-51, how would the P-40 have evolved?



## gjs238 (Jun 1, 2012)

If the P-51 never happened, would evolved P-40's been fielded, and what sort of evolution might we have seen?


----------



## michaelmaltby (Jun 1, 2012)

XP-40Q


----------



## Shortround6 (Jun 1, 2012)

A P-40 was a re-engined P-36. ANY development past 1943 was flogging a dead horse. The Hawk 75 first flew 6 months BEFORE the Hawker Hurricane. If not the P-51 then some other airframe would have come up in the 6 1//2 years between the Hawk 75s first flight and Pear Harbor let alone the another 2-3 years.


----------



## wuzak (Jun 1, 2012)

I would suggest the XP-46, XP-53 and XP-60 would be a good guide.

The XP-46 was a smaller, lighter development with inward retracting gear and belly mounted radiator, but was cancelled in favour of improved P-40s (those already being in production).





Curtiss : XP-46 by San Diego Air & Space Museum Archives, on Flickr





Curtiss : XP-46 by San Diego Air & Space Museum Archives, on Flickr

The next development would have been the XP-53. his had a P-40 fusealge mounted to laminar flow wing with inward retracting main gears and 6 0.50s.

It was to be powered by the IV-1430, but problems with that engine caused delay and eventually led to one of the prototypes being fitted with a Merlin 28 and redesignated XP-60. Due to delays with production of Merlins it was proposed that the XP-60 then be powered by a turbocharged Allison, then a later variant was powered by an R-2800.






The wiki page says that this picture is of the


> XP-60B in flight test with Allison V-1710-75 engine and a Wright SU-504-1 turbo-supercharger


. It is clearly the Merlin XP-60.

The Allison turbo model (with GE turbo) looked like this




.

The XP-60B with the Wright turbo never flew.


----------



## Shortround6 (Jun 2, 2012)

With Curtiss themselves trying 2/3 different airframes by the end of 1941 (both the XP-46 and XP-60 flying for the first time in Sept 1941, design work stated much earlier) There is little doubt that both Curtiss and the USAAC felt that the P-36/40 had limited development potential.


----------



## drgondog (Jun 2, 2012)

For the USAAF, absent P-51B, the only choice for escort was P-38 and continuously improved P-47.. big impact from Big Week through D-Day on 8th AF bomber crews, more US fighter losses, fewer LW casualties in that same period. Probably no start of May Oil/Chemical campaign because of deep penetration prohibitive losses until perhaps 6-7 P-38 Groups fully operational.


----------



## wuzak (Jun 2, 2012)

drgondog said:


> For the USAAF, absent P-51B, the only choice for escort was P-38 and continuously improved P-47.. big impact from Big Week through D-Day on 8th AF bomber crews, more US fighter losses, fewer LW casualties in that same period. Probably no start of May Oil/Chemical campaign because of deep penetration prohibitive losses until perhaps 6-7 P-38 Groups fully operational.



Isn't that a different discussion?

I suppose the answer to the question in the OP "If the P-51 never happened, would evolved P-40's been fielded?" is no.


----------



## davebender (Jun 2, 2012)

I agree. Curtiss needs to start with a clean sheet of paper for their next design.


----------



## wuzak (Jun 2, 2012)

Well, the P-51 "happened" in 1940, so if i hadn't there may have been more of a push for the P-53/P-60. Curtiss were trying to develop new aircraft, but using parts of the P-40 to expidite development.

If the P-51 doesn't happen, NAA must have signed with the British Purchasing Comission to build P-40s and, presumably, whatever came next.


----------



## The Basket (Jun 3, 2012)

The P-40 was an important in production aircraft so would have to assume that the P-40 derivatives would have been pushed forward.

One role of successful aircraft is they do stop other aircraft going anywhere. Why have a new Spitfire when the old Spitfire is working fine. Not sure when the Curtiss antipathy kicked in which would eventually end the maker.

But that P-40Q looks a fine machine.


----------



## Shortround6 (Jun 3, 2012)

The Basket said:


> The P-40 was an important in production aircraft so would have to assume that the P-40 derivatives would have been pushed forward.
> 
> One role of successful aircraft is they do stop other aircraft going anywhere. Why have a new Spitfire when the old Spitfire is working fine. Not sure when the Curtiss antipathy kicked in which would eventually end the maker.
> 
> But that P-40Q looks a fine machine.



Ah, P-40 "derivatives" include the XP-46, the XP-53 and the XP-60 (in _five_ variations) Curtiss antipathy may have kicked in when none of these caught on and a number of other projects turned out to be duds. Or perhaps Curtiss was trying to do too much with too little talent?

Curtiss Seamew, Curtiss Seahawk, the XBTC-1, XBTC-2 and XBT2C-1, XF14C-2 and XF15C-1, XP-62 and XP-72 ( the latter a 40,000lb fighter with twin turboed R-4360 engines driving 8 bladed counter rotating pusher propellers) and the XSB3C-1 ( a stretched Helldiver using a R-3350, tricycle landing gear and a 4,000lb internal bomb load) Throw in the XP-55 and Curtiss had about 14 different aircraft or projects aside from the P-40 going during WW II. It doesn't sound like they were sitting back being fat, dumb and happy on P-40 profits like is sometimes claimed.


----------



## KiwiBiggles (Jun 4, 2012)

> =XP-72 ( the latter a 40,000lb fighter with twin turboed R-4360 engines driving 8 bladed counter rotating pusher propellers).


 XP-71, I think. XP-72 was a Republic development of the P-47.


----------



## Jabberwocky (Jun 4, 2012)

I think the XP-46 is a non-starter. The airframe/engine combination simply wasn't aggressive enough in design and performance was no improvement over those fighters already in combat in Europe (Spitfire II/V, Bf 109E-4 -7/F-2). If wiki is to believed, the bird had VERY short legs as well, about half the range of the already short-ranged Spitfire and 109.

The P-53/60 is more interesting and probably do-able by late 1941/early 1942, but the whole project appears to have suffered from a lack of management and wildly changing requirements on behalf of the end user. Only 4 airframes were built, but they managed to test eight major configuration changes, including 5 different engines/engine sub-types.

The V-1650-1 powered XP-60A (Model 90) reportedly made either 380 mph or 387 mph at 22,000 ft. That's marginally better than the similarly powered P-40F, which achieved about 364 mph at 20,500 ft in US tests and 354 mph at the same height in RAF tests. The light-weight P-40L was able to achieve 357-367 mph (depending on the test) at 21,500 ft.

The XP-60s were quite portly though, so the extra speed would come at the price of a lower RoC. Empty weight was 450 lbs heavier than equivalent P-40Fs and loaded weight almost 700 lbs heavier. Climb to 15,000 ft is reported as 7.3 minutes (online source admittedly). 

I say, get the XP-60 into service ASAP, and then follow it up with a V-1650-3 powered version in 1943. Add the airframe improvements when production switches over to the new engine. 

I believe a two-speed Merlin powered P-60 is going to be more competitive (even marginally so) than the Allison-powered P-40 or P-39 during 1942/43 while the USAAF get the P-47 and P-38 sorted. Convert the P-40 into a dedicated fighter bomber and be done with it.


----------



## wuzak (Jun 4, 2012)

With the XP-53/60 the radiator was found to be a major source of excessive drag.

So if they get the go-ahead for the P-60 (the P-53 being the one to be powered by the IV-1430) I expect there would have been a bit of refining in that area.

One XP-60 (the XP-60A I believe) flew with an Allison and turbocharger (B-series). That may have continued in development alongside the XP-60/60B Merlin variant.


----------



## wuzak (Jun 4, 2012)

Double post


----------



## Shortround6 (Jun 4, 2012)

KiwiBiggles said:


> XP-71, I think. XP-72 was a Republic development of the P-47.



Thank you for the correction.


----------



## Shortround6 (Jun 4, 2012)

Part of Curtiss's problem was that they were designing to USAAC (and Navy) requirements and the USAAC (and Navy) had some rather unrealistic ideas on what was possible. TO be fair they were trying to guess what would be needed 2-3 years in the future and were trying to push the envelope. For example the XP-46 was to have a pair of .50 cal guns in the cowl PLUS eight .30 cal guns in the wing. The XP-52 and first XP-60 were supposed to have EIGHT .50 cal guns. P-47 armament in a smaller wing with a lower powered engine. AS the P-60 program advanced though one change after another the armament was reduced to 6 guns and then to 4 guns with just 250 rounds apiece in an apparent effort to lighten the aircraft. 
The Specification for the XP-62 was issued in January of 1941 and Curtiss had a proposal ready by April 29 41. Powered by an R-3350 with turbo supercharger, equipped with a pressure cabin and armed with either EIGHT 20mm cannon or TWELVE .50 cal MGs. 

Some of the Navy Specifications were about as bad, in the sense they sometimes just doubled the bombload of an existing aircraft while asking for more speed and more range at the same time. Even with R-2800. R-3350 and even R-4360 engines there is only so much that could be done.


----------



## zoomar (Jun 4, 2012)

The P-40 was at the end of its development potential, and Curtiss seemed to have lost its grasp altogether providing a sucessor. Planes like the P-60 or P-62 would have been inferior to both the P-47 and P-38. Had the P-51 never materialized, AAF procurement strategy would have focused on the P-47 and P-38 (and potential successors like the P-72 and P-49 (which what what I believe the "improved P-38" was designated).

Alternatively, if this left a hole needing to be filled by a 2nd high performance single engined plane, why not look at dedicated land-based derivatives of the Corsair and Hellcat?


----------



## Shortround6 (Jun 4, 2012)

Curtiss was trying to supply what the customer said it wanted. If the customer says it wants a plane with eight 20mm cannon in the wings powered by a an R-3350 radial Curtiss only has a few choices. Design according to specification or prepare two detailed proposals, One to the customers spec and one that Curtiss thinks will work better and why and then show both to the customer and try to persuade the customer they are wrong. 
In 1942-43 The USAAC was NOT proposing new fighters armed with just six machine guns and having speeds/ranges only 10-20% higher than existing fighters. They wanted massive increases in armament, speed, range and ceiling and all at the same time in the same airplane.


----------



## spicmart (Jun 4, 2012)

zoomar said:


> The P-40 was at the end of its development potential, and Curtiss seemed to have lost its grasp altogether providing a sucessor. Planes like the P-60 or P-62 would have been inferior to both the P-47 and P-38. Had the P-51 never materialized, AAF procurement strategy would have focused on the P-47 and P-38 (and potential successors like the P-72 and P-49 (which what what I believe the "improved P-38" was designated).
> 
> Alternatively, if this left a hole needing to be filled by a 2nd high performance single engined plane, why not look at dedicated land-based derivatives of the Corsair and Hellcat?



At what point can one say that a certain design's development potential is used up. How can one measure that? Looking at the airframe one can get the impression that if given a powerful enough engine and maybe a relocating of the coolant radiator that the P-40 might be competitive with the Spitfires which also were not low-drag-wonders. At least why shouldn' it be?


----------



## riacrato (Jun 5, 2012)

Spitfire was pretty low-drag for late 30s / early 40s standard, except for a few areas.

AFAIK P-40 had a complex and heavy spar structure, something that wouldn't be easy to change.


----------



## Shortround6 (Jun 5, 2012)

spicmart said:


> At what point can one say that a certain design's development potential is used up. How can one measure that? Looking at the airframe one can get the impression that if given a powerful enough engine and maybe a relocating of the coolant radiator that the P-40 might be competitive with the Spitfires which also were not low-drag-wonders. At least why shouldn' it be?



How many times do you want to re-locate the radiator? 

They tried at least twice after the P-40E and the original XP-40 was tried with 2 different locations and the forward location with at least two different cowls/housings.


----------



## krieghund (Jun 6, 2012)

The first step to improve the P-40 is for Allison to develop a 2-stage supercharger for the V1710 then clean up the aircraft as the P-40F equipped with the V-1650-1 shows a 2-stage engine is not much better than a single stage engine without cleaning up the aerodynamics.

The P-40Q is in the right direction.


----------



## wuzak (Jun 6, 2012)

krieghund said:


> The first step to improve the P-40 is for Allison to develop a 2-stage supercharger for the V1710 then clean up the aircraft as the P-40F equipped with the V-1650-1 shows a 2-stage engine is not much better than a single stage engine without cleaning up the aerodynamics.
> 
> The P-40Q is in the right direction.



The V-1650-1 was a single stage engine. It had a two speed gearbox, unlike the V-1710, which had just the singke, fixed, ratio.


----------



## krieghund (Jun 6, 2012)

wuzak said:


> The V-1650-1 was a single stage engine. It had a two speed gearbox, unlike the V-1710, which had just the singke, fixed, ratio.



Yes thanks for the correction. that is what I meant. The P-40 was more maneuverable than the P-51D and the only ace the P-51 had was its speed, it could disengage at will.


----------



## FLYBOYJ (Jun 6, 2012)

krieghund said:


> The P-40 was more maneuverable than the P-51D.


 And your proof of that? At what speed and altitude, or is that a blanket statment? So please let us know your sources for that...


----------



## GregP (Jun 6, 2012)

I think the P-40 had great potential.

The XP-40Q was about as good as a Mustang, though about 10 mph slower. In combat, 10 mph is meaningless. The real issue with the P-40 was not the basic design, but the wing and airfoil and lack of a high-altitude engine. Had they fielded an upgraded airfoil (higher critical mach number) with a wing area sufficient to give a combat wing loading of, say, 35 – 38 pounds per square foot, and added a 2-stage, 2-speed supercharger OR a turbocharger, then things might have been quite different.

At low altitudes the P-40 was a very dangerous opponent and out-rolled most of the competition. It was also decently fast at about 360 mph down low. On the deck, not many were, in fact, faster. The P-51D, while it could make 437 mph at height, was about a 360 mph at sea level, right along with the P-40.

Let’s remember that they DID add a Merlin to the P-40 in the P-40F. However, it was a single-stage, single-speed unit and the performance was no better than with the single-stage, single-speed Allison. Had they added a multi-stage, multi-speed unit, then things at higher altitudes would have been different. It might or might not have been a world beater, but would have given a nasty surprise to many.


----------



## Trebor (Jun 6, 2012)

michaelmaltby said:


> XP-40Q



lol wow the only thing P-40 about it is the tail, and maybe the nose


----------



## Trebor (Jun 6, 2012)

krieghund said:


> Yes thanks for the correction. that is what I meant. The P-40 was more maneuverable than the P-51D and the only ace the P-51 had was its speed, it could disengage at will.



the P-40 was barely even maneuverable. the only way that the Flying Tigers could defeat Japanese fighters was to take advantage of its ruggedness and speed and take them head on. (I may be missing some things, fellas. if you'd like, contribute)


----------



## Milosh (Jun 6, 2012)

Trebor said:


> the P-40 was barely even maneuverable. the only way that the Flying Tigers could defeat Japanese fighters was to take advantage of its ruggedness and speed and take them head on. (I may be missing some things, fellas. if you'd like, contribute)



How would the Fw190 or the Bf109 have faired against the Japanese fighters.


----------



## Trebor (Jun 6, 2012)

Milosh said:


> How would the Fw190 or the Bf109 have faired against the Japanese fighters.



what? I don't know. I don't think German fighters ever faced off against Japanese fighters


----------



## Shortround6 (Jun 6, 2012)

GregP said:


> I think the P-40 had great potential.
> 
> The XP-40Q was about as good as a Mustang, though about 10 mph slower. In combat, 10 mph is meaningless.



10mph may be meaningless the actual difference is a bit greater. I could be wrong but I believe the P-40Q carried 4 guns with about 200-201 rounds per gun?
Going to six guns or 350-400rpg (or both) may may little difference in speed but a much larger difference in climb, turn and initial roll. Just going from 200rpg to 350rpg for four guns is 180-190lbs. Some sources claim production models would have had six .50s or four 20mm cannon which really would have affected certain aspects of performance. 




GregP said:


> At low altitudes the P-40 was a very dangerous opponent and out-rolled most of the competition. It was also decently fast at about 360 mph down low. On the deck, not many were, in fact, faster. The P-51D, while it could make 437 mph at height, was about a 360 mph at sea level, right along with the P-40.



Please define "down low". On the deck the only way a P-40 was going to get to 360mph unless pulling out of a dive was by using JATO rockets. Most sources give under 300mph with normal military power and one source gives 314mph at sea level for a P-40N using a -81 engine using 57in MAP (13.5-14lbs boost) WEP. This is at 7900lbs which means aluminium radiators and oil coolers, smaller wheels and brakes, no forward wing tank and a few other tricks to lighten the plane. It is a test done by the RAAF and perhaps not up to Curtiss factory standards but it rather hard to see were another 40-45mph is going to come from. 



GregP said:


> Let’s remember that they DID add a Merlin to the P-40 in the P-40F. However, it was a single-stage, single-speed unit and the performance was no better than with the single-stage, single-speed Allison. Had they added a multi-stage, multi-speed unit, then things at higher altitudes would have been different. It might or might not have been a world beater, but would have given a nasty surprise to many.



The engine used in the "F" was a _two speed_ single stage unit, not single speed. Performance was "relocated" compared to an "E" model P-40. Performance "down low" was a bit worse but performance above 15,000ft was better. Some tests (or charts) showing a speed advantage of 30mph or more above 20,000ft for the "F".


----------



## tomo pauk (Jun 6, 2012)

Trebor said:


> the P-40 was barely even maneuverable. the only way that the Flying Tigers could defeat Japanese fighters was to take advantage of its ruggedness and speed and take them head on. (I may be missing some things, fellas. if you'd like, contribute)



Hi, 
It depends what kind of a maneuvre one wants the P-40 to make, at what speed and at what altitude. P-40 was one of the best rollers between 200-300 mph (only Spit w/ clipped wings Fw-190 being better), with the rate of roll being twice as good as the Zero (and almost 3 times as good at 300 mph), for example. If one rolls to slow, he is an awarding target (= ill able to throw off enemy's aim), and will be too late to make a turn.
Of course, trying to make maneuvers with the P-40 at 25000 ft (where his V-1710 acts like he's lacking 6 of it's 12 cylinders) is not something that P-40 drivers should be trying to often.


----------



## krieghund (Jun 8, 2012)

FLYBOYJ said:


> And your proof of that? At what speed and altitude, or is that a blanket statment? So please let us know your sources for that...



Dang, knew someone would call me on that before I could get my source. It is in a P-51 book discussing pilot training in the states flying comparison between the P-40 and P-39 against the P-51D. The only things going for the P-40 were its roll rate and turn rate which I assume is below the critical altitude of the the Allison. 

The same book also describes a USAAF group commander describing how his Allison powered mustangs with ruined bearings would bring them home but a Merlin mustang wouldn't. 

Still looking.........


----------



## FLYBOYJ (Jun 8, 2012)

krieghund said:


> Dang, knew someone would call me on that before I could get my source. It is in a P-51 book discussing pilot training in the states flying comparison between the P-40 and P-39 against the P-51D. The only things going for the P-40 were its roll rate and turn rate which I assume is below the critical altitude of the the Allison.


As indicated earlier, the P-40 had one of the best roll rates of any WW2 single engine fighter but in the end, depending on speed and altitude (and of course pilot ability) it was not going to out-maneuver a P-51 across the board. Where the P-40 had its strengths, the P-51 had other attributes (acceleration, power to weight ratio) that can cancel the P-40s advantages, again this depending on speed altitude and pilot skill.


----------



## krieghund (Jun 8, 2012)

FLYBOYJ said:


> As indicated earlier, the P-40 had one of the best roll rates of any WW2 single engine fighter but in the end, depending on speed and altitude (and of course pilot ability) it was not going to out-maneuver a P-51 across the board. Where the P-40 had its strengths, the P-51 had other attributes (acceleration, power to weight ratio) that can cancel the P-40s advantages, again this depending on speed altitude and pilot skill.



Agreed, however, a p-40 drawing 70" it could give the 'tang a run for its money at lower levels which is where pilot training BFM was probably performed.


----------



## GregP (Jun 8, 2012)

Actually the XP-40Q was almost a stock P-40 airframe. The turtledeck was cut down and the engine installation and radiator were improved, along with the engine itself, and it was fitted with a 4-bladed prop.

There was a LOT of basic P-40 in it.


----------



## Shortround6 (Jun 8, 2012)

krieghund said:


> Agreed, however, a p-40 drawing 70" it could give the 'tang a run for its money at lower levels which is where pilot training BFM was probably performed.



what happens when the " 'tang " pulls 70" ? or even 67"


----------



## FLYBOYJ (Jun 9, 2012)

krieghund said:


> Agreed, however, a p-40 drawing 70" it could give the 'tang a run for its money at lower levels which is where pilot training BFM was probably performed.





Shortround6 said:


> what happens when the " 'tang " pulls 70" ? or even 67"



And do want to start comparing wingloading as well?


----------



## krieghund (Jun 9, 2012)

FLYBOYJ said:


> And do want to start comparing wingloading as well?



And don't forget the airfoil differences between the them as well as prop efficiencies, etc. This could wind down into an Urinary Olympics.


----------



## Shortround6 (Jun 9, 2012)

I have no intention of competing in a "Urinary Olympics" it just that I dislike "caparisons" that say "plane A was as good as plane B if Plane A used XX power level" while leaving out that plane B is at XX minus 20/30%. 

No need to play with airfoils or prop efficiency or adjust weights to equalize things, they were different aircraft. But if one gets to use WEP (or beyond and 70" is beyond any book WEP for an Allison in a P-40) then the other should be compared using WEP. 

There is a reason the P-40 was being phased out in 1943 and it has nothing to do with politics or anything other than aerodynamics. It was a higher drag, older airframe.


----------



## gjs238 (Jun 9, 2012)

Shortround6 said:


> There is a reason the P-40 was being phased out in 1943 and it has nothing to do with politics or anything other than aerodynamics. It was a higher drag, older airframe.



Didn't the Truman Committee investigate this?


----------



## Shortround6 (Jun 9, 2012)

I believe the Truman Committee did investigate the continued production of the P-40 but I believe it was from the point of view of why did the Army continue to buy such an obsolete aircraft for so long. Production ended November 30, 1944. A pilots manual printed in 1943 (month not given) says that no new P-40 units will be formed to go overseas and that the P-40 is basically an advanced trainer. New P-40s may have gone overseas as replacements for units already equipped or as equipment for "allied" nations but apparently the US planners at some point in 1943 had decided the P-40 had no future as a US first line combat aircraft. 
Again. please remember that it could take 3-4 months for a US aircraft to make it from the factory door to a combat theater. The vast majority of US fighters went overseas by ship.


----------



## FLYBOYJ (Jun 9, 2012)

krieghund said:


> And don't forget the airfoil differences between the them as well as prop efficiencies, etc. This could wind down into an Urinary Olympics.


 It could, with the Mustang pissing till St. Paddy's day!


----------



## GregP (Jun 9, 2012)

I very strongly disagree with yout assertions above, Shortround, but then again, maybe you never flew in both a P-40 and P-51. They aren't that far apart below 15,000 feet, and I might even prefer the P-40 below 10,000 feet.

Add an altitude-rated engine and it could very easily be the other way. Don't dismiss it until you have flown both. The P-40 is every inch a good fighter when flown below its critical altitude.


----------



## Shortround6 (Jun 10, 2012)

I have flown neither. Have you flown either at Military power or WEP levels? 

Unless somebody has been lying about the test results the P-40 was a lot slower than a Mustang, at any level, however nice the P-40 maybe to fly.

" The P-40 is every inch a good fighter when flown below its critical altitude".

I am not saying it wasn't. But "good" is not "best". And "good" in 1943 could mean less than second best in 1944/45. 

Comparison saying the P-40 was as fast or faster using 70" of MAP than a Mustang using an unknown amount of MAP doesn't tell us anything except the P-40 pilot was _very, very_ low and beating the crap out of his engine. Unless I am mistaken the "book' figure figure for WEP for a later Allison (9.60 supercharger gear) used in a P-40 N was 57". Book figure for a P-40K with a V-1710-73 (8.80 supercharger gears) was 60" which it could hold to 2500ft. Allisons could stand a lot of abuse and were, without a doubt, flown at times beyond book figures. That does not mean the airframe they were in was as good or better than another airframe being flown at the time with an engine that was _NOT_ being thrashed. Please note that the engines/planes with 8.80 gears might not be able to even pull 70" at ANY altitude without over revving the engine. 

I am not talking about aileron response or turning circle, both of which are very important. Granted the Merlin powered Mustangs have a bit more drag than the Allison powered ones and need a bit more power down low to get the same speeds but the Allison Mustang is 40-50mph faster than a P-40 with the same engine. That should say something about the drag of the P-40 airframe. Sticking an altitude-rated engine into a P-40 airframe isn't going to lower the drag, if anything it will increase it unless it is a simple change in supercharger gear ratio


----------



## GregP (Jun 10, 2012)

Shortround.

Except in the Pacific, WWII was a mostly a high-altitude war. In Europe, most combat happened at 20,000+ feet because that is wheere the bombers were flying and the fighters were there to either attack or defend the bombers. To me, in Europe, "Down Low" means 10,000 - 15,000 feet. The P-40 was a great diver, one of the best rollers on the Allied side, and could take punishment. It also had a 9-g airframe.

People tend to remember the Zero as "the best of the early war," and fail to rememebr that the P-40 beat the Zero at almost every turn. The kill-to-loss ratio of the AVG was about 70:1 versus the Japanese. Yet the P-40 is denigrated. It held the line in North Africa and did not have a bad racord against the Me 109. It was, in fact, a winning record.

You mentioned the XP-40Q had four guns ... correct, as usual. Production version were to have either six 50-cal (12.7 mm) MG or four 20mm cannons. It wasn't selected for production solely due to the fact that the P-47 and P-51 were already in production and doing the job quite well.

As I said earlier, I think the P-40 had great potential for development. You disagree and we can leave it at that. In the real world, Curtiss never did get the development past the XP-40Q, which was a pretty darned good fighter in my book. Since it wasn't acquired by the USAAC, we'll never really have an opportinity to compare it with the deployed fighters in a WWII combat situation. The same can be said of quite a few really good prototypes. The Boeing F8B comes to mind, as does the Chance-Vought XF5U-1, which was built but never flown! With a pair of R-2800's, it wasn't short on power. The CAC-15 also never got a chance, and there are many more, so I suppose the XP-40Q is in good company as a plane that could have been a good one but never got the chance.

Of course, there were also some turkeys, such as the Curtiss XF14C, which flew but was disappointing even wghen fitted with the eventually mighty R-3350.

Again, we'll have to agree to disagree. I like the P-40 and you obviously do not. So be it. I get to see one operated regularly alongside P-51D's, a P-47, a P-38, an A6M5 Model 52 Zero etc at the museum and I must say, it has been robust and reliable, if only a P-40.

Regarding Trebor's post # 28, he must not have a grasp of the P-40 at all. It was one of the most maneuverable Allied fighters at 250 - 350 mph below 15,000 feet and definitely among to top two rollers. It could not match the Zero at low airspeed in pitch (and nothing else could, either), but if the fight got to 300 mph, the P-40 was definitely at an advantage. It might have been not too fast, and the rate of climb might have been a bit low, but unmaneuverable? I don't think so, and neither did most of its pilots or most of Me 109's the P-40 happened to have gotten into a turning fight with.


----------



## FLYBOYJ (Jun 10, 2012)

GregP said:


> People tend to remember the Zero as "the best of the early war," and fail to rememebr that the P-40 beat the Zero at almost every turn. The kill-to-loss ratio of the AVG was about 70:1 versus the Japanese. Yet the P-40 is denigrated. It held the line in North Africa and did not have a bad racord against the Me 109. It was, in fact, a winning record.


No one can dispute the AVG's record even in the most conservative terms, but let's not forget the AVG never fought the Zero.


----------



## Vincenzo (Jun 10, 2012)

the avg P-40 get very good results vs type 1 army fighters but others P-40 USAAF units not get superiour result v/s Type 1 or Zero.
in NA the P-40 not winning the comparison with 109


----------



## muscogeemike (Jun 10, 2012)

GregP, 
“Except in the Pacific, WWII was a mostly a high-altitude war. In Europe, most combat happened at 20,000+ feet because that is where the bombers were flying and the fighters were there to either attack or defend the bombers. To me, in Europe, "Down Low" means 10,000 - 15,000 feet. The P-40 was a great diver, one of the best rollers on the Allied side, and could take punishment. It also had a 9-g airframe.”

Don’t forget the Eastern Front, I’ve read the Soviet pilots thought well of the P-40 in air to air combat - more so then the Hurricane or the P-39 or even their own MiG-3.

“People tend to remember the Zero as "the best of the early war," and fail to remember that the P-40 beat the Zero at almost every turn. The kill-to-loss ratio of the AVG was about 70:1 versus the Japanese. Yet the P-40 is denigrated. It held the line in North Africa and did not have a bad record against the Me 109. It was, in fact, a winning record.”

I agree with you, I don’t think the AVG flew, as is the common belief, an obsolete aircraft. The P-40 was in most ways superior to the JAAF aircraft it faced in 1941-42. Recent research has questioned the AVG’s kill claims, by a lot. I don’t believe this detracts from their reputation.

“You mentioned the XP-40Q had four guns ... correct, as usual. Production version were to have either six 50-cal (12.7 mm) MG or four 20mm cannons. It wasn't selected for production solely due to the fact that the P-47 and P-51 were already in production and doing the job quite well.”

And it was common for the P-51 to have 4 guns on long missions.


----------



## cimmex (Jun 10, 2012)

Vincenzo said:


> the avg P-40 get very good results vs type 1 army fighters but others P-40 USAAF units not get superiour result v/s Type 1 or Zero.
> in NA the P-40 not winning the comparison with 109




According to Girbigs book JG27 the German pilots rated even the Hurricane higher than the P-40 not talking about the Spitfire which was rather rare in NA.
cimmex


----------



## muscogeemike (Jun 10, 2012)

FLYBOYJ said:


> No one can dispute the AVG's record even in the most conservative terms, but let's not forget the AVG never fought the Zero.



It annoys me that even in more recent books pilots of the CATF and the 14th AF still refer to the “Zero’s” they encountered.
According to another thread Daniel Ford extensively researched his 2007 edition of “Flying Tigers, Claire Chennault and His American Volunteers, 1941-42”. His conclusion is that the Tigers actually shot down just over 1/3 of the planes they are credited with but goes to lengths to say this in no way detracts from their acheivements.


----------



## drgondog (Jun 10, 2012)

Greg - do you have any factual sources in the form of a complete Test report on the P-40Q? Details like Gross weight at Take Off, fully combat loaded/not loaded, Critcal altitude of the Allison 1710-121(?) as tested, Hp at speed run altitudes, etc?

Neither the P-40F with the 1650-1 or the P-40N w/1710 @ 57" were remotely close to P-51B (or the heavier D) in any comparison except roll rate and turn (at or below critical altitude). There was nearly a 50mph differential at SL for Allison P-40 at 57" and P-51B at 67" and much worse above Critical altitude of the Allison.

Nobody in the PTO/CBI were wildly enthusiastic about dogfighting a Zero, even though a good pilot could Yo-Yo at high(er) speeds to get parity with the Zero. Nobody was recommending dogfighting the Zero - universally the recommendations were to make high speed pass and keep your speed up in the fight. As soon as you sustain a turn airspeed bleeds off rapidly into the Zero's stike zone for both turn and climb, where even roll is near parity.

John Landers couldn't get away in his P-40F over Rabaul and he was a pretty damn good pilot.. I know several aces who were confident in beating Zero's in meduim speed manuevering but the IJN in general, almost universally held the P-40 in contempt for dogfighting. Ditto LW pilots in 109F and 109G but the P-40K and above scored reasonably near parity in North Africa early 1943... as contrast to P-51B vs Me 109G series.


----------



## Vincenzo (Jun 10, 2012)

P-40 get bad result v/s 109 in NA, Nikademus posted from Shore's books: P-40 (US&allies) losses vs 109: 522, 109 losses vs P-40 (US&allies): 206


----------



## GregP (Jun 10, 2012)

The XP-40Q’s were made from P-40K airframes. They had revised cooling systems, two-stage superchargers, had the turtledeck removed, were fitted with bubble canopies, and a 4-bladed prop. The first XP-40Q was S/N 42-9987. The other two were 42-45722 and 43-24571.

Later, the wingtips were clipped. The engine was the Allison V-1710 fitted with water injection. 20,000 feet could be reached in 4.8 minutes in the XP-40Q-3. Service ceiling was 39,000 feet. The XP-40Q-1 had the V-1710-81 and was later fitted with a -101, 2-stage supercharger unit. Data from Dan Whitney’s Vees for Victory. The XP-4Q-2 could climb at 3,800 feet per minute at 13,000 feet and reached 20,000 feet in 6 minutes. The XP-40Q-3 had a V-1710-121 engine of 1,425 HP. War Emergency power was 1,700 HP at 26,000 feet at 3,200 RPM and this was the aircraft that could make 20,000 feet in 4.8 minutes

As for the German opinion of the P-40 in the desert, Tomahawks claimed 77 aircraft destroyed between June 1941 and May 1943. Kittyhawks claimed 206. Total P-40 claims in the desert for that timeframe were 283 against a loss of 100 aircraft.

Was it a great fighter? Not particularly, but it had enough good qualities to render it a dangerous opponent for any other opponent it encountered and I believe it DID have good potential for development.


----------



## Shortround6 (Jun 10, 2012)

WW II covered almost 6 years. The P-40 was built is about 4 major sub variations and lots more minor sub-variations. It was in production for 4 years and 7 months. It was not the most advance fighter when it went into production but was the best fighter the US could into production in a hurry. The P-40 was not wanted by the British as a fighter in Europe in the "B" or "C" versions. It may have done well against the Italians in NA and this is the Version the Flying Tigers used to establish their record against the Japanese. These early Versions did good work in holding the line and perhaps did more than was expected of them. The D/E version starts to show up in Aug of 1941 and is a worthwhile improvement. The "F"s that start to show up in Jan 1942 are another improvement but the world standard is moving. The "E" "F" ( and the K L) also help hold the line and do much good work in North Africa and the Pacific and the Russian front. But in many cases they are already being used as short range strike aircraft and not air superiority fighters. They can often hold their own after bombs are dropped but are also often given top cover and/or escorted which should tel us something. The late "L"s and early "N"s resort to stripping out operational equipment ( guns, ammo, fuel tanks, electric starting motors, etc)) in an effort to improve performance. These "Stripper" models start coming of the production lines in Jan-mar of 1943 which should also tell us something about how the performance of the regular P-40 was viewed in the fall/winter of 1942. The P-40s continue to give good service but not in the air superiority role ( which does not mean they did not engage in air to air combat, only that it was not usually it's primary role). 
I have no Problem with the P-40 or it's war record from 1940-43. I do have a problem with the 1715 or so P-40s built in 1944. I also have a problem with some people trying to make the P-40 into something it was not. It was a stop gap fighter from day one and while it was a good stop gap fighter (perhaps one of the best stop gaps in any force) the gap had been stopped by Jan of 1944. 
I will freely admit that trying account for the P-40s combat performance vs it's "book" performance is one of the hardest allied fighters to work with. The USAAC didn't officially sanction WEP or WER ratings until Dec of 1942 While many British and more than a few US units did use 55-60in of MAP instead of the "book" 44-45" during this time. This coupled with (until now?) a scarcity of official tests results leaves a lot of guess work as to actual performance or comparisons. 

As far as the P-40 vs Mustang thing goes, the British never used the P-40 as a fighter ( or for much of anything else) from England or North West Europe. They were still using 5 squadrons of Allison powered Mustangs on D-day and still had 2 squadrons of Allison powered Mustangs at VE day. Photo recon planes or not that seems to indicate a level of performance not achievable by the P-40.


----------



## Vincenzo (Jun 10, 2012)

GregP said:


> T
> As for the German opinion of the P-40 in the desert, Tomahawks claimed 77 aircraft destroyed between June 1941 and May 1943. Kittyhawks claimed 206. Total P-40 claims in the desert for that timeframe were 283 against a loss of 100 aircraft.
> .



this numbers are very strange too far from Shore's book data (obviously i'm talking of P-40 losses, their claims have not value).


----------



## drgondog (Jun 10, 2012)

_The XP-40Q’s were made from P-40K airframes. They had revised cooling systems, two-stage superchargers, had the turtledeck removed, were fitted with bubble canopies, and a 4-bladed prop. The first XP-40Q was S/N 42-9987. The other two were 42-45722 and 43-24571.

Later, the wingtips were clipped. The engine was the Allison V-1710 fitted with water injection. 20,000 feet could be reached in 4.8 minutes in the XP-40Q-3. Service ceiling was 39,000 feet. The XP-40Q-1 had the V-1710-81 and was later fitted with a -101, 2-stage supercharger unit. Data from Dan Whitney’s Vees for Victory. The XP-4Q-2 could climb at 3,800 feet per minute at 13,000 feet and reached 20,000 feet in 6 minutes. The XP-40Q-3 had a V-1710-121 engine of 1,425 HP. War Emergency power was 1,700 HP at 26,000 feet at 3,200 RPM and this was the aircraft that could make 20,000 feet in 4.8 minutes_

*So, what was the weight during these speed trails, any armament/ammo installed, new wing span/area? Runs made at WEP? was critical altitude 26K? if not, what? as and FYI this airframe should immediateky be compared to XP-51J, XP-51H and XP-72.*

_As for the German opinion of the P-40 in the desert, Tomahawks claimed 77 aircraft destroyed between June 1941 and May 1943. Kittyhawks claimed 206. Total P-40 claims in the desert for that timeframe were 283 against a loss of 100 aircraft._

Our claim to credit process in NA not as good as ETO. German loss records were pretty good and their records show far fewer losses to all causes than we claim for air to air combat. It really has nothing to do in comparing performance but a lot regarding 'opinions held' by German pilots. The DAF claim to LW loss reporting seems to be closer, and LW claims to credits were also way overblown.


----------



## GregP (Jun 10, 2012)

Drgondog, I am not the world's foremost authority on the XP-40Q. I have what I have found that has been written, and all of them give the test results only. If I find it, I'll post it. I do know that the V-1710-121 engine had the auxilliary supercharger unit installed and made good power at high altitude. At our Allison shop in Rialto, CA, we have TWO aux stages ready for a customer's aircraft. They are very neat units, but I still would prefer an iintegral 2-stage, multi-speed supercharger. Unfortunately, they never made one for the Allison.

But I would not hold my breath if I were you. People may spend yesrs documenting a favorite aircraft, but hardly anyone researches a plane that didn't make production and of which they only made three ... unles it is German. If si, then we find new flight test data 70 years after the fact.

Vicenzo, if the claims are worthless, then the repoarted losses are worthless, too. Both come from the same Air Force. You're saying one number is good but the other is junk? You can't choose only the data you want to believe, Vicenzo. You have to look at the aggregate data, whether or not it supports your theories. I don't see anyone in here saying the Italian Air Force claims should be disregarded, so why are you arguing about reported P-40 claims? Are you saying all claims are worthless or just Allied claims? 

We've had these claim wars before and most everyone overclaimed a bit, but not horribly so. Regardless of the arguments, I recognize the numbers that are accepted by the respective Air Forces on both sides. You, of course, can do as you see fit, but you can't dismiss Allied claims and then turn around and accept Axis claims or you will lose your credibility in here. If you reject some, then you just started an enormous research project for yourself, Good luck.

The fact of the matter is the P-40, while not a first-rate, front-line fighter, held its own in battle with Axis aircraft all over the world until better types came into service. That is not in dispute by anyone who is based in fact.


----------



## drgondog (Jun 10, 2012)

Greg - losses reported by both sides are far more relaiable than claims/credits simply because your aircraft returns or it doesn't - or it returns bady damaged and is salvaged, or it returns damaged and repaired.

If the Command authority asks the Group for a maximum effort count there is no escaping lost or damged aircraft and crews -


----------



## Vincenzo (Jun 10, 2012)

GregP said:


> Vicenzo, if the claims are worthless, then the repoarted losses are worthless, too. Both come from the same Air Force. You're saying one number is good but the other is junk? You can't choose only the data you want to believe, Vicenzo. You have to look at the aggregate data, whether or not it supports your theories. I don't see anyone in here saying the Italian Air Force claims should be disregarded, so why are you arguing about reported P-40 claims? Are you saying all claims are worthless or just Allied claims?
> 
> We've had these claim wars before and most everyone overclaimed a bit, but not horribly so. Regardless of the arguments, I recognize the numbers that are accepted by the respective Air Forces on both sides. You, of course, can do as you see fit, but you can't dismiss Allied claims and then turn around and accept Axis claims or you will lose your credibility in here. If you reject some, then you just started an enormous research project for yourself, Good luck.
> .



yes i'm saying one number is good and the other is junk, Shore's books give detail of all fightning Nikademus did (partial sum, i did total sum) the sum. Obviously maybe there are some wrongs. 
Italian air force?? why this add? the RA have not 109 in North Africa. All the claims are worthless. 
The numbers that i presented are not axis claims


----------



## GrauGeist (Jun 10, 2012)

Can't really say that continuing developement of an older airframe is "flogging a dead horse"...if that's the case, then explain how the Bf109 made it to the end of the war. 

It was afterall, developed in the 30's like the P-36.


----------



## Shortround6 (Jun 10, 2012)

Vincenzo said:


> yes i'm saying one number is good and the other is junk, Shore's books give detail of all fightning Nikademus did (partial sum, i did total sum) the sum. Obviously maybe there are some wrongs.
> Italian air force?? why this add? the RA have not 109 in North Africa. All the claims are worthless.
> The numbers that i presented are not axis claims



the difference between claims and losses is that ones own losses _SHOULD_ be known and accurate. How many aircraft left, how many came back, how many cracked up on landing. There may be a bit of jiggery-pokery in attributing written off airframes to combat or operational accidents. Claims are just that, _CLAIMS_, even with the best faith in the world, gun camera footage and witnesses not all claims can be verified. Damaged or hit aircraft descending through clouds and lost from view? Kill or damaged or probable?


----------



## Shortround6 (Jun 10, 2012)

GrauGeist said:


> Can't really say that continuing developement of an older airframe is "flogging a dead horse"...if that's the case, then explain how the Bf109 made it to the end of the war.
> 
> It was afterall, developed in the 30's like the P-36.



It made it because they too were flogging a dead horse.  

The Germans had no good alternative and the 109 was able to perform fairly well in one of the more important missions the Luftwaffe needed in 1944-45, A short ranged interceptor. 

There were plenty of other airframes from the Mid 1930s that never made it that far (or if they did, never should have) so that the fact that the 109 was still a useful aircraft can be considered an outstanding achievement. 

The US had enough good alternatives that the P-40, with it's limitations, was a waste of time pursuing by 1943. If it was so good why did Curtiss themselves come up with so many successors? WHy not just pitch the latest "improved" P-40 instead of designing new wings/feselages/tails, etc. 
The P-40 could have been improved, most any plane can be improved. The problem is the amount of time, effort and money needed to get a few % of improvement compared to the same amount of time, effort and money spent on a different design. If the second choice gives better results than going with the first option is flogging a dead horse.


----------



## GregP (Jun 10, 2012)

Sorry Shortround and Vincenzo, you are both daft. Let's say we disagree.

The Me 109 was not a dead horse and neither was the P-40. Both could have been and were developed. The P-40 could have been developed a LOT.

Allied claim numbers are no more worthless than Axis claim numbers. Both sides made claims in good faith and sometimes were wrong. Losses were not always accounted for correctly. Heck, we don't even really know how many German planes were made in some cases becuase some of the records were lost. And you think the loss records were accurarte? I beg to diiffer.

But the claims and loss records are what we have to go by. There just isn't anything welse to go by ... unless you have a time machine in your garage.

The Spirfire, P-38, P-39, P-40, A6M, Me 109, and others were produced for the entire war. If they were dead horses, then the war was won by dead horses and you might give them due credit in any case.

Really, your opinions expressed above fly in the face of the history of WWII. The Spitfire and the Me 109 were both very competitive until the last day of the war. You might go read up on it sometime.


----------



## GrauGeist (Jun 10, 2012)

Actually, the P-36 remained in service until the close of the war (and remained active abroad until the mid 1950's) along with the P-40.

The P-40, along with other dead horses (P-38, P-39, F4F, etc) managed to stem the tide of the Japanese in the Pacific and in the Med, the P-40 remained active until late 1944 in U.S. service. Other nations used the P-40 until the close of the war...

So the airframe was sound enough to engage more "modern" designs and in the absense of the P-51, it would have most likely followed the natural progression of upgrades (which, in fact, it did) to keep it a capable fighting machine.


----------



## Shortround6 (Jun 10, 2012)

GregP said:


> Sorry Shortround and Vincenzo, you are both daft. Let's say we disagree.
> 
> The Me 109 was not a dead horse and neither was the P-40. Both could have been and were developed. The P-40 could have been developed a LOT.
> 
> ...



If I am daft then I hope I am in good company, I have done a fair amount of reading. 

"The Spirfire, P-38, P-39, P-40, A6M, Me 109, and others were produced for the entire war" 

well 4 out of 6 might not be too bad. P-39 production stopped in Aug 1944, about 1 year short of the end of the war in the Pacific. P-40 Production ended in Nov 1944 9 months short of the end of the end of the war. 

I hope I am giving them due credit but due credit is not hero worship ( or the equivalent for metal objects). The P-39 and P-40 helped stem the tide and go over to the offensive. They should get due credit for that. Thinking that they were still in the front ranks of world fighters in 1944-45 is not due credit, it is wishful thinking. AS is thinking that ALL designs have the same amount of stretch or development potential. Conditions changed during 6 years of war. A war load (armament) that was first rate in 1939/40 was definitely 2nd class or 3rd class in 1944/45. Targets got tougher, expected ranges got longer and so on. 

Some planes could handle bigger engines better than others. Some planes had room for more fuel and some did not. Some had the room or weight carrying ability to handle much heavier armament and some did not. Some had aerodynamic limitations that no amount of "tweaking" could overcome short of a major redesign (Typhoon to Tempest needed and entire new wing and modified fuselage, where does development stop and redesign begin?). 

The Japanese made the Ki 43 for the duration of the Pacific war, in hindsight perhaps not one of their better ideas. 

If you want to believe the P-40 was a first rate fighter plane in 1944 don't let me stop you. If you think it had the potential to equal the P-51 with just a little more "tweaking" go ahead and think it. I prefer facts and not faith.


----------



## GrauGeist (Jun 10, 2012)

Well, fact or faith...I prefer reality...

If the P-51 was so almighty, then how was it that a lowly old Bf109 could shoot it down?

This scenario puts the Allies into a position of not having the prospect of a P-51, so assuming the British didn't request it's design and development then Curtis would have been hard at work keeping thier prime mover up to date...even if it meant creating a newer version. Without the A-36/P-51, there would have been engine resources available for the P-40 and so on.

Nasty old airframes sometimes offer new and deadly surprises, like the Fw190's offspring, the Fw190D and Ta152 for example.


----------



## GregP (Jun 11, 2012)

Shortround,

If you read my posts, I already SAID that while it was not a first-line fighter, it was good enough to stem the tide until better ones came. I simply feel it could have been developed if Curtiss wanted to do so.

Apparently you think otherwise. That's OK.

I simply disagree and that is not unusual. I have no "hero worship," and I like most of the planes of WWII. I dislike very few and that is apparently where we disagree.

If you were trying to buy a warbird today, you might just find the P-40 among the most expensive since there are comparatively fewer than for some other warbirds. I rejoice that I help build P-40 engines today. They'll be flying for awhile, and I love to fly in them.


----------



## Shortround6 (Jun 11, 2012)

GrauGeist said:


> Well, fact or faith...I prefer reality...
> 
> If the P-51 was so almighty, then how was it that a lowly old Bf109 could shoot it down?



Because a better airplane is no guarantee of immunity. Even a vastly better airplane is no guarantee of immunity. A few 109s were even shot down by Avro Ansons. That doesn't make the Anson a viable bomber to send into defended airspace.



GrauGeist said:


> Nasty old airframes sometimes offer new and deadly surprises, like the Fw190's offspring, the Fw190D and Ta152 for example



True but then the 190 was only about 1/2 the age of the 109 when they turned it into the Fw190D and Ta152 wasn't it? It is also not just about age but size and streamlining or drag. You can't turn a 109 into a Fw190D. the airframe is too small. 

You can develop the P-40, it just needs a new wing, new landing gear, a new radiator installation and some new fuselage parts and a different engine. Do all that and it is still a P-40 right?


----------



## Vincenzo (Jun 11, 2012)

GregP said:


> Sorry Shortround and Vincenzo, you are both daft. Let's say we disagree.
> 
> The Me 109 was not a dead horse and neither was the P-40. Both could have been and were developed. The P-40 could have been developed a LOT.
> 
> ...


 

i've a large doubt who is the daft or who is in bad faith.
None has writed that allied claims are more worthless of axis claims. If a fighter not back, you (the unit) can wrong the cause but is a losses. the lost in german records are limited and i think are not relative to this campaign.


----------



## Glider (Jun 11, 2012)

In the various books that I have read when comparing the P40 against the 109G and Fw 190, the VVS considered the P40 to be outclassed as did the RAF, the USAAF and most importantly the Germans.
I have yet to find any allied fighter pilot who said that they considered the P40 to be a match for the German fighters.

In one book 'Fighters Over Tunisia?' there were a number of interviews with allied pilots and IIRC they rated the fighters as first Spit IX, second Spit V and P38, third P40 and last Hurricane and P39. 
All the books on the ME agree that allied losses dropped as soon as the first SPits arrived as the P40/Hurricnae combination wasn't up to the German fighters

Second question would seem to be could it have been upgraded.? reply is probably yes but not without some serious changes which would make the whole thing a wast of time as I cannot see it being a match for the P51 in range which was so important to the war effort


----------



## drgondog (Jun 11, 2012)

It simply nets out as follows. The P-40 weaknesses against first line Japanese and German fighters, pricipally the A6M and Me 109F were exposed in 1942. Having siad this, both the P-38 and P-47 production was reaching initial substance in late 1942 but still woefully short of equipping both the US and our allies. The P-39 was never an answer but only a P-40 with a two stage/supercharged engine would have brought flexibility of operations to be a stopgap in 1943.

!943 was characterized as introducing the P-47 and P-38 in numbers to equip more than 10 Fighter Groups (combined). The P-51A and Mustang II production continued but both contracts were running out and the A-36 contract was only an emergency move by Arnold to keep the NAA line going while the P-51B emerged.

Net, Curtis kept producing primarily for our Allies and those theatres where backfill production of newer P-40's were required in late 1943 until the P-47s and P-38s reached high enough production volume to go to critical fronts - both of which were superior in every way to the P-40 except cost and mid altitude turn/roll capability.

The wing of the P-40 would have to be re-designed and replaced, along with a 1650-3 or higher engine to be even considered as useful in ETO for any heavy bomber escort role - just to a.) get fuel/range improvement, and b.) competitive performance against FW 190 and Me 109. The P-40K/N could have performed fighter bomber role past D-Day with probable higher losses but it would have served - and did continue to serve in MTO/CBI and some vestige in PTO.

I haven't seen either the dates or the fuel tank capacity for P-40Q test results so I can't speculate on its future versus P-47N or P-38J but it did not, even with the figures presented by Greg, deliver any confidence that it would ever be a contemporary 'go-to' fighter versus either one of them. Certainly the Allison that it was tested with would have performed well - dunno how well relative to range.


----------



## GregP (Jun 11, 2012)

Well said Drgondog,

Though I like the XP-40Q, one cannot tell how good of an operational fighter it might have made since they only built three, none were identical to one another, and the test data are hiding from us even today except for the 422 mph top speed number and the output of the V-1710-121 engine in the third airframe. I like to think it could have been weaked into a good one and others feel it was simply another P-40, despite tet fact that the few numbers we have for it are more than 60 mph faster than most P-40's.

I like to stick with real life rather than what-ifs and, in the war, things happened a certain way. Whether or not the trusty old P-40 could have been deleoped into a first-rate fighter seems to have awakened the passion of some in here.

I'll let it go and say the P-40 acquitted itself well in the war given the circumstrances in which it found itself. In the end, it was a solid if pedestrian fighter that did the job well until being replaced by better equipment, and it soldiered on well after the war was over in many places around the world.

As I am now curious, I'll look into the XP-40Q and see what I can dig up.


----------



## Dcazz7606 (Jun 11, 2012)

My squadron booklet says the P-40Q's top speed was 426 mph. I don't recall what load or at what altitude. Says with that with the P-38,47 and 51 with equal or better performance there was no need for a 4th. Makes sense. I like the P-40 and the Q would have been a winner a year or two earlier IMO.


----------



## GrauGeist (Jun 11, 2012)

Hey Bill, wasn't the XP-40Q running the Packard V-1650 Merlin like the L versions?

They were definately onto something with the Q version with it's 4-bladed prop, squared wings and bubble canopy


----------



## muscogeemike (Jun 11, 2012)

Shortround6 said:


> Because a better airplane is no guarantee of immunity. Even a vastly better airplane is no guarantee of immunity. A few 109s were even shot down by Avro Ansons. That doesn't make the Anson a viable bomber to send into defended airspace.
> 
> 
> 
> ...



Don’t forget a Turbo. I read that Curtiss was reluctant to use a competitors products and spent too much time, effort and money trying to develop one of their own.


----------



## wuzak (Jun 11, 2012)

GrauGeist said:


> Hey Bill, wasn't the XP-40Q running the Packard V-1650 Merlin like the L versions?
> 
> They were definately onto something with the Q version with it's 4-bladed prop, squared wings and bubble canopy



No, the Q ran a 2 stage V-1710.


----------



## wuzak (Jun 11, 2012)

muscogeemike said:


> Don’t forget a Turbo. I read that Curtiss was reluctant to use a competitors products and spent too much time, effort and money trying to develop one of their own.



Curtiss was a part of the Curtiss-Wright corporation. It was the Wright side of the business that was developing a turbo.

Curtiss wasn't opposed ti using competitors' products - the P-36 used a P&W R-1830, for instance, and one version of teh P-60 flew with a V-1710 and GE B-series turbo combination.


----------



## drgondog (Jun 11, 2012)

GrauGeist said:


> Hey Bill, wasn't the XP-40Q running the Packard V-1650 Merlin like the L versions?
> 
> They were definately onto something with the Q version with it's 4-bladed prop, squared wings and bubble canopy



Dave - I believe they were all Allison 1710's and believe Grep was correct with -81, -101 and -121 respectively. The P-40Q offered a lot of promise but the original engine was -81 one stage, one speed, WE Hp same as P-40M/N-1 with 1360 Hp. The -121 wa Two stage at 1800hp WE, and 1100 hp MP at 25K.

I haven't found out yet when the XP-40Q first flew. The first observation is that is was nearly a completely different airplane - not quite as radical as a 51H compared to 51D but tooling up would have taken some time. If it was being tested in spring 44 its competition was the P-51G/J which was One helluva lot better performer.


----------



## Dcazz7606 (Jun 11, 2012)

Dcazz7606 said:


> My squadron booklet says the P-40Q's top speed was 426 mph. I don't recall what load or at what altitude. Says with that with the P-38,47 and 51 with equal or better performance there was no need for a 4th. Makes sense. I like the P-40 and the Q would have been a winner a year or two earlier IMO.


I'll correct myself as this booklet says 422 mph at 20,000 ft. The clipped wings reduced the span by two feet.
Also states there were aprox. 300 P-40 R's which were F's and L's that had their Merlins replaced by Allisons because of a shortage of Merlins. No big deal but interesting.


----------



## GregP (Jun 11, 2012)

The other thing I dug up is that the XP-40Q-1, -2, and -3 all had laminar flow wings simiilar to P-51 wings. The XP-40Q-3 had the wing tips cut down to 35 feet 3 inches. It was a seriously-fast rolling aircraft that could climb with or better than any P-51, possibly other than the P-51J (coincidentally another Allison aux-stage aicraft).

The primary changes from the V-1710-101 to the -117 and -121 were the auxilliary stage gear ratios and the fuel metering calibration. Some of them had the carburetor (actually "fuel metering device")between the Auxilliary stage and the primary stage. Truly a neat engine, and every bit the equal of any high-altitude Merlin of early to mid-1944.

If anyone is interested, we can build one (a -101, -117 or -121), as delivered in 1944 - 1945. In fact, if we look around the shop, we can probably build two since we have two auxilliary stage superchargers in rebuildable condition and all the gear ratios we need to do it along with the "fuel metering devices." Serrious inquiries only, please ... none of this "How much would it cost to build one?" stuff. If you are seriously in the market, you pertty much KNOW how much it will cost to acquire and you also know it will take, probably, in the neighborhood of 12 - 15 weeks to build and test. All our engines come with a guarantee and are run-in until the rings seat and the stacks clean up. We don't sell any "build 'em and ship 'em engines. We RUN 'em in first.


----------



## GregP (Jun 12, 2012)

Vicenzo,

Regarding post #71. Why would you accuse me of "bad faith?" I simply disagree with your assessment of Allied victory claims for the desert P-40's. 

I didn't insult your intergity. In my dictionary, "daft" means slightly crazy ... it doesn't imply bad faith. With the books I have read and the research I have done, the P-40's gave better than they got. You disagree and I assume you have some reason for doubting the reports.

Let's please just agree to disagree. I hope we donl't have to agree to be civil to one another. OK?


----------



## [SC] Arachnicus (Jun 12, 2012)

From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.


----------



## GrauGeist (Jun 12, 2012)

[SC] Arachnicus;907330 said:


> From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.


There were plenty of U.S. fighter types that were capable of "turn and burn" tactics and employed them when the situation called for it.


----------



## GregP (Jun 12, 2012)

Seems to me a lot of people think our planes were boom and zoom, though that term is relatively modern, and does not really apply to WWII fighters.

The most maneuverable fighters of the war, in terms of rate of pitch (which usually defines maneuverability) were the Japanese A6M Zero series, the Ki-43, and probably the Italian Macchi MC.200 series, with the Spitfire being well up there in turn rate but not “nimble” with regard to the fighters mentioned above. However, in Europe, most fighters had a heavier wing loading than the Zero and all were fairly maneuverable with regard to one another … some more than others. 

When I think of “maneuverable” in Europe, I think of the Spitfire, Mustang, Fw 190, and Yak-3 … with the Yak-3 on top. When I think of great climbers, I think of the Spitfire and the Me 109. Late model Me 109’s climbed VERY well.

Maneuverability can also include rate of roll. A fighter who rolls fast will be able to roll quicker than his opponent he is chasing and put a stream of bullets into the other guy if he anticipates well and rolls / fires quickly.

Of course, the best situation is to be a better roller and turner (pitch) than your opponent. If you had to pick only one it would be a tough choice.

Nevertheless, our fighters were, by and large, maneuverable with regard to most of their competition. Even the P-47 was a pretty good roller with regard to the competition. You might notice it has been voted best WWII fighter in our poll. Oops! Just checked and the P-51 overtook the P-47. Ya' never know, do ya'?


----------



## Vincenzo (Jun 12, 2012)

GregP said:


> Vicenzo,
> 
> Regarding post #71. Why would you accuse me of "bad faith?" I simply disagree with your assessment of Allied victory claims for the desert P-40's.



for me this is a confirmation


----------



## FLYBOYJ (Jun 12, 2012)

[SC] Arachnicus;907330 said:


> From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.


Not really. The F-4 was never meant to dogfight and tactics were developed so it was able to survive in a role it was never intended for.


----------



## [SC] Arachnicus (Jun 12, 2012)

Yeah the fact they didn't put a gun on the F-4 was almost a disaster.


----------



## drgondog (Jun 12, 2012)

GregP said:


> The other thing I dug up is that the XP-40Q-1, -2, and -3 all had laminar flow wings simiilar to P-51 wings. The XP-40Q-3 had the wing tips cut down to 35 feet 3 inches. It was a seriously-fast rolling aircraft that could climb with or better than any P-51, possibly other than the P-51J (coincidentally another Allison aux-stage aicraft).
> 
> *The evolution of the lightweight P-51F Mustang - 5 ordered for test Jan 1943, ready Dec 1943. First three 1650-3 Merlin, last two R.M. 14 SM a derivative of the Merlin 100. The latter two were also equipped with Rotol 5 blade prop and designated P-51G
> 
> ...



The RAF fitted the same engine in the P-51B (Mk III) R.M 14 S.M. as the XP-51G. It had max climb rate of 4160 at 67" at 14,000 feet - full internal combat load, 453mph from 18K to 25K. The reduction gearing was changed to a slightly lower rpm to achieve better level speed at altitude (suspect supersonic tip issues at altitude). Further engine mods took the Mk III to 30,000 feet under 9 minutes, and a climb rate of 2160 feet per minute at 30,000 feet with 456 mph.

As later experienced with the P-82's the original Packard merlin 1650-9s had speed performance advantage over the Allison 1710-143/145 of about 10mp for same GW. 

Note that performance of the P-51B/C (or D/K) could have increased significantly with the R.M 14 S.M Merlin and that a production G was right there with the Ta 152 at altitude in all respects - except faster. The H differed from the XP-51G primarily in powerplant, two extra .50's,taller tail and 50 gallon fuse tank. Intuitively the P-51H would achive very close to XP-51G with same engine and no fuselage fuel as a pure interceptor. It was only marginally slower than the P-80, would climb faster/higher, accelerate better and had much longer range. Had it been needed to counter Me 262 it would have been adequate.

Simply (IMO) the XP-40Q had no chance of continuous evolution like the 51. I don't Know this but I suspect even the redsigned Q had a CDo greater than .022-.024 like the P-38 and would always have a hard time exceeding 430mph. If I had some flight test data I could figure it out.


----------



## drgondog (Jun 12, 2012)

[SC] Arachnicus;907395 said:


> Yeah the fact they didn't put a gun on the F-4 was almost a disaster.



You can thank Robin Olds and Bob Titus for the F-4E, at least the vocal and constant bitching about having an internal gun on the 105 and nothing but a shotgun pattern pod on the F4C and D. Through 1968 the F-105 had more air to air kills than the F8 and the F4. Most were internal M61 kills.


----------



## GregP (Jun 12, 2012)

Hi Drgondog,

Let's say we disagree with regard to the development potential of the XP-40Q, but that is pretty much why we do these "what ifs," isn't it?

In my opinion, it should have had another designation since it had a fundamentally different wing. About the only P-40-like thing were the contours of teh tail. So I think it was essentially at the start of its develoment cycle, not the end. The cooling system was different, the engine mount was different, the engine was different, the wing was different, and the basic firewall-back fuselage was similar and, in some cases, identical to a P-40 without the turtledeck. But tehre were a lot of differences.


I wish one were around and flying so we'd at least know more about them. Meanwhile, since they only built 3, I'd say our disagreement is extremely minor ... unless we do more "what if," and I decline in good humor.


----------



## GrauGeist (Jun 12, 2012)

Of the 3 Q versions, the last wasn't bad looking at all.

XP-40Q-1






XP-40Q-2





XP-40Q-3


----------



## wuzak (Jun 12, 2012)

GregP said:


> Hi Drgondog,
> 
> Let's say we disagree with regard to the development potential of the XP-40Q, but that is pretty much why we do these "what ifs," isn't it?
> 
> In my opinion, it should have had another designation since it had a fundamentally different wing.



Did it? Or did it have a shortened standard wing?

The XP-40Qs had rearward retracting undercarriage. The Curtiss development aircraft (XP-46, XP-53, XP-60) with laminar flow wings had inward retracting undercarriage.


----------



## GregP (Jun 12, 2012)

Accoring to what I have as sources, all XP-40Q's had laminar flow wings.


----------



## GrauGeist (Jun 12, 2012)

OOps...Something went wrong when I posted those pics...lmao

I'll correct that right now...sorry guys :/

(the top photo was a standard production P-40...I overshot my target when selecting the files, I guess...lol)


----------



## GregP (Jun 13, 2012)

GrauGeist,

I see you are in California, if a long way North. If you ever get around Chino, stop in any Saturday and ask for Greg in the restoration hangar and I'd be glad to show you around.

Cheers!


----------



## GrauGeist (Jun 13, 2012)

Thanks Greg...I spent a great deal of time at Chino in the 60's and 70's...but it was much different back then!


----------



## krieghund (Jun 13, 2012)

drgondog said:


> You can thank Robin Olds and Bob Titus for the F-4E, at least the vocal and constant bitching about having an internal gun on the 105 and nothing but a shotgun pattern pod on the F4C and D. Through 1968 the F-105 had more air to air kills than the F8 and the F4. Most were internal M61 kills.



Putting the gun on it caused havoc with the radar (APQ-120) as when fired the vibration caused the circuit cards to unseat making the radar inop. Another very important addition later in the war and retrofitted to all 'Es" and "Js" were the leading edge slats.


----------



## Shortround6 (Jun 13, 2012)

GrauGeist said:


> OOps...Something went wrong when I posted those pics...lmao
> 
> I'll correct that right now...sorry guys :/
> 
> (the top photo was a standard production P-40...I overshot my target when selecting the files, I guess...lol)



Top photo may have been the XP-40K with radiators and oil coolers relocated to a fairing or 'glove' under the leading edge of the wing between the landing gear. Either the same plane or another P-40K was modified into the first XP-40Q which never had the bubble canopy and kept the radiator/oil coolers in the wing fairing while being fitted with several different engines. It had round wing tips for it's entire life.


----------



## drgondog (Jun 13, 2012)

Greg - I was really impressed with the restoration facilities at Chino. Looking forward to getting the VIP tour at Wright Pat in October to see what they have and how it compares to Silver Hill.


----------



## RpR (Nov 16, 2012)

Greg if one would put one of the last much improved Allisons into one of the production P-40s, what performance figure might one get as compared to the WWII figures?

Purely speculation if one would chop and channel a P-40 into a duplicate of the Q with the last best two-stage engine and all simple improvements that occur in building engines with time, what lap speeds, by guess and by gosh, do you thing one might achieve at Reno?

One can only hope that some bucks-up Allison and P-40 aficionado some day builds a full-on Reno racer.


----------



## drgondog (Nov 16, 2012)

I can't help but think that if the P-51 never existed that USAAF would have been forced to consider F4U in mid 1942 because of the range limitations on P-40/P-47/P-39 and the gestation/cost issues of the P-38. I imagine Curtis still proceeds with P-40 improvements but it had nearly reached its max viability in 1942 compared to adversary competition -

I also imagine that USAAF might consider modifying/building Spit VIII for long range service.


----------



## RpR (Nov 16, 2012)

Assuming the cluster-f""" that finally destroyed Curtiss was not in play, without the P-51 the Air Corp probably would have used the P-40Q in the Pacific and one of the later P-47 models in Europe.

There would not have been the free-time to dick around with the P-60 sillyness.

Had the Japanese successfuly managed to get the Malay Peninsula I would say the P-40Q and others that were still born would have been in prod. as the Allies would have needed far more aircraft in the Pacific.

I cannot find on the net whent he Q first flew, does anyhone know?


----------



## Shortround6 (Nov 16, 2012)

P-60 sillyness started in 1940-41, Engine for first P-40Q is not delivered until early/mid 1943 and first prototype went through several engine models.


----------



## RpR (Nov 16, 2012)

As far as every thing goes, as they produced over five thousand N models, even with the existance of the Mustang it would have made far more sense to produce the Q but then with what finally took Curtiss out of aircraft production and the asinine dealing with the Allison by the government, stupidity reigned.


----------



## tomo pauk (Nov 17, 2012)

deleted


----------



## tomo pauk (Nov 17, 2012)

Hi, BobR,

Why would it have been much better if they produced the Qs? What was the reason for Curtiss to be out of the business?


----------



## Shortround6 (Nov 17, 2012)

BobR said:


> As far as every thing goes, as they produced over five thousand N models, even with the existance of the Mustang it would have made far more sense to produce the Q but then with what finally took Curtiss out of aircraft production and the asinine dealing with the Allison by the government, stupidity reigned.



They should have stopped the last few thousand N models. 

Can you be more specific about " the asinine dealing with the Allison by the government"


----------



## oldcrowcv63 (Nov 17, 2012)

Looking over this thread I am astonished at how often the statement is made that P-40s did well against the Japanese, and that the P-40E was an improvement over the P-40B/C/D. As interceptors, from December 1941 through August/September, except in a very few instances IJ aircraft seem to have dominated PTO skies. AFAIK, the P-40E was nominally the toughest opposition IJ faced in any numbers during the early war, but it seems to have been essentially brushed aside throughout the PI, NEI, OZ and early NG campaigns. It seems to me USAAF P-40E pilots were simply unable to confront the air forces of IJ on any thing like its own terms. When opportunity presented, for example, after a bombing raid on Darwin, and the IJ Bombers were descending on egress from the target area, P-40Es could successfully attack retreating IJ raiders. But that's like killing the fox after he's eaten your chickens. Damage done. Am I missing some essential facts that are common knowledge in this forum. It seems to me efforts to improve the P-40 to meet the threat were very slow in evolving (P-40Ks and P-38s for the 49th Pursuit Group arriving late October). It looks like Kiser's Lightweight P-40E (with either 2 or 4 MGs) was used as bait to bring the escorting Zekes into play for his more heavily armed squadron mates flying below about 26-27,000 ft. The suggestion that most PAC combat occurred at low altitude seems to be contradicted by the historical accounts (Bartsch and Ferguson/Pascalis) and appears to be a more complex situation wherein the early, high-altitude raids were not typically countered unless they approached the target below 27,000 ft, which they apparently occasionally did. Once the allies went on offense, the raiding P-40Es escorting P-40E fighter-bombers could then expect to control the terms of combat more easily which would also be more likely to occur at intermediate and low altitude where the P-40E was more in its element. JMO and would be happy to learn why there is this general high opinion of the P-40E.

Of course if all that's being said is that ETO air combat occurred more regularly above 27,000 ft. Than that's a fair observation except that the ETO aircraft involved appear to have been operating at or near their operational ceiling as were those in the PTO, except that operational ceiling just happened to be a bit lower (especially for one combatant) than that of the major types in the ETO (Hurricanes, Spitfires, Me-109s and FW-190s, not counting the bombers which were probably flying at altitudes not too dissimilar to that of the IJ bombers.) If P-40Bs or Hurricanes had been employed instead of P-40Es would there have been more generally widespread higher altitude combat?


----------



## tomo pauk (Nov 17, 2012)

Paging JoeB


----------



## Shortround6 (Nov 17, 2012)

There is a *BIG* problem in using _average_ combat heights as a criteria, and that is just the nature of "averages". One fight at 27,000ft and one fight at 7,000ft _equal_ an average height of 17,000. Gee, that is within the capability of the P-40, right?  

Very few fights that started with *one side or the other* at 27,000 ft *STAYED* at 27,000ft. Almost all ended up at a lower altitude. What altitude is used to "report" that combat? If the enemy comes in at 26,000ft and _bounces_ then P-40s flying at 20-22,000ft What is the _height_ of the engagement? 

The P-40s poor altitude performance meant that more often than not the initiative would be with the enemy aircraft. The P-40s could contest part of the sky but could _NOT_ deny or contest the higher altitudes no matter what the _average_ heights of the combats were.


----------



## oldcrowcv63 (Nov 17, 2012)

Shortround6 said:


> There is a *BIG* problem in using _average_ combat heights as a criteria, and that is just the nature of "averages". One fight at 27,000ft and one fight at 7,000ft _equal_ an average height of 17,000. Gee, that is within the capability of the P-40, right?
> 
> Very few fights that started with *one side or the other* at 27,000 ft *STAYED* at 27,000ft. Almost all ended up at a lower altitude. What altitude is used to "report" that combat? If the enemy comes in at 26,000ft and _bounces_ then P-40s flying at 20-22,000ft What is the _height_ of the engagement?
> 
> The P-40s poor altitude performance meant that more often than not the initiative would be with the enemy aircraft. The P-40s could contest part of the sky but could _NOT_ deny or contest the higher altitudes no matter what the _average_ heights of the combats were.



I appreciate and understand that distinction. I wasn't talking/posting about _average altitudes_, or the altitude of the escort air battle with defending interceptors that often followed a raid and typically descended to lower altitude as P-40s dove for the deck in a favored tactic to counter the A6M and stay alive. I was looking at the large number of raids that were reported to approach at altitudes in excess of 26,000 ft. and the inability of the P-40E to forestall them. That appears (in what I've read) to be the standard early IJ tactic to soften a target and achieve air superiority in preparation for an invasion or a ground advance. Of course, excepting the case of Darwin where IJ appeared to just want to minimize its use as a base covering the westward sea approach to Southern New Guinea.


----------



## Shortround6 (Nov 17, 2012)

I am sorry if you thought my comment was directed at you, Oldcrow, it wasn't. It was meant to forestall one or more other posters who keep wanting to reduce things to "averages".

I admire the amount of effort and thought you put into your posts and the amount of research that you do.


----------



## oldcrowcv63 (Nov 17, 2012)

Shortround6 said:


> I admire the amount of effort and thought you put into your posts and the amount of research that you do.



 Well, it's easy for me to say the admiration is reciprocated.


----------



## RpR (Nov 17, 2012)

Shortround6 said:


> They should have stopped the last few thousand N models.
> 
> Can you be more specific about " the asinine dealing with the Allison by the government"


The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e

This is quoted from the Allison home page but has been written about for decades: * 
Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited. 

The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature. All 14,000 P-40s got gear-driven superchargers, and as a result, were never first-class fighter planes. Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era. This may be to some extent the bias of a proud parent, but there is no doubt that the deletion of the turbo-supercharger ruined the P-39 .*

This is from a book written on the collapse of Curtiss as an aircraft company. Get the book--: *Curtiss-Wright. The only American manufacturer capable of immediately meeting the demands of the Allied aviation programs of 1938-43, the corporation concentrated on the quantity production of aircraft that were soon obsolete in light of the rapid pace of technological change. Instead of cross-licensing designs and subcontracting other producers for component parts, the corporation overextended its managerial and engineering resources to expand its own production facilities. 
Consequently, when Curtiss-Wright attempted to introduce new designs, such as the C-46 transport or the R-3350 radial engine, there were significant developmental problems. Curtiss-Wright's promise of untested technologies in large quantities and the failure to deliver them resulted in a considerable loss of prestige and the scrutiny of congressional investigators. *

The P-60 started as an improved P-40 but turned into a pathetic malaise of untested engines, cancelled engines etc.
The YP-60E did not fly till mid 1944, while the Q, which out performed any model of the 60, including the E which was not a bad plane but was not needed, was flying already by mid 1943.
I do not have the book here and cannot find it on the net but if I remember correctly it was Curtiss management that killed the Q, not the Army Air Corp.
they could have been producing the much improved Q bbefore the beggining of 1944 instead of producing a still poorly engined N model. Hell they could have simply put the Q engine into the N and had improvement.


----------



## rinkol (Nov 17, 2012)

BobR said:


> The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e
> 
> This is quoted from the Allison home page but has been written about for decades: *
> Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited.
> ...



I've never seen any evidence of a P-40 with a turbocharger. Such a device is not trivial to add to a conventional fighter with a V-12 engine. The only examples that come to mind are the XP-37, XP-60A and B and FW-190C, none of which were especially successful.

Aside from this, my undestanding is that the original XP-39 was actually a disappointment and could not have come close to the reputed performance figures. I'm sure that, if it would have been an easy thing to effect a good installation in the P39 airframe, the turbosupercharger would have been reinstated at some point. The later P-63 was never fitted with a turbo and used the Allison with a two stage mechanically driven supercharger.


----------



## RpR (Nov 18, 2012)

rinkol said:


> I've never seen any evidence of a P-40 with a turbocharger. Such a device is not trivial to add to a conventional fighter with a V-12 engine. The only examples that come to mind are the XP-37, XP-60A and B and FW-190C, none of which were especially successful.
> 
> Aside from this, my undestanding is that the original XP-39 was actually a disappointment and could not have come close to the reputed performance figures. I'm sure that, if it would have been an easy thing to effect a good installation in the P39 airframe, the turbosupercharger would have been reinstated at some point. The later P-63 was never fitted with a turbo and used the Allison with a two stage mechanically driven supercharger.



*The original XP-39 was built with a V-1710 augmented by a Type B-5 turbosupercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers, NACA aerodynamicists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie. The production P-39 was thus stuck with poor high-altitude performance and proved unsuitable for the air war in Western Europe which was largely conducted at high altitudes. The P-39 was rejected by the British, but used by the U.S. in the Mediterranean and the early Pacific air war, as well as shipped to the Soviet Union in large numbers under the Lend Lease program. The Soviets wer e able to make good use of P-39s because of its excellent maneuverability and because the air war on the Eastern Front in Europe was primarily short ranged, tactical, and conducted at lower altitudes. In the P-39, Soviet pilots scored the highest number of individual kills made on any American, or British fighter type.

The P-40, which also had only the single-stage, single-speed-supercharged V-1710, had similar problems with high-altitude performance.

The P-38 was the only fighter to make it into combat during World War II with turbosupercharged V-1710s. The operating conditions of the Western European air war – flying for long hours in intensely cold weather at 30,000 feet (9,100 m) – revealed several problems with the turbosupercharged V-1710. These had a poor manifold fuel-air distribution and poor temperature regulation of the turbosupercharger air, which resulted in frequent engine failures (detonation occurred in certain cylinders as the result of persistent uneven fuel-air mixture across the cylinders caused by the poor manifold design). The turbosupercharger had additional problems with getting stuck in the freezing air in either high or low boost mode; the high boost mode could cause detonation in the engine, while the low boost mode would be manifested as power loss in one engine, resulting in sudden fishtailing in flight. These problems were aggravated by suboptimal engine management techniques taught to many pilots duri ng the first part of WWII, including a cruise setting that involves running the engine at a high RPM and low manifold pressure with a rich mixture. These settings can contribute to overcooling of the engine, fuel condensation problems, accelerated mechanical wear, and the likelihood of components binding or "freezing up." Details of the failure patterns were described in a report by General Doolittle to General Spatz in January 1944.
*


----------



## Shortround6 (Nov 18, 2012)

Oh boy, where to start.



BobR said:


> The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e



The "government" did not have fetish for the turbo-charger, the _ARMY_ may have. The NAVY did not. The Navy was funding mechanical two stage superchargers (or at least ones from P&W). Allison in 1938 was a very small company in 1938, only 25 employees in the engineering section including the guys that ran the blueprint machine/s. Allison had earlier turned down an Army request/contract to develop a fuel injection system, saying they had too little engineering staff to work on the fuel injection and the other Army contracts at the same time. There were _TWO_ aircraft at the 1939 Army fighter trials using P&W two stage superchargers, the Army was less than impressed. 



BobR said:


> Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited.



This statement is quite true. but be careful of company web site Histories. they may be written by PR people with little knowledge of the actual history and with goal of making the company look good. and with that we are off to:



BobR said:


> The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature.



There were over 10,000 P-38s made meaning over 20,000 Allisons were run with turbo-chargers, not including replacement engines. While that is _fewer_ than the non-turbo Allison numbers it is not what most people think of when told that there were _few_ turbo-supercharged Allisons made.




BobR said:


> Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era. This may be to some extent the bias of a proud parent,



I would hesitate or dislike to say he was lying as he cannot defend himself at this point. Mistaken perhaps? In the 67 years since the end of WW II NOBODY (to my knowledge) has been able to come up with a photograph of a turbo equipped P-40, a good drawing, a factory work order or assembly print/drawing, a test report of even date of a test flight let alone name of the test pilot. Yet there are photos of prototype P-40s with different radiator installations and other modifications. I also wonder about this part "....if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era." The XP-40 was the 10th P-36 of the production line re-engined from the firewall forward. Work on the Curtiss Model 75 (which became the P-36 ) started in November 1934. Which engine was the XP-40 originally designed for? This statement also tends to overlook ( or perhaps Mr. Berlin was referring to this aircraft and NOT the P40?) the XP-37 and 13 YP-37 which used the Curtiss airframe with Turbo-charged Allisons. By 1940 -41 the Army had a pretty good idea of what to expect from a Single engined turbo-charged Curtiss airframe. 



BobR said:


> but there is no doubt that the deletion of the turbo-supercharger ruined the P-39 .



Actually there is quite a bit of doubt. In fact there is a school of thought that says deleting the turbo saved the P-39. 



BobR said:


> This is from a book written on the collapse of Curtiss as an aircraft company. Get the book--: *Curtiss-Wright. The only American manufacturer capable of immediately meeting the demands of the Allied aviation programs of 1938-43, the corporation concentrated on the quantity production of aircraft that were soon obsolete in light of the rapid pace of technological change. Instead of cross-licensing designs and subcontracting other producers for component parts, the corporation overextended its managerial and engineering resources to expand its own production facilities.
> Consequently, when Curtiss-Wright attempted to introduce new designs, such as the C-46 transport or the R-3350 radial engine, there were significant developmental problems. Curtiss-Wright's promise of untested technologies in large quantities and the failure to deliver them resulted in a considerable loss of prestige and the scrutiny of congressional investigators. *



All quite true but it has little bearing on the P-40 or a turbo P-40. 



BobR said:


> The P-60 started as an improved P-40 but turned into a pathetic malaise of untested engines, cancelled engines etc.
> The YP-60E did not fly till mid 1944, while the Q, which out performed any model of the 60, including the E which was not a bad plane but was not needed, was flying already by mid 1943.
> I do not have the book here and cannot find it on the net but if I remember correctly it was Curtiss management that killed the Q, not the Army Air Corp.
> they could have been producing the much improved Q bbefore the beggining of 1944 instead of producing a still poorly engined N model. Hell they could have simply put the Q engine into the N and had improvement.



The P-60 started as the P-53. The first flight of a P-60 (with a Merlin engine) was 18th September 1941. One reason the P-40Q could out perform the XP-60 aircraft was that it carried a rather pathetic armament and the P-60s had been designed around a somewhat too ambitious armament which resulted in a substantially larger aircraft than the P-40 series. 

Curtiss (or any other manufacturer) cannot change the product in mid contract, especially considering that the engines were GFE ( Government Furnished Equipment). The Army contracted with Allison of XXX number of model YYY engines  and shipped them to the airframe makers. Many of these contracts were placed months (if not a over a year) in advance and while contracts were canceled, modified and changed it could take weeks or months to have any effect.


----------



## Shortround6 (Nov 18, 2012)

We are back to one of the greatest WW II aviation myths>



BobR said:


> *The original XP-39 was built with a V-1710 augmented by a Type B-5 turbosupercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers, NACA aerodynamicists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie.*


*

Borderline Windtunnel tests? Please explain that one. 

There is no evidence what so ever that the XP-39 ever came close to the performance numbers claimed for it in any number of books or websites. And quite a bit of information that makes it look extremely unlikely. 

1.The XP-39 flew for 20 minutes or just under on the it's first flight/day of flying. Which is rather normal for first flight and testing but hardly enough time to gather any performance numbers. 
2. The XP-39 was plagued with both coolant and oil over heating problems even in ground running/taxi tests making high speed runs or climb to altitude tests rather unlikely.
3. The XP-39 had the coolant and oil cooler ducts worked on several times between the first flight and being shipped off for the wind tunnel tests meaning that there were also a number of days when it wasn't available for flying. 
4. Calculations had predicted an vibration problem with the original drive shaft in the event of one or more cylinders miss-firing. A bigger diameter drive shaft with heavier walls had been designed/ built but not fitted until AFTER the wind tunnel tests were done. Engine was limited to 2600rpm until the new drive shaft was fitted which also means that any maximum performance tests were extremely unlikely. 
5. the XP-39 first flew on April 6th 1939. On April 21st 1939 Gen. Arnold was issuing orders for the XP-39 to be sent to Langley Field and the NACA wind tunnel. The ONLY full sized tunnel in the US at the time. DO aircraft that are successfully meeting their performance goals need help form the NACA?*


----------



## oldcrowcv63 (Nov 18, 2012)

Gotta love this forum!   when one knowledgable poster meets another we all benefit from the interaction.


----------



## krieghund (Nov 18, 2012)

Ok talking about the P-39 gets emotional sometimes..as well as how history has defaced the V-1710..how ever let's deal "With just the facts Mam"

I have included two NACA reports that deal with NACA drag reduction on various aircraft including the XP-39. Also included is a graph showing the anticipated speeds thru improvements and the original speeds tested prior to installing a low altitude rated V-1710. For those that love to crunch numbers please enjoy..........

And also the part about its maligned history I include an excerpt from Alfred Price's book "Fighter Aircraft" where he gives the V-1710 a scathing review....normally he does a good job of aviation history...so I don't know.......


----------



## tomo pauk (Nov 18, 2012)

So Mr. Price flatly states that V-1710 was proven as unreliable in service? I cannot think what he thinks of Sabre, R-3350, VK-106/107/108, Jumo 222, Homare, BMW-801 etc.


----------



## tomo pauk (Nov 18, 2012)

Hi, BobR, if I may:



BobR said:


> ...
> This is from a book written on the collapse of Curtiss as an aircraft company. Get the book--: *Curtiss-Wright. The only American manufacturer capable of immediately meeting the demands of the Allied aviation programs of 1938-43, the corporation concentrated on the quantity production of aircraft that were soon obsolete in light of the rapid pace of technological change. Instead of cross-licensing designs and subcontracting other producers for component parts, the corporation overextended its managerial and engineering resources to expand its own production facilities.
> Consequently, when Curtiss-Wright attempted to introduce new designs, such as the C-46 transport or the R-3350 radial engine, there were significant developmental problems. Curtiss-Wright's promise of untested technologies in large quantities and the failure to deliver them resulted in a considerable loss of prestige and the scrutiny of congressional investigators.*


* 

If I'm reading this right, the C-W company is to blame for the demise of the C-W company. 




The P-60 started as an improved P-40 but turned into a pathetic malaise of untested engines, cancelled engines etc.
The YP-60E did not fly till mid 1944, while the Q, which out performed any model of the 60, including the E which was not a bad plane but was not needed, was flying already by mid 1943.
I do not have the book here and cannot find it on the net but if I remember correctly it was Curtiss management that killed the Q, not the Army Air Corp.
they could have been producing the much improved Q bbefore the beggining of 1944 instead of producing a still poorly engined N model. Hell they could have simply put the Q engine into the N and had improvement.

Click to expand...


The P-60 got only tested true engines. 
The airframe had it's problems: it was too large heavy for the V-12s, while the R-2800 engined P-60 were unable to offer anything over P-47 (half of weaponry, less fuel, slower).



BobR said:



The original XP-39 was built with a V-1710 augmented by a Type B-5 turbosupercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers, NACA aerodynamicists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie. The production P-39 was thus stuck with poor high-altitude performance and proved unsuitable for the air war in Western Europe which was largely conducted at high altitudes. The P-39 was rejected by the British, but used by the U.S. in the Mediterranean and the early Pacific air war, as well as shipped to the Soviet Union in large numbers under the Lend Lease program. The Soviets wer e able to make good use of P-39s because of its excellent maneuverability and because the air war on the Eastern Front in Europe was primarily short ranged, tactical, and conducted at lower altitudes. In the P-39, Soviet pilots scored the highest number of individual kills made on any American, or British fighter type.

Click to expand...



Mr. Bodie knows a great deal about planes, but NACA beats him in their business fair square. As shown in the chart posted above.
For the XP-39 - I'm the fan of the plane. USAAF has had two choices: wait for Bell to finally deliver the promised high performance fighter (after the AIrabonita and XP-39 failing to meet the promised), or to have Bell really producing something usable, even if it's limited. They opted for later - with P-38, P-43, plus forthcoming Seversky/Republic designs, they reckoned they have the 20000+ ft altitude covered.




The P-40, which also had only the single-stage, single-speed-supercharged V-1710, had similar problems with high-altitude performance.

Click to expand...


True.




The P-38 was the only fighter to make it into combat during World War II with turbosupercharged V-1710s. The operating conditions of the Western European air war – flying for long hours in intensely cold weather at 30,000 feet (9,100 m) – revealed several problems with the turbosupercharged V-1710. These had a poor manifold fuel-air distribution and poor temperature regulation of the turbosupercharger air, which resulted in frequent engine failures (detonation occurred in certain cylinders as the result of persistent uneven fuel-air mixture across the cylinders caused by the poor manifold design). The turbosupercharger had additional problems with getting stuck in the freezing air in either high or low boost mode; the high boost mode could cause detonation in the engine, while the low boost mode would be manifested as power loss in one engine, resulting in sudden fishtailing in flight. These problems were aggravated by suboptimal engine management techniques taught to many pilots duri ng the first part of WWII, including a cruise setting that involves running the engine at a high RPM and low manifold pressure with a rich mixture. These settings can contribute to overcooling of the engine, fuel condensation problems, accelerated mechanical wear, and the likelihood of components binding or "freezing up." Details of the failure patterns were described in a report by General Doolittle to General Spatz in January 1944.

Click to expand...


There is no 'high boost' or 'low boost' mode. The boost can be adjusted, within certain limit. The high boost was unable to cause detonation in engine, it was a consequence of a too high boost. The P-38H and earlier models were having definitely boost limits vs. the P-38J/-L, mostly due to the different intercoolers.
The pilots operating the P-38J, when operating the engine at the low MAP/high RPM were likely to 'kill' the engine, since the air/fuel mixture would over-cool in such a regime, the plane flying high. I agree that the intake manifold was a problematic item, it was changed by Allison, from second half of 1943.
You can note that P-38H and earlier models were unlikely to over-cool the air/fuel mixture, they were having just the opposite problems. Too high a carburetor temperature was there the issue, since the inter-coolers were unable to properly cool the air-fuel mixture, was the hurdle for the increase of boost level (less boost, less power).*


----------



## rinkol (Nov 18, 2012)

The document on the drag cleanup tests is really interesting. One gets insights into how much room there is for refinements.


----------



## RpR (Nov 19, 2012)

Shortround6 said:


> Oh boy, where to start.
> 
> All quite true but it has little bearing on the P-40 or a turbo P-40.
> 
> ...


The quote attributed to this statement has EVERYTHING to do with the P-40.

I do not have the book, I read it quiet some years back, but the attitude of the quote you reject is the very attitude that affected *ALL*Curtiss dealings including why the Q was not produced.
The reason the P-40 was not advanced was not because of the Army or government, it was inside stupidity among Curtiss money crunchers.

There is a new book that is said to be a good deal better than any older one. At least from one review I read, althought it was said it still does not give all of the details of how Curtiss snatched defeat from victory.
------------------
The P-53, which was intended to be an improved P-40 was contracted in Oct. of 1940 and was supposed to have the Continental 1430 and a laminar flow wing. Two months later the Army changed its mind starting the P-60 debacle, which during, Curtiss was still pumping out barely improved P-40s.
Government/Army, you pick the term you prefer, can and do change contracts in the blink of an eye continually; whereas Curtiss had GREAT influence in its dealings with G/A and could have affected contract/production decisions easily.
The quote you said had no influence on the P-40 indicates Curtiss insiders made the decisions that affected what went on inside Curtiss, not the G/A.

The engine in the yp-37 which flew in June 1939 was extremely *unreliable*, which is one reason the single stage P-40 was chosen after NACA tests had eventually got the xP-40 up to 366mph in Dec. 1939.

I wonder, with the comment on turbo-charged planes, if he did not mean the various two-stage super-charged engines that flew.


----------



## N4521U (Nov 19, 2012)

Gate guards and beer cans.....
you guys make my head hurt.


----------



## RpR (Nov 19, 2012)

tomo pauk said:


> Hi, BobR, if I may:
> 
> 
> 
> ...


 
The P-60, before all the a,b,c etc. numbers were added, was supposed to have the -75 Allison with two different types of exhaust driven super-chargers and the sixteen cylinder Chrysler engine (this is all after the cancellation of the Continental powered P-53).
In the mean time after they decided against the Chrysler it was decided to put a R-2800 in and while this was going on some one decided to put a Merlin 61 in.

While this was going on some one decided to use contra-rotating props on the R-2800 but there was concern on the availability of this, so a regular R-2800 was put in.

Back to go-- the Allison powered A model first flew in Nov. of '42, while the C and first version of the E first flew in early '43.

To condense a soap-opera, while the C through variations of E were flying, finding chassis changes necessary for non-contra version, the Q was being developed, tested and flown and had performance that exceeded the P-60 of any sort, even with the standard lousy landing-gear set-up that one test pilot said should be changed.--- _(Which oddly was one thing that the Dutch wanted changed on the CW-21s they ordered and C-W had no trouble changing was the rear-ward retracting landing-gear. The change to inward retracting added 18mph to top speed despite adding weight.
The originals had the same landing gear set-up as the P-40; therefore, while CW-21 originals were shipped to China in early 1940, the changed B models were also shipped in early 1940, which means the change was quick and easy.)_

The P-60 was sent to elimination Army tests and was found lacking, so Curtiss finally ended up producing several hundred P-47G models which due to delays in prod. never left the states.

The should have made the Q.


----------



## tomo pauk (Nov 19, 2012)

BobR said:


> The P-60, before all the a,b,c etc. numbers were added, was supposed to have the -75 Allison with two different types of exhaust driven super-chargers and the sixteen cylinder Chrysler engine (this is all after the cancellation of the Continental powered P-53).



The P-60 (version with turbo V-1710) seem to me as the most balanced one. Unfortunately, someone (Curtiss? USAAF?) decided to go with brand new engine-turbo combo (V-1710-75 + Type B-14 turbo), instead of going with off-the-shelf models. You do loose 100 HP, but you have the powerplant that actually works. 



> In the mean time after they decided against the Chrysler it was decided to put a R-2800 in and while this was going on some one decided to put a Merlin 61 in.
> While this was going on some one decided to use contra-rotating props on the R-2800 but there was concern on the availability of this, so a regular R-2800 was put in.



Who is the 'someone' that decided that two stage Merlin is to be installed? Who is the 'someone' that decided that a contra-rotating prop is to be installed? That version actually flew. The regular R-2800 was powering both versions, regular contra-rotating prop ones.



> Back to go-- the Allison powered A model first flew in Nov. of '42, while the C and first version of the E first flew in early '43.



IIRC the Allison version flew without turbo?



> To condense a soap-opera, while the C through variations of E were flying, finding chassis changes necessary for non-contra version, the Q was being developed, tested and flown and had performance that exceeded the P-60 of any sort, even with the standard lousy landing-gear set-up that one test pilot said should be changed.



The Q means the two stage V-1710 is installed. Production 2 stage V-1710 were not the same as one powering the Q-3, the model making 420 mph. Instead of 1700 HP at 26000 ft at 3200 rpm, the two stage V-1710s in production from mid 1943 to mid 1944 were capable for 1150 HP at 22500 ft at 3000 RPM. So we're looking at a 380 mph P-40Q in 1944? Should we ditch the 2 HMGs and wing tips to make it go 390 mph? It still fails very much far behind the P-51B and P-47D.
The XP-40Q-3 was delivered to the AAF in early 1945. A full year ago the in-service AAF fighters were making 20 mph more, while featuring other benefits as well. The P-51 with 1700 HP at 26000 ft would be making like 470 mph?



> --- _(Which oddly was one thing that the Dutch wanted changed on the CW-21s they ordered and C-W had no trouble changing was the rear-ward retracting landing-gear. The change to inward retracting added 18mph to top speed despite adding weight.
> The originals had the same landing gear set-up as the P-40; therefore, while CW-21 originals were shipped to China in early 1940, the changed B models were also shipped in early 1940, which means the change was quick and easy.)_



Oddly enough, I like the CW-21 very much. It's U/C fairings were much bulkier than those of P-40, so the efford paid off. 
The P-40 going to inward retracting U/C would include cutting two of three main spars, and that does not look like a healthy thing to do.



> The P-60 was sent to elimination Army tests and was found lacking, so Curtiss finally ended up producing several hundred P-47G models which due to delays in prod. never left the states.



The story of P-47G is another sorry one. Republic made the factory from gound up in Evansville and start rolling the P-47s there as hot rolls by 1943, workers there were green as grass. Curtiss was unable to match that effort with a trained manpower. 



> The should have made the Q.



They should have produced P-47s in a proper way.


----------



## Shortround6 (Nov 19, 2012)

BobR said:


> The quote attributed to this statement has EVERYTHING to do with the P-40.
> 
> I do not have the book, I read it quiet some years back, but the attitude of the quote you reject is the very attitude that affected *ALL*Curtiss dealings including why the Q was not produced.
> The reason the P-40 was not advanced was not because of the Army or government, it was inside stupidity among Curtiss money crunchers.



The quote speaks to a general attitude but the specifics leave a lot to be desired. C-46 was originally designed in 1937, first flight in 1940 and production in 1941, it had darn little to do with with the P-36/P-40, considering it was designed/ built at the Curtiss ST. Louis Plant while the P-36/P-40 work was going on in Buffalo NY. The R-3350 work was going on in Patterson NJ. It a different self-contained division. The Company's attitude affected Production of both aircraft and engines by sub contractors but had very little to do with stifling designs, of which Curtiss perhaps tried too many. The Army (the Customer) was not interested in the P-40 in the long term. It was only buying the P-40 to make up numbers while newer/better planes were designed and built. As soon as those newer/better aircraft reached mass production Curtiss production would stop or be shifted. Slapping band-aids on the P-40 wasn't going to save it and Curtiss either knew it or should have known it. The Army (and Navy) over reached in many of their specifications but if Curtiss didn't try to meet the specifications they wouldn't have even gotten a prototype contract. 

Part of Curtiss's problem is that many of their prototypes failed to meet the specifications or performance guarantees in the contracts. 




BobR said:


> The P-53, which was intended to be an improved P-40 was contracted in Oct. of 1940 and was supposed to have the Continental 1430 and a laminar flow wing. Two months later the Army changed its mind starting the P-60 debacle, which during, Curtiss was still pumping out barely improved P-40s.
> Government/Army, you pick the term you prefer, can and do change contracts in the blink of an eye continually; whereas Curtiss had GREAT influence in its dealings with G/A and could have affected contract/production decisions easily.
> The quote you said had no influence on the P-40 indicates Curtiss insiders made the decisions that affected what went on inside Curtiss, not the G/A.



The Army had sunk over a Million dollars in the Continental 1430 (it was Army designed, Continental just built parts and assemblies to Army Specs) and the Army thought it was better than the Allison. Laminar flow wings were the "in thing". You couldn't have a 1940/41 fighter without them. Turns out they didn't really work all that well but no (or few) designs would be accepted that didn't have them. Army may have spec-ed the 8 gun armament which didn't help. P-47 armament in a 1300-1500hp fighter was going to be a problem ( and a reason the wing went to 275 sq ft?). Curtiss could either accept the spec as written and try for the contract or tell the Army that 8 guns were out of the question and four was a much better idea and try to convince the Army they were right. Army was trying to think 2-3 years down the road. What might be _NEEDED_ without _KNOWING_ what the enemy would actually have in 2-3 years.


----------



## RpR (Nov 19, 2012)

tomo pauk said:


> The P-60 (version with turbo V-1710) seem to me as the most balanced one. Unfortunately, someone (Curtiss? USAAF?) decided to go with brand new engine-turbo combo (V-1710-75 + Type B-14 turbo), instead of going with off-the-shelf models. You do loose 100 HP, but you have the power plant that actually works.
> 
> *They tried two versions of exhaust driven (turbo) blowers on the P-60. The A had the above and the B had one from Wright.*
> 
> ...


``


----------



## Shortround6 (Nov 19, 2012)

I believe they _PLANNED_ to try two versions of exhaust driven (turbo) blowers on the P-60. The A had the above and the B had one from Wright. The P-60A suffered a fire while ground taxiing and the exhaust system ans super charger were removed before flying. The P-60B was never completed. It was used to build one of the later versions. 

"All two-stage blown Allisons were at least 1,450-- there were NO 1,150 hp Allison two-stage engines."

No, they were not. The Majority of the early 2 stage engines were 1325 for take-off and "rated" at 1150hp at altitude.

"All 1,150hp engines were single stage." Depends on which rating and what altitude, Allison gave a take-off rating (which varied) and an "altitude" rating which was often 1150hp. The altitude at which the 1150hp was obtained varied with the engine model. WEP ratings are different. 

"The high horse power Q was flying already in mid-1943." 

Depends on what you mean by "Mid" and with which engine. First two "Q"s were converted from other models and one of them first flew with a single stage engine. the first two planes flew with several different engines as part of the development program.


----------



## RpR (Nov 20, 2012)

Shortround6 said:


> I believe they _PLANNED_ to try two versions of exhaust driven (turbo) blowers on the P-60. The A had the above and the B had one from Wright. The P-60A suffered a fire while ground taxiing and the exhaust system ans super charger were removed before flying. The P-60B was never completed. It was used to build one of the later versions.
> 
> "All two-stage blown Allisons were at least 1,450-- there were NO 1,150 hp Allison two-stage engines."
> 
> ...


I edited the power as I realized I was wrong but you read before I did.
The single stage engines, used in the P-40 topped out a 1,150 at combat setting.(Although one chart puts it a little higher if I remember corrrectly)
The engine in the Q from the test I pasted was 1,325 at take-off; nominal 1,150; 1,500 combat setting.


----------



## tomo pauk (Nov 20, 2012)

Hi, BoBR,



> They tried two versions of exhaust driven (turbo) blowers on the P-60. The A had the above and the B had one from Wright.



Thanks for the tidbit about the planned B version. Unfortunately, it seem that neither turbo P-60 never took off.



> If I knew that I would tell you. Both R-2800 versions flew.
> The B flew but it was modified to take the standard 2800 as the first E and they found they needed chassis mods.
> It gets confusing as to what was what or became what and I an not even going to try to straighten that out here.



Okay, no problem 



> (tomo pauk: the two stage V-1710s in production from mid 1943 to mid 1944 were capable for 1150 HP at 22500 ft at 3000 RPM.)
> 
> Tthere were NO 1,150 hp Allison two-stage engines.
> All 1,150hp engines were single stage.
> The high horse power Q was flying already in mid-1943.



All V-1710s, ww2 production, with an auxiliary, mechanically driven supercharger stage, were rated at 1150 HP, military power. I'm not talking about take off power, but the power at altitude. The E-11 was rated with 1150 HP at 22400-22500 ft, the E-21 developed 1150 at 25000 ft, etc. They were much better than single stage ones (1125 HP at ~15000 ft), but also less capable than Packard Merlin. It took to 1945 for Allison to start producing the two stage V-1710s that were capable matching Merlin output.
The war emergency power was being achieved under the full throttle altitude for the military power, not above. 
I'll cover the supposed high power Q further down.



> The P-40 going to inward retracting U/C would include cutting two of three main spars, and that does not look like a healthy thing to do.
> 
> The Q already had air intakes where the standard did not in its laminar wings. I doubt the landing gear switch would have been much of a problem.



One thing is to cut a tunnel in the middle of the spar, tunnel feeding the cooler, another thing is to 'amputate two of three main spars and pray the wing won't break in mid air. The XP-40Q having a laminar flow wing is a neat urban myth - the Qs started their life as the modified Ns, and those were surely non-laminar wing birds. We can also take a look at what speed was achieved on what power. 1700 HP @ 26000ft was needed for 420 mph, for the Q-3. The unloved P-63 was making 415 mph at 1200 HP, with a laminar wing being of cca 20% greater area than the wing of the Q-3. So either the Qs have had about the same wing as the other P-40s (my bet), or that Curtiss 'laminar flow wing' was the worst that ever flew.



> http://www.wwiiaircraftperformance.o...-47-1660-A.pdf---Here is a test pilots report on one of the Qs.



Thanks for the link. 
You can read that the engine powering that Q was the F-27 (or V-1710-101), the engine capable for 1150 HP at 22400 ft, military, or 1500 HP at 6000 ft, war emergency power. The F-28 (V-1710-121) was the "1700 HP @ 26000 ft" machine, and it will take some time for Allison to produce the prototype of it, let alone to start making them in quantity needed for costumer's needs.


----------



## RpR (Nov 20, 2012)

On the P-40 and the laminar flow wing-- in this article book sample--which is extremely long-- go to pages 899 to 904 for the brief incomplete part on the P-40.

The Wind and Beyond: A Documentary Journey Into the History of Aerodynamics ... - National Aeronautics and Space Administration - Google Books

The E-G series had interchangeable parts where the D and earlier had interchangeable parts but between the D and E parts were not interchangeable so outside of the actual blower production, set-up was no issue as the E series was in production before WWII as was the F series.


----------



## tomo pauk (Nov 20, 2012)

Thanks for the link. Unfortunately, it tells nothing about the real application of the laminar flow wing for P-40s..

As for this (by the E, G, F etc, I take it you mean the V-1710E, V-1710G etc):


> The E-G series had interchangeable parts where the D and earlier had interchangeable parts but between the D and E parts were not interchangeable so outside of the actual blower production, set-up was no issue as the E series was in production before WWII as was the F series.



If it's not too much of a trouble for you, could you please elaborate a bit?


----------



## Shortround6 (Nov 20, 2012)

If you are referring the the Allison engine you are both right and wrong.

Allison often designed new parts so that they would fit in old engines. It does _NOT_ mean that you could take an old engine (say a 1941 model F) and run it at 1944 power levels just because you had better fuel available. If you refitted the old engine with NEW parts which did interchange you _might_ be able to use higher power. 

Crankshafts started "plain" and then were shot peened and then were both shot peened and nitrided and finally the late model E,F, and Gs got the new heavier 12 counter weight crankshaft. Later engines got new piston rings, new valve springs and many other new parts, all (or almost all?) of which could be used to overhaul an old engine. I believe the basic block was also beefed up at least once _after_ the E F were first in production. 

Getting a 1425-1600hp Allison was a lot more than just slapping a 2nd stage on the supercharger. 

An early 1150hp E/F was using about 100 hp in friction and about another 100hp to drive the supercharger so it was making about 1350-1400 in the cylinders. A late model two stage engine making 1600 hp + at WEP could be making 150-200hp in friction ( tighter rings, stronger valve springs, wider gears, etc) and 200-300hp to drive the superchargers for 1950-2100hp in the cylinders. 

What is amazing is that the overhaul life actually went up as the loads in the engine went up by around 50%.


----------



## RpR (Nov 20, 2012)

Didn't know this one was posted, erased.


----------



## RpR (Nov 20, 2012)

The E and later series engines were a redesign that shared few components with the earlier engines, which is more or less what you said I guess.

In abstract one could use as an analogy the mk IV and mk V big-block Chevys which were basically from the same basic design but do not, to cannot, share many components.


----------



## bobbysocks (Nov 20, 2012)

no you cant take an old engine ( for the most part ) and run higher octane fuel ( for the most part ). a few steps up may be with in the tolerances of the design but with several steps in the upgrade in octane they would to make a lot of adjustments. besides better material for the valves, pistons, etc. they would have to find ways to improve coolant circulation through water jackets, oil flow and lubrication. the compression ratio could be adjusted and pistons domed and/or cylinder heads shaved. they may have to port the intakes and beef up connecting rods, wrist pins, main bearing/cam bearing journals to withstand the increased stress. take that stock big block chevy... put some 110 octane aviation fuel in the tank and floor it. its going to scream like a banshee for about 1/4 mile then disintegrate....i know this for a fact. at the very least you are going to throw a connecting rod but there will be damage to the other internal componets as well. take that stock big block and rebuild it with better grade components....do a lot of machine work on the block, heads and intake, etc...and it will operate with that fuel....however your duration between rebuilds will be reduced considerabily.


----------



## Shortround6 (Nov 20, 2012)

Actually you can run 110 octane in it. It will lead foul the plugs quicker and perhaps build up more deposits on the exhaust valves and valve seats but 110 octane ( or PN) fuel has NO MORE BTU's per gallon than 100 octane or 91 octane or 87 octane _ gasoline_. Note gasoline and not 90/10 or 85/15 gasoline/ethanol. 

It just won't give any more power either unless you change _something_ on the engine. 

110 octane fuel _ALLOWS_ you to build an engine with higher compression or boost and get more power without suffering from detonation.


----------



## bobbysocks (Nov 20, 2012)

if thats the case they could run 100LL ( low lead ).... and actually i have known a couple guys ( in the mid 70s..early 80s ) who blew engines on avgas. you will also burn valves, and suffer other problems with its use..

lead fouling was a problem back in ww2. i do not know the ratio of hours to change out for normal plugs but when pilots ran thier engines extremely hard for a long period of time they would tell their crew chiefs to check the plugs or put new ones in.


----------



## RpR (Nov 20, 2012)

I drove a Boss 302 with Aviation fuel in it when the leaded premium disappeared.
Ran just fine and was cheaper than adding Moroso power booster.

The mechanic at the airport said I should run a two to one mix, unleaded to leaded, or there abouts, as that would save money and on the street was all it really needed.
So I would go out about once every two or three weeks and top off what ever amount was in the tank with aviation gasoline.

He used to fill it up for me but the airport authority said he should not be doing that so after a while all he could do was turn the pump on.


----------



## bobbysocks (Nov 20, 2012)

dont you wish you had that boss 302 now??


----------



## RpR (Nov 20, 2012)

bobbysocks said:


> dont you wish you had that boss 302 now??


Most certainly.


----------

