# XP-40Q: what was it able to do when?



## tomo pauk (Feb 8, 2013)

In order the discussion about the XP-40Q does not clog the thread about the P-39, Ive started this thread. 
Sometimes in the forum, and on another places, it is stated that it was pity that XP-40Q was not produced used in ww2, beacause of it's great combat capabilities. I disagree with that, my argument being the plane needed too much of engine power to really perform as good as it's contemporaries, while not offering any combat range and punch wanted by it's most likely costumer (USAF).

By GregP:


> Hey guys, I know what I have heard. You don't have to agree. Nobody in 1940 did an airplane in 120 days; it took years.



Maybe NAA was a competent company?



> General Davy Allison (no relation to the engine company), who demonstrated the P-40B/C to Chenault, stated that North American had the XP-40Q plans before they designed the XP-51 (or NA-73). He visited our airshow and the shop and, yes, we let him start our run engine on the stand. He loved it and told some stories. I don't disbelieve him. The preliminary drawings were available well before 1942, especially to the designers and the USAAC, who believed they owned them since they were the customer.



It would be much easier to discuss the technicalities without the red line of 'USAAC owned this or that' or 'we run Allisons just fine'.
So the General demonstrated the P-40s to Chenault, and that makes him a procurement specialist that knows XP-40Q plans were shipped to NAA? That's as believable as the talk the British fuel was the culprit for P-38 troubles.
The XP-40Q featured bubble canopy, the NAA-73 did not. The 2-stage engine was in Q (thinkered about in 1940???), single stage in NAA-73. The Q have had the P-36/-40 legacy, 5 spar wing, the U/C retracting ackward, unlike the NAA-73. The cooling systems were way too different. Fuselage was also a carry on from P-36/-40.



> Heck, the DOD just recently sent Boeing and Lockhhed-Martin each other's porposals for the new tanker to the wrong companies! Anybody remember that? And that was pure horsecrap; they fostered competition. Anybody who believes that was a mistake is in never-never land. ... and Japan is now flying the Boeing tanker while we still aren't.



Why should we believe that current US procurement is other than a pale shade of ww2 procurement? Let alone that it has to do anything with ww2.



> Sure, it was all a nice, 120-day development ... interesting it was never repeated, isn't it, even in the face of wartime necessity? How long did the P-47 take? Or the F4U Corsair? Or the P-39 or P-63? Or even the Curtiss-Wright CW-21? Or the P-61?



Don't think the Bell or Curtiss can hope to match with NAA. The P-47 and P-61 were far more complicated things to pull out than a simple single engined fighter.



> Your opinion may vary, and that's OK with me. Maybe there wasn't any Kennedy conspiracy either. Only one guy who could put two bullets into close targets at 120+ yards in only a couple of seconds with an old beater Russian gun that can't DO that in anybody else's hands including a head shot? I'm not that much of a believer ...



Opinions are one thing. Another thing are facts. So how really good was the Q; when it was bee able to do what is advertised; how much of improvement it was vs. contemporaries; why would the perceived customer buy it?


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## Aozora (Feb 8, 2013)

Two things:
1) Is there any reason to believe that the P-51 was designed entirely from scratch from the time the design was first mooted to the British? It is entirely possible that Edgar Schmued and co already had some preliminary concepts taking shape well before the Brits came along and asked NAA to build P-40s, which is why they were able to propose a new design. Has anyone got  this book (Mustang Designer)  which might help? 

2) Is there any more concrete evidence, and, with respect to GregP what he says is still hearsay, that the XP-40Q was the inspiration for the P-51, rather than the XP-46? The timelines are very strange, because the XP-46 first flew four months after the NA-73X

(This from Curtiss Aircraft 1907-1947, Peter M Bowers) 


> XP-46-The first XP-46, Army serial 40-3053, made its first flight on 15 February, 1941. It bore a general resemblance to the P-40 but was smaller
> and featured an inward-retracting undercarriage. Armour and fuel tank protection were improved and the armament was increased to two '50calibre
> machine-guns in the nose below the cylinder banks and four '30calibre machine-guns in each wing, making it the most heavily-armed US fighter up to that time. Powerplant was the 1,150 hp Allison V-1710-39. Automatic leading-edge slats were installed on the outer portions of the
> wing.
> XP-46A-To save time, the second XP-46, 40-3054, was delivered without armament or radio for aerodynamic testing and was redesignated XP-46A. The XP-46s had no significant advantage over the P-40 except in firepower and the design was not developed further. (page 435)



The basic design and disposition of the armament of the XP-46 were a lot more similar to the NA-73X than the armament and layout of the XP-40Qs, plus, AFAIK the original XP-40Qs were derived from P-40Ks and a P-40N, and first flew in 1943(?):



> Two P-40Ks (42-9987, 42-45722) and one P-40 (43-24571), were extensively modified with revised cooling systems, two-stage superchargers, and structural changes that altered their appearance. When coolant radiators were moved into the wing roots, the two inboard guns were removed.
> The most prominent XP-40Q feature, used on 42-45722 and 43-24571, was the addition of a bubble canopy as on the 'XP-40N'. Later, the wingtips were clipped. Speed increased to 422 mph (679·13 km/h) at 20,500 ft (6,248 m) making it the fastest of all the P-40s. Registered NX300B, the second XP-40Q was an unauthorized starter in the 1947 Thompson Trophy; it was in fourth place when it caught fire. (492)



What is really interesting is that Curtiss tested an XP-60 with Merlin engine and laminar flow wings in 1941 - was _this_ the aircraft Gen Davy Allison was describing?



> XP-60 (Model 90, 90A)-One XP-60, Army serial 41-19508, was ordered on I October, 1940. This used a P-40D fuselage and tail assembly fitted with
> a new wing that featured a laminar-flow aerofoil and inward-retracting undercarriage. The powerplant was the 1,300 hp Packard-built Rolls-Royce V-1650-1 Merlin as used in the XP-40F then under development. The firepower increase over the P-40 was impressive-eight '50-in calibre machine-guns in the thick-section wings. Armour protection was provided for the pilot and the fuel tanks were self-sealing.
> After test flights began on 18 September, 1941, it was found necessary to enlarge the vertical tail and make minor modifications that resulted in redesignation as Curtiss Model 90A. The XP-60 was later redesignated XP-60D. (437)


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## tomo pauk (Feb 8, 2013)

Thanks for the feedback, Aozora. I could not agree more about the likely existence of a concept in NAA egineering staff prior the British approached them.

There was one thing NAA got from Curtiss, for 56,000 $: the data about the XP-46 (mentioned at book Vee's for victory, attributed to Kelsey). Now before people start claiming that Curtiss actually designed future P-51, we can take a look at what XP-46 was able to do. That would be 355 mph (unarmed, almost unpainted), way under what (X)P-51 was capable for, despite it's bigger wing weight. NAA installed a much more refined belly radiator, laminar-flow wing, wheel well covers, along with other, less visible things, making their product excellent. 



> Two P-40Ks (42-9987, 42-45722) and one P-40 (43-24571), were extensively modified with revised cooling systems, two-stage superchargers, and structural changes that altered their appearance. When coolant radiators were moved into the wing roots, the two inboard guns were removed.
> The most prominent XP-40Q feature, used on 42-45722 and 43-24571, was the addition of a bubble canopy as on the 'XP-40N'. Later, the wingtips were clipped. Speed increased to 422 mph (679·13 km/h) at 20,500 ft (6,248 m) making it the fastest of all the P-40s. Registered NX300B, the second XP-40Q was an unauthorized starter in the 1947 Thompson Trophy; it was in fourth place when it caught fire. (492)



Some things are omitted in the excerpt.
There were three subtypes of the Q line:
-latest (Q-3), converted from P-40N AC43-254571, clipped wings, the one capable for 422 mph, using the F-28R engine (1700 HP @ 3200 rpm @ 26000 ft, WER 'wet'; military rating: 1100 HP @ 3200 rpm @ 28000 ft), shipped to USAF for testing in 'early 1945'
-Q-2, converted from P-40K AC42-45722, featuring the F-27 engine ( 1500 HP @ 3200 rpm @ 6000 ft, yes, 6000 ft, WER 'dry'; military rating 1150 HP @ 3000 rpm @ 22400 ft), clipped wings, bubble canopy, revised cooling system (the Q-3 also featured these 3 modifications). No firm date of delivery or/and tests, no known performance either. 
-Q-1, conversion of P-40K AC 42-9987, the F-20R engine (single stage) initially, later the F-27R, without modifications of the wing, canopy cooling system layout. Also no know firm date of delivery testing.

data from 'Vee's for victory'

During January of 1944, 'one of the XP-40Q was flow to Eglin Field' (ie. test facility), the aux supercharger ratio of the F-27R engine changed from to 7,23:1, ie same as F-28R. Without ADI, it still cannot beat a fully fledged F-28R. 
Unfortunately, despite stating the legacy P-40 airframes the Qs inherited, Vee's claim (non-referenced) that the laminar flow wing was installed. A quick look at speed vs. HP needed for the speed quickly disproves that claim - both P-51 and P-63 needed far less power to achieve better speeds, despite having larger wings.


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## wuzak (Feb 8, 2013)

The XP-46 was ordered in 1939.

The P-40 model in production at the time of the British Purchasing Committee signing with NAA was the P-40C, maybe even B.
The one on the drawing board of Curtiss would have been the P-40D, whose improved performance was the reason that the XP-46 progressed no further.

The order for the XP-53 prototypes was signed on 1 October 1940, less than a month before the NA-73 flew. The XP-53 was the first of the Curtiss fighters to have a laminar flow wing. This was to be powered by the Continental IV-1430. Since that engine program was lagging behind, the XP-53 was dropped, and the XP-60 with Merlin 28 (in lieu of V-1650-1) was given the go-ahead.

From Joe Baugher:


> Another urban legend surrounding the Mustang is that it owed a great deal to the Curtiss XP-46 and, in fact, stole numerous design features from that fighter. It is true that the British had insisted that since NAA had no fighter experience they should secure all current data from Curtiss about both the P-40 and the XP-46. Although NAA did pay $56,000 to Curtiss for technical aerodynamic data on the XP-46, there was only a very broad resemblance between the XP-46 and the NA-73X. The Curtiss aircraft shared only a similar radiator/ oil-cooler configuration with the NA-73X, and did not have laminar flow wings. In point of fact, *the development of the XP-46 lagged behind that of the NA-73X*, and prototypes were not ready for flight until February of 1941. In addition,* preliminary design of the NA-73X was completed before NAA gained access to the Curtiss material*. It could even be argued that the XP-46 data was most useful to NAA in guiding them in what NOT to do. The NA-73X appears to owe virtually nothing to any previous fighter design. Nevertheless, despite convincing denials from both Edgar Schmued and aerodynamicist Edward Horkey, the full magnitude of the contribution of Curtiss to the NA-73X design remains controversial to this day.


North American NA-73

There seems little doubt that NAA had dabbled in the design of a fighter before the NA-73 order. So it would seem they at leas had a head start.

Regarding the XP-60:


> The performance of the XP-60 was disappointing as well, with a top speed of only 387 mph at 22,000 feet. It took 7.3 minutes to reach an altitude of 15,000 feet, and service ceiling of 29,000 feet. *Some of the reason for the disappointing performance was due to the wing surface not being finished to the degree of smoothness required for the laminar flow wing*. Another factor was the fact that the Merlin engine did not deliver the guaranteed output.


Curtiss P-60

I thik it was mentioned in Vees for Victory that Curtiss had quality control issues when they were building P-47s later in teh war. Perhaps the wing smoothess issue was an early sign of their quality problem?


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## wuzak (Feb 8, 2013)

The Xp-53/XP-60 looked quite good in its Merlin form

http://upload.wikimedia.org/wikiped...ht_(from_XP-53_design)_061024-F-1234P-013.jpg
http://www.aer.ita.br/~bmattos/mundo/images_jul06/curtiss_p60-3.jpg

The XP-60A with V-1710 and GE B-series turbo not so much.
http://www.nationalmuseum.af.mil/shared/media/photodb/web/061024-F-1234P-016.jpg

Though it did perform well, its orders were cancelled after Pearl Harbour to concentrate on production of existing types.

Here's the XP-46
http://i987.photobucket.com/albums/ae351/markdd/XP-46-_zps3207e1c4.jpg


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## wuzak (Feb 8, 2013)

I wonder if the XP-40Q's low performance for power was partly due to the leading edge (sort of) radiators?

They do seem small compared to the Tempest I
http://upload.wikimedia.org/wikipedia/en/9/9f/Hawker_Tempest_I_HM599.jpg

And Fairey Firefly
http://www.richard-seaman.com/Aircraft/AirShows/Nellis2004/Highlights/FireflyBankingLeft.jpg

Albeit being used with a less powerful engine.


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## Shortround6 (Feb 8, 2013)

Picture of _FIRST_ P-40Q. 

Please notice the startling resemblance to the P-51............







An Earlier P-40 with "wing" radiators.







Original P-40 Prototype, Plane was faster with Chin Radiator; 






Also a P-40F with modified radiator. 






Curtiss seems to have had quite a bit trouble figuring out where they were hiding the plans for the P-40Q.


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## tomo pauk (Feb 8, 2013)

wuzak said:


> I wonder if the XP-40Q's low performance for power was partly due to the leading edge (sort of) radiators?
> 
> They do seem small compared to the Tempest I
> http://upload.wikimedia.org/wikipedia/en/9/9f/Hawker_Tempest_I_HM599.jpg
> ...



The leading edge radiators were just the oil coolers, Prestone cooler was under the chin. Tempest I have had both oil Prestone radiators at the leading edge, so was the intercooler of Firefly.
The engine performance was exceptional, if we talk about F-28R, but the engine was too late to matter for ww2.

Simply got to say this: Tempest I, what a looker.


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## drgondog (Feb 9, 2013)

The Brit Procurement team signed the agreement for the preliminary design of NA-73X, Lee Atwwod's team completed the 3D Pre Design with weights and lines prior to the contract to proceed on May 4. The Brits insisted on a parallel effort to engage Curtis for the P-40 production. Curtiss was contacted on May 4th and the discussions concluded with an agreement between the NAA and Curtis for P-40 data data on wind tunnel data including cooling and drag results of the XP-40. 

Note: the XP-46 was entering mock up stage and had no test data whatsoever at the time NAA took delivery of the XP-40 data. The USAAF ordered two XP-46 prototypes in December 1939, and the first Army inspection of the XP-46 occurred on March 4, 1940.

Dutch Kindleberger ordered Schmued in very late March to prepare 3 View side elevations with weights and balances, specs, performance estimates around an In-line engine with 4x20mm plus some detail about the armament inst'l. These few drawings were in Kindleberger's hands when he went to UK to negotiate with Sir Henry Self. Self signed the PO for 400 NA-50B to NAA Spec 1592 on April 11. Schmeud started on a mock up just prior to the April 11 contract award and completed it in 3 days using plaster of paris, paper mache and plywood. (pages 51-54 Mustang Designer). The NA-50B became the NAA 73 on April 24 for the construction of one "Allison engined pursuit".

The entire Curtiss connection was at the direction of Kindleberger so that he could tell the Brits that NAA was utilizing P-40 experience in the development.

Schmued corrected Lee Atwood's recollection that the radiator design was spawned by Curtiss, noting that Raymond Rice (Chief NAA Engineer and recipient of the box of Curtiss data) was completely dis-connected from the P-51 project led by Schmeud and that the Curtiss data was Not used in the design of the P-51.

It's pretty simple really. One Curtiss had no idea how the design progressed, or how the data was used. Two, Both Ed Horkey (aero) and Schmeud (structures and P-51 Program manager) state unequivocally that nothing from the XP-46 was used, Horkey stating that the Xp-46 data was rehashed P-40, and that the 3 view drawings and mock up were complete before Atwood went to Curtiss two weeks later. Three, neither were sure that any data related to the XP-46 was ever examined at NAA. Four - all the sketches and 3 View and Mock Up were complete weeks before Atwood went to Buffalo to arrange the purchase of the data.

Conclusion - The NA-73 was not not connected to the XP-46 in any way.

Last. The NA 73 first flew on October 26 but the airframe was 100% complete on September 9, 1940. Greg may be under an impression that it was 'two years' or even 'one year' but the actual date from the April 24 Contract, which is earliest time that a full team could be named for the detail design, to October 26 is six months to first flight and four months to completion of the XP-51 airframe. If you measure from the time a paper napkin sketch flowed into the start of a serious three view drawing Kindleberger could show Sir Henry Self - then you have seven months.

Most folks would think that is pretty good even if '100' days is off.


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## MikeGazdik (Feb 10, 2013)

I don't have all the records to look back on. But If you look at the T6 Texan / Harvard, I think its obvious that it is "related" to the Mustang. Particularly in the wing. Much like you can see the design genesis in the P-35 / P-43 from Seversky to the P-47 Thunderbolt.

So is it you can see Curtiss when you look at any of the P-40 series including the X-planes. I think it even extends to the Helldiver and the C-46.


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## GregP (Feb 10, 2013)

Let's say Drgondog and I have heard different stories from people invlolved ... unless he is using reference material and not direct communication to make his post. I don't know and decline to ask. Either one of us or neither could be correct, it depends on who you speak with and what their recollections are ... and the real facts .. which are probably lost to time or are hideen away in files buried somewhere that are unavialble to the causal information searcher.

I KNOW what history records (no evidence of collusion with the XP-40Q plans), but that doesn't make it either true or false, just what has been accepted. The world was also accepted as flat right up until it wasn't. Most criminals deny they did the crime right up until and sometimes even after they are convicted. NAA would never admit if they DID use the Curtiss Data including the XP-40Q initial plans, and Curtiss hasn't "sued" over it, but that doesn't weigh in with me at all either way.

Personally I don't care, but I do WONDER after hearing what we heard. I'll not get in line and accept the word of a rival that he didn't use preliminary design data from a competitor. I bet that never happend in automotive Formula 1, either, huh? Especially ot a "front runner' like McClaren? Oh wait ... it DID about 3 years ago and they are still under suspension ... maybe they are back this coming year ...

Back in 1940, the ability to feret out the truth may well have been much harder than it is today, given the lack of a world wide web that can record everything and electronic copies of communications, etc. ... maybe not. Either way, I still wonder and have simply stated that plus what was said in paraphrase. Nodoby else need consider it, believe it, or think it has merit. It wasn't my own concoction to start with and I probably should not have even mentioned what was said. Certainly, if the proof is there and still exists, somebody would have to believe it, and then take the trouble to dig it up and publish it.

With the posts above, even fans of the time are not inclined to pursue it, much less someone who is NOT a fan. Neither am I at this time.

Doubting posts are not an opinion changer and people who don't consider alernatives are usually "mind made up" and cannot be swayed either way, even in the face of facts, which I don't pretend to have established ... I just passed on what I heard.

Neither am I a follower who blindly accepts the published version of "facts." Indistrial intrigue in the face of huge wartime profits was a fact, not heresay. Whether or not this subject was a part of that is in some doubt ... by me at least. No conviction is likey at this extended time past the deeds or lack thereof.

So, let's get back to the XP40Q (thread subject) and let this one drop. Argument about it is fraught with peorsonal opinion. 

From what I have read, the XP-40Q seems to have been a good fighter with characteristics that made it good ... but it fell slightly short in top speed to the P-51 (422 vs. 437 mph). Why that small difference would be important is beyond me since neither was likely to attain max speed except in a slight dive anyway.

So I ask myself if the XP-40Q, in 1943, would be an asset at the time it was developed..

The answer is yes, if the logistics chain could be justified. Since we were able to produce enough P-51's to meet war needs in the actual event, the obvious answer is that another long, complicated logistics chain with mechanics, spare parts, etc. was probably not justified once the P-51 logistics chain was in operation. It would have been cheaper and more efficient to expand the P-51 chain than to establish a new one to support planes that could be supported by the P-51 production line instead.

Logically then, what happened was probably the better choice, even if the XP-40Q could have been a good addition, which I believe it could have been in other circumstances. Since I am a fan of obscure types, the XP-40Q simply falls in there with other potentially good or great planes that came at just the wrong time or just at the time when circumstances dictated another choice, through no fault of the particular prototype under consideration.

So, though I lament the choice to not build the P-40Q, it was probably the right choice at the time. Curtiss did not long survive in the airframe game after the P-40 anyway, and the P-40Q might simply have prolonged the agony a bit longer.

Long live the P-51 and I wish an XP-40Q survived for at least museum flights.


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## wuzak (Feb 10, 2013)

GregP said:


> I bet that never happend in automotive Formula 1, either, huh? Especially ot a "front runner' like McClaren? Oh wait ... it DID about 3 years ago and they are still under suspension ... maybe they are back this coming year ...



It was 2007. McLaren weren't suspended, but were fined $100m and excluded from the constructor's championship, but not the driver's championship, their drivers finishing equal second by one point. They won the driver's championship (Hamilton) literally at the last corner of the last lap of the last race, and finished second to Ferrari in the constructor's champiosnhip.


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## tomo pauk (Feb 10, 2013)

GregP said:


> <snip>
> 
> So, let's get back to the XP40Q (thread subject) and let this one drop. Argument about it is fraught with peorsonal opinion.
> 
> ...



Sorry, Gerg, but it seems to me that you're comparing an early 1945 plane (XP-40Q-*3*) with mid 1943 plane (Merlin Mustang). That is what makes the whole difference, not 15 mph. Let alone the far better combat range, plus, by mid 1944, 50% more firepower, and no problems when in high speed dive.
Neither the XP-40Q-1, nor XP-40Q-2, and those are still later designs than P-51B, did not have the horse power to attain the much advertised 422 mph, not until they receive the F-28R engine. A plane that can do 422 mph, with short range, in 1945, was NOT like something the AAF was after. 
If AAF was really into a 420 mph, short range airplanes, they could have had the P-63A in service in early 1944 (more than a year before the serial produced P-40Q), looks to me that was not the case. 



> The answer is yes, if the logistics chain could be justified. Since we were able to produce enough P-51's to meet war needs in the actual event, the obvious answer is that another long, complicated logistics chain with mechanics, spare parts, etc. was probably not justified once the P-51 logistics chain was in operation. It would have been cheaper and more efficient to expand the P-51 chain than to establish a new one to support planes that could be supported by the P-51 production line instead.



If we really want an over-performer, produced by Curtiss, they can start to produce the P-47G (but in a proper way, not lame as they did historically), for which they have had the contract signed in June 1942. The logistic chain was there, in all war theaters USAF was fighting. The P-47 did have better range, twice the firepower, and, by 1945, it was circa 50 miles faster - in service vs. a prototype to boot.



> Logically then, what happened was probably the better choice, even if the XP-40Q could have been a good addition, which I believe it could have been in other circumstances. Since I am a fan of obscure types, the XP-40Q simply falls in there with other potentially good or great planes that *came at just the wrong time* or just at the time when circumstances dictated another choice, through no fault of the particular prototype under consideration.



Wrong time, indeed. Too late.



> So, though I lament the choice to not build the P-40Q, it was probably the right choice at the time. Curtiss did not long survive in the airframe game after the P-40 anyway, and the P-40Q might simply have prolonged the agony a bit longer.



Right choice, indeed. Curtiss-Wright also dissapeared as an engine maker.



> Long live the P-51 and I wish an XP-40Q survived for at least museum flights.



Agreed.


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## drgondog (Feb 10, 2013)

GregP said:


> Let's say Drgondog and I have heard different stories from people invlolved ... unless he is using reference material and not direct communication to make his post. I don't know and decline to ask. Either one of us or neither could be correct, it depends on who you speak with and what their recollections are ... and the real facts .. which are probably lost to time or are hideen away in files buried somewhere that are unavialble to the causal information searcher.
> 
> *When Al White and Jim Brooks were at North American Aviation I did meet Horkey but we talked only about the evolution of the P-51 not the 'box of data'. Having said that, reference and cross reference documentation as well as documented dialogue and debate are usually better references than 90 year old memories of persons not part of the inner workings of Curtiss or North American Aviation. Neither White nor Brooks ca 1960-61 had any part of the design but Horkey was the driver behind the lines and the lower cowl design and the NAA Laminar flow wing.*
> 
> ...



I wish a lot of the X frames were still around.


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## GregP (Feb 10, 2013)

Drgondog,

I know the history of the XP-4Q airframes. What I'm talking about is the idea for the design that was originally put on paper. I have heard the design was drawn up in early 1940, but there were other priorities at the time for Curtiss. Since I wasn't around, I cannot either confirm or deny this and I suspect that none of us in here can. Naturally, the USAAC felt they owned the designs since they were the customer for the P-40.

While the design may or may not have been the government's to show to a competitor, Curtiss may have had little practical shoice since teyw ere dependent upon the government for survival.

I posted what I heard. I do not claim that it was absolutely so, I passed on what I heard. If you had been there, you'd have heard it, too and would be free to make your own arguments or conclusions after the fact.

I get probing questions in here when I pass on things we hear at museum talks and people start needling. If you did thath in the presentation, you'd be asked to leave. The public is there to hear the pilot / famous peron talk ... not to hear a member of the audience argue with the guest.

So I do NOT say the real aircraft was available in 1940 and never have. I said the plans may have been compromised, and they well may have ... or not. It is something to consider, not to state as an absolute.


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## drgondog (Feb 10, 2013)

GregP said:


> Drgondog,
> 
> I know the history of the XP-4Q airframes. What I'm talking about is the idea for the design that was originally put on paper. I have heard the design was drawn up in early 1940, but there were other priorities at the time for Curtiss. Since I wasn't around, I cannot either confirm or deny this and I suspect that none of us in here can. Naturally, the USAAC felt they owned the designs since they were the customer for the P-40.
> 
> ...



Greg - posing the question 'did NAA base their Mustang design on the XP-40Q ?' and then continuing to support your statement when others present multiple and credible facts and information to contradict your 'speculation', while you fail to deliver a shred of evidence to support your speculation, reduces your credibility rapidly. 

It's not just defense of the author of the comment, but your own lack of due diligence in making any assertion that you haven't verified - I've experienced that moment of 'oops' but I don't feel picked on when I get clobbered for opening mouth and inserting foot. Nor do most of the posters that are still on the forum after some of the raging debates over stuff that have LOTS of facts to work with.

One of the reasons I spent a LOT of time cross referencing statements made by 355th vets when I was researching the history is that a Lot of recollections about 1943 when solicited in 1980 made it clear that fact verification needed to be the rule of the day. I can recollect a specific argument (disagreement) I had with Yeager that visibly irritated him regarding whether the Square D 100th was 3rd Division when he commented that it was 1st. His specific comment was "G-- D--n It! I was There!!" Had John Sublett (another 357 ace) not 'corrected' Yeager in the conversation it would have been simply stupid to pursue even though I KNEW he was wrong. Yeager was irritated at Sublett, then 

Conclusion drawn.. being there was not always a guarantee of accurately reciting facts..


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## Shortround6 (Feb 10, 2013)

Yeah, there were a whole bunch of other priorities at the time for Curtiss.

The P-46, the P-53 (which did use some P-40 parts and a laminar flow wing, a possible source of confusion?), The P-55, The P-60 ( including a few pieces of the P-53 and by extension a few P-40 pieces) and a few more fighter designs. 

Strange that with "plans" for the P-40Q apparently sitting a drawer somewhere they spent so much time, money and effort on all these other programs. 

What is really strange is that everybody admits/agrees that NA got to look at the data/plans of the P-40 and P-46. The dispute seems to be what use NA made of this information, if any. What is even stranger is that *IF* NA used any of this data it was the Aviation deal of the century because for $46,000 they apparently got _exclusive_ use of the information rather than just a look at the information. *NO* Curtiss aircraft used a radiator set up like the P-51 and *NO* Curtiss aircraft used a wing quite like the P-51s wing.


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## drgondog (Feb 10, 2013)

Dead on, Shortround. In addition there is no data or presented facts even hinting that the data purchased from Curtiss was a.) interesting, or b.) used, or c.) used by Curtiss in subsequent designs including the P-46 which was far from wind tunnel stage, or subsequent Curtiss designs.

The most wide spread version of the Purpose of purchasing the data was so that Kindleberger could state that NAA was prepared to build P-40s for the RAF if the NA-73 was a failure. 

I have researched this across both the History of Curtiss and all the mainstream Mustang histories and have yet to find a definitive statement that NAA even opened the container of Curtiss supplied data, or when the data was actually delivered - much less an inventory of the data or a suggestion of any XP-46 aero data or any theoretical derivative of the P-40 family used in any way toward the Mustang design.

Yet the 'stories' and claims all seem to come from folks that a.) had nothing to do with the Mustang design, or b.) had nothing to do with P-40/53/55/60/40Q designs.


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## The Basket (Feb 10, 2013)

Did the P-40 design go as far as it could go? Or was there any meat left for it go into production 1945?


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## drgondog (Feb 10, 2013)

What did the P-40 have to offer when there were more P-51s and P-47s than could be deployed coming off the production lines.


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## GregP (Feb 10, 2013)

I reserve the right to pass on what I hear about aircraft, companies, and the war from the people who were there. I will endeavor to make it clear that is what what was heard, not what I espouse. Hopefully that will suffice.

However, I don't think like Drgondog or Shortround ... I think like me. Nothing whatsoever wrong with the way they think at all ... insinuated or implied... and no insult intended, I simply think like me. Asking either to change their style of positing to match my own would doubtless have little result. The converse is likely, too and I don't lament that since their posts are usually enjoyable.

And no, General Davey Allison was not invloved in the design of either the P-40 or the P-51, but he was intimately invloved with demonstrating the P-40 and was very close to Curtiss aircraft management. Those were his own words, not mine ... and I have not researched him or his words. Just heard him say it over a pleasant lunch.

Posts like this from the Aviation Enthusiast Corner make me still wonder though:

"My Grandfather Walter Tydon who designed the P-40 wrote a book that I wish to publish. Hum, why is it that the P-40Q looks a lot like the Mustang or is it why does the Mustang look a lot like the P-40Q. Is the Mustang actually the XP-40 and the XP-40Q combined ? 
Mark Lane 
05/16/2006 @ 08:05 [ref: 13293]"

Came from Aircraft: Curtiss XP-40Q Warhawk

Haven't seen his book yet, but am still interested, though I am doing no active research on it at this time. I believe the XP-40Q, at least one or more, did have a laminar flow wing (at least I have seen this in print), but the subject is not very well covered in my references or in what I can find on the internet, and the details of the airfoil are not seemingly available as yet to me. If anyone knows the laminar airfoil used on the XP-4Q please post at least the airfoil number. Just becuase the XP-4Q had a laminar flow wing, it doesn't mean it was the same as the P-51 airfoil, as stated above in a couple of posts. 

I don't claim it was the same since I have no data on it from the Curtiss side other than the engines used and the basic design details.

This stuff is interesting to me, but not overly so and I do not wish to argue about it any further. If the subject surfaces again, at least from me,it will be because some new information has come to light. You never know ... we even have a member who claims to have unearthed new information about the Ta-152 ... but it hasn't come to light yet either. So it is not inconceivable that new information about the connection or lack thereof might surface sometime.

Cheers.


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## Shortround6 (Feb 10, 2013)

The Basket said:


> Did the P-40 design go as far as it could go? Or was there any meat left for it go into production 1945?



The Army only bought the P-40 in the first place because it could be put into production and service quicker than another design ( by about a full year), being a re-engined P-36 it certainly didn't represent the latest and best thinking of 1939. By some point 1943 US Army training manuals were telling student Pilots that the P-40 was a good trainer/transition aircraft but that NO new squadrons or groups would be formed using P-40s. It was supplied to allied forces after this date and some planes were sent out to units as replacements even as many units as possible were re-equipped with other aircraft. The Continued production into 1944 was part of the Trumann Committee investigation into waste and fraud in WW II. Many of the last few hundred P-40s built went directly from the factory to the scrap yards.


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## GregP (Feb 10, 2013)

The P-40 in the Doug Champlin Collection (noe defunct) was one that was flown from the assmbly line to storage. In 1989, the total time was only just over 40 flight hours.


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## The Basket (Feb 10, 2013)

Instantly scrapped? Whole lotta nothing.


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## GregP (Feb 10, 2013)

More like "surplus to war needs at the time." I believe the one Doug had was one of the last few off the line. At least that's what they said in their program. Either way, it was in rather pristine shape.

They're worth more than Mustangs these days because there are fewer available.


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## wuzak (Feb 10, 2013)

I believe some Typhoons went to scrap from the production lines late in the war.

As for storage, sometimes the history of an individual Mosquito will read something like, "built by xxxxx, transferred to nn OTU then to storage then 1 year later allocated to NNN Squadron".

Also, if teh P-40Q design was done in 1940 why did they bother with P-40D, P40E, P-40F, P-40G, P-40K, P-40L, P-40M and P-40N?


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## GregP (Feb 10, 2013)

Hi Wayne,

I don't maintain it WAS done in 1940.

I heard it was, and it never got management approval for development due to no government funds for it and no company funds for it would be allocated. The resulting XP-40Q was supposed to have used a lot of the original design elements adapted to the latest P-40 coming down the line. 

Except for two people (Gen. Davey Allison and the grandson of the P-40 designer), I have never heard that anywhere else. 

If true, then we COULD have had a better fighter much sooner. If not true, then it at leasts makes for interesting speculation that has been brought up by a man involved on P-40 display and with P-40 management and the grandson of the designer. Their pedigree makes me wonder pretty hard, especially after what was done to Jack Northrop after WWII by Defense Secretary Symington. 

All Jack did was to refuse to sell his company to Consolidated and his government contracts were cancelled. If they could do that to a successful company, I believe that, during the war, anything went if it was deemed necessary to the war effort.


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## drgondog (Feb 11, 2013)

GregP said:


> I reserve the right to pass on what I hear about aircraft, companies, and the war from the people who were there. I will endeavor to make it clear that is what what was heard, not what I espouse. Hopefully that will suffice.
> 
> *Nobody questions your 'Right'. *
> 
> ...



Greg - the dispute was not your thinking style, which is beyond criticism. It was about facts in evidence and conclusions drawn anecdotally versus logically based on assembled facts long published and available for compliation.

EDIT http://www.wwiiaircraftperformance.org/P-40/P-40Q_42-9987_Eng-47-1660-A.pdf

The Gross weight at takeoff was 8203, implying that the 400mph stated in the report was after a climb to the critical altitude. If so, the run could have been made at ~ 8150 pounds with about 140 gallons of fuel. The report mentions neither guns nor ammo for the tests. 

The P-51D at that weight would be the pilot, 94 pounds of oil, no ammo and about 30 gallons of fuel but full compliment of 6x 50 cal..


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## GregP (Feb 11, 2013)

Hi Drgondog,

I was aware the P-51 wing was a 45-100 series but was not aware that it was a modified 45-100 since I have not researched the Mustang wing section. I appreciate the information. It may well be that there are no surviving data on the XP-4Q that are useful, but I'll keep my eyes open on the subject since I am interested.

To me, the P-40 was one of the fastest-rolling airframes in US WWII manufacture. The turning circle was decent if not great, and I believe that the XP-40Q markedly improved the basic P-40 and closely approached the P-51 for speed while probably still out-rolling it significantly. I have no data on turning circles and none on diving speed, flight test climb graphs, or other things that would allow a meaningful comparison with the P-51D, so I can't say what it was like to fly from anything other than speculation.

But historically, if the P-40 could make 420 mph and still retain its characteristics or maybe get better at turning and service celiling, it would have been a good thing ... at least for the P-40 fliers. I already stated that we probably made the right desision doing what we did, but I still believe the XP-40Q could have made a decent fighter, if 15 mph slower than the P-51 at the P-51's best altitude. I cannot say if the XP-40Q was slower than a P-51 at the XP-40Q's best altitude because I don' have the data to say it. All I have a a top speed of 422 mph without an altitude or power setting.

I would ask General Davey Allison if he were still alive. Alas, he passed away shortly after his visit to our shop. We toook pics and have one on the wall. His own words were that he often visited the Curtiss factory and knew most of the management quite well, and that they often had lunch when he was there. I have no method of checking his recollections and, while interested, am not interested enough to try to feret out any inconsistencies since there was so little detailed information passed along. He was pretty sure the preliminary XP-40Q innovations were on paper and shown to NAA, but did not elaborate as to why he thought that or what his source was.

His main subject at lunch was his demonstration to Chenault of the P-40B, He used greatly elevated manifold pressure to get sparkling performance out of it. Chennault reportedly told him hat he got more out of a P-40 than anbody else. If he used 75" of manifold pressure on an Allison C-15 engine as he said, that might explain why Chennault obtained P-40's. It was well over the approved boost level and would have made a good show.

Meanwhile, I have no proof of his claims, but appreciated hearing them over lunch.

Just for fun, here's my own side view of the XP-40Q:

View attachment 224440


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## Deuelly (Feb 13, 2013)

NAA Received information from Curtiss about early P-40 developement testing not specifically the "Q" model. The NA-73 was based off of this information. Below are some documents that NAA received from Curtiss.


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## drgondog (Feb 13, 2013)

Deuelly said:


> NAA Received information from Curtiss about early P-40 developement testing not specifically the "Q" model. The NA-73 was based off of this information. Below are some documents that NAA received from Curtiss.
> View attachment 224636
> 
> View attachment 224637



There is no evidence that any part of the NA-73X was derived from any data received from Curtiss. The data purchased from Curtiss was a.) purchased after May 1, and b.) approximately 30 days after Edgard Schmued completed the 3D, performance estimates and weights/balances package was in Dutch Kindleberger's hands by the end of March, 1940 when He took them to Britain to make his pitch with Sir Henry Self.

Just looking at the XP-46 gives you insight to the total divergence of NA-71X from any derivative of P-40 line until early to spring 1943 when the XP-40Q started with a P-40K airframe


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## tomo pauk (Feb 13, 2013)

No doubt that I'd would like to see all of the remaining stuff 

The plane at the picture looks more like a sibling of XP-37, with pilot seated so far aft. The fuel is to be between the engine and pilot? The vertical tail looks it would need more height surface in order to look like NAA fighter. Of course, the drawings of the wing (esp side elevation of the ribs, and spar fuel tank layout) and radiator installation. The main UC - fully or partially covered? The wing tips and tips of empenage parts are not 'square cut', a difference vs. NA-73.
The front part seems to house the C series (featuring the internal spur reduction gear) V-1710, not the F series (= external spur reduction gear, giving higher thrust line). The NA-73 was featuring F series engine.


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## GregP (Feb 13, 2013)

Hi Duelly,

What information do you have that indicate the drawings you posted were used in the design of the NA-73 and what is the source?

I am of the opinion that they used the Curtiss data including the early drawings for what turned into the XP-40Q, but I have no concrete data to prove it ... just supposition that, rightfully, has been called into question by some members. So ... if you have some proof, please offer it or at least say why you posted what you did.

While Drgondog and I may disagree, his questions are spot on and should be supported or the thesis abandoned, at least in public, until such support documents are forthcoming. Stories can be believed or not, but documents that can be corroborated are hard to ignore. Can you help out here?

Thanks!


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## Deuelly (Feb 14, 2013)

Sorry guys I'm new to this thread posting thing and may have let my opinion get in the way of fact. I'm working on a book, kind of a P-40Q in detail thing. I'm using the original P-40Q prints to redraw major structures of the aircraft as 3D models so I can use them for detail pictures. I'm concentrating on the structure aspect of it and not necessarily the would have could have part of it. Anyway, the pictures I posted are from my set of prints I use. From the Curtiss documents I've read though it seems that the information NAA receive wasn't a specific design but airfoil, drag, and structural layout data. Not really for any specific aircraft but things they may have been planning to incorperate into a future project or a P-40 change possibly. Sorry again guys for trying to inject my opinion without any real proof.

Just so you know I have the P-40Q prints I talked about here are a couple scans I've done.


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## FLYBOYJ (Feb 14, 2013)

Just an observation...

There are many times that a "common" or "standard" part or assembly may be used on several different aircraft from the same manufacturer. I see the drawing scanned shows XP-40Q in the NHA/ model block (highlighted). The entries below that seem to show "P-40N" in the model block. If a manufacturer took the time to put together a "drawing tree" one might be able to see common parts and assemblies between two models of aircraft and how they relate to each other and may give an indication when the drawing was first developed. When I worked at Lockheed I used to see this all the time between the "Model 188 Electra" and the "Model 185/ 285" better known as the P-3. I also came across "standard parts" like a ICS foot switch that was common between the P-2 and P-3.


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## drgondog (Feb 14, 2013)

Also Joe, one might note that the signature block (s) on the Drawing are 1943..


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## FLYBOYJ (Feb 14, 2013)

drgondog said:


> Also Joe, one might note that the signature block (s) on the Drawing are 1943..


Yep - saw that too! I think that further validates your point Bill, at least looking at this very small example.


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## FLYBOYJ (Feb 14, 2013)

I came across this earlier...

_As early as 1938 Kindelberger had made numerous trips to Europe seeking orders for his company, and he had the opportunity to see up close some of the airplanes that would be in combat in the war that almost everyone believed would soon be coming. Once hostilities broke out, Kindelberger eagerly sought out combat reports from both sides and developed some ideas of his own.

Although Kindelberger had no experience with fighters, he collaborated with Atwood to formulate an outline for a fighter project. A project team was formed at NAA, made up of such people as Raymond H Rice, Edgar Schmued, Larry Waite, and Ed Horkey. (A sort-of urban legend had grown up about Edgar Schmued that claimed he had once worked for Willy Messerschmitt, and that the Mustang was heavily influenced by the Bf.109.) 

Following the outbreak of war in Europe, the British Purchasing Commission, headed by Sir Henry Self, was posted to New York to determine if American combat aircraft could be of any use to the Royal Air Force. Bell P-39s and Curtiss P-40s were ordered in substantial numbers even though they were not up to the performance standards of the latest British and German fighters.

One of the corporations that Self had contacted was NAA, who had already been building NA-16 trainers for the RAF as the Harvard. In April of 1940 Kindelberger was requested to manufacture Curtiss P-40Ds under license for the RAF. He responded that NAA could do that, but countered that his company could build a better fighter than the P-40 and that they could design a REAL fighter in the same time that it would take to put the P-40 into production. The British commission felt that they could take Kindelberger at his word and, on Apr 10, 1940, accepted his proposal on the condition that the first prototype be ready in 120 days. The design was assigned the company project name of Model NA-73. 

At that time, the USAAC reserved for itself the right to block any foreign aircraft sales that it regarded as not in the Army's interest for whatever reason. On May 4, 1940, the US Army reluctantly agreed not to block the British sale, but added a condition—two examples of the initial British NA-73 lot were to be transferred to the AAC for testing. free of charge.

The NA-73X prototype contract was signed on May 23, 1940. The British insisted that a heavy eight-gun armament be fitted. NAA had actually been quietly working on such a fighter project since the summer of 1939 and had already completed much of the detail design. On May 29 a provisional RAF procurement was issued for 320 aircraft, contingent on satisfactory testing of the prototype. NAA agreed to start deliveries in January 1941. RAF s/ns were issued [AG345/664] and the aircraft given the name Mustang I for RAF service. 

*Another urban legend surrounding the Mustang is that it owed a great deal to the Curtiss XP-46 and, in fact, stole numerous design features from that fighter. It is true that the British had insisted that since NAA had no fighter experience they should secure all current data from Curtiss about both the P-40 and XP-46. Although NAA did pay $56,000 to Curtiss for technical aerodynamic data for the XP-46, there was only a very broad resemblance between it and the NA-73X. The Curtiss shared only a similar radiator/oil-cooler configuration and did not have laminar-flow wings. In fact, development of XP-46 lagged behind that of NA-73X, with prototypes not ready for flight until Feb 1941.*

*As well, preliminary design of the NA-73X was completed before NAA gained access to the Curtiss material. It could even be argued that the XP-46 data was most useful to NAA in guiding them in what not to do. The NA-73X appears to owe virtually nothing to any previous fighter design. Nevertheless, despite convincing denials from both Edgar Schmued and aerodynamicist Horkey, the full magnitude of the contribution of Curtiss to the NA-73X design remains controversial to this day*. _

North American NA-73


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## FLYBOYJ (Feb 14, 2013)

And caught this on "Wiki" for what it's worth...

_A myth surrounding the origins of the P-51 Mustang is linked to the North American Aviation (NAA) purchase of test data on the P-40 and P-46. NAA paid $56,000 to Curtiss for technical aerodynamic data on the XP-46 and although there are certain design similarities in the radiator/oil-cooler configuration, the new NA-73X (the company designation for the future P-51) even in preliminary design had already progressed beyond the XP-46.[1] In addition, after the war, NAA engineers revealed that they had learned of a European study (before the US entry into World War II) which indicated the value of a well-designed embedded radiator, and were eager to apply that knowledge to a new design._

[1] Baugher, Joe. "North American NA-73." USAAC/USAAF/USAF Fighter and Pursuit Aircraft: North American P-51 Mustang, 29 August 1999. Retrieved: 10 August 2010.


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## drgondog (Feb 15, 2013)

The absolute 'smoking gun' was that NAA, specifically Edgar Schmued, head of the NA-73X/Mustang Program did a detailed set of three view drawings, made weight and performance estimates and packaged them for Kindleberger before he went to the UK to present the 'new fighter' to Sir Henry Self. Ergo, the preliminary design was complete no later than March 31st, 1940.

The data (and whatever that means) purchased by NAA from Curtiss was bought in the first week of May, 1940 and there is no definitive date of arrival at NAA... 

Summary - 

1.) design outlines including 'Meridith concept' radiator, trapezoidal wing and tail, Allison 1710, inward folding landing gear had been analyzed and put to Vellum at least 30 days before anybody went to Curtiss to purchase any data in the Hands of Curtiss. The decision to put a laminar flow wing was close to fruition in May 1940. None of the P-40's or any data that could have been included in the May 1940 'package' could have Any Laminar flow data for any P-40 design to date. It is so far not even conclusive that the XP-40Q had a Laminar Flow wing.

2.) the NA-73X and future Mustang looks nothing like the P-40, or P-46, or even the XP-40Q except for the bubble canopy. Notably the NA-73X, P-51, P-51A, A-36 and P-51B/C did Not have a bubble canopy, so there certainly was no indication that the XP-40Q canopy concepts were used for nearly three years. History shows that the first prototype P-51D Mustang canopy design were in parallel to the XP-40Q design - so one might ask - "who was copying whom"?

3.) the XP-40Q, which did not start modification process from P-40K until February 1943, does not look like the P-51 in either radiator design (under wings a la Spitfire and Bf 109), landing gear design, tail design or planform for wing and horizontal stabilizer. On the other hand, the wing and tail of the XP-40Q looks like the P-40 and P-46 and all other Curtiss derivative single engine fighter.

If there is any connection remotely between the P-51 and the XP-40Q, one must presume that somehow NAA had a glimpse more than three years in the future, took the bubble canopy, and sat on it for three years.

Remember last of all. The airframe per se did not get significantly 'cleaned up' for the XP-40Q when they used the P-40K for the bones to perform the conversion... result - the airframe of the P-40Q, extremely light in flight test, with a much more powerful engine was ~13 mph faster than a P-51A with full combat load...


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## FLYBOYJ (Feb 15, 2013)

Although we could agree or disagree or walk away with our own therories on this, this thread is most interesting!!!


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## GregP (Feb 15, 2013)

While this thread certainly indicates that NAA didn’t use any of the Curtiss data for the Na-73, I have heard from at least two people who claim otherwise. One was there at the time and the other is the son of the designer of the P-40. There is no proof of their claims that I have yet uncovered, just their claims that are , so far, unsubstantiated.

As to the XP-40Q before 1943, I heard the study was done early-on and was not called the “XP-40Q,” but was rather a study for a general airframe drag cleanup of the P-40 (which hopefully we all agree it could have used), and that much of the “cleanup” was later incorporated into what later became the XP-40Q. If people think Curtiss “sat on” a cleanup, please remember that during the war the Government didn’t care what you wanted to improve … you had to fulfill the contract that was signed. So if Curtiss had a contract for, say, X number of P-40B/C’s, that’s what they had to deliver. If the prime customer isn’t really interested in your hot new development, you really have nowhere to go with it.

It may well be that the general cleanup was, in fact, the XP-46 and NAA never used that info on an aircraft design that came from NAA. I agree this appears to be the case at this time. However, the XP-40Q did wander into laminar-flow wings, at least according to my sources (including Vee’s for Victory, among others), and was pretty decent aircraft in 1943. The fact remains the XP-40Q wasn’t selected for production and the P-51 was. Pretty much end of story, at least for the P-40 developments. The XP-4Q was the last attempt to make the basic P-40 into a much better aircraft.

So I must agree with Drgondog that there appears to be no objective evidence at this time of the Curtiss data being used early enough to have had an impact on the Na-73.

The bubble canopy thing: it appears to me that the British first used the bubble canopy on the Miles M.20 (first flight: Sep 1940) , I believe, and that everyone else liked the idea. Again, I wasn’t there and can’t make any definite statements, but it appears the Mustang bubble canopy development was underway when the Typhoon was converted to bubble canopy.

Timeline:
2/27/1943: Two P-51 airframes are released from Land Lease contract for bubble canopy development (43-12102 was one).
May 1943: Production of Allison-engined Mustangs comes to an end.
7/21/1943: Contract signed for 2,500 P-51D’s with bubble canopy.
August 1943: Hawker converts a Typhoon to bubble canopy and everyone likes it. Soon is standard.
Sumer 1943: Republic converts the P-47 to bubble canopy.

Since the Typhoon was made in Great Britain, it could easily be the first bubble canopy deployed into service since “service” was only a short hop away. Anything from the U.S.A. would have to be made, accepted, and shipped overseas to get deployed. Of course, “in service” could also mean in the USAAC inside the U.S.A. … I suppose. It appears to have all happened in 1943.

So, I now wonder who was really first with the all-round vision bubble canopy in a deployed fighter aircraft. Popular history has it as the British, but perhaps some research is indicated on this when I get the time and inclination … until I do, I’ll assume it was the British.


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## tomo pauk (Feb 15, 2013)

GregP said:


> ...
> However, the XP-40Q did wander into laminar-flow wings, at least according to my sources (including Vee’s for Victory, among others),
> ...



Mr. Whitney got this one wrong? 
He does say that "XP-40Q had been modernized by giving it laminar flow wing", pg. 184 (it does not have a referrence there, unlike most of the sentences), however at next two pages he lists the exissting airframes that received different engines, canopies, different oil cooling arrangement, and, most importantly, when the wing was clipped (why? if the new wing is of laminar flow). Further, the U/C still retracts in the P-36 style, the armament is reduced because of oil radiators, nobody ever saw any increase in fuel supply - the wing of the XP-40Q has "P-40" written all over it.


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## GregP (Feb 15, 2013)

About the shape, I agree ... pure P-40, but I've heard before that at least one of the XP-40Q's had a liminar flow wing. That was many years ago at an aishow inA rizona when we still had quite a number of former WII pilots around. Airtfoil sections do not dictate wing shape from above. You can make an airfoil into almost any shape.

What objective proof do you have the Dan Whitney was wrong? Any design documents from the completed project?


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## tomo pauk (Feb 15, 2013)

> What objective proof do you have the Dan Whitney was wrong?



I have his own words: all the XP-40Qs were once stock airframes, and changes listed (when those stock airframes became XP-40Q) do not count the laminar flow wing at any time. Mr Whitney, again, does not give a reference to the claim XP-40 have had laminar flow wing - you can note that he gives references for almost every second sentence.


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## GregP (Feb 15, 2013)

I suppose we are interpreting things differently. Since so little is available on it, I say it makes no difference in the long run, the XP-40Q was not selected for production, so it doesn't matter. You could be right or not. With only 3 airframes contstructed, it is a footnote in history at best that never went anywhere.

I'll ask Dan next time I see him, which will probably be our next airshow in May. Usually we have lunch at least once.


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## Rick65 (Feb 15, 2013)

Westland Whirlwind had what was effectively a bubble canopy and first flew late 1938.

Reactions: Like Like:
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## GregP (Feb 15, 2013)

Yep, it did. Thanks. I'd say it was before the Miles M.20 ... but it DID have canopy frames and was not a one-piece unit as far as I know. I could be wrong here.


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