wuzak
Captain
Does the P-51 look like the XP-40Q, or does the XP-40Q look like the P-51?
Super P-39?
- Thread starter R Pope
- Start date
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Some things don't add up.
1st, XP-40Q have had about the 2 things same as P-51D, the Brownings and teardrop canopy.
Fuselage (vintage P-40 stuff), engine (2 stage V-1710), wings (again, same as P-40, modified to take oil coolers instead of inner HMGs), no ventral radiator block etc - everything was different between the XP-40Q. It needed 1700 HP at 26000 ft to make 420 mph, a lousy value when compared with unloved P-63A that was capable for 415 with under 1200 HP at same altitude. P-63D E were making 450 mph with only 1300-1340 HP, WER at altitude, despite the lousy wing gun installation.
The story about XP-40Q having laminar flow wing is just that, a story; the wings needed to be clipped so the plane could make top the 420 mph mark.
The V-1710 offering 1700 HP at 26000 ft was not available until late 1944, one might wonder how fast a P-51 would be with that much power. The 1st XP-40Qs were equipped with engines of less power at altitude, the Q-2 having on tap only 1500 HP at 6000. The Q-3, featuring those 1700 HP at altitude, was in early 1945 issued for USAF to test it. By then, USAF did have far better performers, with more combat range firepower already in service. Actually, it's planes of early 1944 were offering more than Q-3, let alone earlier Qs.
The P-46 was not the one with laminar flow wings, NACA was providing data for NAA about the laminar flow wings for their future P-51. Ref. Gruenhagen's 'Mustang' and 'Vee's for Victory', one can read a lot about the XP-40Q and it's engines in the later Vee's.
1st, XP-40Q have had about the 2 things same as P-51D, the Brownings and teardrop canopy.
Fuselage (vintage P-40 stuff), engine (2 stage V-1710), wings (again, same as P-40, modified to take oil coolers instead of inner HMGs), no ventral radiator block etc - everything was different between the XP-40Q. It needed 1700 HP at 26000 ft to make 420 mph, a lousy value when compared with unloved P-63A that was capable for 415 with under 1200 HP at same altitude. P-63D E were making 450 mph with only 1300-1340 HP, WER at altitude, despite the lousy wing gun installation.
The story about XP-40Q having laminar flow wing is just that, a story; the wings needed to be clipped so the plane could make top the 420 mph mark.
The V-1710 offering 1700 HP at 26000 ft was not available until late 1944, one might wonder how fast a P-51 would be with that much power. The 1st XP-40Qs were equipped with engines of less power at altitude, the Q-2 having on tap only 1500 HP at 6000. The Q-3, featuring those 1700 HP at altitude, was in early 1945 issued for USAF to test it. By then, USAF did have far better performers, with more combat range firepower already in service. Actually, it's planes of early 1944 were offering more than Q-3, let alone earlier Qs.
The P-46 was not the one with laminar flow wings, NACA was providing data for NAA about the laminar flow wings for their future P-51. Ref. Gruenhagen's 'Mustang' and 'Vee's for Victory', one can read a lot about the XP-40Q and it's engines in the later Vee's.
Shortround6
Major General
Just because you have ventral radiator does not mean you are taking advantage of the Meredith effect. You need the right sized radiator, proper changes in internal contours/cross sections and an adjustable exit flap to make full use of it.
The boundary layer splitter helps but if the radiator is too small ( excessive pressure drop through the radiator) or the ducting doesn't allow for the needed changes in airflow speed. (large middle of duct slows airflow and since the drag goes up with the square of the speed through the radiator...) the best boundary layer splitter in world will not help if the rest of the cooling duct design isn't up to snuff.
If Curtiss had the radiator figured out on the P-46 they sure never used that knowledge on any of the P-53/P-60 series. And tehy were still dinking around with different radiator arrangements on later P-40 prototypes.
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GregP
Major
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.
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.
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.
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?
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 ...
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.
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.
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?
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 ...
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I've started a new thread about the XP-40Q:
http://www.ww2aircraft.net/forum/aviation/xp-40q-what-able-do-when-35878.html
http://www.ww2aircraft.net/forum/aviation/xp-40q-what-able-do-when-35878.html
It was a old Italian surplus gun, and 3 shots in 6 seconds, we can't know how long he took for the first shot. A 100 yard head shot isn't that hard for a scoped rifle, we have no ideal how much Oswald might have practiced with that rifle to improve his marksmanship after getting out of the Marines, and any rifle, even surplus beaters , can be greatly improved with just a little gunsmithing, or TLC.
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GregP
Major
OK ... never heard of a "greatly improved" Carcano Model 91/38 ... but maybe so ...
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MikeGazdik
Senior Airman
Not that It belongs here...but.. I totally agree with this. I have not shot an Italian Carcano. I have several military Russian (and others) rifles of similar capabilities. In a day of practice, I could get most anybody reading this to easily perform "head shots" at 120yds with the iron or open sights. Scope not needed. All of those old battle rifles with high power rounds are easily capable of the shot. 100 yards with a high-power rifle is like 25ft to a pistol.
GregP
Major
Yeah, you can make head shots with open sights and an old bolt action rifle. But 3 in 6 seconds at moving targets in a car in a parade would be .... almost unbelievable. We're not talking about a video game; this is real shooting we're discussing, and I doubt the vast majority of marksmen could do it with a Carcano.
Apparently, most people believe it is possible and even happened. I simply don't. No agrument; I just don't. I don't have the facts and nobody else does either except the person or people involved and, if popular belief is right, he is dead and so is the guy who shot him. Convenient, huh? All wrapped up in one neat package with no loose ends. Sound sjust like a novel.
But, if ANY subject is off topic, this is ... so I decline to give it further discussion and apologize for even posting the remark. Please consider it rescinded.
Back to Super P-39. I still think the P-39 airframe was too small and the XP-40Q would have been about right or only slightly small, which COULD have been corrected with minor effort to wing and tail areas. They did that with the Spitfire as power went up. Why not the XP-40Q? Or the P-63? Of course, I'd also scrap the ridiculous 37 mm cannon used in the P-39 and go for a good gun to go with the 2-stage, intercooled engine.
Apparently, most people believe it is possible and even happened. I simply don't. No agrument; I just don't. I don't have the facts and nobody else does either except the person or people involved and, if popular belief is right, he is dead and so is the guy who shot him. Convenient, huh? All wrapped up in one neat package with no loose ends. Sound sjust like a novel.
But, if ANY subject is off topic, this is ... so I decline to give it further discussion and apologize for even posting the remark. Please consider it rescinded.
Back to Super P-39. I still think the P-39 airframe was too small and the XP-40Q would have been about right or only slightly small, which COULD have been corrected with minor effort to wing and tail areas. They did that with the Spitfire as power went up. Why not the XP-40Q? Or the P-63? Of course, I'd also scrap the ridiculous 37 mm cannon used in the P-39 and go for a good gun to go with the 2-stage, intercooled engine.
bluezanzibar
Recruit
- 8
- Feb 26, 2012
Removed due to irrelevance
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CobberKane
Banned
- 706
- Apr 4, 2012
You guys have no idea how to set the groundwork for a good conspiracy theory. Shooting your elected head of government is so sixties (1860's and 1960's). If you really want to get some speculation going you should have the boss charge into the surf in a wetsuit and just disappear - like we did down here.
wuzak
Captain
It would be interesting to have the Secret Service dive in first to come out and say "The coast is clear, all except that Chinese submarine".
Shortround6
Major General
Just because the government has been involved in several conspiracies does not mean that every bone headed stunt or difficult to explain decision was the result of a conspiracy. Although more than one bone headed stunt or difficult to explain decision may have resulted in a conspiracy to cover it up (self preservation by people involved). 
We KNOW the government is not honest, but each case needs to be looked at on it's own an just because the government did something flaky in the 60s doesn't prove it did something flaky in the 40s. Doesn't prove it didn't either.
There was plenty of bad judgement to keep conspiracy people going for quite a while just on the goings on at Curtiss-Wright (why did ONE company turn out so many marginal designs and why couldn't more of them have been stopped before so much was invested in them?).
Minor bad judgement just on the P-39,
Why was it so over loaded with more guns/ammo than the original design?
Keeping the 37mm cannon (good as it may have been against bombers) in preference to going to a belt feed 20mm may be more of an indication of how bad the American 20mm was than how good the 37mm was. Lesser of two evils?
American aircraft ordnance was a disaster for too much of WW II.
Getting back to the original question. The P-39 had to have a stronger, stiffer fuselage than a "normal" fighter. because of the drive shaft. The gear case/prop had to be kept in alignment with the engine. Bell engineers managed to do this with only about a 50lb penalty but it meant that the fuselage from behind the prop to the rear of the engine was sort of a big box beam,
Notice the end of the fuselage center section and start of the tail section.
Notice also the taper and more confined space between the structural members at the rear of the fuselage center section.
Perhaps you could stuff a bigger (two stage) supercharger of some sort back there but it requires considerable redesign of the entire area.
We KNOW the government is not honest, but each case needs to be looked at on it's own an just because the government did something flaky in the 60s doesn't prove it did something flaky in the 40s. Doesn't prove it didn't either.
There was plenty of bad judgement to keep conspiracy people going for quite a while just on the goings on at Curtiss-Wright (why did ONE company turn out so many marginal designs and why couldn't more of them have been stopped before so much was invested in them?).
Minor bad judgement just on the P-39,
Why was it so over loaded with more guns/ammo than the original design?
Keeping the 37mm cannon (good as it may have been against bombers) in preference to going to a belt feed 20mm may be more of an indication of how bad the American 20mm was than how good the 37mm was. Lesser of two evils?
American aircraft ordnance was a disaster for too much of WW II.
Getting back to the original question. The P-39 had to have a stronger, stiffer fuselage than a "normal" fighter. because of the drive shaft. The gear case/prop had to be kept in alignment with the engine. Bell engineers managed to do this with only about a 50lb penalty but it meant that the fuselage from behind the prop to the rear of the engine was sort of a big box beam,
Notice the end of the fuselage center section and start of the tail section.
Notice also the taper and more confined space between the structural members at the rear of the fuselage center section.
Perhaps you could stuff a bigger (two stage) supercharger of some sort back there but it requires considerable redesign of the entire area.
GregP
Major
So are we all agreed that the P-39 was too small an airframe to be any good with a 2-stage Merlin plus intercooler in it?
wuzak
Captain
What was the length of a single stage Allison V-1710 (F-series, not the long nose case C)?
We know that the 2 stage Merlin was 88" long, approximately.
I don't think that the intercooler was much of an issue, as it was essentially within the cross section of the engine, and as a liquid to air type could have the radiator mounted anywhere - like under the nose, for instance.
Weight would be the other big issue. You would also need a downdraft carby version (like the 130-series).
The P-63 with a Merlin was probably a better bet than trying to adapt the P-39, but I go back to my original question, what could a modified P-63 have done that the P-51D or H couldn't do better?
Shortround6
Major General
Under the nose is were the landing gear is. Split on each side of landing gear?
AS for the engine
There is a lot of "junk in the trunk" (or loot in the boot?) behind the basic block on the two stage engine.
wuzak
Captain
There is space ahead of the landing gear. Radiator outlets could go to each side.
Yes, but how long compared to the V-1710?
According to Wiki the Allison V-1710 F30R is but 3 inches shorter than the Merlin 61 - 85.81" (2180mm) vs 88.7" (2253mm).
Allison V-1710 - Wikipedia, the free encyclopedia
Rolls-Royce Merlin - Wikipedia, the free encyclopedia
Lumsden has the same length for 2 stage Merlins. I can't verify the length of the Allison (I have glanced at Vees for Victory but can't see the length).
Without the reduction gear the E-series V-1710 would, of course, be shorter, but so would a Merlin 60-series without its reduction gear.
The Griffon is shorter again, slightly wider, but significantly taller and heavier.
Maybe a 2 speed single stage Merlin would improve the P-39's performance. It would not come at a great weight penalty, and it should fit quite easily - with a downdraft carby.
