Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Vermillion on December 13, 2000, 08:15:00 AM
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Its a well known fact that during developement, the US Army Air Corps decided that the P-39 Aircobra "didn't need" its turbosupercharger, thereby dooming the P-39 to mediocrity in WWII.
Just yesterday, I found an even more interesting fact on the Bell P-63 KingCobra.
Now we know that the KingCobra was somewhat larger than the Aircobra, and that it had a new laminar flow wing similar to the P-51 Mustang wing, along with a 2 stage supercharger (fixing, the largest glaring error with the P-39).
But did you know that the P-63 was suppose to be powered by a Continental V-1430 engine, that produced 2,000hp?
Even with the anemic Allision V-1710 that only produced 1,325 hp, the P-63 had performance near to or exceeding the P-51 in most respects (speed at most altitudes, climb, and acceleration). And it actually handled better in turning ability.
Can you imagine what the P-63 could have done with 34% more power ?
Did Bell Aircraft have some really bad luck or what?
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Vermillion
**MOL**, Men of Leisure
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P-63 could only ever be faster than a P-51D if it has a -117 engine with 1825HP WEP.
With only 1325HP, it's about 25mph slower.
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Yes, its slower at altitude, but the information I was looking at today (online) showed a sea level speed that was approximately equal with the P-51's.
My point is that if the continental engine had panned out, it could have easily outperformed the P-51.
I don't deny that with the Allison engine, that the P-51 is superior.
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Vermillion
**MOL**, Men of Leisure
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The P-63's biggest drawback was lack of range. The USAAF was only interested in planes with very long range at that point, like the P-47D, P-51D, and P-38L. As it is the P-63 only had a range of around 500 miles on internal fuel with the Allison. Imagine how poor the range would be with the 2000hp Continental.
The USAAF had no use for a short-range fighter, regardless of individual performance numbers.
ra
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What largely doomed the P39 was its capacity to kill pilots. It was far too easy to spin. Bill Dunn who is credited by most for being the first American WW2 ace had this to say about the P39. "I felt sorry for the poor SOB's that had to fly those things in combat against real fighter aircraft. The known bad habits of all aircraft were collected together and developed into the P-39's flying characteristics: flat spins, tail plane stalls, tumbling to mention a few of the most dangerous. It was a miserable kite to fly, and a lot of good guys busted their butt in the P-39. We should have set fire to them all; however, we gave them to the Russians. No wonder they're still mad at us." I also new a fellow who was a mechanic and had to work of them. The hydromatic prop seals were constantly blowing and the Allison engines overheated on a regular basis. Most of the time the pilots in the outfit he was assigned were not allowed to engage Japanese fighters in combat. They flew off a safe distance until a raid was over-and then flew back and landed. This made it look like the US still had an airforce when photographed by Japanese recon.
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Ah here we go with the tumbling wives' tales...
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Oleg Maddox's (head developer of IL-2 Sturmovik) word on the P-39:
"Such problems of spin and vibrations were solved quickly with the help of Russian engineers, which were working in Bell to modify P-39 for Russian needs. from the N series there were not present any vibrations and damages of the tail and the mass distribution was changed. So to get in a spin this plane was not easy, like early."
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I dont know much about P39s, only that russians felt little less than veneration for them.
Can't think of anyone feeling veneration towards such a pig as BBgun describes...so something good had to have!.
BTW didnt the highest russian ace fly a P39? Pokhryskin or something like that?
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Hi
P63 could have been good, but it wasnt. The is V1430 the vaunted "hyper" engine that never really worked right, the complete failiure of this engine ruined many other promising fighter projects. Anyway the P39 was never really that good either, even with its turbosupercharger in place. Yes the Bell performance numbers on the P39 prototypes were amazing for the day and were actually achieved on the prototypes. However those planes had no armour, weapons, self sealing tanks, radios, or just about everything else needed in a combat plane etc. etc. Basically they were strippers meant to give Bell spectacular numbers to put in the P39 sales literature. The P63 was a much better design and did well with the Russians in 1944, but it really wasnt very good in any spectacular way compared to 47/51, and IIRC it had bad range. Overall the Bell planes were amazing designs and engineering pieces but they just didnt fit well into the overall US fighter scheme of things in WW2.
thanks GRUNHERZ
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From Yeager's book:
...well, it was true that the drive shaft ran right up the center of the cramped cockpit, that the airplane performed beautifully at low altitudes, but underpowered up high, and that if you stalled it, you might wind up boring a deep hole because it spun like a top going down. But once you had a feel for the ship and understood it, the Thirty-Nine was a fun airplane to fly...
...there were three squadrons in our fighter group, and amoung all those pilots, I was one of the few who loved the Thirty-Nine and would have gladly flown it off to war.
for giggles:
...I told her I had five hundred hours in the Thirty-Nine and thought it was the best airplane I ever flew. She asked me if I wanted to fly it. "Yeah, man," I replied, "I'd give my right arm." So we concocted a little deal.
She was scheduled to fly the show the next morning. She was an ex-WASP, and the P.A. announcer told the crowd all about her just before take-off. We parked her Thirty-Nine away from the crowd. She outfitted me in a woman's wig, and white jump suit, and a blue cap, and off I went. I put on a helluva arobatic show, doing Immelmanns and Cuban eights, thrilled to be back in a Thirty-Nine again. I landed and parked far from the crowd, where she replaced me in the cockpit and then taxied up to the main ramp to receive the cheers.
Some guys will do anything to fly I guess.
- Jig
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Originally posted by GRUNHERZ:
Hi
P63 could have been good, but it wasnt. The is V1430 the vaunted "hyper" engine that never really worked right, the complete failiure of this engine ruined many other promising fighter projects. Anyway the P39 was never really that good either, even with its turbosupercharger in place. Yes the Bell performance numbers on the P39 prototypes were amazing for the day and were actually achieved on the prototypes. However those planes had no armour, weapons, self sealing tanks, radios, or just about everything else needed in a combat plane etc. etc. Basically they were strippers meant to give Bell spectacular numbers to put in the P39 sales literature. The P63 was a much better design and did well with the Russians in 1944, but it really wasnt very good in any spectacular way compared to 47/51, and IIRC it had bad range. Overall the Bell planes were amazing designs and engineering pieces but they just didnt fit well into the overall US fighter scheme of things in WW2.
thanks GRUNHERZ
Actually, the Soviets only used the P-63 against Japan in the Manchurian campaign after Germany capitulated.
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leonid, Kompol
5 GIAP VVS-KA, Knights (http://www.adamfive.com/guerrero)
"Our cause is just. The enemy will be crushed. Victory will be ours."
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Another problem with the P-39 and P-63 was that 37mm cannon. It had a low muzzle velocity and a low rate of fire. Some improvement was made from the P-63A9 onwards as these had the M10 instead of M4 cannon, which was belt-fed to double the ammo capacity and had a slightly higher RoF (170 rpm instead of 140). Still had the same low-velocity ammo, though.
One P-63 was different; the P-63D was armed with the 37mm M9 cannon, a very different beast which fired a much larger and more powerful cartridge and would have made a good tankbuster. Although the gun was adopted for US service, it was never actually issued for some reason. Pity.
Tony Williams
New book: "Rapid Fire: The development of automatic cannon, heavy machine guns and their ammunition for armies, navies and air forces"
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/index.htm (http://www.users.globalnet.co.uk/~autogun/index.htm)
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Originally posted by Tony Williams:
Another problem with the P-39 and P-63 was that 37mm cannon...
Yeah, it was a pretty low velocity shell, but the explosive power of the round was a keeper. Usually, all it took was one hit with a 37mm on a fighter to send it down. Many Soviet P-39 aces in WWII could attest to that fact, I'm sure.
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One thing I heard was that some US pilots reserved the 37mm for air-to-ground work, and only used the MG armament vs fighters. I think this was on Zenos WW2 USAAF P39 traing film, but not 100% sure.
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Is it true that you could not fire the 37mm and nose mounted 2x.50in at the same time - and that the Russians modified their P-39's so they could?
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As far as I know both MGs and cannon could be fired at the same time, but the projectile trajectories and flight times were so different that you probably couldn't hit anything with both weapons simultaneously except at very short range.
Tony Williams
New book: "Rapid Fire: The development of automatic cannon, heavy machine guns and their ammunition for armies, navies and air forces"
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/index.htm (http://www.users.globalnet.co.uk/~autogun/index.htm)
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juzz,
I believe you're correct. I know in Pokryshkin's book he had his mechanic make such a modification. But I think the modification had more to do with the fact that the original fire button for the cannon was in an awkward location.
Tony W,
You are absolutely right, you did have to get close, 200m or less, for sure.
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While I agree the US 37mm was far from an optimum weapon, it certainly has the "one hit one kill" potential that can be critical in a game like this. While in its real application, it would be much harder to use due to the lack of some "aides" like Icons and ranging information, that we take for granted.
Preferentially, I would like to see the Soviet NS-37 37mm or the NS-45 45mm cannons that were fitted on the Yak-9T or the Yak-9UT (among others). Either of those cannons make the US gun seem down right anemic and useless.
I got to talk to "Earl" this summer at the AW Convention. He flew P-39's and P-38's in North Africa and Sicily/Italy. He also flew P47's and P-51's at a later date, back in the US.
According to him the P-39 was a wonderful little plane as long as you weren't above 15,000 feet, and that it was quite responsive. He said that the reason that it got a bad reputation is that most pilots were inexperienced in it, were quite hamfisted and use to less responsive aircraft, which caused them to get into trouble in it.
PS: Hey Tony, want to comment on the age old debate on the Hispano versus MG151/20. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Vermillion
**MOL**, Men of Leisure
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Earl's wingamn, Jack Ogilvie, said the 37mm was a wonderful air-ground gun. They particularly like using it to take out the Axis radar towers on the Southern coast of France.
Earl also said this, "The (P-39) drive shaft was between the pilots legs and made a racket sometimes in sharp turns. The cannon, I think, was in front of the pilot and didn't give me that kind of sensation (re:"The cannon was originally a 37-milimeter antitank gun which fired rather slowly-whump-whump-whump, like that-- and since you were sitting on it, in the little cockpit, your legs straddling it, the firing of it vibrated your prostate so that the whole essence of war became mildly sexual) when firing it. I did resent the slow rate of fire - could only get two or three rounds off each pass on ground targets. I always fired in very short bursts at all ground targets. I classed the cannon as a ground attack weapon rather than an aerial combat weapon."
(http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
-Westy
[This message has been edited by Westy (edited 12-15-2000).]
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Originally posted by Vermillion:
Hey Tony, want to comment on the age old debate on the Hispano versus MG151/20. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
How ccould I resist? The Mauser was a neat weapon, beautifully made, which was better than the Mk II Hispano for most purposes because it was smaller, lighter and faster-firing (although less powerful).
However, the Mk V Hispano which came out at the end of the war (it equipped Tempests but I'm not sure what else saw action with it) was the same weight as the Mauser, slightly faster-firing and more powerful - clearly a better gun.
The Mauser had a "secret weapon" in its M-Geschoss ammo, which despite being lighter than the Hisso's carried more HE. It was therefore more destructive against aircraft targets, although the Hisso had much better armour penetration (and a longer range).
Both guns were adequately powerful for their purposes. The surprise may be that Mauser apparently never sought to improve the MG 151, at a time when the Allies were developing both the Hispano and the .50 M2.
My ideal WW2 cannon would be the Molins version of the Hispano, which hit 1,000 rpm. However, it was decided to make the Mk V instead as it involved fewer changes and so had less effect on the production line. Combine that with 100g M-Geschoss and 950 m/s muzzle velocity (entirely possible) and you have one formidable device....
Tony Williams
New book: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/ (http://www.users.globalnet.co.uk/~autogun/)
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The point that I continually have doubts about concerning the use of the Mauser mine shell Tony, and no one has yet stepped forward with good data, is at what point during the war did its widespread use begin? And even then, how widespread was its use?
Many of the Luftwaffe fans on this board continually point to this mine shell, and thereby say it (the MG151/20) should be more powerful than the Hispano. Especially when we start to do actual lethality calculations of KE and Explosive energy. But this arguement only works if you assume a total loadout of mine shells only. If you assume mixed ammunition belts, the Hispano still comes out ahead.
Now, before I begin my point, lets start with the assumption that Aces High is meant to represent the entire war, and the war in many different theaters.
So how widespread was the mine shell?
The only data I have seen, which is on Gustins page, shows that even during the height of the Allied bombing offensive in the fall of 1944, the typical German loadout in the western theater was 1 mine shell in every 3 rounds of mixed ammunition. And on the eastern front, it was even slightly less with more emphasis towards AP ammunition.
And in my opinon, this would have been the time/theater where the mine shell would have been used the most, considering the emphasis on destroying bombers.
But what about the early channel front battles during 1942? What about the battles in the North Afrika campaigns? And the eastern front? Italy and Sicily?
There was a whole lot of war, that wasn't 1944 and the anti-bomber campaigns and its emphasis on the mine shells (which even then was only 1 in 3).
To me the guns in Aces High have to be representative of the entire conflict, not one relatively small portion of it.
Thats why its my opinon, that the relative lethality in Aces High, of the Hispano being more lethal than the MG151/20 is correct.
What do you think?
Tony, you have any good data on the Japanese HO-5 and any data on its ammunition types? Its one of the few 20mm class guns, that may in my opinon be able to compete on a theoretical basis with the Hispano.
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Vermillion
**MOL**, Men of Leisure
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Work on the M-Geschoss started well before the war (I have factory drawings dating from 1937) but it first entered service in May 1940. I know this because the 20mm MG-FF cannon had to be modified to match the different recoil characteristics of the M-Geschoss (it was much lighter and generated less recoil), the gun being then called the MG-FFM, and this entered service in the Bf 109E-4, which came out in May 1940. Because the ammunition was incompatible with the MG-FF, the older guns were converted to MG-FFM standard over a period of time.
You are right that other types of 20mm ammo remained in service alongside the M-Geschoss. The early version was unable to take a tracer so the previous HE/T loading was altered to match the recoil of the M-Geschoss (i.e. downloaded), and AP rounds were used as well (because M-Geschoss was useless at armour penetration). However, the use of AP was eventually stopped as unproductive.
The 92g 20mm M-Geschoss held 18-20g of HE, whereas the 130g Hisso HEI held only 12-13g. Later in the war a heavy (105g) M-Geschoss was developed which held 25g HE - double the Hisso. The 30mm shells were all M-Geschoss AFAIK; they weighed 335g of which 85g was HE.
There is no doubt that the Luftwaffe saw the M-Geschoss as the main plane killer. Actual ammo belt loadouts varied, particularly towards the end of the war when anything was put together. For example, a large quantity of 30mm MK 108 ammo has recently been recovered, loaded with Hartkernmunition! This makes no sense at all as this APCR projectile was designed for the high-velocity MK 103 and could not have worked effectively with the low-velocity MK 108 - but I suppose it was all they had available.
The Ho-5 is a very neat design - just a scaled-up .50" M2 - which on paper was possibly the best 20mm of the war for its combination of small size, light weight, high rate of fire and reasonably powerful cartridge. The problem was that the Japanese ran out of good-quality steel so they had to download the ammo to avoid breaking the gun. I have a US intelligence report which credits the weapon with only 700-730 m/s despite firing very light (80g) projectiles (although they carried as much HE as the Hisso). So it was pretty weak by the end of the war, and had a short range. The Japanese Navy's Type 99-2 were cruder devices which did not suffer from this problem.
Tony Williams
New book: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/ (http://www.users.globalnet.co.uk/~autogun/)
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Verm good question sir! However doesnt the same question apply to chog, only 200built but in here its the only one anyone flies. Cmon even ull can agree with me on this one. Though now its a moot point a very experienced/knowlegable author says M-Geschoss was used as in Bf109E4 which carried MG-FFm. So there it was very common and was used even in 1940. Lets have it in AH.
thanks GRUNHERZ
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There is no doubt that the Luftwaffe saw the M-Geschoss as the main plane killer.
try to tell this HTC...
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NM
[This message has been edited by Jigster (edited 12-16-2000).]