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There were few old discussions on this. There is no doubt the Zero had the definite advantage over the P-39 over New Guinea, but if you look at the combat record of say the 8th FG, the P-39's combat record wasn't as dismal as portrayed by some historians.I recall reading of one German pilot saying, "The P-39 performed like the 109 at low altitudes."
And in the book "P-39 Aces of WWII" the author points out that in reality P-39 versus Zero losses in the Pacific were about equal. He also points out that when the Soviets got in later aircraft such as the LA-5, Yak-3, and Yak-9 they did not use them to replace P-39's but kept the Airacobras in front line air superiority service.
Sounds to me like a loosely translated reference to speed under optimum conditions as opposed to indicated airspeed under real world conditions. Perhaps akin to the difference in SAE vs DIN horsepower ratings back in the musclecar days. SAE measured the output of the raw engine block, with all accessory functions such as coolant circulation, electrical generation, and carburetion provided by the test rig, while DIN measured horsepower delivered to a transmission by a fully assembled engine as it would be installed in a car. Make sense?I wonder what they mean for "theoretical speed": didn't Germans actually test in flight theirSS planes? And what is this "instrument speed" they speak of?
WHOA!! So far all this weight you've removed seems to be forward of the center of lift. Don't forget this is a rear engine plane with a hint of a tail heaviness problem. If you don't compensate by moving some heavy objects forward, you're going to have a right squirrelly bastard on your hands with some nasty slow flight and stall behaviors and a penchant for unrecoverable flat spins. This wheel has been invented before!So if a 350 lb weight reduction was worth doing then maybe 359 lb would be worth doing.
Well, the P-39 did not have any "Wing Cannons" to delete. But ever since reading Caiden's "Rugged, Ragged Warriors" I have wondered if you could strip a P-39 down a bit to yield a better air to air fighter. They did that with a P-40 in India with a degree of success in intercepting Japanese Dinah recon aircraft.
Take a look at the P-39 Design Analysis. The 37MM gun was not all that useful in air to air combat. It had a rate of fire described as similar to that of a "Roman Candle" which was supposed to be 135 rounds a minute; at 300 mph the airplane would have moved 200 ft between rounds. Even more importantly, the 37MM trajectory was significantly different from that of the .50 cal and .30 cal guns, so it usually was a matter of deciding which gun you wanted to hit the target with.
So let's get rid of the 37MM and replace it with another .50 cal. The 37MM weighs 238 lb and its 30 rounds of ammo weighs 60 lb, for a total of 298 lb saved. One .50 cal gun weighs 80 lb and 400 rounds of ammo for it weighs 129 lb (the two .50 cal guns already there have 200 rpg). So, swapping out the 37MM for a .50 saves 89 lb.
Next let's get rid of the four .30 cal guns in the wings. That saves 92 lb for the 4 guns and 78 lb for the 1200 rounds of ammo. By the way supposedly the P-39 could hold 2000 rounds of .30 cal ammo but they probably did not load all of it. We get rid of another 170 lb, for a total reduction of 259 lb, which is not really very much.
The total weight of armor plate for the airplane is given as 202 lb. I read somewhere that one unit in the Pacific made a big improvement in the P-39 by removing the armor on the belly protecting the radiator. If you are planning on air-to-air work that belly armor is not very useful, but I'm sure it was useful for strafing.
So if you get rid of, say, half the armor and you have stripped the airplane down to three .50 cal guns, it is 359 lb lighter. That does not sound like very much to me. No wonder they never seemed to try it. It appears that the P-39Q-20 without the two underwing .50 cal guns was about 260 lb lighter than the other Q models. The P-39N-0-BE model had four fuel cells removed to reduce the max fuel load by 28 gal, which reduced the max gross weight from 9100 to 8750 lb. So if a 350 lb weight reduction was worth doing then maybe 359 lb would be worth doing.
WHOA!! So far all this weight you've removed seems to be forward of the center of lift. Don't forget this is a rear engine plane with a hint of a tail heaviness problem. If you don't compensate by moving some heavy objects forward, you're going to have a right squirrelly bastard on your hands with some nasty slow flight and stall behaviors and a penchant for unrecoverable flat spins. This wheel has been invented before!
Cheers,
Wes
Explain please? That's a new one on me. Thanks.Keep in mind the P-39 also had 2 CG datum points
It had a vertical and horizontal C/G, just like a helicopter. I'll try to find the W&B formExplain please? That's a new one on me. Thanks.
I don't know why, for me, their performance is respected for what they were, some habitually compare them to a P 51 which was from a different era doing a different job.The more I keep learning about how US aircraft like the P-39 and P-40 performed in Europe, the more it's apparent that these aircraft have been maligned.
Please don't compare historical aircraft performance to a game. Unless you're prepared to make comparisons in full motion simulators that could simulate actual G loading as well as other external stimuli encountered while in combat, or fly the real thing, you're basically guessingFrom the moment I've heard about the type, I've read mostly positive things about it.
Granted it were Soviet experiences with the type... there is a good book about their experiences "Attack of the Airacobras", some very good read.
I may be 'pushing it' a bit if I say that if the game "IL-2 Sturmovik" is ANYTHING to go by, P-39 was truly fearsome weapon if piloted by a grizzled veteran.
Even when confronted by some of the era best aircraft such as Bf-109 and FW-190. Also, curiously I've seen several VVS pilot opinions where they regard 109 as a bit more capable plane that 190. That may be due to nature of Eastern Front warfare and many other things.
To return to "IL-2 Sturmovik"... I've flown/played that game for years and can say without any doubt that (in-game) P-39 is very capable plane, at least on Eastern front scenarios... when you mix it up with enemy fighters the way you shouldn't (flashy dogfights), and you gain upper hand they usually tend to shallow dive away. P-39 can follow them without problem and shot them down. Same thing if they try high speed maneuvers during dive... Cobra is quite fast in such type fights, more capable than early/mid-war Lavochkin and Yak types which often lose their opponents during hi-speed shallow dives. Also that NS-37 nose cannon... lower rate of fire, but I guess once pilot gets some experience under his belt shouldn't be an issue (when compared to the higher rof 20mm cannons). One shot can cripple bomber, and is usually insta-kill vs fighter.
So it is not a surprise to me when I see how several of the highest scoring Soviets flew this type.
Cobra was not so popular on the far East fronts... but then again I guess nothing really was truly popular (allied side) there in those days vs Zero until Hellcat arrived and gained upper hand in performance. At least in pilot's eyes. Because let's face it, if pilot go into actual combat he is not really interested in any kind of equal fights or proving himself in lesser types, what pilots really wanted is a truly superior type which could regularly bring success in combat..