Originally Posted by
Hydro Junkie
Actually, the P-39 was used for ground attack prior to the IL-2 being deployed in great numbers. The nose mounted cannon was deadly to the early German tanks, almost more so than it was to the aircraft used by the Luftwaffe. What is a very unknown bit of trivia is EVERY US FIGHTER used against Japan with little to no success were actually very successful against German and Russian forces. Specifically:
The P-39 was used with great success against the Germans by the Russians
The F2A Buffalo was used with great success by the the Finns against the Russians
Then again, the P-38 and P-40 have been generally thought of as "also flown" fighters in Europe. Truth be told, they not only held their own against the Germans and Italians when used in roles that hi-lighted their strengths, they were more than capable of mixing it up with the more maneuverable Japanese fighters like the A6M Zero until the Corsair and Hellcat arrived.
Even the F4F Wildcat, the plane that held the line against the Japanese prewar elite pilots in their Zeros through the dark days of 1942 in the Pacific, was successful in the Atlantic and over Norway and was actually the first US built fighter to down a German plane in WWII
Well, according to this account, which seems to be informed, the Russians didn't use the P-39 against tanks at all:
"Contrary to popular myth, the P-39 was not employed as a "tank-buster" for two very good reasons: the M4 37mm cannon was slow-firing and only had 30 rounds of ammunition, and the Soviets never received M80 Armor Piercing Shot ammunition for this cannon through Lend-Lease. (Even had they received AP ammo, it was only capable of penetrating 1.0 inches of armor at 500 yards. After 1943 there weren't many German tanks that vulnerable, especially from the top quadrant.) Our government did deliver approximately 1.2 million M54 High Explosive shells, however, and
Soviet P-39 aces put them to good use against both air and soft ground targets." (From
Bell P-39 Airacobra - Fighter Airplane Used by Russia in WW2).
At Kursk, where the Germans lost a lot of tanks, the Russians used Il-2's, which claimed a lot of tank kills but which may have been ineffective. The Wikipedia article on the Il-2 says this about German tank losses in Russia (after reporting impressive claims by Il-2 pilots):
"... Other studies of the fighting at Kursk suggest that very few of German armour losses were caused by the IL-2 or any other Soviet aircraft. In fact, total German tank losses in Operation Citadel amounted to 323 totally destroyed, the vast majority to anti-tank guns and armored fighting vehicles.
[24] In addition it is difficult to find any first-hand accounts by German panzer crews on the Eastern Front describing anything more than the occasional loss to direct air attack. The vast majority, around 95%–98%, of tank losses are due to enemy anti-tank guns, tanks, mines, artillery, and infantry assault, or simply abandoned as operational losses like mostly happened during the last eleven months of the war."
I don't claim any particular knowledge of this myself, but a quick scouring of the internet turns up several sources saying the P-39's that went to Russia never had anti-tank rounds. It does seem clear that the Russians used them mainly as fighters and for ground attack against soft targets. They weren't of much use in Europe because of their poor high-altitude performance, but that wasn't important in Russia.