Good lord, won't this urban myth EVER die.
Air attack against tanks on the western front was almost entirely ineffective (I suspect it was similar on the eastern front, but don't have the proof to back it).
From "Flying Guns: World War II' by Tony Williams:
"The fighter-bomber pilots pressed home their attacks with great
courage throughout the campaign despite the often ferocious light FlaK
which caused loss rates far above those experienced by fighter units
(one Typhoon squadron suffered 100% casualties in an eighteen-month
period). They were confident that any German tank they spotted was as
good as dead, and they earned a considerable reputation for tank
killing, with substantial claims being accepted. However, British
operational research (OR) carried out at the time (but not publicised
for obvious reasons) presented a more complex picture. As the Allies
were advancing, intelligence officers were often able to examine a
battlefield shortly after an air attack, and what they discovered
causes controversy even today. (Much of this section is taken from Ian
Gooderson's "Air Power at the Battlefront", which explores this issue
in great detail).
The evidence gathered by the OR teams indicated that very few tanks
were destroyed by air attack. A British War Office analysis of 223
Panther tanks destroyed in 1944 revealed that only fourteen resulted
from air attack (eleven to RPs and three to aircraft cannon). During
the Mortain battle of 7-10 August, the RAF and USAAF launched
sustained attacks on a German armoured column over a period of six
hours, claiming 252 German tanks destroyed or damaged in nearly 500
sorties. It was subsequently discovered that there had only been a
total of 177 tanks or tank destroyers deployed by the Germans and just
46 of those were lost, of which only nine could be attributed to air
attack (seven to RPs and two to bombs). During the German retreat from
the Falaise pocket later in August, the RAF and USAAF claimed 391
armoured vehicles destroyed. Shortly afterwards, the battlefield was
examined and only 133 armoured vehicles of all types were found, of
which just 33 had been the victim of any sort of air attack. In the
retreat to the Seine, large numbers of armoured vehicles were left
behind and Typhoon pilots alone claimed 222 destroyed, but only
thirteen out of 388 AFVs examined were found to have been knocked out
by RP attack. In the Ardennes salient, just seven out of 101
knocked-out AFVs were definitely or possibly attributed to air attack,
compared with claims for 90. It should be noted that in the prevailing
circumstances of a continuing retreat, there was no question of the
German Army having recovered any damaged tanks in these later actions,
in fact the battlefields were often littered with undamaged tanks
abandoned by their crews.
One source estimates that probably no more than about 100 tanks were
lost due to hits from air weapons during the entire Normandy campaign.
In contrast, the RAF's 2nd TAF (including elements of the Air Defence
of Britain which took part in the campaign) and the USAAF's 9th Air
Force lost over 1,700 aircraft between them.
The ineffectiveness of air attack against tanks should have caused no
surprise because the weapons available to the fighter-bombers were not
suitable for destroying them. Put simply, the heavy machine guns and
20 mm cannon were capable of hitting the tanks easily enough, but
insufficiently powerful to damage them, except occasionally by chance.
The RPs and bombs used were certainly capable of destroying the tanks
but were too inaccurate to hit them, except occasionally by chance."
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You throw in the fact that, to bounce a .50 cal bullet off a road, into the belly of a tank would involve deforming the bullet, dumping much of its energy into the road and then hitting the belly armour of the tank at a very shallow angle and frankly, the idea is so absurd that I have no idea how it has survived this long.
