Please, read this:
http://operationbarbarossa.net/Myth-...hbusters4.html
"During WWII, the large majority of aircraft attacking tanks with aircraft mounted weapons used 20mm cannon or simply HMGs. These include aircraft such as the Supermarine Spitfire, Hawker Typhoon, Hawker Tempest, De Havilland Mosquito, most Ilyushin Il-2s and Il-10s (some had 37mm cannon), Yakovlev Yak-7/9, Petlyakov Pe-2/3bis, Lockheed P38 Lightning, North American P51 Mustang, and the Republic P47 Thunderbolt. The average 20mm cannon with standard ammunition had
great difficulty penetrating the 12-15mm top armour on the Pz IV H, and almost
no chance against the 16mm top armour on the Panther and the 25mm top armour on the Tiger I, even if they managed to hit them! The reader should also bear in mind that on average the strike angle of cannon shells on the top of AFVs was usually in the region of 30 to 60 degrees, because
aircraft could not attack vertically downwards (the Ju 87 Stuka came closest to this ideal attack angle, which also dramatically increases the accuracy of any air launched ordnance). In general 20mm cannon only inflicted superficial damage on even light tanks, with the most severe damage being penetrations through the top engine grill covers and damage to the engines."
"German fully tracked AFV losses on the East Front from 1941 to 1945 amounted to approximately 32 800 AFVs. At most 7% were destroyed by direct air attack, which amounts to approximately 2 300 German fully tracked AFV lost to direct air attack, a portion of which would be lost to other aircraft types such as the Petlyakov Pe-2. From 22nd June 1941 to war's end, 23 600 Il-2 and Il-10 ground attack aircraft were irrecoverably lost.(21) Whatever these aircraft were doing to pay such a high price it wasn’t destroying German tanks. If that was there primary target, then over 10 Il-2s and Il-10s were irrecoverably lost for every German fully tracked AFV that was completely destroyed by direct air attack on the East Front during WWII.
"
WW2 aircraft guns had low armor penetration capability. The GAU-8 Avenger, even with uranium rounds is only capable of penetrating 69mm @ 500m. (only 38mm @ 1000m) The Hispano or the VYa is nowhere near to this monster gun.