So, the obvious question is, What is the correct angle to attack from?
Since the armour has been toughened up(twice actually) 50cals and 20mms are pretty much ineffective at any angle under 30~40 degrees.
Ofcourse, since usually there's like 5~6 aircraft spraying their entire ammo load when there's a single Panzer around, eventually all the 20mms and 50cals landed would knock out the engine, or detrack a Panzer. But compared to what it used to be, one may say that the tanks are pretty much safe from 30cals~20mms.
Empirically, it seems to take continued strafing of over 50 degrees angle, hitting on the top armour of a Panzer, to disable it. Anything less will most usually bounce.
In the case of the 23mms on the IL-2, it will destroy a Panzer if it dives down at 45+ angle and lands consecutive cannon hits at the roof top armour. It will disable/damage the Panzer at any angle, as long as it is not the front armour.
Same with the 40mms on the Hurri2D. High-angle roof top hits will kill a Panzer, and most other low angle shots will disable a Panzer as long as it is not facing the frontal armour.
Tigers are pretty much safe from everything except direct bomb hits. An IL-2 might detrack it or damage the engine if it continues to strafe it from the side or behind, but Hurri2D 40mms are pretty much ineffective at any angle.
