Placing the Bell P39 Aircobra.

[Franek Grabowski]

You put a tank on a range and you bomb it by all means until it is destroyed. Then you count warload spend and you have effectiveness. For example it was found that only a direct hit of Soviet RS-132 rocket could destroy a tank. It was found that none of 134 fired RS-132 hit the target during the test.

[tcolvin]

Originally Posted by Franek Grabowski

You put a tank on a range and you bomb it by all means until it is destroyed. Then you count warload spend and you have effectiveness. For example it was found that only a direct hit of Soviet RS-132 rocket could destroy a tank. It was found that none of 134 fired RS-132 hit the target during the test.

Well, that's exactly the same result obtained from an Operational Research analysis of rocket attacks on targets in the Breskens Pocket. 140 Rocket Projectiles had to be fired by Typhoons to give a 50% chance of hitting a Panther. But that was in battle conditions and not on a range without Flak, which was the test you are referring to. But the OR Report does not say whether the Panther was defended by Flak.
Intense Flak resulted in 2TAF refusing to attack heavily defended targets such as the Rhine bridges and Me262 landing strips. Effectiveness obtained on a range was irrelevant in such cases where it was nil. The Rhine bridges were never brought down by 2TAF, and were eventually destroyed by the Germans themselves.
In some cases Bombphoons dropped bombs under radar control through cloud. Then there was no Flak but it became a form of inefficient carpet bombing.
You have to take the system as employed on the battlefield, IMHO, and not results obtained on a range.