The WGr210 were essentially airborne mortars which propelled a arty grenade. Accuracy was very poor but when fired in large numbers they could have some effect on the formation, especially in scattering the formation thus reducing the effectiveness of defensive fire. One may call it a airborne AAA installation, a first indication of what lay ahead in military aviation (guided missile systems). The WGr210 was designed to be fired from outside the effective range of bomber defensive fire, some 1500 yards or so from directly behind the formation. After this initial mortar attack the fighter formation would break up in smaller groups to attack with guns. Sometimes the Luftwaffe units attacked in a coordinated manner, one fighter formation attacking from the rear with rockets and another one from above with guns. The bomber formation trying to reduce the hit probability of rockets by spreading out, would more easily fall victim to the fighters attacking from above. If the formation stayed tight, the rockets could potentially have a devastating effect. It happened that one rocket knocked out 3 bombers by hitting and exploding the bomber in the middle and seriously damaging the outer two on each side forcing crews to either bail out or turn back.
Once the bomber escort fighters were added to the equation, all zerstörer groups were easy prey and had to be protected by their own escort severely reducing the effectiveness of Luftwaffe fighter formations.
And yes, the weapons installation had adverse effects on aircraft handling and performance much like you described.
< Message edited by Turner -- 11/16/2011 12:48:19 PM >