I can not give a proper answer but I will add two things in the hope that they may solve your challenge:
#1. Do not use a Bf109-3B
(they will not explode no matter what you do... actually there is a way to make them explode but it is not a realistic solution).
#2. while airborne, press the key to ARM the bombs. Otherwise the ignitors remain inactive and the bombs will drop without exploding.
~S~
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