This is a simple bomb drop which allows you to use a Tower Pro SG90 servo to drop one or two bombs. It includes two 'ears' to attach elastic bands to allow any small object to be dropped. It also includes a glue-able flange which allows many small objects to be converted for dropping.
The figure-8 shaped parts are to attach to an elastic band and allow it to release without binding.
A variety of stand-off lengths are included to allow for different clearances below the plane.
In addition to the printed parts, you need a Tower Pro SG90 or equivalent servo and two small pieces of wire (approx 1mm diameter). I inserted them into the second and third holes in a servo horn, then clipped the excess length off the horn. Elastic bands are optional.
I use a FlySky FS-i6 (equivalent to Turnigy i6) and connect the bomb drop to an auxiliary channel which I connect to Switch C, the three position switch - center is neutral and top and bottom positions each drop one of the bombs.