I have just added to the plane a 6ch reciever to a 4ch radio. Which means extra servos! For now im testing a torpedo bomb with a parachute. It is basic and can be upgraded to fire rockets: the drop and ignite type. and this might be the best for my rocket.
Basically, the release is a piece of plastic film wrapped around the torpedo and the end is attached to the wing by masking tape and the other end is placed about 1mm into a slot i cut into the wing a piece of string is attached to the middle of the film. The servo is attached to the string and voila. servo pulls string, pulling the film and releasing the torpedo bomb. here are the pics.
Wing, torpedo wrapped with the parachute, and unwraveled parachute. these are large hi def photos.