I had functional drop tanks on both of my turbine Interceptors.

Luer lock connectors (with the locking ears removed) for the fuel connection between the airplane and the tank.
A servo operated Dzus fastener to lock/release the tank at the front end, and a simple hook on the back of the tank.

Worked great, but the tanks did get a little beat up from dropping.

On the second one I rigged up a time delay parachute, but that added a lot of weight to the tank and it only worked about 40% of the time.