I asked Dave how to add weapons on the payload stations:
"Hi Dan
You need to set the weight for payload station 4 to 1610 lbs to get the torpedo to show. The full set of payload weights is as follows:
station.0 = 200 lb for the pilot (set by default)
station.1 = 260 lb for starboard rockets and rails. Set to 50 lb for just the empty rails.
station.2 = as above for port rockets / rails
station.3 = 200 lb for the observer / gunner
station.4 = 1610 lb for the torpedo. Set to 50 lb for just the empty cradle only.
Rockets & the torpedo are only availabe on the Mk VIc and Mk X, not the Mk VIf night fighters.
Hope that helps.
Dave."
To drop the torpedo you have to add this to a saved flight file (*.flt)
[DroppableObjects.0]
ObjectSet.0=Torpedo, 1
See manual for the rockets. Of course you can add more than 1 for several drops, alltough that's not realistic :-/
