You can use the OS15 NVA from the FP 15. That is available from Tower. Altech dosn't answer emails you whave to call and Carol will take care of it for you.
Dennis

              I was using a OS needle for the 35-40 engines.This was working fairly well.My Enya III was a r/c conversion.My father had the 3304 model which came with 2 venturi sizes.I don't recall the exact sizes,but I used the larger of the two. The engine runs have been pretty effecient except for the end of the run. I get some real lean runs at times nearing the last few laps. I'm using a tongue muffler with muffler pressure on standard vent tank.I'm using a 2 inch oval which fits the nose real well. I might switch to uniflow after 1 more experiment. I recently picked up a FP .15 needle which I just installed. Its too cold to fly currently. I noticed the needle was identical but the spray bar was turned down considerably in the venturi area. I hope this means more fuel for me which might calm down the leaning out. In the event that you do try a FP .15 needle first,I'd like to hear the results. It looks like another few months for myself.                            Ken