Dwight, I'll comment after dinner. Hold that thought!


Ok,

here's my "flying by the seat of my pants" engineering rationale. I annotated the plans with weights and power somewhat based on an educated guess. Having said that, I think that a good rule of thumb for glow powered models is about 0.15 - 0.25 bhp/lb. This translates to about 150W/lb (0.2 bhp/lb) and has electric motor equivalences. I would say that a typical aerobatic electric powered model calls for between 120-140 W/lb. 150 W/lb and above is getting into the 3D space.

I would imagine that the specs on your 15 FP are about 0.4 HP@~15Krpm (~300W) which translates to a good power source for a 2-2.5 lb aerobatic model. So... it all depends on how light you build your Picorare, whether it has retracts or not (or landing gear at all for that matter), whether you have an efficient/powerful exhaust system and what performance you expect from your model.

With that very sophisticated computational analysis out of the way, I would have to say, using your word, it would be a dog. I have rarely seen a model perform particularly well (certainly not pattern aircraft) when powered with the low end of the engine displacement range called for.

In short, I would suggest that if you want to use a .15, an OS .15 CV-A (0.5 hp@18K spec) or similar (Magnum, etc.) would be better. Perhaps better yet would be a K&B .18 aero (1.15 hp@18K w/ TP and 30% nitro !!). Neither of these engines will produce the power claimed but you might be moving into the 0.5-0.6 hp (300-450W) range and your model would now have a serious bark! A .21 may be overkill both on the power and weight/size front unless it was an older engine with lower power output.

BTW, it is possible to install retracts and a pipe on this little pocket rocket. Haven't done it yet but it's all been studied .

http://www.osengines.com/engines/osmg0715.html

http://www.mecoa.com/kb/aero/aircraft.htm

Cheers, David.