Hi! we are two Italian students of aeronautical engineering.

We are designing an UAV (Unhamned aerial vehicle) for our graduation thesis, and we are searching informations about the specific fuel consumption of the engine "OS .91 FX" (the engine chosen for this project).

We are still in the preliminar phase of this project and we desperately need some information for the first calculations of endurance (we still haven't bought the engine and the UAV doesn't exist... we have only the mathematical and virtual model ).

Could someone help us please?

Thanks a lot!

Full throttle lasts aprox 12 min for a 12oz tank. - Easy math, 1 oz per min.

Times will vary depending on fuel mixture and RPM / Prop selection/ Altitude/ Condition of engine, ect.

Of course, you might get better fuel consumption with a 4-stroke...

I would think the Engineers at OS could give you some viable data.

Good Luck.

I would also agree with the 4 stroke recomendation. I would think for a UAV in the 90 sized range that a 4 stroke would be a better choice for lower fuel consumption and more reliability (dont bash me on that one, I think 4 strokes tend to be more reliable especially at idle).

Plus they sound cooler!

Go electric.

Diesel would be the best.

What about nuclear?

A few years ago I flew a "project" airplane with a lot of electronic equipment in it...TT Tiger 60 w/ an O.S. .91 FX 2 stroke.

We had a 32 oz. tank in it and would have approx. 35 to 40 minutes duration with a few minutes reserve. I flew at probably 2/3 to 3/4 throttle most of the time, because the plane was heavy...about 15 lbs.

We used APC 13X8 or 14X6 props, Wildcat 15% fuel, and O.S. #8 plugs...
Engine ran just fine in 50 to 90 degree weather, rain or shine...