Kris,

I just put a 91 FX on mine, and did some prop taching/thrust measurements.

43 degrees, very dry air.

APC 15/4 prop (not modified at all)

Stock muffler w/baffle

New OS#8 plug

Tank at the firewall (new engine to me, so I wanted to take out all variables)

Dubro final filter (large)

15% RedMax fuel.


Tached as high as 10,600, but ran best at about 9600-9900. Transition was much better than I expected.

Idle in the 1800-2000 range. Wobbled alot without the wing on, so I think it would consistently idle at 1800 in flight.

Static thrust was measured several times with a digital fish scale, and we took the average of them.

11.6 lbs at the lowest, and 12.4lbs of thrust at the highest over the course of 10 pulls at full throttle. This gave an average pull of 11.8 lbs of thrust on the plane/engine.

Throttle setting to pull 7 1/2 lbs is just under 1/2 throttle.

This is on a plane that is 7lbs 6oz. Can you say this thing is going to be a blast in the air???? Power to weight ratio is now 1.5-1 or so on a non broken in engine.


Once I get the engine tuned properly and a few tanks run thru it, I will start experimenting with it. Macs header, mousse can pipe, and a perry pump (to move the tank back to the CG again). I had an enya 80 four stroke turning an apc 14/4 prop and it would hover, and pull out, but very slowly.

Hope this helps.

Steve