OS 30 Four Strokes
 

I have finally mounted my two FS-30S on my twinstar. I only have about 3 tanks (~15 oz) through them. I am using wildcat 10% blended with 3oz of Sig castor added for the fuel.

when I first fired them up, I ran them for about 20 seconds to warm them up, then went WOT and leaned them to about 9.8K RPM, but still smoking really good and ran like that for 5 minutes or so. My next run lasted about 5 minutes at about 10.1K RPM. Third run got to 10.2K and flew the twinstar .... WOW, what a sound! It was almost a cross between a B-26 and a Cessna 310.

The third and 4th flights got a bit leaner with my final flight getting 10.6K RPM or so.

The main needles on these engines have silicone tubing sealing the threads against the carb barrel. This makes fine tuning the high end a bit tricky since the silicon tubing has a tendency to 'spring back' the adjustments. This mean in order to get the adjustment I'm looking for, I have to go past the point where I want the setting and let the needle settle back. ?So while tuning I got the engines to peak past 11K RPM.

Once these engines have 1/2 gallon or so, I will get some sustained peak numbers and post them.

These numbers were all gained with Master Airscrew 9.5x6 sanded and balanced, no spinner, approx 80F and 1000' altitude.

This is adequate power for the twinstar, but it would need a LOT more engine to fly any hot-rod stuff. It flys like a heavy bomber. And when the throttle is pulled out, boy does this bird come down! This will take a bit of getting used to, I have to actually fly the airplane instead of aiming it!

anyone else have numbers on the FS-30S?