The ST770 is a 7-cylinder 70cc (4.17 cubic inch) radial engine with a speed range or 1,000 to 6, 000 revolutions per minute (rpm), using a 26-10 propeller. Its maximum speed is 6300 rpm. It burns methanol with castor oil mixed in for lubrication and is capable of producing 4.0 horsepower. This engine is 10″-long, 10″-wide, and 12″ high.