The largest engine in the FX series boasts impressive bhp for its compact external dimensions. Its 'porting' has been optimised for low RPM's and is quite happy turning big props on a scale model or low diameter/high-pitch props on a pattern aircraft. The 'ringed' piston on this size of engine allows easy starting and has a forgiving nature when it comes to 'tuning' the main needle for optimum performance.

Specification
Weight: 925g
Propeller Range: 15x13-14 16x12-14 17x12-13 18x8-10 20x8
Displacement: 26.23cc (1.604cu.in.)
Bore: 33.6mm (1.323")
Stroke: 29.6mm (1.165")
Power Output: 3.7 bhp @ 9,000 rpm
Practical RPM: 1,800 - 10,000