SAITO FG-21 is a 4-stroke gasoline engine exclusively for model airplanes which is designed with emphasis on high performance, durability, and weight saving. This engine is modified based on existing FG-20 gasoline engine, equipped with renewed ignition system. For the airplane on which FA-125 is installed, FG-21 can be replaced easily with minimal change such as fuel tank and lines to gasoline resistant ones.

Displacement: 20.9 cc
Applications: 4-stroke glow 1.00-1.10 class
Bore: 32.0 mm
Stroke: 26.0 mm
Motor weight: 690 g
Muffler weight: 83 g
Ignition system weight: 113 g
Engine mount weight: 156 g
Practical RPM: 2000-9500
Max RPM on Ground (stationary): 9000-10.000
Propeller: APC 15x8" - 16x8"
Static thrust: aprox 3-4 kg
Fuel: Regular gasoline & oil = 20:1 (volume ratio)
Fuel consumption: aprox 15 cc/min (@ full throttle 8800 rpm)
Battery for ignition system: 6-8V with more than 1Ah is recommended