The Saito FA-170R3 is a mid-sized, three-cylinder radial four-stroke glow engine known for its “Saito Sound” and smooth, scale-like performance. It is widely considered one of the best RC radial engines for medium-scale models, prized for its reliability and realistic exhaust sound.
The FA-170R3 is specifically engineered for low vibration and easy starting.
Displacement 27.8cc (1.70 cu in)
Bore 24.8 mm (x3)
Stroke 19.2 mm (x3)
Power Output ~2.0 HP to 2.5 HP
Weight ~1,345g (approx. 47.4 oz)
RPM Range 2,000 – 9,500 RPM
Firing Order 1-3-2
Static Thrust ~6.2 kg to 6.3 kg (with 15×8 prop)
Fuel Type Glow fuel (10%–15% Nitro with synthetic/castor mix)
Recommended Props 15×8 to 16×8
AAC Construction: Features a hard-chrome plated cylinder bore and a single-unit cylinder and head design for superior heat dissipation and durability.
Hemi Head: Utilizes a semi-spherical combustion chamber to improve volumetric and combustion efficiency.
Special Intake Manifold: Designed with a port-type manifold that equalizes the fuel mixture to individual cylinders, ensuring stable idling without the need for constant plug heating.
One Plug Per Cylinder: Unlike larger radials that may use multiple plugs, the FA-170R3 uses a single glow plug per cylinder.
Development: Building on Saito’s 1986 introduction of their first 5-cylinder radial (53cc), the FA-170R3 was developed as a “medium size” option for scale enthusiasts.
Evolution: It is closely related to other models in the radial lineup; notably, the FA-200R3 is a bored-out version of the FA-170R3.
Current Status: While highly sought after on the used market for its “mellow” glow sound, the FA-170R3 has largely been superseded in production by Saito’s FG (gasoline/petrol) series, such as the FG-19R3.
