The O.S. GF 40 combines the user-friendliness and efficiency of a traditional 4-stroke engine with a gasoline engine. Its quick and powerful response is ideal for scale, sport, and aerobatic models. The mounting points are identical to those of the GT 33 2-stroke engine. The carburetor was developed by O.S. in collaboration with Walbro® specifically for this engine.

Technical specifications:

• Cooling: Air
• Width [mm]: 83.7 mm
• Shaft thread: UNF-5/16-24
• Mounting holes lengthwise [mm]: 54 mm high
• Carburetor: WT GF 40
• Total weight [g]: 1378 g
• Height approx. [mm]: 157.2 mm
• Mounting hole Ø [mm]: 5.2 mm
• RPM range approx.: 1800 - 9000 RPM
• Bore [mm]: 40 mm
• Mounting holes crosswise [mm]: 70 mm
• Displacement [ccm]: 39.96 cm³
• Power kW (HP) at: 3.75 at 9000 RPM
• Recommended propeller: 18x8 - 20x10
• Length to hub: 118.5 mm
• Stroke [mm]: 31.8 mm
• Shaft Ø [mm]: 7.8 mm
• Brand name: O.S.
• Application area: Model aircraft
• Includes muffler: Yes
• Fuel: Gasoline
• Design: 4-stroke gasoline
• Manufacturer's article number: OS39400
• The O.S. GF40 engine operates with "regular" gasoline mixture 1:25.