Responding to creative model enthusiasts with high quality stable products has been our unchanging policy. FR7-420, its pet name “Sirius 7”, 4-stroke 7-cylinder glow engine is a new symbol of O.S. carefully designed down to detail, not only for exterior appearance but also for mechanical performance and realistic exhaust sound. We are quite confident that FR7-420 will win modelers’ trust and satisfy them.

V-shaped valve layout matches various scale model airplanes.
Main internal parts such as crankshaft, wrist pin, cam holder and reduction gear are all plated for anti-corrosion. Selected material and proper thermal treatment ensure high durability of the parts.
The inner propeller distributes balanced air-fuel mixture to each cylinder, which has realized long lasting stable idling