Thunder Tiger F-91S
Engines & Exhausts / by Michael Smith / 36 views / New
£120.00
The Thunder Tiger F-91S is a robust, single-cylinder four-stroke glow RC aircraft engine known for delivering excellent torque-heavy performance. Produced through a design collaboration with renowned engineer Tatsuhira “Kaz” Mihara, it is popular for its high power-to-weight ratio and distinct deep exhaust note, making it a highly regarded alternative to equivalent OS and Saito powerplants.
Core Specifications
The F-91S outputs broad power across its timing curve:
Displacement: 14.97 cc (0.914 cu. in.)
Bore: 28.3 mm (1.114 in.)
Stroke: 23.8 mm (0.937 in.)
Practical RPM Range: 2,000 to 12,000 RPM
Power Output: 1.6 BHP at 11,000 RPM
Weight: 742.8 g (26.2 oz) with standard silencer installed
Design Features
The F-91S is easily identified by its signature black-anodised cylinder head. Underneath the casing, its engineering includes several unique design characteristics:
Valves & Cam: It incorporates a special gear-driven camshaft supporting oversized, center-inclined valves. This structural layout creates a highly efficient, oval combustion chamber to maximise fuel burn.
Cylinder Construction: It features an XC2 (extreme composite coating) nickel-plated cylinder liner etched with a special criss-cross pattern to ensure continuous oil retention and high durability.
Carbureation: It uses an updraft, twin-needle carburettor with an air-bleed system engineered for crisp throttle responses.
Corrosion Mitigation: The main crankshaft is dual-ball-bearing supported with a rubber-sealed rear bearing, and the shaft itself is nickel-plated to prevent rust from nitro fuel residue.
Please review the photos carefully, as you will receive the exact items shown. Only the items pictured are included; anything not shown is not part of this listing.
Condition: Unboxed, with signs of age and surface wear. Please see the photos. Any certificates or accessories not shown should be considered missing.
- Listing ID: 291297
- County: Hampshire