This manual provides you with safety operation information about the engine, including preparations before operation, installation, starting, adjustment, etc.
This manual provides operating instructions and safety warnings for the O.S. MAX-91SX-HRING C Spec engine, a high-performance internal-combustion machine designed specifically for F3C competition helicopters. It emphasizes that the engine is not a toy and requires careful handling to prevent injury from rotating parts, exhaust heat, or carbon monoxide.
| Intended Use | Model helicopters |
|---|---|
| Fuel Requirement | At least 18% lubricant by volume |
| Recommended Fuel Additive | 10% to 30% nitromethane |
| Glow Plug Type | O.S. No.8 |
| Mounting Screw Size | 4mm or 4-40 steel Allen type |
A fuel containing 10% to 30% nitromethane is preferable for the best throttle response.
The fuel must contain at least 18% lubricant by volume for consistent performance and long engine life.
The engine comes with an O.S. No.8 glow plug installed.
No, the engine was designed specifically for model helicopters and should not be used for any other purpose.