The Type B gearbox most popular gear ratio is 2.58 to 1. Ratios of 2.24 and 2.0 to 1 are also available where a smaller diameter must be used or more speed is desired. This gearbox is designed for Rotax 447 and 503 engines. Normally, the maximum prop diameter for a Type B gearbox is 68" x 2-blades or 64" x 3-blades. Anything larger and the engine will idle roughly below 2,000 rpm or will be hard to start. For more information on the effects of prop inertia, see Measuring Prop Inertia, Rotax Service Bulletin #11UL91.
The B gearbox weighs 9.9 pounds.