Here's just what you need:

http://www.rcuniverse.com/forum/m_67...tm.htm#6738262


But you need to keep in mind that WWI engines only generated around 1,500-2,000 RPM and because of this they used props that were much larger and with much higher pitch than we can use with with our 4-stroke engines (let alone 2-strokes). For example, the Saito 72 in my Snipe can reasonably turn a 14/5 prop. But a scale sized prop for the Snipe would be more like an 18/11.

So really all we can do it make a nice dummy prop for static display and pick a flying prop for its suitability to the engine. The exception to this would be systems that use a belt drive or the RCV SP engines that because of their novel design can spin a larger prop.