ORIGINAL: suzonka
I have a nice canard and just mounted a BB 25 engine in it stock muffler and engine LEO, its a powerful little motor ,I have 2 props to work with a zinger wood 8x6 pusher and a nylon tornado pusher 9x6 ,question which prop will perform better with this engne and plane 48 inch wing. weight aprox 3.5 lbs.
Looks like nobody has a firm answer for you, 0 replies so far, well one now. Hard to say which will work better, but I would be tempted to try the 8-6 first, mostly because the 9-6 seems on the larger side for the .25, and in a pusher configuration during start up and tuning the lighter load of the 8-6 will result in a bit cooler running. Also the 8-6 will allow the engine to run a little faster and I thinkthis will allow it to generate a little more horsepower, I doubt if the power peak favors the 9-6. If you have a regular tractor 8-6 or 9-6, you can always install that for the first run of the day to get the needles set the way you want, then switch to the pusher prop for flight. Some people do that so they do not have to worry about heating up during extended ground running, but you should use the same size of prop to get the same load on the engine. Of course, running for a short while on the ground in pusher configuration is not a big problem.