RCU Forums - 35% Extra

Quote:

ORIGINAL: F1race79
What prop are you running with BME 110?

I've been flying my BME 110/WH 330 combo for a year now, and could not be more pleased. Two considerations when choosing props are the amount of time you have on the engine, and whether you're using stock pipes or cannisters. Cannisters control noise better than the stock mufflers, and some cannisters (Pefa LL for example) additionally make more power than stock mufflers. I use the large Pefa LL cannisters (shamelessly copying performance work done by BME guru Kr*s). The WH Extra has the room to easily accomodate these cans, and there is NO weight penalty since this combination weighs ounces LESS than a DA with stock mufflers. BTW, an additional benefit is that since these cannisters need the shortest header length possible, the forward position of the cannister helps get the cg in the proper place. I use a rudder pull-pull rather than rear mounted rudder servos (and you must also) and I needed ZERO additional weight to balance the plane within the recommended range.

Getting back to your original question, if your engine is new, a Menz 27x10 is a good prop for break in. By the time you've got three gallons through it, you'll want to move to a 28 inch prop like the Mejlik 28x10 which offers excellent thrust and vertical performance. After 2 or 3 more gallons, my 110 continued to break in and make more power, and soon was ripping that prop like crazy. I went to the excellent Air Wild NX 28x10 that provided more load, excellent thrust, and better downline braking than the Mejlik, while being quieter than the Mejlik. Several gallons later, the BME continued to get stronger and now the NX28x10 was howling like a banshee. My prop of choice now is the Biela 28x10, which is very quiet, pulls like a bear, and has the best downline braking of any other prop I've tried. The main thing is that the Bemmer likes props that load it in the 6100 to 6600 range with 6400 to 6500 being optimum. Keep the airflow adequate and keep the mixture correct (no lean running) and use petroleum oils for 6 or 7 gallons before switching to synthetic, and you'll see the same performance increases as the engine "comes in".

The 110 is a HARD runner with stock mufflers, but the Pefa LLs are worth 200 to 300 rpm more than stock mufflers, which, on a 28 inch prop is POUNDS of additional thrust. Combine that with the fact that the engine is quieter, AND the cannisters help with balance so no "dead" weight is needed, the Pefas offer the best combo if you can swing it. I can post pics of my cannister install if you're interested.