The reduction gear will make a big difference. The much more common direct drive versions require a small fine pitch prop that is very inefficient and doesn't allow the engine to get close to its rated power. With the 2:1 reduction you can use a larger more efficient prop. Powering performance should be similar to a diesel of similar power with the same reduction ratio, though fuel consumption will be much higher. I would guess over a gallon an hour at even reasonable cruising speeds.
Last edited by JimsCAL; 12-04-2011 at 10:20 AM.
Reason: fixed typo