Yes and it is substancial and one only needs to look recommended props are for the 55AX and the forty six. The middle of the road reccomended sport prop for the 55AX is 12x7/8. This is even more propellor than most sixtys will pull and much more prop than either the 46FX (dicontinued) 46AX series 1 (discontinued with possibly some still in the pipeline) and the 46AX series 11 will handle. The 12x 8 is what I use on the Ultimate biplane I pictured in my earlier post.

At your elevations for two strokes 10% is fine 15% becomes much more desirable when density altitudes go past about 3000 MSL and over 5000 and up, 25% can make the differeance in even being able to fly.

Oh and the The 55AX is a drop in for the 46AX which means on your airplane there are no modifications needed at all.

You have never really made it clear if your listed options were existing engines or you were going to buy. Now if you opt for a 46AX you need to be sure and make sure you are getting the series 11 and not the series I. The series 11 is a totally different carburation system and in particular the midrange setup and the new one is far better than the old carbs of the FX series as alway of course just my opinion.



John