OK, so now my little 625 sq. inch Slider has a RO-Jett .65. Hmmm, this is interesting. 625 squares, about 54oz and a really big engine. Seems right to me. Anyway, I've been experimenting with props. Problem is, it is a sort of little plane. So I can't just jump to a giganta-prop. I've seen everything from an 11.5" prop to a 14" on these things. The best so far seems to be an Eather 13 x 4 undercambered 2 blade. It's been depitched just a touch (maybe 3.8 or so). Wish I could find another one. I've tried several three blade props, but haven't found one I like yet. The best was a 12.5 x 4, but it was one that was de-pitched from 5 and I think it still has too much mid-blade pitch (my longer right arm was the first clue. That and the 4.2 second lap times). I tried a 13.5 x 3.75 3 blade, but the yaw was pretty bad. Seems much better with the 2 blader. I suppose what I really need is a 12.5 x 3.75 three blade, but I have found one that doesn't have really wide blades.

What are other's experiences with props for this engine when mounted on a relatively small plane?

Hey Randy,
think wood, yeah yeah,, call Pat he will tell ya'
lol
heck I don't notice a problem on my LA 46 Oriental with a 12.25 wide blade wood prop,, Im thinkin you could get Pat to hack you out a magic prop. lol
ok so I don't know anything about RO Jets,, but really, have you tried a wood prop, something like a 13 4 or maybe 14 4? I might even have one,,
or maybe you need one of my LA 46s to fly the thing, 


 but well,um  I am going back to hibernation now,, lol
well good luck with that anyway Randy, I will now hide,,

I've got two wood props to try. A 2.75 x about 3.9 made from a Zinger 13x4 prop kit and a reworked Rev-Up paddle blade THP at about the same size. I plan to try them out soon. If the weather will cooperate.(that would be a 12.75)

Mike,

I'm running a pipe at about 18.5" and the launch RPM is around 9800. It runs in a hard 4 stroke all the way on the current best prop (a 13.25x3.9 UCT two blade). I keep trying to use a 3 blade, but I tend to get some tail wag (yaw) in hard corners with a 3 blade. I've tried as small as a 12 x 4 three blade and still lose the sharpe corners and get the wag. Doesn't do it with the 2 blade. But the three blade as a bit more authority about 45 degrees. Sigh... Everything is a compromise, I suppose. I haven't found THE prop yet, but has a couple that are close. More testing this weekend if the weather will settle down a bit.