What do you guys think about a 2 stroke .91 magnum on my ultra stick .40 The 46 fx doesn't have near enough power for me. I think it would be fun.

the plane will be torn apart.......... period. Need more power? pipe it or go to a better engine, or up the engine size to a 50 or 58.
d

Bad idea for a couple of reasons. The first is that it will rip it apart and make an unsafe model anyway. the second issue would be that you would have to jack the landimg gear way up to get the needed prop clearance(look silly) and the third you would have to add so much weight in the mod like the extra weight of the engine, necessary weight in the tail to balance it out, added fuel capacity to get a decent flight that the plane would be so sluggish and heavy with a huge wing loading that it would be a real turd to fly, not to mention not fun!, and lets not forget that the servos would need some beefing up do deal with the extra load! I would suggest the same as the last post, pipe it or make a slightly larger engine selection, a .60 while not out of the question would be on the high don't go any highr side. Good luck!

Chris

Have you tried some different props to see if they might give you performance more to your liking?

I've got an Irvine .53 on my Ultrastik, and I think it's plenty. A .90 is a lot of engine, and probably far too much for the airframe unless you do some serious reinforcing. Somewhere along the line you get to the point of rapidly diminishing returns, where the weight penalty kills the benefits of the extra power.

If you are looking for lots of speed then you may want another airframe.

I don't want a ton of speed just some more and I happen to have a 90 sitting around needing a home. I have tried every prop from a 10-6 to an 11-9 to a 12-8 and everything in between I run an 11-7 and it seems to be the best all around.

You might want to try a 12.25 x 3.75 APC. I had that combo and seemed to like the way it flew. It had more pull in the vertical.

BINGO!!!!!! Stay away from that heavy iron you're talking about as the airframe just hold up.

If you are bound and determined to get more speed out of that airframe and don't mind spending some money,you might want to try a K&B 61.They don't weigh much more than most 40's and produce quiet a bit more power.

Bill

My dad just bought an ultra-stick for christmas (for himself) and he bought a 70 4-stoke. He thought that would be enough power for him.

Airplane_boy