I'm building a clipped wing Goldberg Cub to hopefully fly as an aerobatic trainer. I'm thinking about putting a .91 magnum 4-stroke in it. For my application, is this a good engine choice? I've already read a lot of posts on this subject and consensus seems all over the place.

Thanks,

chris

That will blow the wings off it.

An OS 70 or Saito 72 is an ideal combo for the CGM Clipped wing cub. You really don't need any more that that.

I fly my cub with Mag 52 fs. Not a hot rod but does what I tell it to!!! Want scale or mind bender.

How about a .61 magnum 4S? Will that be enough to pull it vertical? I like the .61 better because it weighs about 7 oz. less than the .91.

Geek:

Personally, I'd go with either the Magnum 61 4c or the Saito 72, which I think is lighter yet, as well as more powerful.

Hard to beat the Magnum for overall cost of operation, though.

Bill.

I've got a CG cub, with the full wing. I originally had a Saito 72 in it, and it was very over-powered. It now has an Enya 53 and still has plenty of power. I think anything over a 72 is just added weight.

fun airplane
Larsen

I've had three Goldberg Cubs with an OS 70 in each. Recommend the OS or the Saito in the 70 range. I don't think you'd be happy with anything larger.

I have a Goldberg clipped wing Cub. I initially installed an OS70FS and was very happy with its performance; it will knife edge horizon to horizon if that's your cup of tea!

I then fitted (couldn't resist it!) a OS FS91 series 2. Strangely, performance wasn't that much better; maybe something to do with all the extra tail weight I had to add.

So I have now refitted the OS 70. It's a fine plane/engine combination which I still enjoy flying from time to time. I love tootling around with it like a trainer and, when I get bored with that, letting rip with some nice low slow or four point rolls or sustained (low!) knife edge. I'm an ex pattern flyer and my clubmates often say that they didn't realize a Cub could do these things! Believe me, the CG Cub can!

Another vote for the 70 size Fs. Mine has full span wings and it takes off after about 5 foot run. I put a tiny O.S. .48Fs in one for a friend. It flew very well. Another choice would be a YS .63Fs.

Dru.

Even a saito .65 works great. Almost vertical. You could also consider Saito .80, Enya .80, or YS .63
Don't consider the magnum .80...way too heavy. .90s are too much .52-.53 may be a little too close to scale for you.

I have always been in the more power the better group, but on that particular plane, I fly it with a saito 56 and wouldn't put more than a 70 on it. Like everyone else said, the 91 would tear the wings off and it really wouldn't be a fun plane. It is great with the 56, a 70 would be a little better, but 91 is way too much.

i would say a YS-63.....i have one on a GP cub and it is super.