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!