RE: Too much engine for Hog Bipe??
 

The plane was designed for a .61 two stroke. It will not give unlimited vertical, but will fly it fine. The .91 two stroke should be able to give you the unlimited vertical you seek. Just be sure the engine and muffler are not over about 26oz and the balance should be manageable. Personally I think a bi-plane has to have a four stoke in it for the sound.

RE: Too much engine for Hog Bipe??
 

Yeah, I can understand that point of view too. The Saito 1.00 weighs in around 20.9 oz while an OS .91FX is about 24.3 (both weights with mufflers). The Saito puts out about 1.8 hp while the OS throws around 2.8 though, from horizon and tower's specs. I'm interested in power and lower maintenece, however I don't want to be flying an engine around. Can't beat the sound of that 4 stroke, but is it worth the power loss and US$70.00? I'm undecided.

RE: Too much engine for Hog Bipe??
 

The Saito 100 will swing a 15x6 APC real well, around 9,500 rpm, and that is a great prop for the plane. It will give you unlimited vertical if your plane is not an overweight brick. The OS 91 FX will swing a 15x6 APC real well too, around 10,000 rpm. I would not recommend going with a prop larger than 15" to be sure you have good prop clearance. I like both the 15x6 and 15x4W APC props on the hog. My TT 91 4-stroke likes the 15x4W a little better so that is what I use now. Another club member has an OS 91 4-stroke with the 15x6 APC on his hog. We can fly around side-by-side and both go vertical, but his drops off when mine keeps going. He gets a good couple hundred feet before that happens though.