I have a tower heavy duty starter rigged to a $15 7 amp gel cell from Academy and it has no trouble starting my Saito 180.

On another note, I'm thinking about getting the 40 size UCD and I have a few questions:

1. Is there very much coupling in knife edge?

2. Can it do knife edge spins?

3. I was going to put a Saito 82 in it, but is anyone flying it with a 91 size 4 stroke?
A Saito 91 for example weighs less than an OS 70, about 20 grams more than the 82, costs less than the 82, and can swing a bigger prop.