ORIGINAL: Varad
it worked very good for mine (real tailheavy with a .40) by taking the fuel tank out if you already built it and cut the wood support under the fuel tank and placing the battery there w/ a lot of foam rubber to keep it secure, then put the fuel tank back and it doesnt move at all. I didnt think id get it in there, but it does with an average 5 cell flat pack.
Thats what I was talking about
I had a AAA pack though so I did'nt have to do any cutting.
RCjon-- Don't worry about this being a radical design....lol. It will be easier to fly than your first trainer and you will also be able to fly it much slower.