cmsrp,

I'd have to check but I think it is a 12x4 or so. Believe me...the GMS 47 has more than enough for this plane. I flew it last weekend and the throttle spent most of the time just above idle. I am thinking of swapping out the stock tank for one half the size. One of my flights was 25 mins long and I landed under power. I still have some CG things to work out but its a fun plane and seems to be strong enough too. I did some high speed walls and it handled them fine.

Terry