aspeed,
No muffler pressure, just suction feed.

Tony,
I know the bladder will work better. I built these for fun so I'm not to concerned. It will turn pretty good. It's just funny to be able to cut it and listen to the engine sag.
I have some 5x3 and 5x4 props for the engines because we also have an Ace GLH pylon racer with a Norvel in the works. It's replacing my son's Sig Hummer we wore out. My son has been flying stunt kites since about 1999- 2000. He can fly most anything but he hesitates to fly one of my full size stunt models. He says he doesn't want to tear up one of my big planes. I got the Hackers to let him fly something that cuts quick and he can work on the pattern. I am finishing up a Midwest ME109 for him because I know once he tries it he will like it.
Thanks for the suggestions!