If you have really problem with electric call me I can set you up with with cheap brushless motor. The AstroFlight is not way to go.
I have only electric models:
7 lbs. /Hacker B50 10L w/6.7:1/20x11 prop/ 16 cells=unlimited vertical
See the video of Diablotin Super:
http://www.espritmodel.com/images/diablotin1.mpg