Tornado

This is basically a cross between a helicopter and a rocket. I used two A3-4T engines, and it looked like it flew about 50-75 feet, but I didn't have a good way to measure the altitude. The idea is that the fan spins and this generates the lift, but the engines are on a 15 degree angle which also gives it a boost. The normal Estes 6V launching systems are a bit underpowered, and sometimes the igniters don't go off right away, so I used an 18V Milwaukee battery because the motors have to fire at exactly the same time.I used a 3/8 inch steel rod for this instead of a typical rocket launching pad so that even if one of the engines does fire slightly before the other one, the rod won't bend and throw it sideways. I designed the holes for the motors slightly too large and wrapped a few layers of tape around them so they are tight. (On one test they were too loose, and one of them fell out because the other one ignited a split second before the other.) I also put several layers of foil tape on the backs of the engine enclosures so when they backfire the engines will pop out without melting the plastic. Note: It is important to lubricate the steel bar.  I just rubbed it with a little bit of lip balm and that worked great.