flew a scratch built rocket, "Frankenstein", using a homemade, experimental motor. The motor, rated as a J260, used an eroding nozzle to alter the thrust curve. At liftoff, through the smallest orifice, the motor would produce the greatest thrust. As the flight progessed and the nozzle opened up, the thrust would drop off and produce a longer burn. The motor had performed well during a static test fire and functioned perfectly for the flight. Unfortunately, the rocket turned out to be unstable. The rocket had been damaged on a previous flight and repaired, but apparently the repair altered the cg/cp relationship enough to cause it to be unstable. The rocket left the pad beautifully
, but at less than 100 feet it decided to do a vertical 360. This certainly got everyone's attention! The rocket did another vertical, tight 360 then fell horizontal to the ground. The rocket suffered moderate damage. Moral of the story: after you repair a rocket, do another cp/cg check to insure it is still stable. Click here for a 3Mb video
of the doomed flight.