As a kid I built an Estes "Scout" model. It didn't have a parachute and was recovered by tumbling back down to earth once the engines ejector charge went off and shifted half way out the rocket, making it unbalanced. It worked as intended, a few times. On its final voyage, the engine did not eject, it stayed in tight. I then heard this loud whistling, it was coming straight down, FAST. It buried itself in the ground as I ran away.