At the tender age of nine years I recall building a balsa wood somethingoranother that was powered by one of those Jetex engines. After three months of my mother complaining about wood shavings, dust, and the smell of shellac... it flew for the first and only time. It was a fantastic flight, but the whole thing went up in flames. The engine was still burning (and thrusting) after it departed the aeroplane. Forty six years later, and retired from flying the real thing, I'm considering trying it all again.
PS: I still have the scar on my hand from where I was burned by trying to handle the Jetex carcass shortly after an engine test burn... the engine being held in the jaws of a pair of pliers! I somehow doubt that kids of today would be allowed to purchase anything even remotely similar to Jetex pellets!
TCF