When I was a kid, several centuries ago, I knew this older boy who got the brilliant idea to create a self propelled kite. He attached a 0.89 glow plug model aircraft engine to the top of the kite, with a small fuel tank. After finally getting it to start, he cranked the throttle wide open and launched the kite into the air. It climbed in a circular spiral until the wind caught it. We never say it again. The boy resolved never to do that again without a string attached. The moral of the story was obvious, "It went out of sight and he put it out of mind"!