I like these motors! I know what you're thinking...why would you put a C motor in a D motor body? Especially one with such a high average impulse. Blink and you'll miss it takeoff followed by a low altitude flight. It's simple. The motors are cheap. Rockets are, by comparison, expensive (especially once you take into account the time spent designing/building them). Using one of these motors you can test just how far your rocket may drift before trying a full-fat D12 and therefore avoid losing it. They also make a lovely rachet at launch. Get a few for your D motor rockets.