Great choice for mid-power rockets
I have used these engines in a modified (for black powder E engines) Quest Green Machine, the Estes Mean Machine, and the LOC/Precision Blaster, and this is a great engine! Fast off the launch pad and very reliable, this is the engine to get for E power in a black powder motor.
Decent Engine
Although we love more power, the E12-6 is not always the best bet for a 24 mm engine rocket. If your launch area is too small, you are most likely going to lose the rocket. If you want a better option for a small field, purchase D12-3.