Now what I'm talking about is this particular model that we've assembled. There are certain engines that you want to fly it with, and the manufacturer suggests certain types of engines. This particular model, the manufacturer suggests, suggest flying it with A83s, B42, B44, B62, B64, B85, and C65. Like I said in my previous segment those all mean how much impulse, or how many pounds of thrust, or kilograms seconds of, of thrust will be applied for how much time for a model. So it goes anywhere from five pounds of thrust about all the way up to twenty pounds of thrust, I'm sorry, ten pounds of thrust. I believe I got that wrong, twenty pounds of thrust. And that would be a C engine. The B engines are ten pounds of thrust. In this model we're going to select the B44 for its first flight. There is a recommendation to use a B62. B62 two seconds of tracking charge is very short for our first flight, and I want to be able to recover this model.