USING AUTOMOTIVE DIESEL ENGINE PUMP FOR FUEL/OXIDIZER INJECTION

A disadvantage of such pumps is that they're high-pressure/low-volume pumps. NOT what you need for a rocket motor.

Weight, complexity, failure modes.

Please not the X-1 did not have pumps, but used compressed (nitrogen?) gas to pressurize the fuel tank. I think the oxidizer tank was self presurizing.

Look at space ship one, I believe I saw Nitrogen tanks in there as well, for the same reason.

My first thought would be the weight involved... unless of course you're building a vehicle to carry something the size of a Hummer into orbit...!!!

Igniting rubbers? Is this a new kind of "safe rocketry" hybrid? :)

Well, a few problems... one, the flow rate is going to be much too low for even a small rocket engine; two, a diesel pump will deliver its output in a series of intermittent pulses when what you want is a continuous flow; and three, the materials of the pump will not be compatible with hydrogen peroxide: it will corrode, and decompose in contact with, the bare steel surfaces which are exposed to the fluid inside such a pump.

If you want a simple static test setup to fire liquid propellants, the best bet is a pressure-fed system with no pumps at all: just use tanks strong enough to contain the desired engine inlet pressure, and use an inert gas like nitrogen to pressurize the ullage volumes and force the propellants into the engine. (Some engines for static firing have been designed to use gaseous oxygen, which can be regulated to the desired pressure from a standard welding tank.)

-dave w