Although feed system pressure loss for each propellant can be estimated using the Darcy Weisbach equation, as well as by using the Cv's of all fittings, it is still necessary to empirically evaluate the pressure loss throughout the feed lines for each propellant. For this test, the injector or an orifice fitting can be used at the end of the fluid circuit; using an orifice fitting may be advantageous if the injector has not been machined yet. The fact that the injector/orifice fitting will empty into ambient pressure does not matter as long as it the circuit is tested at various tank pressures. From these tests, we will be able to size our injector annulus/slits with better accuracy.