Inside the combustion chamber the cotton igitor should immediately burst into flame in the oxygen atmosphere. The operator may have difficulty ascertaining that the cotton is actually burning although small flaming bits of material may be ejected from the nozzle. The fuel control needle valve is now opened very slightly to allow fuel to flow into the combustion chamber. A flame should immediately appear at the nozzle exit and a low whistling sound should be heard. The oxygen and fuel flow rates should now be rapidly and simultaneously increased by opening the control needle valves until tie combustion chamber pressure gauge indicates that desired conditions Exist inside the chamber.
More oxygen is required if the exhaust is bright yellow or smoky.
Remember that as you vary the fuel and oxidizer flows you are changing not only the amount of material passing through the engine but are also affecting the temperature of the burning gases. Both of these effects will affect the combustion chamber pressure. The noise from the engine will he quite high, but it is a good indicator of engine operation. It may be necessary to wear ear protection because of this high noise level. The operator should have a timer or have someone time the engine run.