Turbopump Propellant H2O2 System
The hydrogen peroxide monopropellant (H2O2) used to drive the turbopump is contained in a 10-cubic-foot spherical supply tank with a capacity of 854 pounds (77.5 US gallons).
A swivel-type pickup feed line allows positive feeding of the monopropellant regardless of airplane attitude. The system includes a combination vent, pressure relief, and tank pressurization valve; a jettison valve; a hydrogen peroxide throttle control metering valve; a safety valve; a shutoff valve; and a gas generator. This system is controlled by switches and a control lever in the cockpit and is put into operation whenever the engine starting sequence is begun.
For a description of these controls, refer to "Engine Controls" in this section.
When the engine is not operating, the tank is vented to atmosphere if the vent, pressurization, and jettison control lever [11, fig. 5-4] is at VENT and control gas is available.
The tank is pressurized with helium control gas, to feed the H2O2 to the gas generator, which provides steam power for turbopump operation. Tank pressure can be read from a gauge in the cockpit. Refer to "H2O2 Tank and Engine Control Line Pressure Gauge" in this section.
The system also includes a jettison feature that permits the H2O2 to be forcibly expelled overboard.
Note: The remaining quantity of turbopump hydrogen peroxide can be monitored on the system monitor panel.
An amber H2O2 compartment-hot caution light [58, figure 5-1], on the instrument panel, comes on when temperature in the upper area of the turbopump propellant compartment reaches 538°C (1000 °F) or when temperature in the lower area of the compartment reaches 427°C (800 °F). When illuminated, the light reads "H2O2 COMP HOT". The light is powered by the primary DC bus and may be tested through the indicator, caution, and warning light test circuit.
An electrohydraulic servo system is used as an actuation and reference system between the turbine speed and H2O2 flow. Its main components are a power package, a governor, a throttle synchro, a servo amplifier, a governor actuator, and an H2O2 throttle control metering valve.
Pressurized oil from an electrically driven hydraulic pump is supplied to the governor and metering valve. When the engine throttle [12, fig. 5-4] (throttle synchro) is moved, the governor speed adjustment lever is set to the desired position by the governor actuator. The speed of the turbopump is sensed by the governor, and the hydraulic pressure balance between the governor and metering valve is adjusted to control peroxide flow into the gas generator.
Decrease or increase of the turbopump speed from that required for the selected thrust causes a hydraulic imbalance between governor and metering valve. As the governor reacts to restore the hydraulic balance, hydraulic pressure to the metering valve is increased or decreased, as necessary, to alter the rate of H2O2 flow to the gas generator and thus restore the turbopump to the desired speed.
In this section:
See also:
Engine and Propellant Control Helium System