F-1 engine cut-off sequence


The row of engineers in front of the F-1 rocket engine illustrates the sheer size of the engine.
The F-1 produced about 680 metric Tons of thrust. Five of these engines were used to lift the 2800 metrics Tons heavy Saturn V from the launchpad.

credit to NASA / Marshall Space Flight Center

The five F-1 engines at the base of the first stage (S-IC stage).

credit to NASA
Scanning credit to Kipp Teague

START OF CUT-OFF SEQUENCE

The cut-off sequence is started by energizing the stop solenoid of the Control Valve.
Hydraulic closing pressure will be made available to the closing ports of the fuel, LOX and gas generator valves. At the same time hydraulic opening pressure is released from the opening ports of these valves.

FUEL, LOX AND GG VALVES ARE CLOSING
COMBUSTION IS TAPERING OFF

Propellant pressure to both the main combustion chamber and the gas generator combustion chamber is decaying.

ENGINE CUT-OFF COMPLETED

The fuel igniter valve and the ignition monitor valve are closed.
When the pressure inside the thrust chamber drops below a pressure threshold value, the fuel igniter valve and the ignition monitor valve are closed.
The combustion process in both the main combustion chamber and the gas generator combustion chamber has stopped.


Acronyms
GSE Ground Source Equipment
GG Gas Generator
LOX Liquid Oxygen
RP Rocket Propellant

References
  1. Saturn V Flight Manual SA-506
    George C. Marshall Space Flight Center
    MSFC-MAN-506

  2. F-1 rocket engine data manual
    NASA-CS-143972, R-3896-1, March 1967, May 1972
    by Rocketdyne



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