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 launch pad. 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 seqence is started by energizing the stop selonoid 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 Propellenat pressure to both the main combsution 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. Combustion process in both the main combustion chamber and the gas generator combustion chamber has stopped.

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Copyright 2022 by   Sander Panhuyzen All pictures and drawings contained on and through these pages are the author's, unless otherwise noted. No unauthorized reproduction without permission.