F-1 (rocket Engine) - History

History

The F-1 was originally developed by Rocketdyne to meet a 1955 US Air Force requirement for a very large rocket engine. The eventual result of that requirement was two different engines, the E-1 and the much larger F-1. The E-1, although successfully tested in static firing, was quickly seen as a technological dead-end and was abandoned for the larger, more powerful F-1. The Air Force eventually halted development of the F-1 because of a perceived lack of requirement for such a large engine. However, the recently created National Aeronautics and Space Administration appreciated the usefulness of an engine with so much power and contracted Rocketdyne to complete its development. Test firings of F-1 components had been performed as early as 1957. The first static firing of a full stage developmental F-1 was performed in March 1959.

For seven years of development F-1 tests revealed serious combustion instability problems which would sometimes cause catastrophic failure. Progress on this problem was initially slow, as the problem onset was intermittent and unpredictable. Oscillations of 4 kHz with harmonics to 24 kHz were noticed. Eventually engineers developed a technique of detonating small explosive charges (which they called "bombs") outside the combustion chamber through a tangential tube (RDX, C4 or black powder were used) while the engine was firing, which allowed them to determine exactly how the running chamber responded to variations in pressure and to determine how to nullify these oscillations. The designers could then quickly experiment with different co-axial fuel-injector designs to obtain the one most resistant to instability. These problems were addressed from 1959 through 1961. Eventually the engine's combustion was so stable it would self-damp artificially induced instability within 1/10 of a second.