SpaceX Raptor Engine 600 Hz Vibration Problem Fixed so Hopper Ready To Hover

12 thoughts on “SpaceX Raptor Engine 600 Hz Vibration Problem Fixed so Hopper Ready To Hover”

  1. but, but….based on your ‘reporting’ , I thought we were already at a production rate of at least a thousand raptors per year

  2. Judging by the frequency, the oscillation probably involved gaseous fuel/oxidizer, so likely after the first combustion. I’d expect vibration involving liquids to be higher frequency, since the speed of sound is much higher.

  3. I suspect it was acoustic vibrations in the combustion chamber. This has been a frequent problem with rocket engines. Essentially the throat makes them act like organ pipes, and it can be quite powerful enough to shake the engine apart.

    At the temperatures in the combustion chamber, the speed of sound is higher, so it could be quite a bit smaller than 2 ft. Some dimension of the chamber resulted in a 600 Hz note.

  4. It depends on what sort of harmonic mode it was, with liquid pumps longitudinal “pogo” vibrations are typically the hardest to engineer out of. If you can change the flow rates/thrust characteristics you can modify the plume acoustics. Sometimes requires nozzle redesign. Move things around, change components to change sympathetic frequencies, change mounts, re-do analyses, re-do quals. Vib 101.

  5. 600 Hz indicates that the part that was excessively vibrating was big, a bit less than 2 ft in size. Maybe a pump housing that was a little too loose.

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