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Old 02-01-2015, 09:16 PM   #27
stugray
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Join Date: Sep 2013
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Quote:
Originally Posted by BRZnut View Post
I saw video of two guys from Australia discussing our engines and they said that if the Cams go out of sync, this can lead to oil starvation and ultimately failure of the engine.
Quote:
Originally Posted by zkv476 View Post
I'm under the impression that the oil system would be properly sized to handle continuous camshaft timing changes without incessantly reducing oil pressure. But in any case, a properly functioning AVCS system only should use oil when adjusting timing from what I understand.
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Now that you get me thinking, I wonder if either a failed cam position sensor, or a bug in the software could cause continuous commanding of cam position?
The most basic code would say:
If cam_position_sensor_phase < commanded_phase then command_more_phase

If the cam position sensor stopped responding (or the cam got stuck), then it would just open that valve to command more phase and leave it open because the cam never reaches the target position.

I dont know if they have fault protection that would cover that case, but it is interesting.

On a related note, I know of two rockets that were lost because the system ended up using more hydraulic than expected.
On one of them one of the control system parameters was off by a bit (Delta-III).
The most recent was SpaceX's attempt to land on that barge.
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