I take it back, the limits are set right to catch a true hardware failure. But to what degree did the valve fail? Would 5 have produced no thrust, partial thrust, exploded? Or could it have sub optimal but stable?They can't lose an engine at liftoff but can they have a weak one and still get off the pad? What's the margin?
They can't lose an engine at liftoff but can they have a weak one and still get off the pad? What's the margin?
Check valves 'usually' have a spring (or similar device) in them to keep the seated closed, so as to ensure a positive seal, or to create a specific amount of pressure drop as a fluid passes through it.If the spring mechanism failed, it could have restricted the check valve by preventing it from fully opening, creating the issue of a lean mixture (oxygen rich, assuming it was the fuel check, which corrolates with the issues they have presented).
Quote from: robertross on 05/19/2012 11:31 pmCheck valves 'usually' have a spring (or similar device) in them to keep the seated closed, so as to ensure a positive seal, or to create a specific amount of pressure drop as a fluid passes through it.If the spring mechanism failed, it could have restricted the check valve by preventing it from fully opening, creating the issue of a lean mixture (oxygen rich, assuming it was the fuel check, which corrolates with the issues they have presented).I wonder if not seating correctly at the last shutdown could also be a possible failure mode.
Hard to say if this would have caused LOM without seeing the data and knowing the engine pretty intimately. If the engine was trending toward high power, it could've been a runaway condition on the turbopump, which would either cause a immediate rotor RUD or it could settle into an out-of-power condition where some point of flow on the engine chokes and cannot physically increase any more. That's something that can either be flown through or an eventual RUD due to high stress and fatigue.
Pardon the ignorance, I get 'LoM', but what is 'RUD'?
Quote from: Antares on 05/19/2012 11:48 pmHard to say if this would have caused LOM without seeing the data and knowing the engine pretty intimately. If the engine was trending toward high power, it could've been a runaway condition on the turbopump, which would either cause a immediate rotor RUD or it could settle into an out-of-power condition where some point of flow on the engine chokes and cannot physically increase any more. That's something that can either be flown through or an eventual RUD due to high stress and fatigue.Pardon the ignorance, I get 'LoM', but what is 'RUD'?
Unscheduled
undesirable
Unplanned
Anyone else have any fun euphemisms for an energetic engine failures?
Quote from: edkyle99 on 05/19/2012 11:41 pmQuote from: robertross on 05/19/2012 11:31 pmCheck valves 'usually' have a spring (or similar device) in them to keep the seated closed, so as to ensure a positive seal, or to create a specific amount of pressure drop as a fluid passes through it.If the spring mechanism failed, it could have restricted the check valve by preventing it from fully opening, creating the issue of a lean mixture (oxygen rich, assuming it was the fuel check, which corrolates with the issues they have presented).I wonder if not seating correctly at the last shutdown could also be a possible failure mode.Depending on the size of check valve, some sort of debris could also cause the valve to not seat properly, which can cause backward leaks. Debris was by far the most common cause of check valve issues at Masten, but there are probably other ways to get a check valve to jam part way open.~Jon
Doesn't the last page of posts belong in the discussion thread?Quote from: jongoff on 05/20/2012 12:12 amAnyone else have any fun euphemisms for an energetic engine failures?I seem to recall reading "engine-rich combustion" or something like that for certain engine failures.
Also, I'm partial to 'punted' pintles...
Quote from: deltaV on 05/20/2012 12:19 amDoesn't the last page of posts belong in the discussion thread?Quote from: jongoff on 05/20/2012 12:12 amAnyone else have any fun euphemisms for an energetic engine failures?I seem to recall reading "engine-rich combustion" or something like that for certain engine failures.We like to call it HRC... Hardware Rich Combustion. Gives you GREAT ISP......for about 1 second.Also, I'm partial to 'punted' pintles...