I suspect that most of those engines in the old lit were developed for
specific vehicles flying specific missions, so "acceptable operation"
went largely without saying as whatever would allow a given vehicle to
fly a given mission with acceptable reliability. ("Acceptable
reliability" could of course vary widely, from as low as 70-80% for
expendable weapons to 99%+ for human spaceflight.)
So I think if you define a notional vehicle and mission, you can then
start to derive answers to your questions. Given the real mission is
teaching, I would expect that the way the derivation varies with
variations in vehicle/missions could be more instructive than the
specifics of any one notional vehicle/mission...
(I am not a teacher, nor do I play one on TV.)
Henry
On 1/28/2021 12:20 AM, Nathaniel Van Rumpt wrote:
My student team (12kN, LOX/Kero) is trying to determine what flight engine qualification criteria should look like. Most old literature merely contain phases such as "the engine shall be tested to confirm acceptable operation," yet they often don't define what "acceptable operation" looks like.
We had a few questions in particular about:
* What would be an acceptable level of chamber pressure fluctuations?
* How would one measure and determine an acceptable vibration level?
* How quickly should steady state operation of the engine be achievable?
* How long should one test the actual flight engine before
assembling into the rest of the rocket?
Furthermore, what other engine acceptance criteria should we be considering?
Cheers,
Nathan