Originally Posted by pitzel
Originally Posted by 53' Stude
Originally Posted by Astro14
Exactly.
Point is: military flying is hard on equipment.
It has to be, so that the mission can be accomplished.
Astro14: my stepdad read what "pitzel" wrote and just shook his head. Good reason I have him on "ignore" as he knows nothing about aircraft
That's unfortunate. Because I merely asked how bad for an engine it would be to always be changing the thrust settings as the B-2 obviously does as part of its stability control system. Gas turbines, at least in industry, do not like constant changes to their fuel flow/thrust as such stresses internal components beyond just that implied of steady state operation. Obviously in an aircraft, some thrust changes are unavoidable, but the extreme frequency with which the B-2 engines are changing their thrust settings as part of their stability control *may* induce reliability-related issues.
Its worth noting that engines on the fighters (ie: that use the F101 engine) are not changing their thrust every few seconds. Nor are engines attached to airliners. Reliability of an engine impacts the mission-capable rate of an aircraft and ultimately the cost of the system to the warfighter/taxpayer. Obviously such was one of the design compromises made to achieve the B-2's low-radar-observability characteristics. My question was at what cost to reliability?
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If the military flew like you wanted, minimal thrust changes. they would not be able to accomplish the mission. Can't in flight refuel. Can't fly combat maneuvers. Can't fly carrier landings. Can't do anything except straight and level airliner flying.
Combat manouevres, carrier landings, in-flight refueling, that's a small fraction of the overall operational time on those engines in those applications. Maybe 2-5% of flight hours. The rest is spent in straight and level flight which involves minimal (or extremely gradual) thrust changes. In the B-2, the engines are changing thrust, and quite significantly, literally *all the time*.
So what I'm asking is whether this substantially reduces the TBO or introduces unique failure modes that are not experienced on engines that spend 95% of their operational life operating with minimal to no thrust changes. If the TBO or "on-wing" time is classified on the B-2, I can accept that, but I just can't buy the argument that changing thrust settings nearly 100% of the time as part of the stability control system doesn't have a negative impact on certain engine components.
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How much turbine flight time do you have, on which you're predicating your position?
Flight time would be irrelevant as the question is one of maintenance. A pilot is no more of a turbine maintenance expert than a car driver or even quickie lube tech is an expert on motor oil or ICE maintenance.
Thanks for the insult Pitzel. Mods notified also. I'm not a quickie lube tech btw so thanks for that snarky jab
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