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Old 27th Nov 2009, 09:12
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Dick Whittingham
 
Join Date: Oct 2000
Location: Bristol
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Hello Old Smokey,

What did I do wrong to be flamed in red and bold?

I plead guilty to being imprecise, but if we are being nit-picky then consider your response. EAS is the same as TAS at ISA sea level DENSITY and is "equal" to CAS only at speeds where comprssibilty is not a factor.

And I don't see your point about EAS being lower because of reduced compressibility. I was referring to the fact that if you hold a given TAS then the EAS and CAS required to achieve this at high altitude, low density, are less than that required at low level. Maybe I should have used CAS all the time

I never meant the question to wander off into the stratosphere, and in any case when I said thrust would reduce I meant thrust at a given RPM, not drag.

If I read your reply correctly you are saying that there is no general answer to my question, but that it depends on engine design.

Seriously, I have the greatest respect for you, and thank you for the answer

Dick
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