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Old 12th December 2006 | 15:58
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Mad (Flt) Scientist
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From: La Belle Province
Originally Posted by GroundBound
From that, I would conclude that the drop in pressure with a small change in height had the same effect as the large rise in temperature (23 degrees).
Thus height has more effect than temp?
Am I wrong?
GB
Correct for the case you worked out.

It's important to note that you chose a case which was essentially inside the engine flat rating - you can see from the kink in the SL line that the engine is flat rated to 35 degC at sea level.

If you did a similar exercise at, say, 6000ft and 24 degC (right at the 'kink' for that altitude) you'd find that a 2000ft increase in altitude was now the same as about 12 degC - in other words, once off the flat rating the temperature effect becomes twice as significant.
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