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Old 8th January 2012 | 12:20
  #4 (permalink)  
OPEN DES
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Joined: Apr 2004
Posts: 509
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From: United States of Europe
Hi DH,

EPR is a good measurement of thrust as you know. The problem lies in the higher by-pass ratios nowadays which means that the actual EPR as a number has become pretty meaningless operationally. As you said: 1.050 is pretty meaningless. I remember that on the MD-80īs for example EPR was around 1.80-2.00 or so for take-off. Pilots used to have rules of thumb for EPR numbers for different phases of flight, and used EPR operationally as their main thrust parameter.
In the newer high-bypass ratio engines the EPR has become a pretty meaningless control parameter for the pilot. Airbus still refers to N1 rules of thumb even for EPR equipped aircraft. Problem is that the governing parameter is EPR which is directly proportional (give or take) to thrust lever angle. N1 however is not directly proportional to EPR/thrust lever angle, which makes manual thrust control slightly more difficult. i.e. TLA not linear with N1.
My thoughts anyway.....

I canīt think of any alternative to EPR... Not familiar with the A380, what does the Thrust parameter indicate?

Regards

O.D.
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