PPRuNe Forums - View Single Post - The CMF56-7B engine and power rating
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Old 15th May 2006 | 09:55
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RYR-738-JOCKEY
 
Joined: Jul 2005
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From: Europe
I'm not a tech expert, but from what I know; The N1 percentage is the RPM of the low pressure stages of the engine, and is a reference for thrust setting/primary engine indication. But 100% N1 does not necessarily give you full rated thrust as it varies with temperature and pressure. For high temp and low pressure - the thrust output will be lower for a specific N1 percentage, and vice versa. So commanded N1 does not correlate to output thrust.
Moving the thrust lever to the forward stop will through the EEC's (Electronic engine control) give full rated thrust, f.ex. 26k, depending on engine version.

However, you have engines with an EPR (engine pressure ratio) indication (f.ex. MD80's) .A specific EPR is an indication of output thrust and will not vary with temp and press.

Last edited by RYR-738-JOCKEY; 15th May 2006 at 11:33.
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