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stancioiu
11th Apr 2006, 16:23
Hi!
Can someone explain me why the climb power is greater than cruise power for the PW127E engines fitted to ATR42-500 when outside the flat rated envelope?
In the torque tables inside the flat rated area, torque is always greater for the climb power than for the cruise power for the same propeller speed and same aircraft speed. Outside the flat rated area cruise torqe is greater than climb torque, again for the same propeller speed and IAS. The manual states that climb pwr is 2160 BHP and 2132 for cruise. Since Pwr= TQ x Np cruise pwr is greater than clim pwr outside the flat rated area.
Am I missing something or is my judgement incorrect?

Clandestino
14th Apr 2006, 12:29
This one really puzzles me. I always thought that cruise power has to be lesser than climb power. Obvious answer is that higher TQ comes from lower Np setting in cruise, but since Np is the same... is there any 42/72-500 driver out there that can verify this?

galahad
17th Apr 2006, 10:17
I suspect that there're different sets of power

100% TQ in climb phrase power = 2160 BHP and the same 100% TQ of
cruise power = 2132 BHP.

kind regards,