Hello,
I am trying to understand ATR42/72-500 power plant especially EEC control function. I have several questions, so I will try to structure them one by one into posts. Any help is very appreciated, thank you.
Question one: What is expected torque (TQ) in CRZ and CLB power management modes where PL are set to RAMP (PLA 81deg) or to WALL (PLA 100deg). NP for these two modes is 82% RPM (at least for PL in NOTCH = PLA 67deg).
Please see attached picture from ATR75 FCOM:
If you look at power curve for C (CLB) or D (CRZ) power management modes, then you can see, that at when PL is put to ramp 100% Power = 2750SHP shall be produced (sea level ISA temp). As Power is function of:
Power = Np * Torque
and nominal NP is 82% for CLB and CRZ modes, than TQ > 100% (~122%) will be produced! Is this really correct? I can see multiple problems with this including over stressing power plant components.
There is only one other possible explanation of picture as above and it is, that when moving in CLB or CRZ power mgmt mode PL from NOTCH position to RAMP position, NP is also increased from 82% to 100%, so Torque will not overshoot 100%.
Thank you for any help.