Old 15th Nov 2018, 05:55
  #768 (permalink)  
Join Date: Nov 2006
Location: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
Posts: 1,493
However, the FADECS would sort this out really quickly.
Or maybe not - appreciate that the FADEC has inputs from control positions i.e. collective and TR pitch, torque, and atmospheric data and that is mapped inside the ECU to a fuel flow required to achieve the net result.

Actual speed governing might not be a good as "normal" if you had a full left pedal input to the ECU with no resulting increase Q load from the TR would probably give you an unintended result.

NR is normally referenced to the current DA and speed is governed by pre-empting the relationship between CLP and TR pitch. Quite often with CLP and TR pitch inputs are attached to either end of an LVDT (Linear Variable Displacement Transducer) and this value via the map in the ECU will give you a fuel flow pretty close to that required without being reactive to a change in NR.

Current FADEC controlled engines are great. They are also great at masking the true characteristics of the main rotor. When the FADEC is removed from the loop (autorotation) many are surprised at how "lively" the main rotor is to RPM. control.

Loss of input data will normally give you a "DEGRADE" warning but more likely not in this case.
RVDT is offline