Patent ID: 9580182
Date: 2017-02-28
CPC Classifications: B64C,B64D

Claim:
1. A method of regulating a speed at which at least one rotor of a rotorcraft is driven in rotation, referred to as a NR speed, which NR speed varies over a predefined range of NR speed variation under a control of at least one control unit generating a setpoint, referred to as a NR setpoint, which NR setpoint is used by a regulator to regulate a speed of operation of at least one turboshaft engine supplying at least a mechanical power needed for driving at least one rotor at a NR speed in compliance with the NR setpoint, the method comprising: detecting that the rotorcraft is flying under icing conditions; using an on-board instrumentation of the rotorcraft to detect an ambient outside air temperature (OAT) surrounding the rotorcraft and to detect that the rotorcraft is flying in an outside environment at an ambient outside air temperature (OAT) lying in a predefined range of values, referred to as a critical temperature domain (Dct), as identified between a predetermined high temperature (Th) and a predetermined low temperature (Tb); and then after detecting that the rotorcraft is flying in an outside environment at an ambient outside air temperature (OAT) lying within the critical temperature domain (Dct), and taking into consideration a low temperature icing range (Ptb) and a high temperature icing range (Pth) respectively that extend on either side of a temperature lying within the critical temperature domain (Dct) between the high temperature (Th) and the low temperature (Tb), and referred to as a middle temperature (Tm), the control unit applying a relationship for calculating an NR setpoint, referred to as a relationship (Lg) for calculating NR under icing conditions, as follows: