METHOD OF REGULATING THE SPEED AT WHICH A ROTORCRAFT ROTOR IS DRIVEN UNDER ICING CONDITIONS

摘要

A method of regulating the NR speed at which the rotor of a rotorcraft is driven in rotation. On detecting that the rotorcraft is flying under icing conditions in a previously identified critical temperature domain (Dct), the NR speed is either decreased in the situation where the ambient outside air temperature (OAT) lies in a low temperature icing range (Ptb) of the critical temperature domain (Dct), or else it is increased in the situation where the ambient outside air temperature (OAT) lies within a high temperature icing range (Pth) of the critical temperature domain (Dct).

主权项

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