Patent ID: 6059226
Filing Date: 2000-05-09
Classification: G05D

Abstract:
Apparatus for providing a groundspeed envelope for a helicopter, comprising:means providing a true wind direction signal indicative of the direction of wind in the environment of the helicopter;means providing a true heading signal indicative of the true heading of the helicopter;means providing a wind speed signal indicative of the speed of the wind in the environment of the helicopter; andmeans for providing a relative wind direction signal as the difference between said true wind direction signal and said true heading signal, for providing a longitudinal wind speed signal as the wind speed signal multiplied by the cosine of said relative wind direction signal, for providing a lateral wind speed signal as the product of said wind speed signal and the sine of said relative wind direction signal, for providing a forward airspeed limit signal, an aft airspeed limit signal, a right airspeed limit signal, and a left airspeed limit signal, said limit signals being indicative of the airspeed safety envelope of the helicopter, for providing a forward groundspeed limit signal as a summation of said longitudinal wind speed signal and said forward airspeed limit signal, for providing an aft groundspeed limit signal as a summation of said longitudinal wind speed signal and said aft airspeed limit signal, for providing a right groundspeed limit signal as a summation of said lateral wind speed signal and said right airspeed limit signal, and for providing a left groundspeed limit signal as a summation of said lateral wind speed signal and said left airspeed limit signal.