Method for determining the horizontal airspeed of helicopters in higher speed ranges

US4766767A · kind A · utility

Assignee

• LITEF GmbH · DE

Inventors

• Wolfgang Hassenpflug · Freiburg im Breisgau, DE
• Rainer Schwable · Garbsen, DE

Key dates

• Filing date: Jun 2, 1987
• Grant date: Aug 30, 1988
• Expiry date: Jun 2, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01P5/00
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for determining the horizontal airspeed of a helicopter in the high speed (v.sub.e >20 m/s) range. Pitch angle and the longitudinal control signals are recorded by sensors such as an inertial navigation system and a potentiometer connected to the pilot's control lever. Equivalent speed signals are calculated from the measured pitch angle and longitudinal control signals by means of calibration equations. These signals are then filtered and weighted. The horizontal airspeed is then derived from the sum of the weighted signals divided by the sum of weighting factors k.sub..theta. and k.sub..delta.x determined in accordance with the sensed pitch angle and longitudinal control signals. The horizontal velocity signal may be filtered, if necessary.