Integrated system for measuring the low airspeeds of helicopters

A.A.Porunov, V.V.Soldatkin, V.M.Soldatkin

Kazan State Technical University named after A.N.Tupolev

K.Marx Str., 10, 420111, Kazan, Russia

 

When solving the problems on helicopter's flights and their safety control, wide use is made of data on airspeed vector magnitude and its direction specified by the angles of attack and slip. The measurements of the airspeed vector parameters is hindered, especially in the region of low and near-zero velocities, by the significant distortions of its aerodynamic field due to inductive flows from the rotorcraft flight structure as well as due to spatial flow around the Pitot-static tube placed in the vicinity of the helicopter's body or on the remote airspeed boom. It constrains the application on the helicopter's board the methods and measuring means for measuring the altitude/speed parameters, used conventionally in aircrafts.

The team of specialists from the Kazan State Technical university named after A.N.Tupolev develops at present, jointly with пбп (Ul'yanovsk, Tatarstan), the system for measuring the helicopter's low airspeeds; the system is based on the stationary multi-channel aerometric data receiver probe (MCAP) and the jet-convective (hot-wire air flow metering) measuring channels.

In this article it is discussed author's approach. The herein-presented structure of the stationary multichannel aerometric data receiver probe and the corresponding algorithms for processing of primary pneumatic signal arrays make it possible to carry out the spatial measurements of the helicopter's airspeed vector magnitude and direction; the use of the jet-convective measuring channels allows to extend significantly the lower limit of the helicopter's flying speeds. The suggested schemes of automatic adjustment and adaptive control of automatic adjustment periodicity make it possible to significantly decrease the number of the additive errors of the aerometric system for measuring the helicopter's low airspeeds due to scattering and instabilities of characteristics of the jet-convective measuring channels and provide the reassigned accuracy of the aerometric system operation at real flying conditions.

The proper implementation of the principles of integration and optimal filtration make it possible to significantly improve the accuracy of airspeed vector parameters measured in the region of low and near-zero flying speeds when the errors of the aerometric system exceed the maximum admissible values. The above-considered schemes, algorithms for data processing, and some distinguishing features of integration make it possible to carry out the well-grounded analysis and synthesis of different variants of constructing the integrated system for determining the low speeds of helicopters.