Design and manufacture of instrumented rotor blades for a helicopter test rig

Abstract

Rotor blades have been designed, optimised, and manufactured for a national wind tunnel facility in the UK. The design included constraints such as blade diameter, to fit into existing wind tunnels, prescribed maximum centrifugal loads, and a unique fully articulated rotor head, capable of operating both as a conventional rotor and as a tilt-rotor. Two rotors having four instrumented blades each were finally produced. The rotors are mounted on a common rotor head on a rig, with or without rotorcraft fuselages. With the rotor head and hinges designed independently, important structural constraints were imposed on the overall blade design and aerodynamic loads. The Mach number scaled profiles were expected to generate 2.5 KN (at 2,500 rpm) and 3kN (at 3,000 rpm) of thrust for the helicopter and the tilt rotor blades, respectively. The maximum permissible radial hub load was 15kN. The embedded instrumentation was used to capture the blades vibration modes. The use of carbon fibre composites enabled a successful design and manufacturing of instrumented blades.