Press Release FLIGHT INTERNATIONAL, 5 April 1986
Dowty Boulton Paul is to supply the fly-by-wire (FBW) Harrier tail-plane actuation for BAe and the Royal Aircraft Establishment. The Harrier has been converted by the College of Aeronautics at Cranfield, and will be tested by RAE Bedford as part of Britain’s vectored-thrust aircraft advanced flight control (VAAC) programme.
The digital FBW flight control system will test British Aerospace’s VAAC design concepts, the most important research element of which will be investigations in the pitch plane. Dowty has produced the FBW actuator and a hydraulic spring box for control of the Harrier tail-plane.
The FBW actuator has duplex electrical signalling with linear velocity displacement transducers for servo valve spool position and ram position feedback. Output loads from the actuator are controlled by an integral load limit valve. In the event of failure, the actuator is deenergised by a solenoid valve and the FBW system is declutched from the existing mechanically signalled control circuit.
Since 1956, when a Tay-Engined Viscount became the first aircraft to fly with an FBW flight-control system, which was designed and manufactured by Dowty Boulton Paul, the company has evolved FBW equipment for a range of aircraft including the Vulcan, Buccaneer, VC10, Concorde, Tornado, BAe One-Eleven, A300-600, Augusta 129, AMX, FBW Jaguar, and BAe’s latest Experimental Aircraft Programme (EAP) fighter demonstrator.
Dowty Boulton Paul becomes the first British supplier to the Boeing-Bell V-22 Osprey. After a two-year “hard sell” of its advanced active control expertise, the British company has been awarded a contract worth potentially £10 million for the supply of two actuators per rudder, each full time fly-by wire and operating at 5,000lb/in2.