Development of the Cranfield University Bulldog flight test facility

Abstract

Cranfield University's National Flying Laboratory Centre (NFLC) has developed a Bulldog light aircraft into a flight test facility. The facility is being used to research advanced in-flight instrumentation including fibre optic pressure and strain sensors. During the development of the test bed, Computational Fluid Dynamics (CFD) has been used to assist the flight test design process, including the sensor requirements. This paper describes the development of the Bulldog flight test facility, including an overview of the design and certification process, the in-flight data taken using the installed fibre optic sensor systems and lessons learned from the development programme, including potential further applications of the sensors.

On the development of flight-test equipment in relation to the aircraft spin

“…Firstly, Lawson et al [61,63] describes the development of the fibre optic sensors for flight test measurements of surface strain and unsteady pressure, using a Scottish Aviation Bulldog. Fibre Bragg gratings (FBGs), distributed along the port side wing were used to record wing strain data.…”

“…The performance of the fibre optic sensors was verified by Lawson et al [61,63] before the same instrumentation was used in a further study regarding the effect of mass distribution on the characteristics of a spin [42]. The tests involved altering the fuel load on board to identify the changes in moments of inertia during a spin.…”

Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 1. Measurement of strain

“…To-date, aerospace applications of OFS have predominantly concerned their use on fixed-wing aircraft [2,3,[13][14][15][16][17], with examples of flight tests with OFSs bonded to the wings of a twin turboprop aircraft, Jetstream 31 [3], and to the wings of an aerobatic single propeller aircraft, Scottish Aviation Bulldog [2], measuring strain during extreme manoeuvres including banked turns [3], stall turns, barrels rolls, loops and spins [2]. The use of OFS on rotorcraft has been been less widely reported.…”