BAE Systems

106 The Aircraft of British Aerospace and BAE SYSTEMS 1977 - 2017

Experimental Aircraft

Programme

The Experimental Aircraft Programme

(EAP) was built to demonstrate several

recent developments for the first time.

These included full authority digital

fly-by-wire, and unstable canard delta

configuration, electronic cockpit design,

digital engine control, composite

materials and stealth. Initially there were

to be two EAPs, one each in Britain and

Germany but in December 1983 the

German the Italian governments

withdrew support. Germany was to have

built the centre and rear fuselage, but

without its contribution the airframe was

built by BAe at Warton and employed a

Tornado rear fuselage and fin/rudder.

Aeritalia invested some of its own funds

to remain in the project, fabricating one

of the carbon-fibre wings and BAe built

the other. Equipment suppliers were

eager to stay connected the project.

Turbo-Union leant two RB199 engines

and German and Italian firms donated

equipment to the EAP; though more than

half of the equipment suppliers were

from the UK. Carbon fibre was used in the

wing, foreplane, cockpit substructure and

side panels, accounting for 25 per cent of

the structure weight. If the two partner

countries had not dropped out this

proportion would have been even

greater.

The EAP was a single-seat delta

canard powered by two Turbo-Union

RB199 with reheat each developing

17,000 lbs thrust as installed on the

Tornado F3 interceptor but without their

thrust reversers. The EAP’s chin intake

with a hinged lower lip which rotated

down at slow speeds and higher angle of

attack to improve flow into the engine. At

higher speeds it moved up to minimise

spillage drag.

The compound delta wing with its 57⁰

sweep inboard and moderate 45⁰ sweep

outboard was 36ft 8in wide. There were

13 control surfaces, including camber

changing leading edge slats and flaps to

provide maximum lift in subsonic

combat and minimum drag in supersonic

flight. Pitch control was provided by the

all-moving canard foreplane and trailing

edge flaperons. Twin airbrakes were fitted

on the upper rear fuselage. Because the

EAP was 15% more unstable than the

ACT Jaguar and with its plethora of

control surfaces the flight computers

operated at three times the speed of the

Jaguar ACT. Overall length was 48ft 3in

and the fuselage was area ruled to

reduce drag, the nose was drooped to

offer good visibility. Fuel was mainly

carried in the wings but 14 smaller tanks

were fitted in the fuselage.

In many respects the EAP was

fundamentally different from its

predecessors. Manufacturers no longer

just developed the airframe leaving the

remainder to sub-contractors; avionics is

at the heart of the combat aircraft’s

capabilities and BAe brought that

technology in-house.

XX765 was flown with ballast as an unstable aircraft and was then fitted with large wing leading-edge strakes, to

further decrease longitudinal stability. These yellow strakes are clearly seen in this photo prior to painting. It was

retitled the Jaguar ACT (Active Control Technology). (BAE SYSTEMS North West Heritage)

‡ XX765 flying with Tornado F2 ZD901. The large wing leading-edge strakes are now painted and the ‘ACT’ on the fin

is for ‘Active Control Technology’. (BAE SYSTEMS North West Heritage)