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Propulsion Controls on the Concorde

Published online by Cambridge University Press:  04 July 2016

Pierre Young*
Affiliation:
Olympus 593, Bristol Siddeley Engines Ltd

Summary

One of the novel problems presented by supersonic transports is the control of the complex powerplants needed to achieve optimum efficiency over a very wide range of forward speeds.

The subject is a large one and its proper understanding involves the disciplines of aerodynamics, thermodynamics, servo-theory and finally human engineering, because its end product is a set of knobs, levers, lights and dials which must be usable by the flight crew.

This paper is intended as an elementary introduction, using the special case of the Concorde as a basis. First, an attempt is made to give the aerodynamic and thermodynamic reasons for the large number of powerplant variables which the control systems must manipulate. On this basis, a functional specification of the control systems is established and, finally, the crew's job of propulsion management is described step-by-step in the course of a typical mission.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1966

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References

page 866 note * Another way of looking at Fig. 4 is to regard the constant LP rpm line as displaying the behaviour of a single-spool engine of 15:1 design pressure ratio and the constant HP rpm line as corresponding to a single-spool engine of 4-8:1 pressure ratio.

page 868 note * The variable primary nozzle means that jet-pipe temperature is no longer simply related to TET and the limiter datum is, in fact, biased by the intake temperature to overcome this.

page 870 note * The only main items of hardware not duplicated in the standby system are the intake temperature and jet pipe temperature sensors and their associated wiring. Thus a useful weight saving is effected at the cost of:

  • (1) A slight increase in crew work load resulting from the necessity of driving the engine manually where jet pipe temperature is limiting.

  • (2) Slight sfc penalties at low Mach numbers arising because the nozzle trim unit law is no longer based on N/√T but on simple rpm. (The simplified law assumes the design supersonic cruise value of intake temperature so that, as intake temperature decreases the chain dotted line of Fig. 2(a) moves to the right, Thus the sfc penalties will only arise in some stand-off cases.)

page 870 note * For so-called “dual stream” intakes where a significant proportion of the total intake capture air is taken through the throat bleed a small range of throttle movement is made possible through adjustment to the throat flow and it may be beneficial to operate with the intake slightly supercritical.

page 875 note * The prototype will be fitted with pneumatic rams capable of selecting the fully open or closed position and providing some damping. They will appear on production aeroplanes only if they are shown to be necessary during development flying. From the crew’s point of view at the most, a three-position switch would be required.

page 875 note * Each centre tertiary door must be closed for ground running to ensure sufficient cooling air flow through the engine bay.