Aeronautics

Safe life concepts, previously developed for aircraft structures, were also applied to aircraft engines, where the significance of low cycle fatigue of high temperature turbine and compressor discs, induced by the cyclic heating and cooling had become apparent. By continuous monitoring of parameters which indicated engine health, the need for expensive periodic inspections was reduced. Helicopter transmission systems were a particular area of concern to the RAN; the fatigue properties of gear materials had to be studied, the life of gear trains determined under various cycles of loading, and the whole related to the patterns experienced in service. As it became required, individual aircraft of a fleet were fitted with load monitoring equipment so that the accumulation of fatigue damage could be observed continuously.

Modern military aircraft had become complex carriers of even more complex avionic sub-systems. A knowledge of the operation and the optimum programming requirements of the computer-based items had to be acquired. The process of mathematical modelling of performance of both the aircraft, the sub-systems and their interaction was accepted as a valid task. A.R.L. performed modelling studies on the existing Service aircraft.

When the RAAF decided in 1976 to seek replacement fighter aircraft for the ageing Mirage-III-0 fleet (which had been in service for twelve years) it faced the problem of selection from amongst many overseas offerings. A high level of scientific support was clearly needed.[65] The complex of laboratories of the DSTO were well placed with experience and equipment to assist. Given the necessary data concerning the construction of airframes and the materials used, the engine design and operation, they would be able to arrive at a fairly precise estimate of the aircraft capability, its safe life and maintenance requirements.

To the knowledge of aircraft characteristics, mainly worked out at ARL, the other Establishments of the DSTO were able to contribute estimates of the effectiveness of radar, weapon systems, navigation etc., and of the behaviour of the various materials used in the total aircraft assembly. The choice of the McDonnell Douglas F/A-18 as the replacement aircraft was made with greater knowledge than had been possible hitherto, and with confidence that all possible factors had been taken into consideration.

The advanced technology incorporated in that new aircraft made it imperative that research support be made available for many years after its introduction. To ensure this, a program of modernization of the laboratory facilities was planned.[66] Included in this were the development of new wind tunnels capable of investigating in a credible fashion aircraft behaviour in the difficult transsonic region and subsequently to Mach number 1.4; a small engine test facility and access to the large engine test facility at CAC; and a new combustion test house and structural test laboratory. A new computer was installed. The laboratories thus became equipped to offer timely and confident advice on problems likely to arise in this and other aircraft operating at the forefront of technology.

Australian Academy of Technological Sciences and Engineering