Extensive use of reinforced plastics has contributed significantly to the success of small VTOL engines, notably the Rolls-Royce RB 162 series in whose compressors it has been possible to demonstrate their versatility and ruggedness. The choice of reinforced plastics for such obvious reasons as lightness, specific strength and corrosion resistance has been fully justified, while apparent deficiencies in stiffness and rain erosion resistance have not proved embarrassing.

Considerable use has been made of epoxy resin pre-impregnated sheet incorporating non-woven parallel aligned glass fibre, in particular the “Scotchply” series of “pre-pregs”. Exceptionally high fibre contents have been achieved, resulting in higher strengths and moduli than are usual with glass-reinforced plastics and furthermore, since Scotchply has proved so uniform in composition and ply thickness it has been possible to precision-mould most components with such accuracy that machining is eliminated—a major economic factor. Further economies have been achieved by minimising press curing times by the use of latent catalytic type hardeners for the resin systems which, in addition, confer long storage life and good heat resistance. The use of very thin sheet material has allowed much ply orientation within laminates, resulting in substantial and controllable variations in anisotropy, allowing properties to be tailored more nearly to meet the conditions imposed.