Numerical studies of infrared signature levels of complete aircraft

Abstract

Abstract This paper begins with an outline of the procedure for predicting the infrared signature emissions from the airframe, engine casing, and the plume, and their attenuation by the intervening atmosphere. These emissions are contrasted against the background, to obtain the infrared signature levels. The infrared detector’s — noise equivalent flux density, is proposed as an operational constraint on the flight envelope. The shift of this newly imposed constraint on the flight envelope for several engine-operating conditions, and for turbojet and turbofan engines is studied. The signature levels from the casing and plume, of a turbofan and equivalent turbojet engine, are compared at different operating points on the flight envelope. Result in the form of a polar plot of infrared signature level variation with aspect is also examined for low flying missions. The results are analysed to direct stealth design and operation.