Flat Rating Concept Introduced in the GTX Engine

Abstract

An attempt has been made to explain the flat rating concept introduced in the GTX engine being developed at GTRE. The contemporary high pressure ratio engines lose thrust rapidly with increase in compressor inlet total temperature (T1). This loss of thrust with increase in T1 becomes significant in the case of bypass engine, with thrust drop increasing with increase in bypass ratio. The concept of variable cycle achieved by varying the maximum cycle temperature in order to increase the available dry thrust is explained. In recent days this concept of variable cycle has been recognised in the design of engines for combat aircraft with particular reference to supersonic cruise at altitude. An attempt has also been made to explain the control law in order to achieve the flat rating.