Turbofan calculator for public use Turbofan calculator. The formulae correspond to P.G.Hill and C.R. Peterson, "Mechanics and Thermodynamics of Propulsion", Addison-Wesley, 1970. The sketch explains the notation. Diffuser input: Specific heat ratio γ= (for air 1.4) Diffuser adiabatic efficiency ηd= Flight Mach number M = Diffuser output: Stagnation temperature/ambient temperature T0d/Ta= Stagnation pressure/ambient pressure p0d/pa= Compressor input: Compressor pressure ratio prc= Compressor specific heat ratio γc= Compressor adiabatic efficiency ηc= Compressor output: Stagnation temperature/ambient temperature T0c/Taa = Stagnation pressure/ambient pressure p0c/pa= Fan input: Fan pressure ratio prf= Fan specific heat ratio γf= Fan adiabatic efficiency ηf= Fan nozzle adiabatic efficiency ηfn= Gas constant (fan nozzle) Rf= in J/(Kg K). (For dry air it is around 287.) Ambient temperature Ta= in grad K Fan output: Stagnation temperature/ambient temperature T0f/Ta= Stagnation pressure/ambient pressure p0f/pa= Fan nozzle exhaust velocity uef=m/s Burner input: Burner pressure ratio rb= Stagnation temperature T0b= in grad K Effective heat of reaction ηb QR= in kJ/kg (for typical aviation kerosene QR=45000 kJ/kg) Specific heat ratio of the combustion products cp= in J/(kg K) (for dry air it is around 1005) Burner output: Fuel-to-air ratio f= Stagnation temperature/ambient temperature T0b/Ta= Stagnation pressure/ambient pressure p_0b/p_a= Turbine input: Specific heat ratio (turbine) γt= Turbine adiabatic efficiency ηt= Bypass ratio β= Turbine output: Stagnation temperature/ambient temperature T0t/Ta= Stagnation pressure/ambient pressure p0t/pa= Nozzle input: Specific heat ratio (nozzle) γn= Nozzle adiabatic efficiency ηn= Gas constant (nozzle) Rn= in J/(kg K) Gas constant (air) R= in J/(kg K) Nozzle output: Stagnation pressure/ambient pressure p0e/pa= Exhaust stagnation temperature T0e= in grad K Exhaust velocity ue= m/s Flight velocity u= m/s Specific Thrust = kN/(kg/s) TSFC= (kg/s)/kN Propulsion efficiency ηp= Thermal efficiency ηth=ηb x Overall efficiency ηo=ηb x