Answer to Question #7529 in Molecular Physics | Thermodynamics for Peter

Question

The General Electric J79 turbojet1 produces a maximum thrust of 48 kN (10,000 lbf) dry; 69 kN (15,600 lbf) with afterburner at sea level. The inlet diameter is 1.0 m. It uses conventional hydrocarbon fuel with a heating value of 45000 kJ/kg with fuel-air ratio, f=0.02. An F-104 Starfighter equipped with the J79 has a maximum speed of 384 m/s at standard sea level, estimate:
a.The jet velocity relative to the airplane
b.Propulsion efficiency
c.Thermal efficiency and
d.Take-off thrust.
e.At an altitude of 10668 m (35,000 ft) its maximum speed is 2125 km/h. Draw a graph showing the variation of propulsion efficiency with flight speed for the range 1000 km/h to 2000 km/h.