A medium-range military and civil freighter (a typical example is the U.S.S.R ANTONOVAN-12 CUB) is powered by

Fantastic news! We've Found the answer you've been seeking!

Question:

A medium-range military and civil freighter (a typical example is the U.S.S.R ANTONOVAN-12 CUB) is powered by four turboprop engines. The mass of the airplane (m) is expressed in terms of the flight distance(s) as
m = a(106) ) 105(s))0.3 kg
where s is expressed in (km). The takeoff mass is 65,000 kg. The maximum range is 3500 km.
The heating value of the fuel used is QR = 45, 000 kJ/kg, the lift-to-drag ratio (L/D) is 16, the airplane speed is 100 m/s, the propeller efficiency is 0.8. It is required to
a) Calculate the value of the constant (a) in the above mass-distance equation.
b) Calculate the final mass of airplane if the distance traveled were 3500 km
c) Calculate the overall efficiency ηo