Question

An Airbus A320 has a total wing surface area of 122.6m^2 and a drag coefficient of 0.0872. In cruise, the aircraft files at 840 km/s (233m/s) at an altitude of 10,000m where the air density is 0.4135 kg/m^3. If the max engine is 100 kN engine, what percentage of that thrust is the pilot going to be using in cruise?

*A380 has 2 engines

Answer 1

When the aircraft is cruising, the Lift generated is equal to the weight of the aircraft and the thrust is equal to the drag force on the aircraft. Hence the thrust required at cruising speed is equal to the drag of the aircraft. The drag force is given by,

Substituting values we get,

Hence this should be the total thrust generated by the two engines, The maximum thrust that can be generated by the two engines is 200 kN. Hence the percentage of thrust supplied by the pilot is,

Hence the pilot uses 60% thrust at cruise speed.