Consider a commercial transport aircraft with the following properties.

W _initial . . .. . . . . . . . . . . . 400,000 kg

W _fuel . . . . . . . . . . . . . . . . .175,000 kg

η ₀ . . . . . . . . . . . . . . . . . . . . 0.32

L/D . . . . . . . . . . . . . . . . . . . 17

Q _R . . . . . . . . . . . . . . . . . . . 42 Mlilcg

g . . . . . . . . . . . . . . . . . . . . 9.81 m/sec1

Applying the Breguet range equation, we calculated previously that the range of the aircraft is 13,400 kilometers, neglecting the fuel required for takeoff, landing and reserve. Suppose that the overall efficiency (propulsion plus aerodynamic) is 1% lower than that given above. That is, the revised product of η ₀ and L/D is (0.99)(5.44). This might happen for example if the design predictions were in error by 1%. Or, as the engine is used, its efficiency tends to decrease overtime due to wear.

One way to estimate the magnitude of this impact is to determine the required decrease in initial weight (keeping the same amount of fuel) in order to maintain the same cruise range at this decreased values of η ₀ and/or L/D. For a commercial transport aircraft, this decrease in initial weight would translate to fewer passengers for this cruise range.

Assume that the average weight for a passenger (including baggage) is 100 kg. For η ₀ (L/D) = (0.99)(5.44)), how many fewer passengers can fly while still maintaining the original cruise range?

Answer rating: 100% (QA)

The range of an air craft is given by following formula R QRg 0 L... View the full answer