A Boeing 767 takes off at 315,000 lbs. and burns 15% of its 112,000 lbs. of fuel

Question

A Boeing 767 takes off at 315,000 lbs. and burns 15% of its 112,000 lbs. of fuel for taxiing, takeoff, and climb to a beginning cruise altitude of 35,000 ft. Given that C = 0.5 #fuel/(#thrust x hour), Sref = 3,050 sq.ft., e = 0.8, AR = 8, CD0 = 0.0171, Max Thrust @ Sea Level = 120,000 lbs., Max Thrust @ 35K ft = 40,000 lbs.: a. Find the velocity for maximum rate of climb at sea level and 315,000 lbs. What mach number is this? b. Find the maximum rate of climb at the conditions asked at a. c. Find the velocity for maximum rate of climb at 35,000 ft and the heaviest cruise weight. What mach number is this? d. Find the maximum rate of climb at the conditions asked at c. e. Find optimum cruise velocity at 35,000 ft., at the heaviest cruise weight. What mach number is this? f. Find L/D for optimum cruise g. Calculate the best range at 35000 ft., assuming 10% of total fuel is left for reserves. h. Calculate the best endurance (loiter time, minutes) using all reserves. i. Calculate the time to climb from 0 to 35,000 ft.

Explanation / Answer

To calculate your possible climb speed vzvz, you will need

Calculate how much power is needed to overcome drag, and any excess can be used for climbing:

vz=vsin=vTDmgvz=vsin=vTDmg

Note that this equation makes use of several simplifications, but works well for propeller and slow turbofan aircraft with moderate flight path angles .

To do this with more precision, you need to account for the fact that the aircraft should accelerate during the climb to stay at the same polar point. Now you further need:

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