Question

A Boeing 747-8I aircraft has a mass of 447,700 kg. This includes loading. The combined area of ​​both wings is 554 m2. The cruising speed is M0.855 (917 km / h). Determine the speed of the wind above the wing to maintain the aircraft's lift. The air density is 1.29 kg / m3

Answer 1

Calculate the required pressure difference () in above and below of the wing to maintain the weight of the aircraft,

ΔP = F/A

= mg/A

= (447700*9.81)/554

= 7927.68 N/m^2

Now Apply Burnolli's equation on above and below of the wings,

ΔP= 1/2*ρ*(v1^2 - v2^2)

v1^2 - v2^2 = (2*ΔP)/ρ

v1^2 = v2^2 + (2*ΔP)/ρ

Substitute the given values values,

v1^2 = (917*5/18)^2 + (2* 7927.68)/1.29

= 648834.41 + 12290.98

v1 = 813.1 m/s

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