In 1923, the United States Army (there was no U.S. Air Force at that time) set a
ID: 1463321 • Letter: I
Question
In 1923, the United States Army (there was no U.S. Air Force at that time) set a record for in-flight refueling of airplanes. Using two refueling planes, an Airco DH-4B biplane was able to remain in flight for 35 hours. During the flight, the refueling planes were able to air-transfer a total of 687 gallons of fuel to the plane in 9 refueling transfers. Assume that the refueling nozzle had a diameter of 1.25 inches and each refueling took 2.43 minutes to perform. Calculate the velocity of the fuel through the nozzle. Assume that the fuel filled the entire cross-sectional area of the nozzle.
Explanation / Answer
volume of the fuel = 687 gallons
= 687*3.7854 L (since 1 gallon = 3.7854 L)
= 687*3.7854*10^-3 m^3
= 2.6 m^3
diameter, d = 1.25 inch
= 1.25*2.54 cm
= 3.175 cm
= 0.03175 m
cross sectional area of the pipe, A = pi*d^2/4
= pi*0.03175^2/4
= 7.917*10^-4 m^2
let v is the speed of fuel
we know volume flow rate = A*v
V/t = A*v
2.6/(2.43*60) = 7.917*10^-4*v
0.0178 = 7.917*10^-4*v
v = 0.0178/(7.917*10^-4)
= 22.5 m/s <<<<<<<<<<<<--------------------Answer