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 36 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 1.35 inches and each refueling took 2.49 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.

Answer 1

given

an Airco DH-4B biplane was able to remain in flight for 36 hours

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 1.35 inches

and each refueling took 2.49 minutes to perform

so velocity = volumetric flow rate / velocity

V = ( 687 / 9 X 2.49 X 60 ) X 0.13368 / ( 3.14 / 4 ) X ( 1.35 / 12 )²

V = 0.51 X 0.13368 / 0.785 X 0.0126

V = 0.06817 / 9.891 X 10^-3

V = 6.8921 ft /sec