In 1923, the United States Army (there was no U.S. Air Force at that time) set a
ID: 1774646 • 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 38 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 2.49 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.
Explanation / Answer
volume= 687 gallons=2.80058 m3
time=9*2.49=22.41 minutes=1344.6 seconds
rate of flow= volume/time= 2.80058/1344.6=2.08x10-3 m3/s
diameter= 1.25 inches=0.03175 m
radius=0.015875 m
area = a= pi r2= 3.14 (0.015875)2=7.91x10-4m2
now rate of flow= a v
2.08x10-3=7.91x10-4 V
V=2.63m/s
so velocity= 2.63 m/s