AE1350.Homework.Set.2

AE1350.Homework.Set.2 - 2 . Determine the wing span and...

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AE 1350 Homework Set #2 Due on Monday February 4, 2008 1. Starting with the standard atmospheric conditions at sea level, determine the standard atmospheric properties at 12 km and 18 km. Verify your answers against standard atmospheric tables, or against the results from an applet that will be posted in the class web site. Pay attention to units. Show the units in your calculations, and ensure that they cancel properly to give the correct final dimensions. 2. Calculate the values of pressure, density, and temperature at 15000 feet, 25000 feet, 36150 feet, 45000 feet, and 55000 feet. Up to 36150 feet, the lapse rate is -0.00356 degrees R/foot. Above 36150 feet, a=0. 3. In this problem, we will examine the effects of payload ratio and wing loading on (a) the wing span and (b) average chord. We will assume that the wing has an aspect ratio of 5, and that they payload is 10,000 lb. Consider three payload to gross weight ratios: 0.15, 0.20 and 0.25. Also consider three wing loadings: 100 lb/ft 2 , 120 lb/ft 2 and 140 lb/ft
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Unformatted text preview: 2 . Determine the wing span and average chord (Wing area/Wing span) for each of these nine combinations. Present your results by filling in the empty squares below. Although the calculations are not intensive or long, you may wish to use to use a programmable calculator, or a spreadsheet program. Wing Span (in feet): P/L Ratio=0.15 P/L Ratio=0.20 P/L Ratio=0.25 GW/S=100 lb/ft 2 GW/S=120 lb/ft 2 GW/S=150 lb/ft 2 Average Chord (in feet): P/L Ratio=0.15 P/L Ratio=0.20 P/L Ratio=0.25 GW/S=100 lb/ft 2 GW/S=120 lb/ft 2 GW/S=150 lb/ft 2 Hint: Consider the payload ratio of 0.15, and GW/S= 100 lb/ft 2 as an example. 1. Since the payload is 10,000 lb, GW= 10,000/0.15 = 66,666 lb 2. Since GW/S = 100 lb/ft 2 , and GW = 66,666 lb, Wing area S=666.66 ft 2 . 3. Since Aspect ratio = (span) 2 /Wing Area = 5, Span= [ 5 x 666.66 ft 2 ] 1/2 = 57.73 feet 4. Average Chord = Wing Area/ Span = 666.66 ft 2 /57.73 ft= 11.55 feet. Repeat these calculations for the other P/L ratios and wing loadings....
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