PROBLEM 9.1 A Boeing 747 has a wing span of 195.7 feet and a 6.95 aspect ratio. It cruises at 500 mph at a weight of 550,000 pounds at 35,000 feet (density of 0.000737 slug/ft). Assume that the Reynolds number can be approximated using: R =9324 x V xe where V is the average speed in mph, e the average chord in feet. Assuming that the wing sweep and twist combine to give an essentially elliptical spanwise circulation distribution find: 1. From the given data, show that the span area is 5511 ft. 2. From the given data, show that the average elliptic chord is 35.85 ft. 3. From the given data, show that the Reynolds number is 1.67 10%. 4. Show that the cruise speed is 733 ft/s. 5. Show that the coefficient of lift is 0.50. 6. Show that I, 6.6 x 10 ft/s. 7. Show that downwash velocity is -16.9 ft/s. 8. Show that the coefficient of induced drag is 116 counts. 9. Show that the induced Drag has a value of 12.7 x 10 lb. 10. Show that the induced angle of attack is approximately 1.32. 11. Show that the coefficient of profile drag is eq=0.0088. Assume you can use the value for a flat plate with a correction factor of 1.75. 12. Show that the coefficient of proof drag at cruise is c-0.0250. (See chart, next page) 13. Show the total coefficient of drag is 0.0455. (proof+ profile + induced). 0.8 0.6 0.4 0.2 0 -0.2 0.0 Cruise Drag Polar, M=.84, Alt=35 kft 88*** 0.02 -0.03- HTT 04 0.05 0.06 0.07 0.0 Nominal Cruise Point, 636kips CD