This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Solutions HW5 ENG 103 Fall 2011 P5.72 A onetwelfthscale model of a large commercial aircraft is tested in a wind tunnel at 20 ° C and 1 atm. The model chord length is 27 cm, and its wing area is 0.63 m 2 . Test results for the drag of the model are as follows: V, mi/h 50 75 100 125 Drag, N 15 32 53 80 In the spirit of Fig. 5.8, use this data to estimate the drag of the fullscale aircraft when flying at 550 mi/h, for the same angle of attack, at 32,800 ft standard altitude. Neglect Mach number differences between model and prototype. Solution : Compute the model drag coefficients and Reynolds numbers, plot them, and extrapolate in the spirit of Fig. 5.8 of the text. For the first point, 50 mi/h = 22.35 m/s. At 20 ° C and 1 atm, ρ = 1.20 kg/m 3 and μ = 1.8E5 kg/ms. Compute the first dimensionless data point: Do this for all four model data points: Re c 402,000 604,000 805,000 1,006,000 C D 0.0794 0.00753 0.00702 0.00678 Now plot them and extrapolate to the prototype Reynolds number. Now plot them and extrapolate to the prototype Reynolds number....
View
Full
Document
This note was uploaded on 12/18/2011 for the course ENG 103 taught by Professor Chattot during the Fall '08 term at UC Davis.
 Fall '08
 Chattot
 Ode

Click to edit the document details