Dne dmin minimum total drag in pounds

Question

Weight (W)                  15,000 lb         C_DP                              0.021

Wing Area (S)             230 ft²             C_Lmax at Stall               1.5

Aspect Ratio (AR)       5.3                   Note: Assume the drag polar is a parabola

Span Efficiency (e)     0.85                

Temperature               Standard

Altitude                        Sea Level

Complete the following table for this particular typical transport jet. Start the table at stall speed, VS. Then answer the questions at the end using the values from the table. You can use an excel spreadsheet to create the answers for the table.

 

V (KTAS)	q (psf)	CL	CD	CL / CD	DP (lb)	DI (lb)	DT (lb)
VS
120
140
160
180
190
200
220
240
260

Equations for Table:

q =                           C_L =                   C_Di =[1/ (πeAR)] C_L²

C_D = C_DP + C_Di                        C_D = C_DP + [1/ (e AR)] C_L²                         Dp = C_Dp q S

Di = C_Di q S = [1/ (e AR)] C_L² q S                           Dt = Di + Dp = C_D q S

1. Determine VSTALL (Stall speed in KTAS).

2. Determine DMIN (Minimum total drag in pounds).

3. Determine VDMIN (Speed in KTAS at minimum drag).

4. Determine the parasitic drag at DMIN (pounds).

5. Determine the induced drag at DMIN (pounds).

6. Find Glide Ratio at VDMIN.