NO. 4 



WIND TUNNEL EXPERIMENTS IN AERODYNAMICS 



55 



VIII. SWEPT BACK WINGS ^ 



Bv H. E. ROSSELL and C. L. BRAND, Asst. Naval Constructors, 



U. S. Navy 



Part I. — Lift, Drift, and Center of Pressure 

 To determine the effect on the aerodynamical properties of a wing' 

 of sweeping- back the wing tips, as in the so-called German " Pfeil " 

 aeroplanes, a series of tests was made on the model described as 

 R. A. F. 6. The right and left halves of the wing were swept back 

 lO, 20, and 30 degrees to the normal position as shown in figure 17. 



Fig. 17. 



I. 



II. 



III. 



I\'. 



The first part of the investigation deals with the variation in lift and 

 resistance coefficients, and the movement of the center of pressure 

 for the dift'erent models as the angle of incidence changes. The wind 

 velocity of 29.85 miles per hour of standard air ' remains in the plane 

 of symmetry of the wing. 



The curves of the above characteristics for the four wings are 

 given in figures 18, 19, 20. 



The ratios of lift to resistance coefiicients are given in figure 21. 



^ Abstract from a research submitted for the degree of Master of Science 

 in the Department of Naval Architecture, at the Massachusetts Institute of 

 Technology. 



' Standard air is of density 0.07608 pound per cubic foot. 



