 The original pylons which wrapped around the leading edge of the wing had to be cut back to reduce excessive cruise drag.Wind tunnel testing of the next Douglas commercial aircraft, the Douglas DC9 which had no under-wing engines, showed a cutback engine pylon would be beneficial to wing lift and upwash at the tail at the low speed stall.The pylon was reduced in size and became the vortilon ( VORTex-generating-pYLON).