Idea is to increase static pressure at backward facing surface to reduce drag.

Can I reduce drag with channeling freestream air at the backward facing surface, like picture suggest?

enter image description here

  • $\begingroup$ I suppose there would be a so big pressure loss in the pipes virtually neglecting any benefit $\endgroup$
    – sophit
    Dec 15, 2023 at 21:39
  • 2
    $\begingroup$ Is the flow within those pipes turbulent? How much drag happens within them? The wing works by having lower pressure above the wing than below, but this drawing seems to introduce air of equal pressure to both top & bottom, which ought to reduce total lift, requiring more AoA to compensate. Not seeing the positive value here, unless I'm missing something. $\endgroup$
    – Ralph J
    Dec 16, 2023 at 1:18
  • $\begingroup$ you're basically reinventing the slotted flap aviation.stackexchange.com/questions/30960/… $\endgroup$
    – Federico
    May 14 at 13:26

1 Answer 1


You're sort of close conceptually, but from a practical point of view taking space from the fuselage or wing structure for plumbing may not work out.

But this thinking is on the right track. The rearward portions of aircraft structure are where the boundary layer can become more and more turbulent, increasing drag.

"Blowing" these regions can lead to reductions in drag, leading to improvements in fuel economy.

Props have been mounted on the trailing edges of wings and/or fuselage, and jet engines placed on aft portion of the fuselage can also help "clean up" the air flow.

Related reading here. Application: drag reduction high speed trains.


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