4
$\begingroup$

What would be the advantages / disadvantages of the following wing planform for supersonic aircraft?

High-Sweep Wing Planform

The suggested planform is in red; a more conventional, delta planform is illustrated for comparison in white. I was wondering if a zig-zagging leading edge would increase efficiency at high speed due to the increased leading edge sweep without a decreased aspect ratio. I was also wondering if improved control at high angles of attack would be an added bonus, like the "dogtooth" on the F-4 Phantom. I suspect that reduced structural strength could be a disadvantage.

Improve this question
$\endgroup$
2
  • 1
    $\begingroup$ Equalizing the cross section will be difficult. And it loses the structurual advantage of a delta to be light weight. $\endgroup$
    – user3528438
    Aug 18, 2017 at 11:29
  • 1
    $\begingroup$ @user3528438: Just what I thought: you'd have to make the pointy triangle part a lot stronger, or else it would just fold back. $\endgroup$
    – jamesqf
    Aug 19, 2017 at 18:46

1 Answer 1

Reset to default
4
$\begingroup$

That's called sweep variation along span. What you've done is combine an inner W wing with an outer M wing.

enter image description here

Both of which were never used.

  • W-wing: A reversed M-wing. Proposed for the Blohm & Voss P.188 but studied even less than the M-wing and in the end never used.
  • M-wing: the inner wing section sweeps forward, and the outer section sweeps backwards. Allows the wing to be highly swept while minimising the undesirable effects of aeroelastic bending. Periodically studied, but never used on an aircraft.

The chordwise flow would be something like this:

enter image description here

The blue area marks an area of very low-pressure and flow detachment. The outboard wing will experience high pressure due to converging flows1. The wing will want to bend up from the middle, and bend down from the tips, structurally that's a nightmare.

The M wing on the right does resemble birds, but birds had to retain their 'arm' joints from their ancestors, and they don't fly at Mach 0.8 speeds.

1 Answer is a wiki for a reason, this is a guess.

Improve this answer
$\endgroup$
3
  • $\begingroup$ I am not sure, but I suspect it is the other way around with the pressure, because higher speed means lower pressure. So the blue area will indeed have little flow and thus detachment, but detachment means pulling in high pressure stagnant air, while the area of converging flow will have low pressure, but the speed will be so high that it will eliminate the advantage of the sweep—the flow is straight, so it goes supersonic. $\endgroup$
    – Jan Hudec
    Aug 21, 2017 at 17:53
  • $\begingroup$ @JanHudec - My reply is also a guess: wouldn't the "eliminate the advantage of the sweep" mean less lift, i.e., higher pressure on top? $\endgroup$
    – user14897
    Aug 21, 2017 at 18:04
  • $\begingroup$ yes, but only above critical Mach number, where the high speed would cause early formation of shock wave and flow separation behind it. Below critical speed, it should generate more lift. $\endgroup$
    – Jan Hudec
    Aug 21, 2017 at 20:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.