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In addition to winglets and other techniques like sweeping wing back what are the other techniques that delay the formation of local shock wave over the wing?

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    $\begingroup$ Welcome to Stack Exchange! Your question is a little confused, in the sense that you are asking two questions in one post. Could you please align the question title and question body? $\endgroup$ Feb 17 at 14:44

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Winglets are not used to delay shocks. They help to squeeze a bit more lift from a wing and reduce induced drag for a wing of given span.

Winglets help to increase the pressure difference between the top and bottom side of the wing near the tip. This leads to higher overspeeds and earlier shock formation. Note that in a well balanced design the first shocks appear at about the same speed over the whole wingspan, so adding a winglet will let shocks appear first near the tip and a slightly lower speed.

The prevailing techniques for delaying the formation of shocks are to:

  • fly more slowly. Especially for turns or pull-ups, speed should be reduced beforehand.
  • increase wing sweep.
  • adjust pressure distribution over chord such that suction peaks are avoided. This means that most lift will be created by rear loading, so a larger horizontal tail and more torsional stiffness of the wing are required.
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    $\begingroup$ To anonymous downvoter: Why did you downvote this answer? Do you disagree with the statements contained in it? $\endgroup$ Feb 17 at 17:49
  • $\begingroup$ I edited the title to reflect the body of the question, you might want to adjust your answer consequently. +1 from my side $\endgroup$
    – sophit
    Feb 17 at 20:20
  • $\begingroup$ Sorry if I'm not picking something up in the provided link, but what is meant by rear loading? Also +1 from me $\endgroup$
    – Wyatt
    Feb 17 at 20:52
  • $\begingroup$ @Wyatt Rear loading means litte camber in the thick forward part of an airfoil and high camber in the thinner, rear part. This shifts lift production especially at low angle of attack to the rear part of the chord. $\endgroup$ Feb 18 at 0:40
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In addition to Peter Kämpf's fine answer, shocks can be weakened, delayed, or avoided by:

  • Reducing thickness of the wing.
  • Reducing lift coefficient (related to his turns and pull-ups comment)
  • Local area relieving where lifting surfaces meet non-lifting surfaces. For example, coke-bottling a tip tank can prevent the superposition of two areas of super-velocities.
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    $\begingroup$ Should have thought of reducing thickness myself! +1 $\endgroup$ Feb 18 at 0:11
  • $\begingroup$ @PeterKämpf Sometimes we miss the obvious. $\endgroup$ Feb 18 at 5:35

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