For fix-wing aircraft, the pressurized air can travel from the engine through the wing and into the cabin. However, a tilt-wing aircraft, such as the CL-84 Dynavert (shown below), will have its wings "detach" from its fuselage. How would such an aircraft send pressurized air to the cabin?

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    $\begingroup$ I fall to understand why the pivoting wing precludes transferring pressurized air to the fuselage. You don’t have to use rigid connections. $\endgroup$
    – Eric S
    Sep 26, 2021 at 22:02
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    $\begingroup$ Given (except for the V-22) you are talking about experimental aircraft, they may not be pressurized. $\endgroup$ Sep 26, 2021 at 23:04
  • $\begingroup$ @EugeneStyer: V-22 is tiltrotor. Tiltwings are different. Confusing names, I know. $\endgroup$
    – user14897
    Sep 26, 2021 at 23:11
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    $\begingroup$ I went through the list of tiltwing aircraft on Wikipedia and couldn't find a single one that is pressurized. Are sure there is a pressurized tiltwing? $\endgroup$
    – Bianfable
    Sep 27, 2021 at 8:19
  • $\begingroup$ I don't think there is any tiltwing with a pressurised cabin. If there would be one, I don't see why it would need to be pressurised while the wing is tilted, since that typically happens only at low altitude during take-off or landing. It seems you are looking for a problem that does not exist. $\endgroup$
    – DeltaLima
    Sep 29, 2021 at 8:55

2 Answers 2


It's pretty easy. Flexible ducting is readily available. Of course yours would twist in torsion, but it doesn't have to. It can be arranged to bend instead.

The wings are held on by a big, tough horizontal spar. It's round because the wing rotates on it. It's hollow because that's strongest for weight. Thus you are guaranteed to have a big, hollow, round pipe running from the fuselage to at least the mid-wing.

If the bearings could be sealed from blow-by, or if some leakage of bleed air through the bearings is tolerable, the bleed air could be run directly down the hollow spar. Otherwise the spar could be "sleeved" with a plastic tube, which is designed to be OK with 90 degrees of torsion over 15 or so feet of its length. The torsion of the tube would be spread down its entire length, which isn't asking a lot.

  • $\begingroup$ And presumably there would be tubing with similar issues for fuel and for hydraulic controls. $\endgroup$ Sep 30, 2021 at 23:55

This is done in the engineering world all the time, using something called a rotary seal. installing one of these in a pipe allows the ends of the pipe to rotate relative to each other without losing pressure in the pipe.

Rotary seals also are used anywhere a rotating power shaft emerges from a gearbox or an engine block that has oil under pressure inside it, to prevent the oil from squirting out of the shaft hole.

  • $\begingroup$ I am asking about tilt wing aircraft though, wouldn't the pipe from the wing just simply be detached from the pipe on the fuselage when the wing is tilted? $\endgroup$
    – Faito Dayo
    Sep 27, 2021 at 4:01
  • $\begingroup$ no, the rotary seal would allow the wing to tilt while maintaining connection to the engine and the cabin. $\endgroup$ Sep 27, 2021 at 4:30
  • $\begingroup$ But rotary seal just enables the end of pipes to rotate, i can't see how it works when most of the wing is separated from the fuselage. Is there anyway you can use a picture to illustrate what you mean? $\endgroup$
    – Faito Dayo
    Sep 27, 2021 at 13:43
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    $\begingroup$ the pipe runs through the pivot axis of the wing hinge, and the rotary joint is inside the hinge. $\endgroup$ Sep 27, 2021 at 15:46

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