On this video from Captain Joe, you can see that the landing gear of the airplane has got some sort of v-shaped strut connecting the two moving parts. v-shaped strut

I think that I saw the same thing on some vespas with a suspension in the front wheel.

What are they for ?

  • 1
    $\begingroup$ Good question, and on-scope for this site. However, you might have better luck at Aviation, since that's full of people who know airplanes. $\endgroup$
    – Wasabi
    Jul 30, 2018 at 19:14
  • $\begingroup$ Indeed, but I saw the same thing on motorbikes $\endgroup$
    – Frank
    Jul 30, 2018 at 19:19

2 Answers 2


This is the mechanism that allows the piston to move so absorbing the landing forces, while making sure that there is no rotation of the wheel assembly which would create a huge amount of side loading and possibly cause the landing gear to fail.

I have had the opportunity to visit Airbus and stand next to some of the units used to test these... serious engineering, but then 230 tonnes does take some controlling...

  • $\begingroup$ +1, To my naive eye it seems that a spline-shaft coupling would serve the same purpose. Why was a spline not used for this? Perhaps manufacturing tolerances are difficult to achieve because of the complex geometry of a spline? Are there any planes that do use spline shaft couplings for landing gear? Seems like the gear in the pictures would be heavier. $\endgroup$
    – user6335
    Jul 30, 2018 at 21:44
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    $\begingroup$ That piston - well the one I looked at for real - not just a photo, was 30cm diameter approx - given the loading and the high pressures the hydraulics run at 200bar then trying to seal a splined shaft and socket would be a challenge. $\endgroup$
    – Solar Mike
    Jul 30, 2018 at 21:55
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    $\begingroup$ it also provides a support for a constant length path down to the wheels for the hydraulic and electrical lines (there is another lighter strut doing the same in front) $\endgroup$ Jul 31, 2018 at 10:57

I have a small plane and also fly with other small single engine prop airplanes, Such as Cessna, Cherokee, Moony and the like.

They do have a similar structure providing alignment and resisting shimmying of the wheel when the plane hits a bump on the tarmac.

This is likely the same structure except possibly doing some more sophisticated things in addition to that.


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