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I realised that full gear swing tests require an aircraft to be fully jacked up; and I think it would make sense to locate the jack points close to the landing gears themselves, on the same load-bearing structures (e.g., main wing spar), since those structures are already designed to support the weight of the aircraft.

Is that generally the case, and are there considerations where designers would locate the jack points elsewhere (and presumably have to specially reinforce these other locations)?

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    $\begingroup$ You would also need to consider the bulk of the jacks and make sure the gear (or the panels) won't hit them on swing test. $\endgroup$ – ratchet freak Nov 17 '17 at 16:38
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Yes indeed, at strong points such as landing gear structure, engine support, or wing strut. The jacks need to be out of the way of the swinging doors of course, but as close as possible to the fuselage.

http://n357v.com/wp-content/uploads/2015/08/Image-12.jpg

https://www.kyb-ksm.co.jp/english/dat/upimg/pi-113206394150.jpg

https://mechatronicjacks.jimdo.com/mechatronic-jacks/

This one has a special design man leg jack.

https://i.ytimg.com/vi/0Uw9fGS4Wio/maxresdefault.jpg

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  • $\begingroup$ Close to the fuselage - presumably to reduce bending in the wing? Thanks for including different examples like the high-wing and the GA plane supported at the tail. I also noticed one of them used a plate to distribute the weight, while others seem to do fine with a smaller contact point. $\endgroup$ – aerobot Nov 18 '17 at 9:24
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    $\begingroup$ Yes to reduce bending in the wing. The wing normally supports the aircraft in flight, but the force is neatly distributed over the area of course, with relatively more air pressure near the root. The landing gear is the only spot in the wing that is designed for concentrated full force, with the aircraft coming down at 10m/s/.. $\endgroup$ – Koyovis Nov 18 '17 at 10:07
  • $\begingroup$ Smaller planes have relatively over-dimensioned skin due to the sheet metal having to have a minimum thickness for workability etc, placement of the jacks does not seem very critical there. I've used aircraft jacks to jack up flight simulators for installing them on their motion base but that is a steel frame, some of the practices i've seen with GA aircraft make me nervous. Wood always seems a good idea $\endgroup$ – Koyovis Nov 18 '17 at 10:08

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