a training rig for either students or engineers, in a WW2 classroom for hydraulics

http://3rdstories.yolasite.com/resources/Dwight_Turner/GS%20A.%20C.%20T.%20S.%20%20Chanute%20Field%201941%20Landing%20Gear%20Mockup%20in%20Hydraulics%20Section%20-%20Dwight%20Turner.jpg