The simplest (from a geometric viewpoint, hardly needing explanation), is when the hinge is mounted atop the wing surface (left), over the fold joint: the outboard wing section (red) simply rotates up around the hinge, just as on a typical door. As one starts to bury the hinge halfway or more into the wing (right), rotation becomes limited due to binding against the inboard root (blue), depending on how deeply-sunk into the wing it is.
Obviously, burying the hinge deeper into the wing improves aerodynamics - and such a progression was indeed seen between development of, for example, the pre-war TBD Devastator and mid-war SB2C HellDiver - the latter arriving at complete burial of the hinges entirely below the wing upper surface:
Albeit among the most desirable overhead-folding scheme - and thus one you'll need to install among the most frequently - this variant is unfortunately also the most complex, as inboard- and outboard wing surfaces won't clear each other at all (left) - unless employing offset joints (right), straddling the hinge on opposite sides and connected by (some form of) cantilevered arm(s) - at least one, most often two - which ride on it like a see-saw. Typically each arm is fixed to the outboard wing, while the hinge is fixed inboard, so that during folding the arm's inboard tip drops down, while the outboard wing lifts up - to clear the opposing surfaces in both instances, as shown.
This latter scheme, which I will call "Lifting-Arm", remained in use post-war on the F2H2 Banshee - on which build I struggled repeatedly - until finally realizing that this installation (and probably all of the above) would be most easily and reliably achieved on wings which have not yet been separated along their fold-lines! Indeed - and completely counterintuitively - it turns out the easiest models on which to install actual, folding wings are those not designed to depcit wings folded! (Oiy! ) Although my Banshee started out as such a kit, it has long since been repeatedly bashed-upon, its wings not only separated but significantly crapped-up, as well.
Therefore, the examples below will use other kits to demonstrate how to "get it right" (or very nearly so) for the above types of Overhead Wing-Folding, on the very first time around.
Cheers,
-Matty
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