Partial wire bracing


Well-Known Member
Supporting Member
Feb 13, 2010
World traveler
As you can see in these two pics of Clutton FRED G-BMMF, Eric Clutton used an interesting hybrid of cantilever and braced wing design in FRED.

6391977499_cdd3d83f96_o.jpg 6391983675_c205667b6a_o.jpg

Essentially, it's two-spar cantilever wooden wing with built-up Warren-truss spars, a plywood-covered D-cell leading edge, a plywood covered drag spar at the root, all siting on the cabane struts. See this album of pics of an uncovered FRED at the Newark (UK) Air Museum for details: Newark Air Museum.

What's interesting is the choice to use an inverted V of tie rods to brace the wings fore-and-aft and against positive G loads. The rods do essentially nothing about negative G loads. IIRC, the tie rods are mild steel rods welded to mild steel fittings, though that's just from memory, and I think cables were also an option though I have never seen those on a FRED. When the wings are folded the wire Vs simply hinge up and clip against the center section roots, you can just make them out in this screen grab from a slideshow.

folding fred freeze frame.jpg

When I asked Eric about this, he said it was to brace the wing against twisting--not torsional forces as if a giant were trying to twist off a wingtip, but as if the giant were tying to rotate the wing one way and the fuselage the other in a horizontal plane. Thinking about it, a potential advantage I could see is the possibility of building wing spars with identical top and bottom caps (or plain plank spars) and the tie rods would give greater positive vs. negative G strength.

Would any of the more mathematical and engineering-minding folks be willing to take a stab at the pros and cons of this approach?
Last edited: