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.
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.
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?
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.
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?
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