Do you have any pics or drawings? Thanks.My Shoestring 200 cubic inch racer project has a one piece wing with a tip to tip laminated wood spar. The spar sits on flat gussets welded to the fuselage sides. Two hat shaped steel straps bolt vertically through bushings welded to the fuselage on the fwd side of the spar, entend up and over the spar and bolt in the same fashion to the aft side of the spar. The straps are fairly wide and are fabricated from .063 4130 sheet. Plywood plates protect the spar where the straps comes in contact. There are provisions to prevent the spar from shifting in inboard or outboard. There are no penetrations through the spar. This attachment was designed by Lockheed engineers and seems to have passed the test of time.
I'd love to assist you here, but you have to realize there are no "one size fits all" solutions here.What is the best spar attachment for strength for wing load? Also should the wing be one piece, going through the fuselage with a one piece spar going from wing tip to wing tip?
How are acrobatic aircraft wings/spars constructed and attached to allow such a heavy wing load?
In all my composite work over the years, I have learned that pour foam is absolutely verboten for ANY kind of load bearing use. This is because the densities vary in the final cure from too soft to too hard and everything in between. As the densities vary, so does the weight. It is only good for making plugs or making temporary bonds when planking 2 pound Dow foam. Bottom line up front...it has ZERO structural properties.As an aside, I wonder if pour-in-place plastic foam would significantly stiffen tubular spars by preventing compression collapse inwards????
Thanks for the great advice! Super appreciate it!Similarly, a larger diameter front spar may be lighter and the larger radius leading edge will tame stall characteristics. Those spar tubes will still need solid inserts at bolt/pin attachments.
Go look at Kolb and Avid ultralights to develop a better TLAR “eye.”
As an aside, I wonder if pour-in-place plastic foam would significantly stiffen tubular spars by preventing compression collapse inwards????