Hi Dave,
What are my thoughts?
You might regret asking that one.
As you're about to experience, I'm the classic over-thinker and you'll be flying yours while I'm still pondering mine ... 5 years from now.
I place a huge importance on torsional stiffness and this will be handled by carbon cloth at +/-45 under a timber veneer skin.
It's the bending stiffness vs strength that has me pondering.
Each time I think I'm happy with a spar arrangement, I recall the Southern Sailplanes Kestrel 17.
http://members.optusnet.com.au/~rlearmont/Kestrel.html.
It uses/used a foam core with balsa skins and ZERO spar. Nothing!
And, from memory, there was an aluminium tube only about 200mm long that accepted the joiner rod, the end of which wasn't supported by anything other than the foam core. There may have been a web on one side of the aluminium tube to the top or bottom skin to fill a slot from the hole cutting process where the tube goes into the core, but that was it.
Yes, it's "only" 4.25m span, but I saw a few of these fly and none of them failed during loops or winch launches. The wing flex was a load indicator and the elevator was adjusted accordingly.
I too will be flying my '22 like "an old duffer" with the occasional low-level, high-speed pass, but I have no intention of high "G" manoeuvres.
I used the word "intention" deliberately. Where my quandary lies is, do I account for the unintended "G" manoeuvres that may never happen.
I've seen some funky stuff happen to sailplanes on tow when the tow goes pear-shaped.
I've chosen to make the wing in 6 panels. What I'm thinking is to use a spar/web setup for the root panels, then use Drela-style weblets instead of the spar for the mid and tip panels. Remembering that there's a timber veneer 'stressed skin' to add bending stiffness, too.
David.