I've finished the wing design, which was quite an excercise in wetware stress analysis. Trying to make sure the wings are securely anchored for positive and negative G's. I have read where aerobatic models routinely undergo 12g's and on up to 20 g's. I've seen that figure quoted a few places and it does pass the sniff test, which leads to an interesting calculation.
Lets assume the weight of the fuselage is 8 pounds at 1G (yes I know I should talk slugs or grams, but easier to think about) then at 20Gs it impart a 160lb force acting about its center of mass. Assuming uniform wing loading (a bad assumption, but probably not terrible) then that force will need to be reacted by 4 cabane connections and a wing saddle in positive Gs (not so bad) but in negative Gs it will be reacted by the same 4 cabanes and... two dowels and two nylon screws. hmm.. so..
160 lbs / 2 wings = 80lbs per wing == 20lbs per cabane or dowel/nylon screw.
That's not.. terrible.. but that force is going to then be transmitted through the frame, and while it's cliche it remains true: a chain is only as strong as its weakest link. Want to lose a week? Download this game:
http://www.bridgebuilder-game.com/bbg-info.phpIt teaches you how to construct bridges and results in some surprising stress concentrations.
So anyways I have that on my mind (inverted alien wall, anyone?
I think I'm finnaly ready to collect all the parts and send them out for a cutting quote. I have tried to reduce partcount but there are still a lot of intricate parts here, like how much is this bulkhead going to run me cut from 1/8" lite ply.. ? $5? $10? $50? I doubt I could cut it myself to the precision required. Guess I'll see.
I've attached some shots that include the built-up wing, but I think at some point this just becomes noise so I'm not going to post gratuitous pics anymore probably until I actually get some parts in.