Load distribution

I tried to do a proof load, but couldn't figure out a great way to get over a hundred milk jugs hanging from a central point.  A friend recommended trying a beam just like the spars would be, and placing the weight along the beam.  That just wasn't as balanced as I'd hoped, so instead I've decided to trust that this structure is okay and push toward the actual loading.  It didn't budge when both my wife and I hung from it, which is certainly not +1000lb, but it's sturdy.

Yesterday morning while it was raining, I pulled up the AVL model and set up the model to have 50 strips.  These were merged into 25 pairs and the strip forces calculated.  The strip forces give load distribution along the span, and that was scaled up to 3.0G's.  I could always add more mass in a second test based on this same scaling.  I had been saying 3.5G's for a long time, and now that I've done all this work, the extra half-G probably should have been put into this water weight.  Oops.

Anyway, here's the pile of water all ready to be hung.  Every jug was individually measured and matches the load within a few tenths of an ounce.  If you look closely, you can see the masses written on the jugs.  It's a 75% leading edge, 25% trailing edge split, using the actual distribution from the AVL model.

Last night I spent two hours cutting and tying lines between pairs of jugs for looping those over the spars, and bending clothes-hangers into makeshift hooks for the singles.  It's ready to go.

I took off the wheel from the nose section for getting some additional height, and the aileron crank arm for setting up the sling without that in the way.  The pick point looks good.  I can either push the slings out toward the strut connection points or inward toward the wheel support struts.  Outward is more similar to the loading point from the pilot sitting in the nose, but riskier if the slings try to slide inward.  Inward is easier and directly transfers load to the wheel struts which then transfers to the strut connection points, but less representative of how the pilot's weight transfers to the struts.  Either work in my assessment and will depend on feeling out the setup when hanging.

So it's Sunday now and it's quite windy and gusty outside.  This just isn't conducive to a large-scale load test with literally a decade of work hanging in the balance.  Everything is back staged in the garage waiting for better weather and my availability.  Hoping for next weekend, or it'll have to wait until June...