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Old 12th Oct 2016, 12:30
  #99 (permalink)  
BRDuBois
 
Join Date: Nov 2015
Location: Seattle area
Posts: 213
Well, I CAN alter the aileron settings, but I don't. Once the turn is initiated I leave the ailerons in that position for the remainder. I use a variety of settings in different runs, but it's stable within each run. There's a little jiggling out past the second decimal, but that's generated by the sim and I can't control it. For this series of tests and examples, I'm presuming the ailerons aren't moving after the cable parted. I've been doing some other runs using a scenario where the ailerons return to neutral, but no useful results yet.

It's possible the ailerons were moving significantly after the break. In order to test possibilities, I need a backstory to justify the exploration. I can't presume they were moving at random and find all the outcomes. Statistically such research is impossible because the permutations are endless. Logically it becomes meaningless because I could concoct any movements I like in order to bolster my case.

If there's a solution (and there's no guarantee I'll find one) it needs a rational scenario for a framework. The system returning to neutral is one. The idea that they were doing something that resulted in some sudden movements is interesting, but I'm not sure how to approach it. The most accessible premise is that there was no movement, since the deflection noted in witness marks is a reasonable deflection to start a moderate turn.

Take a look at https://www.youtube.com/watch?v=MDc4fHJFchY

That's a demo I did to illustrate ideas in an email thread I've got going with a couple pilots. I've been exploring the reaction when the left rudder is initiated at different points after the cable failure using different rates of change and different degrees of aileron deflection. I'm not getting satisfactory results, but it's getting closer.

I've been doing some experiments with hand-flying the simulator in high-angle banks with hard left rudder, to see how it behaves and to see at what point it can't maintain altitude. It's possible that the real answer lies in a higher bank than I'd previously considered, maybe in the mid-50 range, with a rapid left rotation on first impact.

The damage geometry says the plane was banked no more than the mid-30's when the prop left scars on the embankment, but the embankment actually had several strikes. I'm impressed with how fast the plane rotates counter clockwise about its longitudinal axis and right about its vertical axis when it hits the right wing a glancing blow, and then straightens again under rudder influence. Perhaps the answer is that it hit the embankment at a mid-50 bank, and left prop marks while in a mid-30 posture within a matter of a few dozen feet.

I don't know how much weight we can put on impact behavior in the sim, since it's a flight sim and not a crash sim. It's very doubtful that we can trust the plane model to accurately reflect the effect on the plane from tearing off half a wing.
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