Adam Tippin wrote:
I am certain that the clamping force of the nuts and bolt have a Direct impact on the structural integrity of the WAF’s.<
---------------- I worked for years in Aerospace and Defense as a mechanical engineer, which doesn't make me an expert on anything. But on the NASA projects I worked on (mostly Space Shuttle and Shuttle experiments), NASA wouldn't even count "friction" (such as clamping force) in strength calculations for many bolted joints, presumably because a nut could loosen. I'm not saying they didn't care about torque values, but in overall strength-of-joint calculations. I specifically asked an incredibly talented ME stress expert I worked with about that same KR WAF joint, and he said something like "as long as the bolt doesn't fall out, it'll work for the intended use."
Another question that came up on KRnet many years ago was about the weakness of the spruce spar itself, given that if you follow the plans, you'll end up with a very small edge distance from WAF bolt hole to the upper and lower surfaces of the spar faces. But the spars are in longitudinal tension and compression (lower and upper) along the grain, which puts the bolts mostly in shear. I have some WAFs with spars attached to both ends that were remains of a KR crash. Both main and outer spars are broken near the WAF joint, but the WAFs are fine, if that's any indication. It's worth noting that there are no known inflight failures of these WAF joint in KRs, and I assure you some of them have WAF connection bolts are not very tight....N56ML is one of them. I'll send a photo of the crashed WAF joint later after I grab it from my hangar. I'm guessing the bolts and nuts are pretty tight, but again, I don't think it matters. The joint is apparently "good enough for KR" work..... Mark Langford m...@n56ml.com http://www.n56ml.com Huntsville, AL
-- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet
