Mac; All materials must deform to resist a load. Trees bend in the wind until their tissues "take the load", and steel does too. If you pre-load a structure in tension, by tightening and stretching a bolt for instance, you can take the applied stress without further deformation. This same technique can improve the resistance of concrete to tensile loads by pre-stressing it in compression, and the surface of tempered glass is pre-stressed in tension by chilling it, making it resistant to crack propagation. So we have bridges and the cars that cross them. Peter
-----Original Message----- From: Mac McConnell-Wood via KRnet <krnet at list.krnet.org> To: KRnet <krnet at list.krnet.org> Cc: Mac McConnell-Wood <mac.xm657 at gmail.com> Sent: Mon, Aug 31, 2015 6:30 am Subject: Re: KR> Reaming WAFs Just to add my 2 cents of limited knowledge - I remember during my time as an airforce tech, torqueing a critical bolt so that the Length of the torqued bolt was *increased* by a set figure.......what was all that about ?! Mac On Mon, Aug 31, 2015 at 1:31 PM, Robert7721 via KRnet <krnet at list.krnet.org> wrote: > Concur with Mark. No need to get concerned about this one folks. I > actually did a bad thing and forgot to tighten one, I found it during > another maintenance check later. Probably flew with the nut loose for a > couple hundred hours but it didn't make any difference. > > > Rob Schmitt > > > > > -----Original Message----- > From: Mark Langford via KRnet <krnet at list.krnet.org> > To: KRnet <krnet at list.krnet.org> > Cc: Mark Langford <ml at n56ml.com> > Sent: Sun, Aug 30, 2015 6:00 pm > Subject: Re: KR> Reaming WAFs > > > Nobody's shown me a torque for KR wing attach fittings. It's not in the > > plans. Why is that? Because friction was not even considered in the > > analysis of the wing attach joint. It was a pure shear calculation. > It's > simply a pinned joint, and safe enough on that basis alone. > > Although I'm > certainly not advocating anybody do this, you could likely > fly around with > cottered pins in place of the bolts to keep them from > sliding out of place, > and you'd be fine. I'm pretty sure there are > airplanes and ultralights that > use simple pinned joints. > > Sure, torquing the bolts to some reasonable number > is the common-sense > thing to do, and as Larry pointed out, people do exactly > that. > Calculating optimal torque for a lubricated fastener and nut is > > commendable, but not necessary. > > I'm a mechanical engineer, and recognizing > that it's simply a pinned > joint, I just torqued them by feel and got on with > my business. > Sure...considering friction would be nice, but the designer > simply can't > count on these connections being done perfectly, so he designs > them to > be foolproof, and then add a factor of safety on top of that. That's > > what we're dealing with on these WAFs. After all, this plane was touted > as > being buildable with only simple tools... > > > Mark > Langford > ML at N56ML.com > http://www.n56ml.com > > > > _______________________________________________ > Search > the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe > from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet > info at http://www.krnet.org/info.html > see > http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > > _______________________________________________ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > _______________________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
