ghris We used them on VP's and never heard of a failure. There were five spread over about seven inches that supported the entire horizonal tail plane. I forget the name for it but it is one piece and ay least five foot long and a foot and a half wide. The whole thing is the elevator, no tail plane. It would get loose, you could move the ends up and down several inches but didn't seem to effect the way it flew. Of course we were flying around 70. Mr. Evans designed this in the early 60's and to date there has never been a structural failure on a VP-1.
Steve Bray Jackson, Tennessee > >Chris Wrote: I am told the rod end bearings have a habit of cracking and >failing > > >Chris, I too have used the now famous Dr Dean concept, in terms of bearing >failures, you needn't worry, (My opinion) been designing control systems >with bearings for the better part of 20 years, I could send you some data >if you let me know what bearings you are planning to use. > >In my KR2S I used the MS21151-8 (Now found as AS21151) rod end bearings, >greased for life, very low rotational drag and are self aligning, but >mostly I picked because I had some laying around. > >On thing to consider is that most rod end type bearings are designed to >take >a load in the radial direction (that is perpendicular to the bolt) as such >the side load (in line with the bolt) is the weak load path. Care should >be >taken not to preload the bearings in this direction, the Bearing needs to >be >clamped to the ear of your fitting, if that's the KR channel type hinge I >would recommend that that a slip bushing be used on one side so that when >you tighten the bolt it will load the bearing face against the opposite >ear. >What I have done is used Aluminum angle and simply bolts the rod end to the >single leg. The 1/4 diameter bolt size rod ends in my case are serious >over >kill each having a radial limit load of 1720 pounds. I used 5 on the >elevator and 4 on the rudder. They only weighed .10 pound each. > > >Jim Mullen >KR2S, Everett Washington > > > >_______________________________________ >Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >please see other KRnet info at http://www.krnet.org/info.html
