Take a look at the third picture on the page link below. Gene Byrd's lap belt was attached with 1 - 3/16 bolt through the spar cap. You will notice that the left seatbelt is missing. The impact (certainly not 20 Gs) split the spar and the belt pulled out. His shoulder harness was attached by cable to the tail wheel pad. Gene walked away with minor cuts and bruises,The worst bruise was across the shoulders where the shoulder harness restrained him. My belts will be attached to both spar caps. I'm not an Engineer but it seems to me that it would be better to have a channel aluminum under the spar to spread the load the width of the spar and not allow the impact force to focus in a small point. I don't plan on doing that though. http://jackandsandycooper.com/byrdcrash.html
> [Original Message] > From: Mark Langford <n5...@hiwaay.net> > To: KRnet <kr...@mylist.net> > Date: 6/24/2004 7:40:41 AM > Subject: Re: KR> seat belts and spar strength > > Barry Kruyssen wrote: > > > I wouldn't change from the plans. > > And what do the plans say? I looked for seat belts last night and didn't > see it anywhere. I thought I'd seen someplace to just run a 3/16 bolt > throught the spar cap, period (although that may have been in an old > KRnewsletter, rather than the plans). There's a shoulder belt "addendum" > put out by RR, and it's located at > http://home.hiwaay.net/~langford/seat1.jpg and > http://home.hiwaay.net/~langford/seat2.jpg , and it makes no mention of spar > strength, just assumes it's strong enough. > > All I'm pointing out is that before we go crazy designing big beefy brackets > and using huge bolts is that they need to be attached to something that's > not going anywhere. If you're not worried about 20g crashes (and I'll admit > that I'm not expecting one either), then don't sweat it. Larry's thin > brackets and small bolts are probably all you need... > > Mark Langford, Huntsville, AL > N56ML at hiwaay.net > see KR2S project N56ML at http://home.hiwaay.net/~langford > > > _______________________________________ > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
