Based on a section modulus of 18.5 in3 and yield strength of spruce at 5000 Psi, the center spar should yield at 92500 lb in. bending moment. I don't know how that translates to wing load.
On Feb 22, 2015 4:58 PM, <PPaulVsk at aol.com> wrote: > > Just an idea. We have a gathering coming up in September. I would imagine there is a set of fwd spars lying around gathering dust somewhere. If we can get them to McMinnville with some sandbags and do our on test. I would be willing to pitch in to help defray the cost. > > I might be able to talk to Eric at Wicks to donate some of there scrap spruce if someone would like to build a AS5048 Spar. We would just need a center and one outboard spar. > > Paul Visk > Belleville Il. > 618-406-4705 > > In a message dated 2/22/2015 10:23:07 A.M. Central Standard Time, krnet at list.krnet.org writes: >> >> On Sun, Feb 22, 2015 at 1:29 AM, Flesner via KRnet <krnet at list.krnet.org> wrote: >> > >> >> >> >> The Spreadsheet says we should be using aluminum spars to make more >> >> than 2G load factors. >> > >> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> > >> > It's been a long held belief that the WAF's were the weak point in the KR >> > spars. I've had the opportunity to inspect 3 crashed KR's, unfortunately >> >> both front and rear spars together can easily take 3.8G at 1200 lbs >> mtow. but thats a rough calculation. i'm actually overestimating the >> stresses because tapered wings have more or less 10% lower bending >> moments than rectangular wings overall. I was assuming a rectangular >> wing. >> >> a more accurate computation will require more accurate load >> distributions with flap and aileron deflections considered. only >> shrenk's approximation and similar procedures can do that. >> >> _______________________________________________ >> 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
