I have looked at the set up on your construction pages and it looks very stiff to me. Why don't you, have you, considered a long strut coming out at an angle to give some spring action?
-----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Scott Watts Sent: Thursday, July 02, 2009 8:05 PM To: KRnet Subject: Re: KR> Wing Assembly Progress Larry, Very thoughtful questions. > Why are you using UNI cloth when the KR uses a BID cloth. I am using two layers of UNI 45 degrees off of the spar and 90 degrees off of each other. So you could argue that I am using a BID, just a thicker variant. > The concern I have is with the landing gear leg mount. Mounting > the leg between two foam / glass ribs doesn't seem anywhere > near strong enough to me. What additional reinforcement will be > added? The ribs that the gear are mounted to are not foam/glass where the the gear leg attaches, these ribs are made from three materials: phenolic, aircraft grade ply and foam. The forward section where the gear leg bolts is 1/4" phenolic. The construction of these special ribs can be found here: http://krsuper2.com/ribs4.html . Then 10 layers of BID the full height of the ribs is laid up on both sides of both ribs and extending on to the spar. the layers are staggered in pairs to extend onto the spar 2", 4" 6", 8" and 10" to minimize the stress points. This rigid structure transfers the landing loads to the spar. > I guess I have one more observation. Why go through the trouble of > sanding the "notches" in the foam between two ribs? Why not use > a good straight wider sanding board and sand it to shape using those > two ribs? Seems like that would be easier than trying to "blind" sand > with a short board using the notches as a reference. I guess there's > more than one way to make a sandwich so whatever works is fine. When sanding the wing to shape it is important to keep the sanding block orthogonal to the chord line of each rib at all times. This technique of marking like points on the inboard most and outboard most ribs, and then sanding the notches achieves this. I agree this is probably overkill, but the only way I could think of to communicate and proceduralize the process. If one skews the long sanding block there will be low spots in the middle of the wing and the airfoil will be compromised. Think of the exaggerated condition where the sanding block touches the spar at inboard rib and the leading edge at the outboard rib. > > Oh, one more question? Are you building any twist in the wing for > aileron control during a stall as in the KR2? Yes, I do have washout in the wing. I am using the new KR airfoil with the 15% AS5045 airfoil at the tip, and 18% AS5048 airfoil at root.and I use a Wing Root incidence of 1 degree leading edge up and a Wing tip incidence of 1.5 degree down. Each rib has a level line that places it at the proper orientation. I plan to experiment with stall strips on the inboard leading edges of the wing once flying. I like a nice stall warning buffet, especially when I am flying aerobatics. Take care, Scott _______________________________________ 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
