KR> kr wings
- Original Message - From: Don Chisholm<mailto:chizmsupholst...@rogers.com> To: kr...@mylist.net<mailto:kr...@mylist.net> Sent: Sunday, August 21, 2005 9:36 PM Subject: KR> kr wings having the outer panels out of the way now then fabricating the rest of the airplane puts you way ahead of the game I did my outer wings first but wished I hadn't. They were always in my way, every time I wanted to do something on the fuselage I had to move them out of my way. Mike Turner Jackson, Missouri
KR> kr wings
KR> kr wings
Mike; I put my wings in another room when I finished them their not in my way
KR> kr wings
Steve; seeing as how you haven't installed your center spars yet may I make a suggestion, food for thought. I built my outer wing panels with my center spars mounted in a rollover jig made from angle iron. It allowed me to turn my assembly over so I could glass my foam cores top side up, bottom side up, leading edge up or trailing edge up. When I built my KR1, and hated doing the outer wing panels on the airplane. This time around I decided to get them out of the way first. It is so much easier to build them this way and using a lazer level and the TET airfoil templates allows you to achieve complete accuracy easily. The outer panels can be completely finished including maintaining aileron alignment by leaving a 48 in. template on the butt of the outer panel. You rig your jig to accommodate the fuselage so you maintain your center spar to outer spar alignments then glue them in.I think anybody that has built a KR will attest with a little after thought that having the outer panels out of the way now then fabricating the rest of the airplane puts you way ahead of the game as it is my consideration that the outerwing panel construction is the trickiest part of the airplane
KR> kr wings
Gav The KR2 (not S) centre main spar is 83" long and the centre rear spar is 84" long. To run your 48" template at right angles on the end of the former will place it 1/2" in from the end of the rear on each side. The difference in spar length compensates for the fact that the rear outer spar sweeps forward and allows for the bends in the outer rear WAFs to align in parallel with the inner rear WAFs. In my view you need a 48" ply template at right angles to the main spar both on the outer end of the centre section and another on the inner end of the wing. They are essential when it comes to sanding down your foam to shape with a very long board. Regards John The Martindale Family 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA phone: 61 2 66584767 email: johnja...@optusnet.com.au - Original Message - From: "GavinandLouise" <gdono...@bigpond.net.au> To: "KRnet" <kr...@mylist.net> Sent: Monday, December 13, 2004 5:49 PM Subject: Re: KR> kr wings > Yes you have read properly, and no I haven't added the foam and glass to the > so called butt end of the centre section as yet. maybe I should do that and > that will fix my problem. > It's just that the plans call for the ply rib to be used as the guide and it > also says that the rib should be a little way in from the end as well, which > doesn't work out. > > Gav > > . > > I hope I read Your problem correctly > > Don Chisholm chizmsupholst...@rogers.com > > > > ___ > > 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 > > > > > ___ > 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
KR> kr wings
No big deal, but a thought that may be maybe worth expressing. My concern with pre-fab wing skins (any wing skins) is the quality of bond with the spars. We need to remember that the airplane is literally being picked up by the skin of its wings (well 2/3 of it is). That may not translate to a great force per sq. ft - a typical KR has a wing load of maybe 10 lbs /sq. ft. At say 4G that is 40 lbs /sg Ft - so maybe 27lbs of actual tug on each square foot of wing. We know that the load distribution is not even over the entire wing and the bit covered by the fuselage is counted, but carries zero aerodynamic load, so some areas must handle a bit more - say 38 lbs /sg ft for those parts in a heavy G turn /pull-up. On the face of it, no big deal - that is a mild 1.3G load for a piston twin. Consider the KR wing structure (below the skin) and imagine dividing the top surface of the wing into 1' x 1' squares and screwing a cup hook into each square. Turn it over and hang 38 lbs on each of the 80 or so cup hooks. How comfortable will we be with the bond between the skin and the spar(s)? How about coming back and hanging these weights on the wing after the bird gets to be 20 years old and sees many great gatherings sitting in the sun. The point is that the combined load is transferred to the wing structure via a much smaller area - for a KR this is essentially the spars. The COP moves around a lot, but typical numbers would suggest that the main spar carries the bulk of the load - particularly under high G loads when the COP tends to sneak fwd - maybe even ahead of the main spar. The typical, KR main spar (top surface area) amounts to maybe 2 sq ft. that could well be carrying up to 700 lbs or more. Still not a very big deal, that is only 700/288 = 2.4 lbs /sq ft, but we do need to keep this in mind when bonding the top skin. With his wing skins DD suggests that we taper the spar in section only and leave the plan view (width) constant for more glue area Have a great Sunday Steve J Mark J - Y Haaa (hee haw) ?
KR> kr wings
"Consider the KR wing structure (below the skin) and imagine dividing the top surface of the wing into 1' x 1' squares and screwing a cup hook into each square. Turn it over and hang 38 lbs on each of the 80 or so cup hooks." Hello Net This is long, if you have a KR to work on, repair , or fly, don't waste your time on this!! It's 29 and snowing here in SE Michigan. For me it's a good day to learn something new. About this G loading of a KR wing, I guess I really would like to learn more, especially since my KR is over 20 years old. It doesn't have wing skins, just the one's I made. I thought that in flight the air traveling over the curved upper surface caused low pressure on the bottom surface and that's what caused lift. As a pilot I learned that in a climbing turn, that one wing is closer to stall then the other, and also that in a pull up, the wing panels transfer the lifting force, what ever the G's to the spars and in particular for the KR, the attach fittings. Such that in an overloaded +G condition the force acting on the wing would be downward as the fuselage trys to pull up. In this situation I always thought the forces were pushing down on the top of the skin. Following that in a -G condition, the wing would try to continue to fly with lift from the bottom while the fuselage trys to force downward, causing the wings fold in failure. I would think that as the spar bends, that the adhesion of the skin to the spar would act to prevent the bending. I can see where gluing the wing skins really good is important. I can't see where the force to lift the skin from the spar comes from. As you will note, I present this as things I would like to learn, since I don't have much aerodynamic training. In a practical since I'm not sure that if I attached a 38 pound weight on the unsupported wing skin, say the space between the spars and ribs, that the thing would not drop through. I'm positive that my original wing covering of one layer of Dynel would not. I have seen pictures and read articles about load testing of wings where nearly a ton a sand bags have been stacked on the aircraft wing to simulate the G loading and read of some that have continued to stack till failure. There tests looked for the destruction of the wing as whole. Over the years the only non straight and level flying that I do is the occasional high speed pass with a pull up. I have no idea at what amount of G's. Orma Southfield, MI N110LR celebrating 20 years Flying, flying and more flying http://www.kr-2.aviation-mechanics.com/ Do not Archive
KR> kr wings
> It's 29 and snowing here in SE Michigan. For me it's a good day to > learn > something new. About this G loading of a KR wing, I guess I really > would > like to learn more, especially since my KR is over 20 years old. It > doesn't > have wing skins, just the one's I made. I thought that in flight > the air > traveling over the curved upper surface caused low pressure on the > bottom NO! THE TOP SURFACE! > surface and that's what caused lift. As a pilot I learned that in a > > climbing turn, that one wing is closer to stall then the other, and > also > that in a pull up, the wing panels transfer the lifting force, what > ever the > G's to the spars and in particular for the KR, the attach fittings. > Such > that in an overloaded +G condition the force acting on the wing > would be NO! UPWARD! > downward as the fuselage trys to pull up. In this situation I > always > thought the forces were pushing down on the top of the skin. > NO! PULLING UP! Following that > in a -G condition, the wing would try to continue to fly with lift > from the NO! TOP! > bottom while the fuselage trys to force downward, NO! UPWARD! causing the wings > fold in > failure. I would think that as the spar bends, that the adhesion of > the > skin to the spar would act to prevent the bending. I can see where > gluing > the wing skins really good is important. I can't see where the > force to > lift the skin from the spar comes from. > Please rethink your + and - G Forces > As you will note, I present this as things I would like to learn, . Orma> Always good to keep learning, Virg > > > ___ > 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 > > Virgil N. Salisbury - AMSOIL www.lubedealer.com/salisbury Miami ,Fl
KR> kr wings
> I thought that in flight the air >traveling over the curved upper surface caused low pressure on the bottom >surface and that's what caused lift. I think that you were tired when you posted. The low pressure is on the top surface. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 lar...@socal.rr.com
KR> kr wings
"The low pressure is on the top" Thanks Larry, you and Virg are correct, that was a typo of the mind. Orma
KR> kr wings
I tried a different approach to building wing sets that makes doing outer wing panels fast and almost painless. my idea was to get them out of the way early in the project. I found when I built my KR1 that building the outer wing panels on the aircraft was awkward and the space needed to build full planform was hard to find here north of the 49th. If you've already installed your center spars in the boat you are already past this point. what I did is precision install my center section wing spar sets on a rectangular upright jig made from angle iron with another rectangular section added on a 90 degree plain to the first to be able to roll the jig into 4 positions in order to be able to position the assembly upright, leading edge up, bottom up or trailing edge up. Using a lazer and AS5046 templates I set my spar sets up full span and installed my ribs with complete accuracy. Using a half way rib I used polystyrene foam and hot wire shaped them to the installed airfoil .templates.I installed the center template because you get too much wire drag past 60 inches on the hot wire. Being able to turn the wing over easily made glassing the panels a snap.I left the 48 inch butt rib on to be able to maintain alignment when I install the ailerons. When I set up the jig I configured being able to accommodate the fuselage as the jig retains proper alignment of the center spar set to the outer wing panels .The spars are fastened into the fuselage retained in the jig. The outer wing panels are the worst part of the project , it's nice to have them out of the way first. Don Chisholm chizmsupholst...@rogers.com
KR> kr wings
Don doing the same here but using 5/8 inch (sold as R12) 24 by 96 inch sheets at Home Depot. Extruded Polyurethane Foam insulation. Added 5 ribs to outer panel to facilitate easier installation of panels. Glassed both sides and hard as a rock. As soon as the fuel assembly arrives and gets installed closing up the wing will be a breeze and the best part, Very little sanding. Got to love it. Epoxy resin is a no brainer but since they are wet wings had to go with vinylester. Works well as long as you got the mix right, otherwise the foam melts. Doug Rupert Simcoe Ontario
KR> kr wings
seems to me if you followed the plans you would have foamed and glassed your center section first to the division line between the center section and the outer wing panel line on a plane that corresponds to the wing attach bolts you could have used the butt end of the foamed and glassed center section airfoil profile as your sanding guide for your outer wing panel root end sanding guide. otherwise you will have to extend the 48 inch AS50whatever template to the attach bolt line to be able to use as a sanding or hot wire guide. however you have determined to shape your foam cores . I hope I read Your problem correctly Don Chisholm chizmsupholst...@rogers.com
KR> kr wings
Yes you have read properly, and no I haven't added the foam and glass to the so called butt end of the centre section as yet. maybe I should do that and that will fix my problem. It's just that the plans call for the ply rib to be used as the guide and it also says that the rib should be a little way in from the end as well, which doesn't work out. Gav . > I hope I read Your problem correctly > Don Chisholm chizmsupholst...@rogers.com > > ___ > 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 >
