From: krnet-bounces@mylist.net To: John Bouyea Subject: KRnet Digest, Vol 346, Issue 91 Date: 6/1/2004 9:00:11 PM Send KRnet mailing list submissions to krnet@mylist.net To subscribe or unsubscribe via the World Wide Web, visit http://mylist.net/listinfo/krnet or, via email, send a message with subject or body 'help' to krnet-request@mylist.net You can reach the person managing the list at krnet-owner@mylist.net When replying, please edit your Subject line so it is more specific than "Re: Contents of KRnet digest..." Today's Topics: 1. RE: firewall installation (Doug Rupert) 2. wing (outer) weighs? (Dan Heath) 3. RE: firewall installation (Stephen Jacobs) 4. Mark L cautions (Stephen Jacobs) 5. Re: Mark L cautions (Mark Langford) 6. RE: firewall installation (Doug Rupert) 7. power/weight (larry flesner) 8. epoxy safety (Brian Kraut) 9. Foam in the sun (no, not fun in the sun) (Brian Kraut) 10. Re: epoxy safety (Ron Eason) 11. RE: epoxy safety (Wolfgang Decker) ---------------------------------------------------------------------- Message: 1 Date: Tue, 1 Jun 2004 02:55:53 -0400 From: "Doug Rupert" Subject: RE: KR> firewall installation To: "'KRnet'" Message-ID: <002b01c447a5$7e1cf760$aa04e440@office> Content-Type: text/plain; charset="us-ascii" Stephen if you get control flutter problems, fuselage integrity is the least of your problems, unless you want those on the ground to have a nice neat box to plant you in. The point here is structural integrity of the wings and tail are of far more importance should you encounter flutter problems. If the boat is to fail, it's already too late as your wings and tail probably have left the scene as they are where the controls are hinged and take most of the stress. Doug Rupert Simcoe Ontario ------------------------------ Message: 2 Date: Tue, 1 Jun 2004 06:28:37 -0400 (Eastern Standard Time) From: "Dan Heath" Subject: KR> wing (outer) weighs? To: "krnet@mylist.net" Message-ID: <40BC5A55.000007.03536@COMPUTER> Content-Type: Text/Plain; charset="iso-8859-1" RE: how much a wing (outer) weighs? I have 9.8 gal tank, aileron w/balance, attach fittings, and nav lights & wiring, weight is 49 lbs. We have the long Diehl wings, no lights, no tanks weighed with no ailerons or paint, fully primed. They weigh in at around 53 pounds each. On the Little Beast, with KR2 stock built wings, they weighed around 45 pounds each without paint. Your weights look good to me for all the stuff that is included. See N64KR at http://KR-Builder.org - Then click on the pics "There is a time for building and a time for flying, and the time for building has long since expired." Daniel R. Heath - Columbia, SC See you in Mt. Vernon - 2004 - KR Gathering See our EAA Chapter 242 at http://EAA242.org ------------------------------ Message: 3 Date: Tue, 1 Jun 2004 15:19:58 +0200 From: "Stephen Jacobs" Subject: RE: KR> firewall installation To: "'KRnet'" Message-ID: <000001c447db$29fd1bc0$4a64a8c0@home> Content-Type: text/plain; charset="us-ascii" fuselage integrity is the least of your problems +++++++++++++++++++++++++++++++++++ Hey Doug - thanks for the input. As I said before - flutter has been a big issue for a long time, but this phobia got worse after I actually experienced it in a mundane old C206. I did a great deal of experimenting via my other interest, giant scale radio control models. A typical test bed would be 25 to 40 lbs, of similar wood/composite structure as a KR and around 8 to 10' span. I considered this big enough to be representative (and a great deal less painful to crash). Believe me when I tell you that the fuselage takes a beating - I have had a model survive aileron flutter (other then stripped servo gears) but the fuselage had to be rebuilt - more than half of the glue joints let go. You are no doubt right - I am leaning toward overkill - we have seen all sorts of anomalies on home built birds and very few reports of flutter - I have not heard of any on a KR. The matter is mostly academic - with what I have learnt from my experimenting and from this (and other) discussion groups - I seriously doubt that I will come up against this beast. I have evolved a set of rules for myself and I don't mind if they are over-kill. At the risk of being boring: = Go to every effort to keep the moving surface light and rigid (without compromising strength). = At least balance statically - preferably static and aerodynamic - even for the 120 mph birds. = Counter-weights evenly spread (or divided evenly between tip and control horn). = Consider likely G loads when designing counterweight attachments. (There was some input from Oz requiring something like 30G capability. I don't know about that - I would make sure the attachments could handle the same G as the wing spars. It was good for me to read about this - with all the other trouble I was going to, I never considered this important aspect. = Zero slop in the hinges and linkages (rather have them a tad tight). = The moving surface must never be thinner (at the hinge line) than the fixed surface - I will always make the elevator / aileron / rudder a tad thicker than the mating bit just to be sure. = Test results passed on to me via KRnet indicated NO drag penalty even with the control surface 10% thicker. I am referring to wind tunnel tests by a US university. I forget who gave me the info - maybe he will pick up on the post and fill us in. Give all the same consideration to trim tabs - they can set off the whole party. Steve J Zambia ------------------------------ Message: 4 Date: Tue, 1 Jun 2004 15:52:25 +0200 From: "Stephen Jacobs" Subject: KR>Mark L cautions To: "'KRnet'" Message-ID: <000001c447df$af3b6180$2064a8c0@home> Content-Type: text/plain; charset="us-ascii" Mark L cautions: This might be a good time to point out that just about everything on my plane is untested, unproven, and subject to change as I get smarter. Plagiarize at your own risk! +++++++++++++++++++++++++++ This is fully understood and accepted (by me). Fact is that most things on your site are innovative and logical - even the stuff you thought off when it was too late to use on 56ML. I will have the bent wing spars (thank you) and stretched the centre section to half span (thank you). Most of us appreciate the lateral thinkers in the group - particularly the guys that are happy to share their ideas (albeit the caution). Please say something about access to bolts (nuts). I would appear that most KR builders secure the nuts (typically the elevator hinge attach bolts) and then glass over everything - so no more access to the nut ever again. Surely the wood may (will) shrink over time creating some free-play - even if the nut is locked to the thread and cannot move? I never really thought about this until my drawings got to that stage, but I would like to be able to check on everything during an annual (including corrosion) and re-torque or maybe replace. One may argue that corrosion is highly unlikely in a sealed environment. I like the concept of catering for some adjustment of the HS incidence. I opted for 4 vertical bolts holding the stab down to a foundation plate built into the top stringers and well tied into the lower fuselage via the fin spar gusset. Shims will be used to adjust. We had a good discussion going with Larry F re incidences et al - sadly I got busy for a while and fell out of the loop. Every time I see the pic of his bird in flight (quarter rear view) I am tempted to change my drawings back to the plan incidence set-up - it really looks good running with the nose down. Take care Steve J ------------------------------ Message: 5 Date: Tue, 1 Jun 2004 15:27:39 -0500 From: "Mark Langford" Subject: Re: KR>Mark L cautions To: "KRnet" Message-ID: <01c001c44816$e2e40050$1202a8c0@basement> Content-Type: text/plain; charset="iso-8859-1" Steve Jacobs wrote: >(thank you) You're welcome. > Please say something about access to bolts (nuts). I would appear > that most KR builders secure the nuts (typically the elevator hinge > attach > bolts) and then glass over everything - so no more access to the nut > ever again. I'm going to take the time-honored "hail Mary" approach on that one too. I don't think it's a problem that I'm going to worry about. I have a set of rudder pedals here that were ripped out of a KR during a crash. They are still bolted to the upper shelf and some blocks, etc. None of the nuts are loose. I guess if it's never been a problem on previous KRs, it's not a big problem in my mind. And loads on these control surface hinges is not all that great. One that probably DOES need to be tightened occasionally would be the landing gear brackets where they go through the spar. Marty Roberts' brackets loosened up to the point that they poked a hole in the top of his wings, so it can and has happened. You'd need an access plate to do that, but I don't have one. Also, in most cases (like gear brackets) I epoxied the brackets directly to the wood. The bolts could probably fall completely out and not cause a problem... Mark Langford, Huntsville, Alabama N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Message: 6 Date: Tue, 1 Jun 2004 17:56:53 -0400 From: "Doug Rupert" Subject: RE: KR> firewall installation To: "'KRnet'" Message-ID: <003c01c44823$5ce80020$0c04e440@office> Content-Type: text/plain; charset="us-ascii" Right you are Stephen. Now the model and the real banana will not necessarily react the same but the idea is right. My experience with control flutter was always a result of something not being properly adjusted at the plant and "most" of the time I managed to keep it under control and limp back for repairs. The military is very sticky with regards to production control and that is why they tend to keep their own pilots at production facilities to fly each and every bird and turn her inside out to see if it breaks prior to acceptance. They would rather have their test pilots bust her up than have something go wrong at a most inopportune time or with a relatively new pilot at the controls. I myself prefer to build them strong and opt for a bigger engine if required. It would be interesting to check the weights of those KR's flying along with their flight characteristics. I would venture to say that those with the higher weights the ones that handle the best. I believe the rather squirrelly behavior of the earlier models was due to lighter wing loading rather than a design problem. One has to keep in mind that Ken designed the little bird to be built on the cheap which sometimes can contribute to poor flight characteristics. Doug ------------------------------ Message: 7 Date: Tue, 01 Jun 2004 19:01:19 -0500 From: larry flesner Subject: KR> power/weight To: KRnet Message-ID: <3.0.6.32.20040601190119.00798e60@pop.midwest.net> Content-Type: text/plain; charset="us-ascii" > I myself prefer to build them strong and opt for a bigger engine if >required. Doug +++++++++++++++++++++++++++++++++++++++++++++++++++++ All else being equal, I'd go for light weight AND a big engine. Have you ever watched a 400 hp Pitts doing aerobatics? !!!!!!!! I wish my KR was 100 pounds lighter and I was getting another 20 hp from my 0-200. Even the boys "down under" would hear my YEE HAA's then. :-) 56 hours and counting........ Larry Flesner ------------------------------ Message: 8 Date: Tue, 1 Jun 2004 20:57:21 -0400 From: "Brian Kraut" Subject: KR> epoxy safety To: "KRnet" Message-ID: Content-Type: text/plain; charset="us-ascii" When I was at Sun and Fun I was working at the Wicks booth with their manager that had been with them for twenty something years. He told me that of all of the people he knew that had serious health problems from epoxy, that most of them were using gasoline, MEK, or Acetone to clean the epoxy off of their hands. Aside from the other nasty things those chemicals can do to you, they also open up your pores and let the epoxy get in them. Obviously, it is best to uses gloves, but if you do get epoxy on your hands use something a little safer to get it off. Brian Kraut Engineering Alternatives, Inc. www.engalt.com ------------------------------ Message: 9 Date: Tue, 1 Jun 2004 20:57:18 -0400 From: "Brian Kraut" Subject: KR> Foam in the sun (no, not fun in the sun) To: "KRnet" Message-ID: Content-Type: text/plain; charset="us-ascii" I had a tail stand that I used when my plane was upside down for a while. I used the spray can type of urethane foam to make a cradle that exactly fit the tail section snugly. After I was done with it I stuck it near the garage window and put some junk on it for a long time. I noticed that the part that had the sun shining on it turned to dust when you touched it from the UV and I wondered if the sheets of urethane did the same thing. Well, a few days ago while working on my garage I stacked some sheets outside and they were in the sun about ten hours. I was amazed that after that short time there was a very distinct color change in the foam. The parts in he shade were still pink and the parts in the sun were an orange brown. Scraping away with my finger nail showed the change to be over 1/8" thick. I couldn't tell any difference in the strength of the foam yet. This makes me wonder about problems with the glass pulling off of the foam being caused by UV degredation of the foam. I will always keep the plane covered with a tarp when I roll it out of the garage now until the smooth prime is on it. I have another piece of foam outside to experiment with. I will see if it turns to dust after a while. I have a piece of unpainted fiberglass sheet that I will put on a section also and see what happens. In the meantime, keep your unpainted plane out of the sun. Brian Kraut Engineering Alternatives, Inc. www.engalt.com ------------------------------ Message: 10 Date: Tue, 1 Jun 2004 20:14:30 -0500 From: "Ron Eason" Subject: Re: KR> epoxy safety To: "KRnet" Message-ID: <000801c4483e$f52c4d30$6501a8c0@CADENGINEERING> Content-Type: text/plain; charset="iso-8859-1" I've been using Lacquer thinner for years maybe since I was 12 years old, I am now 64. Thinner, then soap and water follow-up. I have never had a epoxy reaction, but fiberglass? Yes, from insulation and epoxy/fiberglass work. Those micro pieces of glass will get into you pores if you don't wash with soap and water. I have stayed away from gasoline [a poor solvent], MEK, or Acetone. I sill use latex gloves though, because epoxy is sticky and messy stuff. KRron ----- Original Message ----- From: "Brian Kraut" To: "KRnet" Sent: Tuesday, June 01, 2004 7:57 PM Subject: KR> epoxy safety > When I was at Sun and Fun I was working at the Wicks booth with their > manager that had been with them for twenty something years. He told me that > of all of the people he knew that had serious health problems from epoxy, > that most of them were using gasoline, MEK, or Acetone to clean the epoxy > off of their hands. Aside from the other nasty things those chemicals can > do to you, they also open up your pores and let the epoxy get in them. > Obviously, it is best to uses gloves, but if you do get epoxy on your hands > use something a little safer to get it off. > > Brian Kraut > Engineering Alternatives, Inc. > www.engalt.com > > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > ------------------------------ Message: 11 Date: Tue, 1 Jun 2004 23:22:28 -0400 From: "Wolfgang Decker" Subject: RE: KR> epoxy safety To: "KRnet" Message-ID: Content-Type: text/plain; charset="us-ascii" As with all chemicals it is advised to read the Material Data Safety Sheets (MSDS) that are associated with the chemicals. This is for resins, but also for any kind of solvent. If the data sheets do not come with the product, they can be ordered by from the manufacturer (who have to provide them, as required by OSHA). The MSDS contains information about problems with exposure to skin, eyes and breathing. They also give ideas what to use when in contact with skin. Typically water and soap is the choice of cleaning agent, when in contact with resin. Aceton disolves all fats in the skin, dries it out and helps transport the resins into the skin, making exposure even worse. Be aware of Latex gloves, as they are not as tight as you may think. In fact, Aceton goes right through it. Better are Nitril or Butylen gloves. In my line of work I have to work a lot with acrylic monomers, some of which are extreme skin sensitizers, others are less harmful. From there I also know that some poeple react very quickly to some of the chemicals, while others to not appear to have any problem whatsoever. All in all, the best defense is to use proper protective wear such as nitril gloves. Wolfgang -----Original Message----- From: krnet-bounces@mylist.net [mailto:krnet-bounces@mylist.net]On Behalf Of Brian Kraut Sent: Tuesday, June 01, 2004 8:57 PM To: KRnet Subject: KR> epoxy safety When I was at Sun and Fun I was working at the Wicks booth with their manager that had been with them for twenty something years. He told me that of all of the people he knew that had serious health problems from epoxy, that most of them were using gasoline, MEK, or Acetone to clean the epoxy off of their hands. Aside from the other nasty things those chemicals can do to you, they also open up your pores and let the epoxy get in them. Obviously, it is best to uses gloves, but if you do get epoxy on your hands use something a little safer to get it off. Brian Kraut Engineering Alternatives, Inc. www.engalt.com _______________________________________ to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net please see other KRnet info at http://www.krnet.org/info.html ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 346, Issue 91 ************************************** ================================== ABC Amber Outlook Converter v4.20 Trial version ==================================