Date: Wed, 13 Sep 1995 12:43:33 -0500 "Marc J. Zeitlin" From: tims@enet.net (Tim Sullivan) Subject: Core cutting Just a general question for those who have made it through chapter 10. If the templates are slightly oversized during core cutting then resized to spec. Would this save time filling with micro all of the divits created by the whoops in the hotwiring. The resized templates are then used as sanding guides to bring them down to spec. size. Does this make sense are is there a problem that I'm not seeing with this idea? Tim Sullivan (tims@enet.net) Phoenix, AZ | * | Cozy MK IV Builder #470 |-----(/)-----| The journey begins 8/10/95 / \ o o From: Marc J. Zeitlin Subject: Core cutting (fwd) Date: Wed, 13 Sep 95 16:04:58 EDT Tim S. asks: >...... If >the templates are slightly oversized during core cutting then resized to >spec. Would this save time filling with micro all of the divits created by >the whoops in the hotwiring. The resized templates are then used as sanding >guides to bring them down to spec. size. Does this make sense? My $0.02: In theory this might work, but in my case at least, the spar caps were the reason for 95% of the micro filling and sanding on the canard. My cores looked good, and the rest of the canard required VERY little filling. I don't know that it would be worth the effort, and I'm not sure that you'd get a better surface by sanding the foam than you get by hot-wiring it. I wouldn't bother. -- Marc J. Zeitlin Mail Stop: MS-460 Email: marcz@an.hp.com Date: 13 Sep 1995 13:48:13 U From: "Judd Stewart" Subject: Core cutting I have built one set of wings for the long ez and helped on numerous others. Cutting cores is a art that can be learned and forgotten. If you cut the cores at the proper temp you shouldn't have any ridges in the core. The proper temp is the point when angel hair is just formed when you exit. Too hot and the wire melts the core thus reducing the overall dimension and causes ridges during those minute pause's (like breathing, repositioning your feet etc.), too cold and the pressure required to pull the wire will cause the wire to lag particularly in the leading edges and spar cap area. I suggest that you get a helper and practice on smaller pieces and develop the skill before starting the big stuff. Don't just lobe off right angles cut curves! I haven't started on my Cozy wings yet but you can count on me buying extra material to practice on. "The better your cores are the LESS work (read as LESS WEIGHT) during finish" Judd #005 Date: Fri, 15 Sep 1995 09:39:31 -0500 "Marc J. Zeitlin" From: tims@enet.net (Tim Sullivan) Subject: Re: Core cutting >Use the right size template to begin with and use the Inconnel wire from >Alexander Aeroplane to cut the foam cores with. It's better than the >stainless and you can get it a lot tighter to minimize wire lag. I used a >hand held wood plane for removing the excess micro that results when you glue >the foam cores together. It does a better job without leaving a ridge like a >sanding block would do. Will do. One more item to add. I have found is very useful to use in light stregth applications for foam binding using a glue gun instead of micro. Hot wiring goes right though the glue with no fuss. The bigger stuff might fall aprt with this method. Tim Sullivan (tims@enet.net) Phoenix, AZ | * | Cozy MK IV Builder #470 |-----(/)-----| The journey begins 8/10/95 / \ o o Date: Thu, 28 Sep 95 7:44:23 EDT From: "Nick J Ugolini" Subject: re: Core cutting (fwd) Here is my two cents on making wing cores. I have talked to a Berkut builder and he told me this is very easy to do. On the Berkut this is the procedure for cutting the wing cores. 1. Make an oversized template (approx 1/4" larger than the final wing size). 2. Hot wire the wing core. 3. Make the final template to exact size. 4. Sand the wing core with a long sanding pole. (in this case a piece of channel Aluminum with rough sandpaper glued to it. 5. Sand to exact size. This is very quick since the foam sands easily. It sounds like more work, but you end up with a perfect wing core that requires no filling (weight and additional prep work) prior to applying the fiberglass. Nick U. Date: Mon, 02 Oct 1995 10:29:26 -0500 From: tims@enet.net (Tim Sullivan) Subject: re: Core cutting (fwd) >Tim, > What kind of sanding "stick" did you use? Was it an Alum. channel? > How much oversized did you cut the hotwire templates, and did you make the >final templates out of Alum. or some other material? Thats the best part. We cut them to size after seeing the perfect cut on one of his oversized cores. No sanding required. Ray spent the better part of the last month perfecting his cutting tool and a regulated power supply to keep the temps stable (he's an EE). I couldn't have bought them from featherlight any better. It doesn't even look like a wire cut was made. Hats off to Ray. >Sounds like you were very successful. I would just like to know a little >more of the details on how you did it and any problems you encountered. I would attribute the cutting tool tension and aluminum templates as the major resons for our success. Only one problem. The torque tube template is too small for the elevator. Anyone out there have a proper sized template? Tim Sullivan (tims@enet.net) Phoenix, AZ | * | Cozy MK IV Builder #470 |-----(/)-----| The journey begins 8/10/95 / \ o o Date: Thu, 30 Nov 1995 15:40:13 -0800 From: nt_ma@qualcomm.com (Mike Anderson) Subject: Formica Templates I noticed in the plans that the templates used for the carnard and probably the wings are made from formica. Is everyone using formica? The only way I have seen it available is in jumbo size sheets, and the places won't sell half sheets. Of course, I could seek out a cabinet company that puts in sinks and ask for the hole piece that was cut out. Could masonite or something else be used instead?? Thanks, Michael Anderson Cozy IV #484 From: Michael Antares Subject: RE: Formica Templates Date: Thu, 30 Nov 1995 17:51:13 -0800 Not wanting to cut up the plans (for no good reason, just my thing!), I = traced the templates onto 1/2" particle board (why 1/2" particle = board?--again no good reason except I have quite a bit of it and it = makes a very substantial and rugged template; no tendency to bend). I think the bottom line is that it's pretty much your call as long as = they are accurate and reasonably stiff. Probably heavy cardboard would = work perfectly fine... $.02, Michael (1.38.193.5/16.2) id AA26163; Thu, 30 Nov 1995 20:23:02 -0500 From: "Volk, Ray" Subject: Templates Date: Thu, 30 Nov 95 18:23:00 PST Encoding: 18 TEXT Mike writes, < Could masonite or something else be used instead?? Mike, I have had good luck with epoxying the paper template right onto a sheet of ether 1/16" or 1/8" aluminium sheeting, cure 24 hours, cut out with a band saw, (cuts like hot butter), and use a sanding machine to fine tune up to the lines. The final templates are rugged, can be made rather quickly, alinement holes are accurate, and the information, ie numbering and verbage, is permanently on the front face. Hope this helps. Ray rvolk@honeywell.com Fri, 1 Dec 1995 15:05:46 +1000 Date: Fri, 1 Dec 1995 14:56:32 +0200 From: parkyn@citr.uq.oz.au (Nick Parkyn) Subject: Re: Formica Templates If you are using these templates for hot wire cutting, formica or similar laminate has always been the preferred material for this purpose. It will not chip when cut or burn from the hot wire. It will produce accurate templates with extremely smooth surfaces for skip free travel of the hot wire. Aerospace Composites Phone ((800) 811-2009) sell a similar laminate (Phenolic Wing Template Board),in small pieces. They recommend it for this purpose. Thicker material when used for the templates may well cause the wire to drag on the templates. Nick #0022 >I noticed in the plans that the templates used for the carnard and probably >the wings are made from formica. Is everyone using formica? The only way I >have seen it available is in jumbo size sheets, and the places won't sell >half sheets. Of course, I could seek out a cabinet company that puts in >sinks and ask for the hole piece that was cut out. Could masonite or >something else be used instead?? > >Thanks, > >Michael Anderson >Cozy IV #484 Date: Fri, 1 Dec 1995 09:27:58 -0500 From: Phillip.Johnson@Lockheed.on.ca (Phillip Johnson) Subject: RE: Templates I used 1/4" plywood and that seemed to work well although you have to be careful not to stop and burn the wood. If you do it will hang there every time there after. I think that thin aluminium sheet would work the best but be cautious in using epoxy to stick the templates to the plate. The wet epoxy may cause the paper to change shape and distort the template. Michael Antares says: > Not wanting to cut up the plans (for no good reason, just my > thing!), I traced the templates onto 1/2" particle board (why 1/2" > particle board?--again no good reason except I have quite a bit of > it and it makes a very substantial and rugged template; no > tendency to bend). Although this is OK for the canard you need to be careful with the wings. I found that my 1/4" plywood caused a noticeable error when cutting the wings because of the template thickness and the wing rake back. 1/2" templates would be worse. You may find that the match of the wings at the core intersections will look like there has been a 1 inch section removed ( 2 pieces of 1/2" ) and this somehow has to be blended. WARNING The canard templates received with my set of plans were not identical in particular around the leading edge (the most critical area). According to the long-eze fraternity this is a known problem and should have been rectified long before our plans were ever issued. I'm not sure which one is correct A or B. I made the mistake of using both templates, one for each end, only to find that they did not match. I was pulling my hair out trying to decide what I had done wrong. Fortunately I had copied the master and was using the copy. I thought that perhaps the copy was distorted so I compared them with the master. They matched the master exactly. I called Nat and got the stock answer. "There are eight hundred builders out there and no one else had commented". Eventually he said that I should take the average of the two. Not a very satisfactory solution but at least it halves the error. Before you cut the templates you may want to try to identify the correct template. The second error has already been pointed out by Nigel Field. This error is the undercut (concave curve) for the slotted flap elevator, this should blend into the top surface but it does not, it is about 1/8" low. This should be raised and blended so that it provides a glass to glass contact with the upper surface without modification to the aerofoil. Many builders find the problem only after they have glassed the bottom surface and are cutting off the fish tail. Some builders modify the top surface to ensure the glass to glass contact but this modifies the aerofoil,NOT A GOOD IDEA. I called Nat after I had cut the cores and before I began any glassing. I got the stock answer again, see above, he said that the undercut caused by the hot wire cutting should be enough to remove the 1/8 error. Not on mine, nor Marc Z's it would seem, nor many others. I sanded the region in question before I did the bottom lay-up to bring it to shape, I also added two plies of spanwize UNI in the region of the glass to glass lay-up to ensure sufficient thickness so that I could adjust the condition after completion. The result, no problem with elevator movement. Phillip Johnson Date: Fri, 1 Dec 1995 09:35:00 -0500 From: Dick.Finn@FNB.sprint.com Subject: Re: Formica Templates ______________________________ Reply Separator _________________________________ Subject: Formica Templates Author: nt_ma@qualcomm.com at INTERNET Date: 11/30/95 6:47 PM I noticed in the plans that the templates used for the carnard and probably the wings are made from formica. Is everyone using formica? Thanks, Michael Anderson Cozy IV #484 ______________________________________________________________________________ A friend used aluminum for his Long-Eze templates. The upside was that they lasted for several planes (he loaned them out). The downside was that they took a long time to build. I was told that they were the same as for the Mark IV so I borrowed them and found that they are indeed different. I believe they are correct for the Cozy Classic though. In any case, Mark IV builders be aware that the Long-Eze wing templates are different. I used formica purchased at a small lumber yard as a cutoff for $10. It was several sheets of about 2'x4'. Phone shop a bit at smaller yards or cabinet shops. Do not buy formica laminated to particle board. Just get the plane 1/16" (or there abouts) thick formica. I started cutting the templates out of particle board and after completing one I threw it out. The problem is that it is thick material. If youend up beveling the edges you can match the template to the plans but still have the hot wire saw cut it too large. Cut \|/______________Template ________/ | Wing | Not a good drawing but maybe it will help. Also, I found it was faster to cut all the templates at once. Don't just do the canard, do all of them. Dick Finn Cozy #46 Date: Fri, 1 Dec 1995 10:25:07 -0500 From: RonKidd@aol.com Subject: Re: Formica Templates I think that if you went to a company that specializes in counter top fabrication or kitchen remodeling, you could buy a trunk full of end pieces and scraps for 10 bucks or less. I think Formica (or clones) make the best templates. It can be fine sanded to a very smooth edge and will hold it thereby limiting hot saw bumping. Ron Date: 1 Dec 1995 09:19:21 U From: "Judd Stewart" Subject: Wing Templates Wing Templates I recommend templates made of about .040 thick aluminum. Masonite/Formica are easily damaged by to much heat. The use of thin alum has the advantage of minimizing the local thermal heat-sink effect on the wire thus causing an unacceptable cut. If you adjust the heat to get a good cut locally the center of the wire is too hot and creates craters. I suggest that each builder retain there wing templates for the life of the plane. My rational for this is in the event that a wing or a section needs to be replaced. By having the original "custom template" you will have a better chance of creating a wing that is close to the original. Judd From: DMDS%mimi@magic.itg.ti.com Date: Fri, 1 Dec 95 14:59:33 CST Subject: Long-Eze wing templates versus Cosy MkIV wing templates From: David de Sosa DMDS Subj: Long-Eze wing templates versus Cosy MkIV wing templates Dick Finn wrote: >I was told that they were the same as for the Mark IV so I borrowed them >and found that they are indeed different. I believe they are correct for >the Cozy Classic though... Back when plans were not yet available for the Cozy MKIV, a lot of people were told they could start on the wings (they were the same as the Cozy Classic plans, even the Long-Eze I believe) in order to keep busy until the MKIV plans were completed. My project happens to have been one of these This is the first that I have heard of any difference between the wings of the two Cozys. Is this true? What kind of difference are we talking about? The last thing I need to think about having to redo is my wings!!! David Date: 1 Dec 1995 17:08:31 U From: "Judd Stewart" Subject: Re: Long-Eze wing templates RE>Long-Eze wing templates versus Cosy... 12/1/95 I think the area that was changed is from BL31 to BL69 ( don't have plans in front of me) The trailing edge was straightened to align with the rest of the wing. BL69 to the tip is the same. Judd Date: Sat, 2 Dec 1995 22:35:13 -0500 From: Danky01@aol.com Subject: Re: Templates In a message dated 95-12-01 19:08:48 EST, Phillip Johnson wrote: > The canard templates received with my set of plans were not identical > in particular around the leading edge (the most critical area). > According to the long-eze fraternity this is a known problem and > should have been rectified long before our plans were ever issued. I'm > not sure which one is correct A or B. I found the same error when I did my canard. I just kind of split the difference and hoped for the best. At the time I thought, the whole thing gets covered with micro and then sanded smooth anyhow, so it seems that the finish process could also bring some small changes to the airfoil. I have since read some articles about airfoil design that would indicate that very small changes in the shape can change the characteristics of the airfoil. I have no training in this area so I cant say for sure. At OSH this year I did get a chance to look at lots of EZ type planes and I always take note of how good the wings and canard look when sighting down the length. Some of these are so smooth you would swear they came out of a high tech mold, others where about as smooth as the pacific ocean on a windy day. Truth is though I cant bad mouth any of the planes at OSH too much though, because they all flew there and my Cozy sits in the garage waiting for me to put the engine on and a few other minor details In summary, 1) I wish that the templets were both exactly the same. 2) They are not. 3) The amount of difference from A to B is small. 4) I hope that the amount is small enough not to mater. Kyle Dansie Cozy IV # 86 Date: Sun, 3 Dec 1995 04:14:20 -0500 From: StetsonE@aol.com Subject: Re: Long-Eze wing templates In a message dated 95-12-01 20:40:18 EST, Judd writes: >I think the area that was changed is from BL31 to BL69 ( don't have plans in >front of me) The trailing edge was straightened to align with the rest of the >wing. BL69 to the tip is the same. > Interesting. I didn't know the Cozy wing had a straight trailing edge. The Long-EZ trailing edge is bent, i.e., the root end is about 1" higher than the trailing edge of most of the wing. It begins this upward transition at about the inboard aileron cutout. Don't quote me, but I believe I recall that the only reason this was done was to allow a VariEze cowl to fit on a Long-EZ. That way the cowling manufacturer (at the time) wouldn't have to retool for a new Long-EZ cowl. The Berkut has a straight wing, and I put a Berkut cowling on my "bent wing" airplane. So for those of you who may have built bent wings for your Cozy, getting the cowling to fit *shouldn't* be too big a deal. Stet Elliott Perpetual Long-EZ builder Mon, 4 Dec 1995 10:13:34 +1000 Date: Mon, 4 Dec 1995 10:04:21 +0200 From: parkyn@citr.uq.oz.au (Nick Parkyn) Subject: RE: Templates Philip Johnson wrote: > WARNING > > The canard templates received with my set of plans were not identical > in particular around the leading edge (the most critical area). > According to the long-eze fraternity this is a known problem and > should have been rectified long before our plans were ever issued. I'm > not sure which one is correct A or B. I made the mistake of using both > templates, one for each end, only to find that they did not match. I > was pulling my hair out trying to decide what I had done wrong. > Fortunately I had copied the master and was using the copy. I thought > that perhaps the copy was distorted so I compared them with the > master. They matched the master exactly. I called Nat and got the > stock answer. "There are eight hundred builders out there and no one > else had commented". Eventually he said that I should take the average > of the two. Not a very satisfactory solution but at least it halves > the error. Before you cut the templates you may want to try to > identify the correct template. Accurate templates are essential. While you may consider that inaccuracies can be addressed during filling and fairing, it is best to start out with the correct shape, so that filling is limited to only really filling the weave. There are a number of problems associated with the accuracy of these templates 1.) The number of times they are copied / re-drawn and thickness of the lines 2.) The cutting and sanding to shape of the Formica templates 3.) The instability of the paper which the plans are supplied on. The templates with the plans should be supplied on Mylar film or similar stable drawing material as humidity and other environmental factors distort paper based materials significantly. Even in the yacht design (marine) industry, it is common to supply templates on mylar film. The ideal would be to CNC cut a set of templates on Formica from computer based co-ordinates and these could compensate for undercut of the wire - this would eliminate all three problems indicated above. Nick #0023 Date: Mon, 4 Dec 1995 09:30:00 -0500 From: Dick.Finn@FNB.sprint.com Subject: Re: Long-Eze wing templates versus Cosy MkIV wing templates David, Here's a little more detail. I was getting ready to work on the wings and was talking to Jim Rios, a Cozy Classic builder from Brookfield,IL. Jim had obtained a set of jigs and the wing templates from a fellow at our EAA Chapter. These were aluminum templates that the fellow had used for his Long-Eze. Jim wasn't ready to use them (still isn't for that matter) so he loaned them to me. I decided that I wanted my own set so I traced the templates from theplans, and glued them onto some formica. After rough cutting them I was going to use double sided tape to attach them to the aluminum templates and then quickly and easily file/sand them to the exact shape using the aluminum templates as a guide. When I got to that point I found that the templates didn't match with my formica templates. At that point I elected to shape my formica ones the old fashioned way. I also checked the jigs Jim loaned me and found that they didn't match. One of any number of things could have happened: 1. The templates may have come from something other than a Long-Eze. 2. The templates could have been customized by the original builder. 3. The wings are indeed different. 4. The templates were different because they were designed to be used at different butt lines on the wing (they were labled at the Cozy butt lines however so I very much doubt this to be the case). I also started my project a long time ago and heard the same thing you did about the wings. I can't say for sure what the actual situation is but suggest you check your templates against the plans. I can't remember what the differences were specifically but think that spar cap was off by a little (inch or so) and the Mark IV templates were slightly larger (1/4 to 1/2") on the inboard side. Basically small differences. Please let me know what you find. Dick Finn Cozy #46 ______________________________ Reply Separator _________________________________ Subject: Long-Eze wing templates versus Cosy MkIV wing templates Author: DMDS%mimi@magic.itg.ti.com at INTERNET Date: 12/1/95 4:15 PM From: David de Sosa DMDS Subj: Long-Eze wing templates versus Cosy MkIV wing templates Dick Finn wrote: >I was told that they were the same as for the Mark IV so I borrowed them >and found that they are indeed different. I believe they are correct for >the Cozy Classic though... This is the first that I have heard of any difference between the wings of the two Cozys. Is this true? What kind of difference are we talking about? The last thing I need to think about having to redo is my wings!!! David Date: Mon, 4 Dec 1995 10:13:00 -0500 From: Dick.Finn@FNB.sprint.com Subject: Re[2]: Long-Eze wing templates My wings also have the root bent upward. I panicked when I finished glassing the first one and saw this. I immediately called Nat who told me that all is well. I compared it against a Long -Eze which also has the bend. Dick Finn Cozy #46 ______________________________ Reply Separator _________________________________ Subject: Re: Long-Eze wing templates Author: StetsonE@aol.com at INTERNET Date: 12/3/95 4:32 AM In a message dated 95-12-01 20:40:18 EST, Judd writes: >I think the area that was changed is from BL31 to BL69 ( don't have plans in >front of me) The trailing edge was straightened to align with the rest of the >wing. BL69 to the tip is the same. > Interesting. I didn't know the Cozy wing had a straight trailing edge Stet Elliott Perpetual Long-EZ builder