From: cdenk@ix.netcom.com Date: Thu, 8 Jan 1998 14:01:49 -0600 (CST) Subject: Re: COZY: post-cure (long) Was surprised to hear people using plastic pipe for canard jig. THe plastic is prone to being out of alignment, would prefer using steel. Either way be sure to check straightness before starting canard construction. Date: Thu, 08 Jan 1998 16:40:41 -0500 From: bil kleb Subject: Re: COZY: post-cure (long) cdenk@ix.netcom.com wrote: > > Was surprised to hear people using plastic pipe for canard jig. plastic is called out in the cozy iv plans as the first choice: "Iron pipe is heavy and expensive, so the PVC pipe would be our first choice." > Either way be sure to check straightness before starting canard > construction. without a doubt. i think the plans say this three times in the same paragraph! -- bil From: lschuler@cellular.uscc.com Date: Thu, 08 Jan 98 16:31:50 -0600 Subject: Re: COZY: canard >Was surprised to hear people using plastic pipe for canard jig. THe plastic is >prone to being out of >alignment, would prefer using steel. Either way be sure to check straightness >before starting canard >construction. I think the PVC is Nat's prefered pipe in the plans. When setting the pipe down (canard flipped over) into the tail initially, the existing canard bottom layup and the supporting jigs are what supports the pipe. No clamping used when bondoing, and the bondo is fairly good at filling in any slight gaps between tail and pipe. So the pipe only needs to be "reasonably" straight. If the bottom skin and jigs are waivy at the tail before the pipe is stuck on, the pipe isn't going to improve it any no matter how straight it is (unless it's clamped on with something very staright on the opposite side of the skin). The PVC I used was (as is normal for the stuff) just tiny bit off. The tail of my canard came out dead straight per taught string line both before and after post cure. The jigs used for bottom layup were string-straight also. FWW Larry Schuler lschuler@cellular.uscc.com Date: Wed, 21 Jan 1998 16:56:26 -0500 From: bil kleb Subject: COZY: chap 10: canard core shape the past discussion of difficulty trying to obtain the "proper" gap between the canard main element and the elevators was affirmed in the latest cozy newsletter. nat recommends taking a 1/16" off of the main canard element along the upper portion of the elevator cut-out. anyone have suggestions on how to easily/accurately remove this material after the cores are joined together (i.e., just before the bottom skin is laid-up)? -- bil Date: Thu, 22 Jan 1998 07:58:09 -0800 From: C Van Hoof Subject: Re: COZY: chap 10: canard core shape bil kleb wrote: > > the past discussion of difficulty trying to obtain > the "proper" gap between the canard main element and > the elevators was affirmed in the latest cozy newsletter. > > nat recommends taking a 1/16" off of the main canard > element along the upper portion of the elevator cut-out. > > anyone have suggestions on how to easily/accurately > remove this material after the cores are joined together > (i.e., just before the bottom skin is laid-up)? > > -- > bil I would use a router, start at one end and work towards the other. the last bit using a handsander, after marking the template side of the foam...but i'm not in your shoes...:-) chris #219 in Ch 09 From: Epplin John A Subject: RE: COZY: chap 10: canard core shape Date: Thu, 22 Jan 1998 07:38:54 -0600 > -----Original Message----- > From: bil kleb [SMTP:kleb@ab00.larc.nasa.gov] > Sent: Wednesday, January 21, 1998 3:56 PM > To: cozy_builders mailing list > Subject: COZY: chap 10: canard core shape > > the past discussion of difficulty trying to obtain > the "proper" gap between the canard main element and > the elevators was affirmed in the latest cozy newsletter. > > nat recommends taking a 1/16" off of the main canard > element along the upper portion of the elevator cut-out. > > anyone have suggestions on how to easily/accurately > remove this material after the cores are joined together > (i.e., just before the bottom skin is laid-up)? > > -- > bil [Epplin John A] I used a sanding block and eyeball. If I remember I sanded the glass almost to a feather edge at the trailing edge. Whatever I did, ended up with elevator lower surface in the same plane as canard lower surface and a gap of .2 in, also made the min travel numbers. What I did was make some thin cardboard templates of the canard and elevator and using the hinge hardware played with these on the table till I was satisfied that everything would work. This gave me an idea of what to remove to get things to come out right. Remember to allow for the skin thickness. John epplin Mk4 #467 Date: Thu, 22 Jan 1998 09:37:51 -0500 From: bil kleb Subject: Re: COZY: chap 10: canard core shape C Van Hoof wrote: > > I would use a router, start at one end and work towards the other. i would prefer to do it with a router, but i cannot figure out a decent jig set-up for it. as it is now, the canard main element is sitting upside down, bonded to the ten "k" jig blocks. the region to be routed is shown in the latest newsletter, or next to and including the trailing edge peel ply strip as shown in figure 37, page 6, chapter 10. getting into this concave region from the top (bottom of the canard) with a router (standard size or dremel) is a bit of a problem unless you have an extremely long shank on your cutter? i'll have to take a look at trying it from the trailing edge with a dremel router, or sanding? -- bil From: wkasty@ix.netcom.com Date: Thu, 22 Jan 1998 12:01:02 -0600 (CST) Subject: Re: COZY: chap 10: canard core shape Bill, What I did was take a cardboard tube, like the ones the fiberglass cloth comes rolled on, and covered it in a spiral with sticky-backed sandpaper I had laying around from a hobby store. The tube was straight and I carefully ran it back and forth the full length of the bottom trailing edge. I never worked on just one spot bacause it would cause a low spot locally. You could run a marker down the trailing edge, allowing the ink to soak in to a certain depth and then have a visual reference as to how much you took off. I am happy with my canard, it has the .2 gap and the bottom is very close to flush with the elevator bottom. But, you better wait several years to ask me how it flys! Bill Kastenholz wkasty@ix.netcom.com Cozy MKIV# 536 From: Jim Hocut Subject: RE: COZY: chap 10: canard core shape Date: Thu, 22 Jan 1998 10:47:28 -0800 Apparently, Feather-Lite has been taking this extra 1/16" off for some time now. I've had the cores from them sitting in a corner for 3 or 4 months and finally ran out of excuses not to build the canard. Anyway, when I saw the note in the newsletter, I made a new set of templates, very carefully taking off the 1/16" where Nat showed, with the intention of using them to remove material from my Feather-Lite cores either with a hot-wire cutter or by sanding. Anyway, after I finished the new templates, they matched my cores exactly (oh pleasant surprise, no extra work). Moral of the story.... don't just blindly remove the extra foam if you've got pre-fab cores, it may have already been removed for you. (I wasn't going to relay this story 'cause I figured nobody would do something that stupid, but then got to thinking back as to why I'm building a 2nd canard, had to repair electrical ducts, had to re-build a landing brake, .....) Jim Hocut jhocut@mindspring.com From: lschuler@cellular.uscc.com Date: Thu, 22 Jan 98 16:09:03 -0600 Subject: Re: COZY: chap 10: canard core shape Bill Kleb wrote: >nat recommends taking a 1/16" off of the main canard >element along the upper portion of the elevator >cut-out. >anyone have suggestions on how to easily/accurately >remove this material after the cores are joined >together (i.e., just before the bottom skin is >laid-up)? I did the deed on my templates, but obviously too late on your foam. Assuming the foam is upside down in the jigs (prep for bottom layup: The 'tail' thickness (top to bottom) should be fairly constatnt from end to end. You could measure this and draw a line along the rear of the trailing edge 'tail' subtracting 1/16" from the bottom (now facing 'up'). Figure about where you would be tapering this new tail to meet the existing curvature, say about a 1/2" or a bit more (you decide) in from the rear of the tail. Mark another line there. Carefully spline sand between the two lines trying to "leave" both showing a bit. You could follow up with some fine hand (one finger) sanding to get a slight concave to match the tail's curve; sanding away the inside line only. Easier than trying to rig up a router or something. Just be carefull of the micro joints, they don't sand away as easily as the foam (but you knew that). When I changed my templates, I used a french curve in that concave area, but now after having just done the top layup, I don't think it will be that important; especially only changing 1/16". Good luck. Larry Schuler lschuler@cellular.uscc.com Date: Sat, 24 Jan 1998 08:30:14 +0200 (GMT) From: pine@global.co.za (pine) Subject: COZY: Perfect canard templates Hi All I wanted to send this letter two days ago. I'm the sales manager for a company that manufactures bare pc boards. To have perfect templates made is so easy, I imported the points into a very powerful software pack joining them with a "Spline" command, scaling it for the LE and exported it to the CNC router. This was then cut out of 1.55mm FR4 pcb material accuret to +/-0.1mm (this material is a 8 ply fiberglase sheet) I'm sure your friendly pcb manufacture would be happy to do this for you at a reasonable cost. If not contact me !! Further most big pcb companies have laser photo plotters. Ours can plot a sheet 600x600mm 8000 dpi with a accuracy of +\- 0.5 thou over 600mm Best of luck Pine Pienaar pine@global.co.za From: Jim Hocut Subject: COZY: Ch. 10 - Shear Web? Date: Fri, 23 Jan 1998 20:22:39 -0500 OK, got a stupid question. I've got my canard all jigged up ready for the shear web layup. When I measure the height of the shear webs I show pretty close to 3 inches (there's a front and back so we're up to 2 sides at 3 inches each). The width varies slightly from inboard to outboard, but is pretty close to 2 inches. Now if I remember back to 2nd year calculus, 3 + 3 + 2 = 8, right? OK, so why do the plans call for me to cut glass that is 10 inches wide? It seems like it would be easier to just go ahead and cut it 8 inches wide (besides, the instructions caution us that it is preferrable to come up maybe 1/4 inch short instead of having glass bunching up into the corner of the recess). We're supposed to cut the uni at 45 degrees, and the layup is at 45 degrees also, so we obviously don't pull and tug the 10 inch wide uni down to 8 inches and come up with some magic angle. Thanks, Jim Hocut jhocut@mindspring.com Date: Thu, 29 Jan 1998 16:05:12 -0500 From: Ian Douglas Subject: COZY: Outboard Canard Trough Depth Hi All, Peter and I cut all of the canard cores yesturday (2 hours HA! Well it might be less time if you aren't using scrap pieces that you have to cut square before starting) and I was wondering about the trough depths at the outboard ends. They appear to be only 1/16" deep. Seems to me I'm only going to have enough room for the shear web and not much else (spar cap will sit proud of trough). Anyone measure one of these? I went through all of the archives but there is nothing about the depth. There was also a large discussion on the number of layers you can lay in it, was there ever any concensis on the number of layers? -- Best regards, Ian D.S. Douglas Director of Technology Workplace Technologies Corporation If you write software, send me your resume! From: Jim Hocut Subject: RE: COZY: Outboard Canard Trough Depth Date: Thu, 29 Jan 1998 13:23:51 -0800 > I was wondering about the trough depths at > the outboard ends. They appear to be only 1/16" deep. Seems to me > I'm > only going to have enough room for the shear web and not much else > (spar > cap will sit proud of trough). Anyone measure one of these? > > That actually sounds about right. I just got done doing the shear web layup on cores that I got from Featherlite, and while I didn't actually measure the depths your 1/16" measurement seems realistic. Jim Hocut jhocut@mindspring.com From: SWrightFLY@aol.com Date: Thu, 29 Jan 1998 19:02:38 EST Subject: Re: COZY: Outboard Canard Trough Depth In a message dated 98-01-29 16:51:10 EST, douglas@ibm.net writes: << They appear to be only 1/16" deep. Seems to me I'm only going to have enough room for the shear web and not much else (spar cap will sit proud of trough). Anyone measure one of these? I went through all of the archives but there is nothing about the depth. There was also a large discussion on the number of layers you can lay in it, was there ever any concensis on the number of layers? >> Sounds like you're in good shape. Just follow the plans. You fill the spar trought with enough to fill it and no more or you will get a bump over the spar and lots of problems. I just finished my canard. Give me a call if you wish and I can give some pointers. Steve Wright Date: Fri, 30 Jan 1998 08:45:59 -0500 From: Ian Douglas Subject: Re: COZY: Outboard Canard Trough Depth Steve, My plan of attack is to use alum. I-beams to hold the cores straight (they will be bolted to the table and hinged). I also plan to vac bag the shear web, spar caps and skins. I figure that 6 x 12' I-beams will be enough to ensure that the whole thing is kept straight... one at the LE, one just behind spar cap, and one along trailing edge - the weight of the I-beams should be enough to keep the cores straight while skinning (I hope!). See any problems with the plan? Yes, it is a lot of extra work to make jigs etc. but we are going to build another Cozy IV right after we finish the first one. -- Best regards, Ian D.S. Douglas MK0069 and MK0626 Date: Sat, 31 Jan 1998 08:06:06 -0500 From: "Jeff S. Russell http://www.AeroCad.com" Subject: Re: COZY: vac bag on canard Ian Douglas wrote: > My plan of attack is to use alum. I-beams to hold the cores straight > (they will be bolted to the table and hinged). I also plan to vac bag > the shear web, spar caps and skins. I figure that 6 x 12' I-beams will > be enough to ensure that the whole thing is kept straight... one at the > LE, one just behind spar cap, and one along trailing edge - the weight > of the I-beams should be enough to keep the cores straight while > skinning (I hope!). > See any problems with the plan? I have vacuum bagged quite of few canards and wings. The first problem you can find, is loss of reference on if you have twisted your airfoil. The vacuum bag will hide your ability to check for twist. Next will be if the bag is totally sealed. Use a gauge reading the pressure on the part and also in-line to compare the both. A leak can strip out resin and make your part too lean. Skin wrinkles can also show up. Wire mesh, perf mylar can help with this problem. If I was a first time builder and had never bagged a airfoil, I would try a scrap (small part) as a trial and see if you like what you see. We went to molding the top skin of the canard because of how difficult I found the vacuum bagging was on that kind of part. If someone wanted me to vacuum a wing, I would have to say no. The weight savings is not enough to overcome the problems of skin wrinkles and twisting. You can't cut out the ailerons ribs because they will crush making the building of the ailerons harder in the long run To sum this up, I think vacuum bagging is best left in a mold. Even with a mold I can have things happen that make a part not as good as a hand made one without a mold. Build test pieces and the rest will go better. My .02 cents -- Jeff From: Jim Hocut Subject: COZY: CH 10 - Shear Web Date: Fri, 30 Jan 1998 19:50:04 -0500 Don't know if I caused myself a problem or not. I haven't heard back from Nat yet so I'll throw my question out to some of this groups fabulous mechanical/structural talent so that hopefully I can get a good warm fuzzy feeling before continuing. In the heat of the battle of single handedly doing the canard shear web layup I misinterpreted the instructions and did the 39 inch long BID ply last instead of after the 45 deg UNI plies. In other words, I should have done this: But instead did this: 8X4 Bid 39X8 BID 9-Ply Pad 8X4 Bid 39X8 BID 9-Ply Pad UNI UNI UNI UNI UNI UNI UNI UNI UNI UNI UNI UNI My gut feeling tells me this isn't a problem, but then I play with electrons for a living and don't pretend to know squat about load paths, shearing forces, etc. Thanks, Jim Hocut jhocut@mindspring.com From: Marc J. Zeitlin Subject: COZY: CH 10 - Shear Web (fwd) Date: Sun, 1 Feb 98 19:20:23 EST Jim Hocut wrote; >I should have done this: But instead did this: > >8X4 Bid 39X8 BID >9-Ply Pad 8X4 Bid >39X8 BID 9-Ply Pad I won't tell you what you should do with a structural layup like this, but I will say that if I had done the same thing, I would have no reticence at all about leaving it at is, as long as I had no air voids at all around the BID pads and covering layups. The pads are their (as it says in the plans) to distribute the load from the lift tabs to the shear web - they should still do so. -- Marc J. Zeitlin Email: marcz@an.hp.com From: lschuler@cellular.uscc.com Date: Thu, 29 Jan 98 17:48:25 -0600 Subject: Re: COZY: Outboard Canard Trough Depth Ian Douglas wrote: >snip >They appear to be only 1/16" deep. Seems to me I'm only going to >have enough room for the shear web and not much else (spar cap will >sit proud of trough). >snip Didn't measure mine, but sounds about right with more on top than bottom. Shear web in place, I belive I started the bottom cap with 2 layers of tape at the outboard ends. Top cap started with 4. I think there is a description in the plans verbage... read it through. Larry Schuler From: Jim Hocut Subject: RE: COZY: CH 10 - Shear Web - One Final Note Date: Sun, 1 Feb 1998 22:10:26 -0500 Marc Z. wrote: I won't tell you what you should do with a structural layup like this, but I will say that if I had done the same thing, I would have no reticence at all about leaving it at is, as long as I had no air voids at all around the BID pads and covering layups. I also received a reply from Nat today via e-mail expressing the same sentiment. See, I'm getting educated while I build this plane. Maybe one of these days I'll know everything there is to know about fiberglass structures, and will do everything right the first time (yeah - dream on). Anyway, I feel a lot better about what's going to be under the skin of my canard now. Another list member also expressed concern over the orientation of the layups. All plies were at 45 degrees exactly as per plans, and except for the slight shuffling of their order it was an extremely good layup (I was hurting my arm patting myself on the back for doing such a good job when I noticed my slight screw up. Thanks, Jim Hocut jhocut@mindspring.com Date: Fri, 27 Feb 1998 07:57:05 -0600 (CST) From: "Tom G. Brusehaver" Subject: COZY: Frustrated, I think I hit the first wall. I built the canard through most of january, For the bottom sparcap layup, I wasn't sure what the overlaps would be, but thought a little longer would be better. Bad move, I had big bumps, that I ended up belt sanding off. The top, I went the other extreem, and shortened 'em a little (not so much), so now the top skin is wavy, there. I am looking at this with dissapointment, but am a little nervous about quality, nothing specific, but just so much went wrong, I probably did something undetectable wrong. The first thing I did after unjigging the canard was to set up two chairs, one at each tip, and sat on the center. Huh, it held, I musta done something right. Well anyway, I then did the elevators, figuring that even if the canard is trash, I can use the elevators on the next canard. Everything through the bottom layup came out wonderful. I looked at the drawings, and was mostly sure I understood what was happening, but I mis-read FIG. 12 (chapter 11). I didn't do glass to glass bond, but I did glass to micro to glass bond. It wasn't until yesterday while sanding the TE that I noticed this was obviously wrong, and that I gotta re-think, and rebuild. We were teased with a couple days in the 50's here, so I was cleaning out the garage getting ready to jig the fuse. As things are here, it is gonna snow this weekend, so it'll probably be a month before it really gets warm here. I guess I can wait. So now I got a canard to build and a pair of elevators to do. Just like I was two months ago. I think I might look into building some electronics, at least I can fix those :-/. There is a Sport-Air builders seminar in April, I am thinking of waiting until after attending that, before doing anymore fiberglass work. From: Marc J. Zeitlin Subject: COZY: Frustrated Date: Fri, 27 Feb 98 9:55:12 EST Tom Brusehaver wrote: >....... The top, I went the other extreem, and shortened >'em a little (not so much), so now the top skin is wavy, there. I am >looking at this with dissapointment, but am a little nervous about >quality, nothing specific, but just so much went wrong, I probably did >something undetectable wrong. I don't know why you'd _assume_ that there's something wrong. The spar takes the bending loads, and the skin takes the torsional loads. If you've got the correct thickness of spar caps, you're OK there. If the skin waviness is within the parameters called out in chapter 25 (not really explicit there, but a bit of waviness is acceptable - you can never get the fibers perfectly straight) then you're alright there as well. Remember, if the problems are localized, you can always repair them using the techniques in chapters 3 and 25. >......... I didn't do glass to glass bond, but >I did glass to micro to glass bond. It wasn't until yesterday while >sanding the TE that I noticed this was obviously wrong, and that I >gotta re-think, and rebuild. Rather than completely rebuild, you also have the option of sanding off a couple of inches of the bottom skin (less aerodynamically critical than the top in that region), making the step for the G-G bond to the upper skin, and then laying up a new strip of skin that taper overlaps the existing bottom sking and bonds with the upper skin at the TE. You can then fill the step with micro. This would probably be substantially less work than recreating the elevators. I did essentially this on the TE of both of my winglets, because I was not happy with the way they came out. >So now I got a canard to build and a pair of elevators to do. Just >like I was two months ago. I think I might look into building some >electronics, at least I can fix those :-/. Don't despair - I think you can either use what you have (on the canard) or fix it easily (on the elevators). >There is a Sport-Air builders seminar in April, I am thinking of >waiting until after attending that, before doing anymore fiberglass >work. While it certainly cannot hurt to take this seminar (I've never heard a bad word about it from ANYONE), I wouldn't be so hard on yourself. Remember, most people who built flying composite aircraft did so without taking this class (or having built a composite aircraft before - everyone's got to do it a first time). Hope this helps. -- Marc J. Zeitlin Email: marcz@an.hp.com From: "L. Wayne Hicks" Subject: COZY: A solution for "Frustrated" Date: Fri, 27 Feb 1998 10:23:42 -0500 -----Original Message----- From: Marc J. Zeitlin [SMTP:marcz@hpwarhw.an.hp.com] Sent: Friday, February 27, 1998 9:55 AM To: Cozy MK-IV Builders Subject: COZY: Frustrated Tom Brusehaver wrote: >There is a Sport-Air builders seminar in April, I am thinking of >waiting until after attending that, before doing anymore fiberglass >work. Marc Z: Don't despair - I think you can either use what you have (on the canard) or fix it easily (on the elevators). [L. Wayne Hicks responds:] I've never attended the Sport-Air clinic (I plan to), but I bet they cover the "how-to's" for making repairs. I bet they also bring stuff to demo on. It might be worth a shot at offering up your canard and elevators as "ginnea pigs" and letting Sport-Air do demo'ing on them. From: lschuler@cellular.uscc.com Date: Fri, 27 Feb 98 09:56:27 -0600 Subject: COZY: Frustrated, Tom Brusehaver wrote: >I think I hit the first wall. Happens to all of us from time to time. Hang in there. >I built the canard through most of january, For the bottom sparcap >layup, I wasn't sure what the overlaps would be, but thought a little >longer would be better. Bad move, I had big bumps, that I ended up >belt sanding off. Not a bad move at all. Actually, I did spar caps essentially the same way "Intentionally". After caps cured, I laid duct tape on the foam and belt-sanded the caps down to the tape; checking with template for curvature etc VERY VERY frequently. Took a while, but got them absolutely perfect with zero bumps or tape transitions to fill later. If you belt sanded the bumps after laying up the skins over the spar caps; you'd better think seriously about scraping the canard. >The top, I went the other extreem, and shortened 'em a little (not so >much), so now the top skin is wavy, there. I am looking at this with >dissapointment, but am a little nervous about quality, nothing >specific, but just so much went wrong, I probably did something >undetectable wrong. As for structural integrity after laying the top skins over caps that may be slightly lower than ideal here and there: depends on how many layers of cap tape you got in. I believe I ended up with 12 total at the center section. But I sanded maybe 1/2 of the last one away. Your 'waviness' is probably right along the spar cap to foam intersection and I understand this may be normal (why I overfilled and belt-sanded). After the skins are on, these depressions are simply filled with dry micro for contour. If you ended up with air bubbles, that's another issue. Do NOT fill with micro before skinning; you must have a good glass-glass contact; even if it's a bit 'wavy'. >The first thing I did after unjigging the canard was to set up two >chairs, one at each tip, and sat on the center. Huh, it held, I >musta done something right. Nice confidence chaeck! "BUT" watch out for point loading. Could cause a delamination. Put some old carpet or foam on the chairs first. Same for when you decide ya just gotta sit in the tub. Protect the fuselage bottom from high point loading with foam or old carpet. >snip >I didn't do glass to glass bond, but I did glass to micro to glass >bond. It wasn't until yesterday while sanding the TE that I noticed >this was obviously wrong, and that I gotta re-think, and rebuild. >snip Good luck. Larry Schuler MK-IV plans #500 lschuler@cellular.uscc.com From: Jim Hocut Subject: COZY: Canard Finishing - Tolerances Date: Tue, 17 Mar 1998 10:31:23 -0800 In between doing several other tasks on my project I've been futzing around with trying to get my canard to perfectly match the templates. It's close, real close in fact, but still not perfect. I've got an area a little ways up from the leading edge that seems to be about 1/64 to 1/32 low. A couple more sessions of filling & sanding & filling & sanding ought to get it. I'm wondering if correcting that small of an error is even worth the effort. How about an honest assessment from some of you guys who are flying now, did you get your wings and canard to match the templates PERFECTLY? Thanks, Jim Hocut jhocut@mindspring.com Date: Tue, 17 Mar 1998 17:42:36 -0500 From: Tom Teek Subject: Re: COZY: Canard Finishing - Tolerances Hi The most important part of the whole plane is the Canard! Make it as right as you can. Tom LE N58AT Repairs complete and ready for paint and Sun , n fun From: "Nat Puffer" Subject: Re: COZY: Canard Finishing - Tolerances Date: Tue, 17 Mar 1998 16:28:55 -0600 Dear Jim, Back in the Varieze days I saw some canards (GU airfoil) which were pretty sorry. They differed in the affect of rain. Burt used to say they should be accurate down to .005 in. But with the Roncz canard, I haven't heard what tolerance was required. I'm sure your airplane will fly. How it compares to a perfect airfoil, I can't say. Regards, Nat ---------- > From: Jim Hocut > To: 'Cozy Builders' > Subject: COZY: Canard Finishing - Tolerances > Date: Tuesday, March 17, 1998 12:31 PM > > > In between doing several other tasks on my project I've been futzing > around > with trying to get my canard to perfectly match the templates. It's > close, > real close in fact, but still not perfect. I've got an area a little > ways up from > the leading edge that seems to be about 1/64 to 1/32 low. A couple more > sessions of filling & sanding & filling & sanding ought to get it. I'm > wondering > if correcting that small of an error is even worth the effort. > > How about an honest assessment from some of you guys who are flying now, > did you get your wings and canard to match the templates PERFECTLY? > > Thanks, > > Jim Hocut > jhocut@mindspring.com Date: Thu, 19 Mar 1998 03:38:11 -0500 From: David Domeier Subject: COZY: Canard Tolerances (message sent to Jim Hocut) Jim, The MKIV is my second project. I built an early LEZ with the GU canard and I am sure it was not perfect as I am sure my current MKIV canard is not perfect. The LEZ was flown for 6 years and at times in weather not so good. When it was wet the airplane climbed about 500 fpm and when it dried off, it descended about the same rate. The condition was easily trimmed out. The canard also stalled as advertised when loaded up in a tight turn , i.e., it felt like riding across rail road ties - bump-bump-bump. And would only do that when wet. No doubt we should strive to get the airfoil as perfect as possible, but it will work if not absolutely perfect, I know that to be true. There are many canards flying and they are not all the same. I think the elevator balance is very critical. They must balance within specs or the flight will really be outside any established envelope. dd PS I hope to find out how mine does this summer. Date: Sun, 09 Nov 1997 10:04:25 +0100 From: Jean-Jacques CLAUS Subject: Re: COZY: Chapter 13 Canard Attachement lschuler@cellular.uscc.com wrote: > > 1/8" CLT LIFT TAB is ok. But with the 1/4" CLT LIFT TAB, the Cosy Classic enter in the "utility category" ( +4.4g , -2.2g ) with a safety factor of 1.5. The canard's top attach points are reinforced too. If anyone wants to receive drawings of these modifications, please let me know. Happy building, Jean-Jacques CLAUS French Cosy Builder From: "peter von szilassy" Subject: COZY: RE: [canard-aviators] Wing/Canard storage Date: Wed, 1 Jul 1998 16:31:45 -0400 I stored my canard after glassing, no finish or prime for about 3 years with no affects. Hung it from the ceiling in my garage close to the ceiling and supported every 4 feet with rope covered with a foam pad. The foam pads were those foam pipe insulators you can buy in any hardware store for 1 inch pipes. Can be cut to any length and ropes slide through them easily. Used same system for wings except used rope and pulleys so I could lower or raise the wings as needed. Provided same supports under wings once raised. Ropes were essentially tied out to large eye hooks (3/8 inch type) threaded into the joists. Up in the ceiling area no UV dares go. Would at least cover the canard (or wings) with an old sheet (works great) or such to keep dust off it. After first year, my canard had a visible layer of dust on the top surface without the sheet. Pete From: "Nat Puffer" Subject: Re: COZY: Wing/Canard storage Date: Wed, 1 Jul 1998 13:19:01 -0500
Larry,
Without knowing what they might be exposed to (UV, dirt, grime, etc) it
would probably be a good idea to cover them. Clyde Rutledge, who moved
quite a bit and whose project took a long time wrapped his components in
brown rapping paper.
Regards,
Nat

----------
> From: lschuler@cellular.uscc.com
> To: cozy_builders@canard.com; canard-aviators@canard.com
> Subject: COZY: Wing/Canard storage
> Date: Wednesday, July 01, 1998 2:01 PM
>
>
> With some recent discussion on wing storage I was wondering:
>
> I will be storing my canard as soon as the nose is completed.  Is it
> appropriate/necessary to prime the wings, canard, etc before storage for
> UV/grime protection?   Final fill and sanding is done.
>
> Seems safe to assume my canard and elevators will be 'hanging' around for
a
> couple years at least.
>
> I have been working my 5-year project for over two years now and it looks

> like my guesstimate was right on.... I still have 5 years to go.  :-)
Must
> be about the place where lots of folks toss in the towel and go for spam.
>
> Larry Schuler Cozy MK-IV plans #500
> lschuler@cellular.uscc.com
>
>