From: David de Sosa Subject: COZY: Canard fit problem Date: Thu, 10 Jun 1999 14:52:31 -0700 Has anyone experienced this scenario? Canard doesn't fit onto fuselage mounted pins at all until air temperature warms up above 85% or so. Then it fits although very snugly which I assume is how it is supposed to fit. I do seem to remember originally installing the pins during the warm weather months but did not anticipate a problem like this! Is there enough of an expansion or contraction rate difference between the fuselage and the canard section length that fits adjacent to it to cause this type of problem. Has anyone else experienced a problem like this? I seem to remember similar issues reported about the Canopy/turtleback assembly since it is exposed to a wide variation in temperature at altitude vs. sea level. David de Sosa Cozy MkIV #080 Date: Fri, 11 Jun 1999 06:01:13 -0400 From: Jeff Russell Subject: Re: COZY: Canard fit problem David de Sosa wrote: > Has anyone experienced this scenario? Canard doesn't fit onto fuselage > mounted pins at all until air temperature warms up above 85% or so. David, what type of resin system are you using? Sounds strange :-) -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com 2954 Curtis King Blvd. Ft. Pierce, FL. 34946 Shop# 561-460-8020 7:00am to 3:30pm Home# 561-344-6200 Website: http://www.Aerocad.com Composite workshop info: http://www.Sportair.com From: "cliffordfamily" Subject: Re: COZY: Fuel valve location Date: Mon, 14 Jun 1999 03:40:06 -0400 someone questioned about the canard fit and I lost your address. Your question was about temperature and fit. I have not yet gotten to the canard chapter, but will share with you what I know about composit material. Some years ago I built checking fixtures for automobile parts out of metal. Most often the models were made of composites. When the metal checking fixture was built and tuned to the required tolerances of plus or minus 1&1/2 thousands,(.0015), of an inch, it was expected that those tolerances would change as the temp varied. The composit model would expand with a temp increase and contract somewhat when cooler. This would make our go/no go of .003 almost impossible to maintain in a uncontroled temperature enviroment. The engineers always kpt that into consideration when checking for tolerances. Composits WILL expand and contract somewhat with temperature changes. My only thoughts are that your tolerances for clearance are too close. Dave & Mike From: "guy Terren" Subject: COZY: canard clearance Date: Thu, 8 Jul 1999 14:46:26 +0200 I'm fixing the canard and i need some details Do i need a clearance around the canard at the fuse entrance above F22 to allow canard flexion? Thanks for an answer Guy From ???@??? Sat Jul 10 11:40:53 1999 Return-Path: owner-cozy_builders@betaweb.com Received: from twc2.betaweb.com (majordomo@betaweb.com [206.43.209.18]) by acestes-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with ESMTP id WAA11562 for ; Fri, 9 Jul 1999 22:02:05 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id VAA30004 for cozy_builders-list; Fri, 9 Jul 1999 21:22:28 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from ligarius-fe0.ultra.net (ligarius-fe0.ultra.net [146.115.8.189]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id VAA29999 for ; Fri, 9 Jul 1999 21:22:24 -0400 Received: from zeitlinhome ([146.115.235.235]) by ligarius-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with SMTP id VAA16832 for ; Fri, 9 Jul 1999 21:20:42 -0400 (EDT) Message-Id: <4.1.19990709211710.009824a0@pop.ultranet.com> Message-Id: <4.1.19990709211710.009824a0@pop.ultranet.com> X-Sender: marcz@pop.ultranet.com X-Mailer: QUALCOMM Windows Eudora Pro Version 4.1 Date: Fri, 09 Jul 1999 21:17:10 -0400 To: Cozy Builders Mailing List From: "Marc J. Zeitlin" Subject: Fwd: COZY: canard clearance Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: "Marc J. Zeitlin" X-UIDL: 604b2afd689de99b919e47df8699077d guy Terren asks; >Do i need a clearance around the canard at the fuse entrance above F22 to >allow canard flexion? If I understand the question correctly, the answer is no. When you attach the canard to the fuselage in Chapter 12, you do leave a small gap underneath when shaping the cutout so that the BID layup will have some space. There is also some space around the elevator torque tube assembly, but it's small as well. There is no other space required or called out for "flexing" of the canard. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ From: "Tonya Davis" Subject: Re: COZY: canard clearance Date: Fri, 9 Jul 1999 21:27:12 -0500 >guy Terren asks; >Then Marc answered: >>Do i need a clearance around the canard at the fuse entrance > >If I understand the question correctly, the answer is no If I may chip in here: I believe that technically Marc is correct. In practice it may be better to leave a very small gap; say 1/16 of an inch or so. When you reinstall the canard (after paint), fill the small gap with silicone for an air/water tight joint. When the canard does flex ever so slightly, it won't chip your paint. 'this is only worth one cent. Mike Cozy MkIV N141MD flying quite well From: cdenk@ix.netcom.com Date: Sat, 10 Jul 1999 07:02:18 -0500 (CDT) Subject: Re: Fwd: COZY: canard clearance Was said Mine is less than 1/8". Part of the tube opening is framed by a piece attached to the fuselage, and part to the canard. I DO NOT weatherstrip the elevator tube opening, concern for water freezing the elevator in position as passing into freezing air during climb. I do have a small interior rain gutter under the tube opening, but for some reason its not effective. Thats the only place water gets in the plane either on the ground or in the air in heavy rain. The most we have seen between the pedals and instrument panel is a half cup per side. Date: Sat, 10 Jul 1999 11:54:13 -0500 From: Bulent Aliev Subject: Re: Fwd: COZY: canard clearance I wander if someone has tested a very loose boot on the inside of the fuselage? One side tight around the tube and the other fixed to inside of fus. The loose material, like rubberized cloth will allow for the movement of the tube and stop any draft ?? Bulent cdenk@ix.netcom.com wrote: > Was said > Mine is less than 1/8". Part of the tube opening is framed by a piece attached to the fuselage, and part to the canard. I DO > NOT weatherstrip the elevator tube opening, concern for water freezing the elevator in position as passing into freezing air > during climb. Date: Mon, 13 Sep 1999 11:26:07 -0500 From: David de Sosa Subject: COZY: Canard Position Off Several years ago I acquired an early Cozy MKIV project which has several differences from the current plans built version. I just discovered that the distance from F-28 to the wing spar is one inch shorter that called out in the plans. This effectively puts the canard position one inch closer to the wing spar. Since the wing spar is already attached and the fuselage built with bulkheads in place, I am going to have to live with this situation. Other than having to recalculate my C.G. envelope, are there any other issues I need to be aware of especially concerning possible adverse effects to any flight characteristics? David Cozy MkIV #080 From: "Schuler, Larry" Subject: RE: COZY: Canard Position Off Date: Mon, 13 Sep 1999 13:43:00 -0500 David de Sosa wrote: >Several years ago I acquired an early Cozy MKIV project which has >several differences from the current plans built version. >snip >Other than having to recalculate my C.G. envelope, are there any >other issues I need to be aware of especially concerning possible >adverse effects to any flight characteristics? First and foremost, you have a tottally new airplane. Untested flight characteristics. Just "calculating" won't be good enough. It will need to be "proven". Seems to me you might expect a more "forward" aft CG limit and higher front seat weight limit along with higher one-person balast requirement; but you will need to determine what all the new limits are through extensive flight testing. Be very careful of deep stall as you explore the new envelope. Nat had a neat movable weight setup for his testing. Good luck and let us know what you come up with. Interesting mod. Any idea why original builder did that? Larry From: MARC_ZEITLIN@HP-Andover-om1.om.hp.com Date: Mon, 13 Sep 1999 16:06:33 -0400 Subject: COZY: Canard Position Off Larry Schuler wrote; > First and foremost, you have a totally new airplane. > Untested flight characteristics. Just "calculating" won't be good enough. > It will need to be "proven". While I agree that it's a relatively major change, I don't think it's quite as bad as Larry's making it out to be. Moving the canard rearward is similar in effect to making the canard smaller (as recommended in the plans). _If_ the difference in canard position is similar in effect to the reduction in canard size, then you might be able to just build the original size canard (add 3" each tip) and be back in business. You will have to "prove" (as Larry says) your plane just like everyone else who builds one, since no two plans built aircraft are ever identical. > ... Any idea why original builder did that? I'm going to guess that it wasn't intentional :-). You could, of course, rip out the canard mount points and move them forward one inch. This would _not_ be an immense amount of work..... -- Marc J. Zeitlin email: marcz@an.hp.com Cardiology Products Division phone: 978-659-3223 Agilent Technologies fax: 978-659-4373 3000 Minuteman Drive Mailstop: 0223 Andover, MA 01810 Non Impediti Ratione Cognitanis (C&C) From: cdenk@ix.netcom.com Date: Mon, 13 Sep 1999 16:48:08 -0500 (CDT) Subject: Re: COZY: Canard Position Off Was said Don't think one could calculate a new allowable weight balance envelope, thats determined mainly from test flights or some very detailed engineering calculations that very few have the necessary starting data and expertice to execute. It would mean test flights to determine if there is the possibility of deep stall. 1" doesn't seem like much, maybe several percent of some important distance, like to the C.G. of wing lift. Shorter distance would mean the canard has to provide more lift at all speeds, in particular takeoff and landing. More sensitive elevators are also possible. I would investigate using the firewall location (aft edge of the spar) as the starting point for fuselage stations, locate the canard, landing gear (both mains and nose) to that stationing. I don't think the seat locations is critical, when the aircraft is weighed, get several (at different times) people in the seats, add fuel, etc. and read the scales. Then calculate the C.G. of the seat and fuel loads. These will be the numbers that become your plane's lever arms for C.G. calcs. Caution loosing 1" between F-28 and the instrument panel, could be an issue with radio installation. From: Epplin John A Subject: COZY: Elevator torque tube seal Date: Mon, 20 Sep 1999 08:40:31 -0500 In the process of finishing the canard cosmetic fitup it occurred to me that the torque tube through hole may be easy to take care of. It seems to me that any air leakage would be outward, the cockpit would be pressurized somewhat with ram air form the fresh air vents or heated air from the bottom NACA scoop. One would want to minimize the air loss, however. I put a piece of 1/4 in. foam in place with 5 min. epoxy on the canard that closes the gap, just under flush with the outer fuselage skin. Did not worry about the torque tube at the time. The plan is to glass this both sides with one or two BID to the canard after removing the canard. Then make a bushing from aluminum or wood 3/4 od and 3/16 id. Put the hinge pin in with the bushing outside the seal piece, cut the seal out to clear the pin and push the pin into place. Slide the bushing against the seal and transfer the 3/4 od. to the seal. Remove the pin and bushing, cut out to the mark plus some clearance and flox the edge. This will need to be only a half circle so the torque tube can be installed. I have the fuselage aft part already cut to a half circle, used the same technique to mark it some time ago. My guess is that the leakage will be outward, if cold you will have cabin heat on therefore icing should not be a problem. I don't intend to collect any ice but...... Anyone see any problems with this approach? John Epplin MK4 #467 N100EP Lost track of how many kits of Super-fill.....most of it on the floor, sand and sand some more. Date: Mon, 20 Sep 1999 10:34:11 -0500 From: David Domeier Subject: Re: COZY: Elevator torque tube seal John, re "My guess is that the leakage will be outward, if cold you will have cabin heat on therefore icing should not be a problem. I don't intend to collect any ice but......" "Anyone see any problems with this approach?" Absolutely not. However, the air flow in this area is definitely "in". In fact it comes in everywhere, around the canopy, the nose gear area, and the canopy access door hinges. I have no lack of fresh air, which may not be a bad idea since I am suspect of the quality of the air coming forward for heat. This airplane has lose exhaust pipes at the slip joints and there must be some exhaust leakage in that area. However, the CO detector has stayed bright yellow so there has been no CO detected. Sealing the canopy turned out to be the most important item of controlling heat loss (or should I say cold air coming in) One can fly most days without heat if the sun is shining as the cockpit is like a green house. I can't prove this notion, but I think air comes in forward and exits aft around the main gear strut area. The interior is slightly pressurized. The elevator torque tube holes are slightly off parallel to the air flow as the fuselage is still getting wider in this area, hence the "in" flow. Some guys are installing an exit hole aft to facilitate the flow through the cockpit. I don't think about ice at the elevator torque tube area because there is no way I am going to fly this airplane in icing conditions. Period. dd From: cdenk@ix.netcom.com Date: Mon, 20 Sep 1999 16:31:18 -0500 (CDT) Subject: Re: COZY: Elevator torque tube seal May not plan to fly in icing conditions, but in almost all parts of the country freezing conditions can be encountered (cruising at altitudes), and if there is any free water available (could have come from an overnight rain) and the seal allows it to span the gap, frozen controls could result. This is the only place I have ever had water enter the Cosy. Maintain an 1.8" gap all around the elevator offsets. negligible amount of air enters. Spend the effor on a decent heating system. See the archives for mine. With all the talk lately of manufacturer's liability, this is one spot to avoid. HAve cancelled more than several trips due to freezing and rain or clouds, but also have picked up some ice several times, and been in rain with temps in the low 40's. From: cdenk@ix.netcom.com Date: Mon, 20 Sep 1999 16:39:45 -0500 (CDT) Subject: RE: COZY: Elevator torque tube seal Was said, ice won't stick to teflon. If a nice highly polished surface, MAYBE NOT. But one needs to machine the hole, I doubt one could polish it to a high enough microfinish, not to allow some tooth action. Also the teflon could cause water to bridge the gap and lock up the controls. Generally like in an icecube tray, the bond is broken by putting the interface in tension. Here the interface is in shear (sliding), where much more force is required to break the bond. Try taking an ice cube in a tray with near parallel sides and push on the bottom, not bending the tray, I think much force will be required to break the bond. Date: Mon, 20 Sep 1999 20:00:36 -0400 From: "L. Wayne Hicks" Subject: Re: COZY: Elevator torque tube seal Epplin John A wrote: > > In the process of finishing the canard cosmetic fitup it occurred to me that... -------> I'd like to add my two-cents.... I finished the cosmetics at the spool pieces by taping/waxing the part, then filling the gaps with flox. The flox filled in like a "U" under the spool piece and the clark filler foam formed the other half the circle (upside-down U) over the spool piece...all with 1 mm clearance. SPIFFY! Just like I had intended. I was patting myself on the back for a job well done until..... .....Guess what? With the torque tubes, spools, and elevators in place, I cannot slide the canard forward enough to get the alignment tabs off the alignment pins. The spool pieces are locked in place by the floxed "U". Viewing the starboard spool piece, what I need to do is to re-make the clark filler piece to cover from the 9 o'clock position all the way around clockwise to the 6 o'clock position, then taper the flox to fill the areas from 6 o'clock to 9 o'clock, with a nice straight taper from F22 to the 6 o'clock spool position. I'm sorry the words make this sound complicated. I'll update with a picture to my website soon. Wayne Hicks Cozy IV #678 Chapter 18 http://www.geocities.com/yosemite/falls/2027 From: cdenk@ix.netcom.com Date: Mon, 20 Sep 1999 21:12:19 -0500 (CDT) Subject: Re: COZY: Elevator torque tube seal Thats basically what I did, stuff some 3/8" fuselage side foam into the gap with an 1/8" clearance. Then 1 ply BID and finish it. Yes it requires some planning to allow the canard to slip out. From: "Larry & Jenny Schuler" Subject: Re: COZY: Elevator torque tube seal Date: Tue, 21 Sep 1999 18:57:46 -0500 Wayne Hicks wrote: >intended. I was patting myself on the back for a job well done >until..... > >.....Guess what? With the torque tubes, spools, and elevators in place, >I cannot slide the canard forward enough to get the alignment tabs off >the alignment pins. The spool pieces are locked in place by the floxed >"U". Wayne, Might try the AN3s in place of the tab pins. Makes removing the canard a snap. Description is in the archives. Larry From: "Wilhelmson, Jack" Subject: RE: COZY: Elevator torque tube seal Date: Mon, 20 Sep 1999 17:04:04 -0400 John: There is major positive pressure around the torque tube hole. A very tight seal is required to keep the air from freezing your feet, even with cabin heat. I have found that a tight ice proof seal can be made of solid Teflon. It can fit the torque tube like a bearing. +/_ .005. Ice will not stick to Teflon. I made mine about .25 thick. The best way is make a split ring 3" dia. or more with a .75 dia. hole. Slip on the MKNC12A by using the split in the ring. (I assume your building a MKIV.) Then trim the ring to fit the canard and the fuselage. Fit it with flox which also will not stick to it. Jack Wilhelmson N711CZ.