From: marc_zeitlin@hsgmed.com Subject: COZY: Newsletter 56, page 5, Envelope Expansion Date: Tue, 16 Jul 2002 12:00:19 -0600 Paul Stowitts writes: >That does explain my sensitive pitch. But I'm currently at >the tolerance limits. How much more do I go? I was hoping to stay out of this discussion publicly, but I think that people are becoming alarmed, possibly needlessly, regarding planes that fly just fine. I'll try to respond from an aerodynamics point of view (I do have two degrees in aeronautical engineering), but if I'm a bit rusty, I know that there are others with aeronautical backgrounds that can step in and correct me. Nat Puffer writes: >If you require more elevator than you should for level flight, it means >that the canard is at too a low an angle of incidence, and >isn't providing enough lift to hold the nose up without requiring a lot >of elevator. Then, if you use a little back stick, you have suddenly >increased the angle of attack on the canard, which causes it to >generate a lot more lift, and the nose will pitch up more than you >intend. If the canard is set to an incidence angle lower than the design specified, then adding elevator (back stick) will increase the EFFECTIVE AOA by increasing the camber of the canard - it does not increase the actual AOA. This increase in camber increases the lift to the point that it would have been if the incidence angle had been correct (for that particular velocity). There is nothing "sudden" about it, nor is there any reason that the nose would pitch up more than you "intend". Small deflections of the elevator (and hence small increases in camber of the canard) add lift in a relatively linear fashion, and there's no reason that the nose would pitch up more in the second 5 degrees of deflection than it would in the first 5 degrees of deflection. >.... This is known as pitch instability, which means that your >airplane will want to diverge from positive stability, and do >uncommanded things in pitch. I'll have to respectfully disagree with this assessment. Pitch instability occurs when the CG is in back of the neutral point, and this is determined by the CG envelope. If the CG is in the correct place, the aircraft will be longitudinally stable, no matter what the incidence angle or AOA of the canard is (within reason - meaning that we're not near stall). See: http://adg.stanford.edu/aa241/stability/staticstability.html For a discussion of longitudinal static stability. The equations hold for canards as well as standard configuration aircraft. The COZY will NOT be longitudinally unstable just because the incidence of the canard is a degree or two different from the design point, and will NOT do "uncommanded things" in pitch. >....... this >condition will allow you to get the nose up high enough to stall out >the main wing. You should ground your airplane until you correct this >problem. Believe me! If you replace the "will" with "may", this statement would be true. The question is whether the small incidence angle is enough to allow the canard to get to a high enough angle so that the main wing will stall. This can only be determined by experimentation. It may be the case that with the 1" margin that Nat says the COZY design has between the rearmost CG and the actual neutral point, a SMALL canard incidence angle error would not be in any way dangerous or even noticible, or it may be possible that the aircraft is incredibly sensitive to small incidence angle changes and can get into a main wing stall situation with just a tiny error in canard incidence. Personally, I don't believe the second option is true. I believe that if the incidence angle is set a degree or two too low, one may reduce the safety MARGIN at rearward CG's, but that hardly equates to unsafe. >....The lift contributed by the fuselage is destabilizing, however, >because the lift of the fuselage increases as the angle of attack >increases. The lift of any airfoil/lifing body increases as the AOA increases - this is an innate characteristic of anything in an airflow. The reason that the fuselage is destabilizing is because of the added pitching moment, which is dependent upon AOA. The above URL discusses this as well. This does affect stability, but stability is not the issue in main wing stall. The fuselage contribution to lift DOES affect main wing stall, and must be considered, but not from a stability standpoint. >... Because of this, it is necessary to increase the angle of >incidence of the canard as compared to that of the long EZ, so the >canard will reach its maximum angle of lift sooner, because the >fuselage lift is increasing. If you change the wording from "because the fuselage lift is increasing" to "because of the extra contribution of lift from the COZY fuselage over the L.E. fuselage", then I will agree with this statement. >If you wish to fly around in cruise with your elevators >trailing edge down, be advised that you are endangering your life, and you have been warned! This is somewhat alarmist at best. It would be more useful to see an aerodynamic analysis that showed what the tolerance is to canard incidence angles, and what the safety margin is in the standard design versus the modified (i.e. slightly different incidence angles) design. With this analysis, we could understand exactly how far out of specification the canard incidence angle could be before we have to start worrying. Without this analysis, we are all just hand-waving regarding safety margins. I would assume that this would be a relatively simple modification to the original calculations regarding the canard incidence angle and should be easily available. I would be happy to carry them out if provided with the original equations and calculations. I hope this helps shed some light on this topic and somewhat allays the fears of those that are flying with a slight canard incidence difference from the plans. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://users.rcn.com/marc.zeitlin/ http://www.cozybuilders.org/ From ???@??? Mon Jul 22 19:12:02 2002 Return-Path: Received: from mx03.mrf.mail.rcn.net ([207.172.4.52] [207.172.4.52]) by mta02.mrf.mail.rcn.net with ESMTP id <20020718041007.ZDN7355.mta02.mrf.mail.rcn.net@mx03.mrf.mail.rcn.net>; Thu, 18 Jul 2002 00:10:07 -0400 Received: from alum.mit.edu ([18.7.21.81]) by mx03.mrf.mail.rcn.net with esmtp (Exim 3.35 #5) id 17V2cB-0000ZT-00 for marc.zeitlin@rcn.com; Thu, 18 Jul 2002 00:10:07 -0400 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id AAA03046; Thu, 18 Jul 2002 00:10:04 -0400 (EDT) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id g6IC9gY02274 for cozy_builders-outgoing; Thu, 18 Jul 2002 12:09:42 GMT X-Authentication-Warning: ensim.rackshack.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from ensim.rackshack.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id g6IC9gb02269 for ; Thu, 18 Jul 2002 12:09:42 GMT X-ClientAddr: 208.129.255.5 Received: from goinpostal.extremezone.com (enterprise.extremezone.com [208.129.255.5] (may be forged)) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id g6IC9gG02264 for ; Thu, 18 Jul 2002 12:09:42 GMT Received: from default (ip-189-23-34.phx.extremezone.com [204.189.23.34]) by goinpostal.extremezone.com (8.11.3/8.11.3) with ESMTP id g6HHn9H05215; Wed, 17 Jul 2002 10:49:09 -0700 (MST) Message-Id: <200207171749.g6HHn9H05215@goinpostal.extremezone.com> X-Spam-Filter: check_local@goinpostal.extremezone.com by digitalanswers.org From: "Nat Puffer" To: , Subject: Re: COZY: Newsletter 56, page 5, Envelope Expansion Date: Wed, 17 Jul 2002 11:03:20 -0000 X-MSMail-Priority: Normal X-Priority: 3 X-Mailer: Microsoft Internet Mail 4.70.1155 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Nat Puffer" Dear Marc, Since the beginning of this forum, I believe that the advice you have given to Cozy builders has been mostly sound. But I don't believe it is constructive to get into an argument about aerodynamic theory. What I do believe is constructive is to communicate to builders what Jim Patton and I learned in our flight test program, what I have learned in accident investigation, and what I have learned in helping builders improve the performance of their airplanes. 1) In our flight test program, we obtained data on elevator position at different speeds and different c.g.s We used that data to calculate the c.g. position for neutral stability, as we explained in newsletter #56. That position was aft of our approved c.g. range, meaning that the Cozy Mark IV had positive stability throughout its c.g. range, if built similarly to the airplane we tested. 2) I assisted the FAA and NTSB in the investigation of an airplane registered as a Cozy, but not built according to plans. It was determined that one of the contributing causes of the main wing stall was the canard was not mounted at the recommended angle of incidence (the elevator position was about 4 degrees trailing edge down). Another contributing cause was a 2 inch mistake in the calculation of c.g., which meant he was testing stalls at aft c.g. with too low an angle of incidence on the canard, as well as missing vortilons. 3) I consulted with a Long EZ pilot who complained that his airplane did not have positive pitch stability. After inquiring about his elevator position in cruise (trailing edge down), I suggested that he increase the incidence of his canard. He did so, and thanked me afterwards for the increased stability. 4) In the last 5 years, I have suggested to two Cozy builders (who reported trailing edge down elevators) that increasing the incidence of their canards would make their airplanes more stable. They did so, were pleased with the results, and thanked me for it. Now I am not sure what aerodynamic priniples or laws of physics apply, but I am pleased that we have been able to help our builders. Best regards, Nat From ???@??? Wed Jul 17 20:36:01 2002 Return-Path: Received: from mx03.mrf.mail.rcn.net ([207.172.4.52] [207.172.4.52]) by mta02.mrf.mail.rcn.net with ESMTP id <20020717152449.WPQN7355.mta02.mrf.mail.rcn.net@mx03.mrf.mail.rcn.net>; Wed, 17 Jul 2002 11:24:49 -0400 Received: from alum.mit.edu ([18.7.21.81]) by mx03.mrf.mail.rcn.net with esmtp (Exim 3.35 #5) id 17UqfZ-00050Z-00 for marc.zeitlin@rcn.com; Wed, 17 Jul 2002 11:24:49 -0400 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id LAA04620; Wed, 17 Jul 2002 11:12:11 -0400 (EDT) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id g6HGCot06655 for cozy_builders-outgoing; Wed, 17 Jul 2002 16:12:50 GMT X-Authentication-Warning: ensim.rackshack.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from ensim.rackshack.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id g6HGCnH06650 for ; Wed, 17 Jul 2002 16:12:49 GMT X-ClientAddr: 192.25.240.36 Received: from msgbas1.cos.agilent.com (msgbas1x.cos.agilent.com [192.25.240.36]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id g6HGCnZ06645 for ; Wed, 17 Jul 2002 16:12:49 GMT Received: from msgrel1.cos.agilent.com (msgrel1.cos.agilent.com [130.29.152.77]) by msgbas1.cos.agilent.com (Postfix) with ESMTP id 6465EB752 for ; Wed, 17 Jul 2002 09:11:48 -0600 (MDT) Received: from axcsbh2.cos.agilent.com (axcsbh2.cos.agilent.com [130.29.152.144]) by msgrel1.cos.agilent.com (Postfix) with SMTP id 1968A2D5 for ; Wed, 17 Jul 2002 09:11:48 -0600 (MDT) Received: from 130.29.152.144 by axcsbh2.cos.agilent.com (InterScan E-Mail VirusWall NT); Wed, 17 Jul 2002 09:11:46 -0600 Received: by axcsbh2.cos.agilent.com with Internet Mail Service (5.5.2653.19) id <35530D7X>; Wed, 17 Jul 2002 09:11:46 -0600 Message-ID: From: marc_zeitlin@hsgmed.com To: cozy_builders@canard.com Subject: FW: COZY: Newsletter 56, page 5, Envelope Expansion Date: Wed, 17 Jul 2002 09:11:42 -0600 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain; charset="iso-8859-1" Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: marc_zeitlin@hsgmed.com Nat Puffer wrote: >You have heard the advice of the designer, who did the prototyping, the >design, and the flight testing, and you have heard the advice >of those who have academic credentials, but have not yet finished their >airplanes, or flown them, or conducted extensive flight tests, and had >other test pilots test their airplanes. On the other hand, my post was based upon aerodynamic facts, and I provided a link to a URL which clearly explains the basis of longitudinal stability. I assume that you're not going to claim that academic credentials are completely meaningless, just as I would not claim that they're all important. And whether or not I have flown my plane (as will occur in August) does not change either the laws of physics nor the well known and studied equations of flight. This is not a contest of who knows better - this is a study of aerodynamic performance and facts. I am certainly open to ANY technical argument that can show where I am incorrect, or any analysis that points to factors or characteristics that I have missed. I wrote: > I would assume that this would be a relatively simple modification to >the original calculations regarding the canard incidence angle and >should be easily available. I would be happy to carry them out if >provided with the original equations and calculations. This offer stands - if I'm provided with the original analysis, I'd be happy to do a tolerance study or sensitivity study to investigate this matter further. >..... Believe whom you wish. But >don't blame us if you follow the advice of others and it turns out to >be faulty. This is always the case. However, causing people to panic without showing the facts or analysis behind the recommendations (and three anecdotes without any indications of relative incidence angles, CG positions, speeds, or other factors does not represent facts or analysis) is less than optimally responsible. If you would like to continue this discussion on a factual basis, I'd be happy to do so, otherwise I'll withdraw. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://users.rcn.com/marc.zeitlin/ http://www.cozybuilders.org/ From ???@??? Mon Jul 22 19:12:20 2002 Return-Path: Received: from mx03.mrf.mail.rcn.net ([207.172.4.52] [207.172.4.52]) by mta02.mrf.mail.rcn.net with ESMTP id <20020718155050.WXDH7355.mta02.mrf.mail.rcn.net@mx03.mrf.mail.rcn.net>; Thu, 18 Jul 2002 11:50:50 -0400 Received: from alum.mit.edu ([18.7.21.81]) by mx03.mrf.mail.rcn.net with esmtp (Exim 3.35 #5) id 17VDYH-0002Kd-00 for marc.zeitlin@rcn.com; Thu, 18 Jul 2002 11:50:49 -0400 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id LAA21133; Thu, 18 Jul 2002 11:50:47 -0400 (EDT) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id g6INmlN06344 for cozy_builders-outgoing; Thu, 18 Jul 2002 23:48:47 GMT X-Authentication-Warning: ensim.rackshack.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from ensim.rackshack.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id g6INmlY06339 for ; Thu, 18 Jul 2002 23:48:47 GMT X-ClientAddr: 209.185.241.118 Received: from hotmail.com (f118.law3.hotmail.com [209.185.241.118]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id g6INmlG06334 for ; Thu, 18 Jul 2002 23:48:47 GMT Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Thu, 18 Jul 2002 08:48:10 -0700 Received: from 143.182.124.3 by lw3fd.law3.hotmail.msn.com with HTTP; Thu, 18 Jul 2002 15:48:10 GMT X-Originating-IP: [143.182.124.3] From: "Ryan Amendala" To: Cozy@extremezone.com, marc_zeitlin@hsgmed.com, cozy_builders@canard.com Subject: Re: COZY: Newsletter 56, page 5, Envelope Expansion Date: Thu, 18 Jul 2002 09:48:10 -0600 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 18 Jul 2002 15:48:10.0542 (UTC) FILETIME=[8496CCE0:01C22E72] Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Ryan Amendala" Nat, Have all the planes that you have helped installed the canard according to plans? Are you saying we should increase angle from Template G (I believe) from level? I am currently working on the elevators and should be installing the canard in the next few weeks and I do not want to do it twice. Thanks Ryan Amendala Cozy MKIV #855 Monument, CO From ???@??? Mon Dec 23 15:23:27 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by sccrgwc03.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021223190902.MSTL10343.sccrgwc03.attbi.com@alum.mit.edu>; Mon, 23 Dec 2002 19:09:02 +0000 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id OAA16786; Mon, 23 Dec 2002 14:09:01 -0500 (EST) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id gBNJ0Br26382 for cozy_builders-outgoing; Mon, 23 Dec 2002 19:00:11 GMT X-Authentication-Warning: twctex.lidar.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from twctex.lidar.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id gBNJ0Bu26377 for ; Mon, 23 Dec 2002 19:00:11 GMT X-ClientAddr: 199.131.12.22 Received: from sv2wo.wo.fs.fed.us (sv2wo.wo.fs.fed.us [199.131.12.22]) by twctex.lidar.net (8.11.6/8.11.6) with ESMTP id gBNJ0Av26372 for ; Mon, 23 Dec 2002 19:00:10 GMT Received: from sv8wo.wo.fs.fed.us by sv2wo.wo.fs.fed.us (USDA-FS/WashDC/10-10-2002) using ESMTP; id OAA53158 for ; Mon, 23 Dec 2002 14:01:52 -0500 Subject: RE: COZY: Latest newsletter templates - canard incidence To: cozy_builders@canard.com X-Mailer: Lotus Notes Release 5.0.7 March 21, 2001 Message-ID: From: "Mark Knaebe" Date: Mon, 23 Dec 2002 13:01:46 -0600 X-MIMETrack: Serialize by Router on ENTWOA/E/USDAFS(Release 5.0.11 |July 24, 2002) at 12/23/2002 02:01:51 PM MIME-Version: 1.0 Content-type: text/plain; charset=iso-8859-1 Apparently-To: Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by canard.com id gBNJ0Bu26378 Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Mark Knaebe" Nick Ugolini writes- Overall, my trailing elevator is 1/4" up in cruise, my take off rolls are dramatically reduced and my stall is 58 knots.. I couldn't be happier. ?????. I'm leaving spaces between thoughts so it will be easier for you to point out my mental errors. Please, not all of you. In flight, the elevator with trailing edge down results in a virtual canard incidence greater than the actual incidence. The greater the elevator is out of level (zero) the more drag. By design, the canard has greater wing loading than the main wing and will therefore stall at a higher velocity than the main wing. I would think this would be the case no matter what (within reason) the incidence of the canard is. By moving the cg back you reduce wing loading on the canard reducing drag but at the horrific potential of main wing stalling. Given the above I would think you would want to install the canard so that at cruise the elevator is at zero; where the virtual incidence = actual incidence. 2nd issue - One way to increase the canard wing loading is the mandatory span reduction of the canard but wouldn't a forward movement of the CG limits have accomplished the same thing while maintaining a slightly slower stall speed? ****************************************** Mark Knaebe ch5 Date: Sun, 22 Dec 2002 14:59:13 -0500 From: "Marc J. Zeitlin" Subject: COZY: Latest newsletter templates - canard incidence Jay Hegemann writes: >I got the new "F" template to mount my canard....... > It seems that those who are flying with a few degrees trailing edge > down elevator, (which is alot really) would result in quite a bit of drag. So this brings up an interesting question, given that I probably have a canard that's 0.5 - 1.0 degrees low. Although this doesn't have any safety implications for my aircraft, as I've already done stall testing at aft CG over the full range of weights and bank angles, there may (as Jay postulates) be some performance advantage to bringing the canard to a higher incidence angle. Since the lift tabs and rear canard alignment tabs are fixed, both in vertical position and angle, and the canard cover is rigidly attached to the canard, just how exactly would I go about re-mounting the canard with the minimum amount of work if I were to choose to do so? I suppose I could cut the canard cover off the canard and then glass it back on later without a whole lot of fuss (except for some paint touch-up - it's not structural in any way), but the lift-tabs and alignment tabs? If others have done this (and I think a few have), how did you go about it? Thanks. -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://marc.zeitlin.home.attbi.com/ http://www.cozybuilders.org/ Copyright (c) 2002 From ???@??? Tue Dec 24 17:51:08 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by sccrgwc01.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021223020141.IKFW10177.sccrgwc01.attbi.com@alum.mit.edu> for ; Mon, 23 Dec 2002 02:01:41 +0000 Received: from smtp.comcast.net (smtp.comcast.net [24.153.64.2]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id VAA26719 for ; Sun, 22 Dec 2002 21:01:41 -0500 (EST) Received: from office (pcp991058pcs.nchrls01.sc.comcast.net [68.59.32.185]) by mtaout06.icomcast.net (iPlanet Messaging Server 5.2 HotFix 1.07 (built Nov 25 2002)) with ESMTP id <0H7J00D3FUY31N@mtaout06.icomcast.net> for marc_zeitlin@alum.mit.edu; Sun, 22 Dec 2002 21:01:27 -0500 (EST) Date: Sun, 22 Dec 2002 21:01:16 -0500 From: Nick U Subject: RE: COZY: Latest newsletter templates - canard incidence In-reply-to: <5.1.0.14.2.20021222145413.00a96d00@mail.attbi.com> To: "'Marc J. Zeitlin'" , "'Cozy Builders Mailing List'" Message-id: <001801c2aa27$30e69720$6900a8c0@office> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Mailer: Microsoft Outlook, Build 10.0.2627 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Importance: Normal X-Priority: 3 (Normal) X-MSMail-priority: Normal Marc, I too had to change the incidence of my canard. It was 1 to 1.5 deg down resulting in elevator trailing down (about 1/4 -1/2"). This resulted in extra long take off rolls and a high angle of attack for canard stall. Nat had a great deal of concern about it, so on his advice I began immediate repairs. I seem to recall reading something in the canard pusher a while back on how to resolve the issue. On the LongEZ there are two pins on the canard cover for aligning the canard. I didn't changes those since it would be much harder to align the canard and subsequently drill them out. I took off the nut plates on F22, floxed the existing holes up put a couple of extra layers of glass on F22. Then I put the new template on the canard with the longerons properly leveled. Then redrilled the holes in F22 using the tabs on the canard as a guide. I then glassed the nut plates back on. All this work will screw up your canard cover (mainly on the cockpit side (aft)of the cover). I just cut the glass off the top part, sanded the foam own to the right height and put two layers of glass on it. You'll have to put micro on the cover to close the joints. It required a bit of put the canard in place, check for alignment of filler, then take off and sand a bit more... You could never even tell it has been done now. I think from start to finish it too 5 or five evenings... Mostly for the epoxy to harden. You only will have to repaint the canard cover, but I painted just the top of the canard. Overall, my trailing elevator is 1/4" up in cruise, my take off rolls are dramatically reduced and my stall is 58 knots.. I couldn't be happier. Nick Ugolini LongEZ, Cozy3 Charleston, Sc From ???@??? Sun Dec 22 21:16:21 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by rwcrgwc51.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021223021049.EPRT5246.rwcrgwc51.attbi.com@alum.mit.edu> for ; Mon, 23 Dec 2002 02:10:49 +0000 Received: from relay01.roc.frontiernet.net (relay01.roc.frontiernet.net [66.133.131.34]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id VAA27872 for ; Sun, 22 Dec 2002 21:10:48 -0500 (EST) Received: (qmail 25730 invoked from network); 23 Dec 2002 02:10:46 -0000 Received: from unknown (HELO r2h8m4) ([209.130.147.144]) (envelope-sender ) by relay01.roc.frontiernet.net (FrontierMTA 2.3.1) with SMTP for ; 23 Dec 2002 02:10:46 -0000 From: "jepplin" To: "Marc J. Zeitlin" , "Cozy Builders Mailing List" Subject: RE: COZY: Latest newsletter templates - canard incidence Date: Sun, 22 Dec 2002 20:08:04 -0600 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Importance: Normal In-Reply-To: <5.1.0.14.2.20021222145413.00a96d00@mail.attbi.com> Marc J. Zeitlin writes: Since the lift tabs and rear canard alignment tabs are fixed, both in vertical position and angle, and the canard cover is rigidly attached to the canard, just how exactly would I go about re-mounting the canard with the minimum amount of work if I were to choose to do so? I suppose I could cut the canard cover off the canard and then glass it back on later without a whole lot of fuss (except for some paint touch-up - it's not structural in any way), but the lift-tabs and alignment tabs? If others have done this (and I think a few have), how did you go about it? ........... Good questions. I have been contemplating doing this. As you say, the cover is not a big problem. The alignment tabs could be cut off and replaced without a lot of trouble. The lift tabs are another problem. I talked to Vance Atkinson at OSH this summer about this. His suggestion was to cut into the bottom of the Canard at the lift tab until you find the bolts and remove the existing tabs. Make new tabs from thicker material, same alloy specs, and mill one side to match the present attach point. Seems possible but a lot of work. I wonder if going from 1/8 to 3/16 and putting the required bend in it would be reasonable? The loading is in tension for the most part, should not be a problem. Another approach would be to make a taper shim to put between the existing tab and the bulkhead. The problem with this is the 1/4 in hole would be egged out to get a bolt in. What about removing the nut plates and replacing with 5/16 in nut plates and redrilling through the bulkhead and the tab, making a good bolt fit again. IIRC, there is an aluminum bushing in the bulkhead that could be drilled and align reamed with the shim and lift tab. The down side is the angle change is in the wrong direction, the shim would be thickest at the bolt location, placing a bending load on the bolt. Increasing the bolt size may offset this, at least partially. A matching tapered washer would be needed under the bolt head, not a big problem. Thinking about it, I believe making matching shims for each side and maybe pinning them to the tab with a small spring pin might be better. Any comments? John Epplin, MkIV, with down elevator. From: "Paul" Subject: RE: COZY: Latest newsletter templates - canard incidence Date: Sun, 22 Dec 2002 18:17:39 -0800 Marc, When I changed my canard incidence, I started by cutting off the top aft glass flange. I removed the top alignment bushings by heating them with a small soldering iron and twisting them out with pliers (this worked very well). I then re-drilled larger bushing holes in the plywood mounting pieces. I mounted the bushings on the alignment pins with some grease, put some flox in the larger holes and strapped the canard in place at the new incidence. Since my initial change was not that large, I made no changes with regard to the lift tabs. As a matter of fact, the canard was easier to install after I made the change. I then glassed on a new aft flange & used micro to fair it in to the top cover. The front flange was up a little and I faired that area in with micro as well. Unfortunately, my canard incidence is still too low. The plywood bushing tabs now rest against the bulkhead so I cannot use the same technique to make the fix. I believe I am going to have to remove some of the foam cover, cut off the bushing tabs and reset them to the new incidence. The cover will then need to be repaired to match the new position. I am not sure how this is going to affect the lift tab alignment. I can apply flox with saran wrap to get a flat surface for it to mate to but the alignment of the bolt to the tab hole may be a problem (but, then again, it may not). I am not planning on this surgery until the warmer months come back and I get a little more time. Like you, I have tested the plane's stall characteristics and have not encountered any problems. Paul Stowitts Cozy Mark IV N166PT From ???@??? Tue Dec 24 17:52:20 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by sccrgwc02.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021223034926.JOCA11044.sccrgwc02.attbi.com@alum.mit.edu> for ; Mon, 23 Dec 2002 03:49:26 +0000 Received: from mclean.mail.mindspring.net (mclean.mail.mindspring.net [207.69.200.57]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id WAA12920 for ; Sun, 22 Dec 2002 22:49:26 -0500 (EST) Received: from user-38ld0se.dialup.mindspring.com ([209.86.131.142] helo=yourfulkl1oh2q) by mclean.mail.mindspring.net with smtp (Exim 3.33 #1) id 18QJam-0000qU-00 for marc_zeitlin@alum.mit.edu; Sun, 22 Dec 2002 22:49:25 -0500 Message-ID: <004301c2aa36$4d8bf910$8e8356d1@yourfulkl1oh2q> From: "Baine Whipkey" To: "Marc J. Zeitlin" References: <5.1.0.14.2.20021222145413.00a96d00@mail.attbi.com> Subject: Re: Latest newsletter templates - canard incidence Date: Sun, 22 Dec 2002 22:49:30 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 - Hello Marc, I talked to Mike Melville about changing the canard incidence angle. He told me the way he does it is to remove the two alignment pins by using a pair of vicegrips pliers. Turn them first to break them loose then pull them straight out [it is easy]. He said he had done it three times, it think. That was several years ago. If your's is like my Long EZ, this was the way I did it. Once you get the pins out, elongate the holes so that the pins will rest in the holes without being in a strain when the canard is in the position you want. Then fill the elongated holes with Flox and reinstall the canard in the position you choose. As you put the pins in, the flox will be forced out of the holes so make sure to protect the canard rear face so that it doesn't get stuck. Try to make sure there are no voids in the flox {air bubble} I used new pins. Except for refinishing the top of the canard again, that is all there is to it. The changes in the angle of the lift tab on the F 22 is so small that it won't be a problem. Mike said, he liked his airplane's elevator trailing edge to be at neutral by the time he reaches 120K. Meaning, starting off with down elevator becoming less and less as you accelerate until at about 120 or 130 it will reach neutral. I know the Cozy may be somewhat different. I hope this helps. Good Luck. Best Regards, Baine From ???@??? Tue Dec 24 17:05:29 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by sccrgwc03.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021223235630.GNXW10343.sccrgwc03.attbi.com@alum.mit.edu>; Mon, 23 Dec 2002 23:56:30 +0000 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id SAA25999; Mon, 23 Dec 2002 18:56:29 -0500 (EST) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id gBNNnpL27601 for cozy_builders-outgoing; Mon, 23 Dec 2002 23:49:51 GMT X-Authentication-Warning: twctex.lidar.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from twctex.lidar.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id gBNNnoQ27596 for ; Mon, 23 Dec 2002 23:49:50 GMT X-ClientAddr: 208.129.255.5 Received: from goinpostal.extremezone.com (enterprise.extremezone.com [208.129.255.5]) by twctex.lidar.net (8.11.6/8.11.6) with ESMTP id gBNNnov27591 for ; Mon, 23 Dec 2002 23:49:50 GMT Received: from 0022765262 (i022-2.phx.extremezone.com [208.152.73.22]) by goinpostal.extremezone.com (8.11.3/8.11.3) with SMTP id gBNNsuI39237 for ; Mon, 23 Dec 2002 16:54:56 -0700 (MST) X-Spam-Filter: check_local@goinpostal.extremezone.com by digitalanswers.org Message-ID: <010001c2aae0$11fec260$504998d0@0022765262> From: "Nathan D. Puffer" To: "Cozy Builders" Subject: COZY: Canard incidence Date: Mon, 23 Dec 2002 17:04:15 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Nathan D. Puffer" Dear builders, If your Cozy Mark IV is already completed, the easiest way to change the incidence on your canard is as follows: 1) Remove your canard. 2) Remove a slight amount (less than 1/8" most places) of the fuselage sides where the bottom of the canard and the torque tube rest. 3) Cut all around the cosmetic fuselage piece on top of your canard with a hacksaw blade. The only place the cutline should show is where you separate this piece from the top of the canard. Then strip off the top skin of the cosmetic piece. 4) Pop out the incidence bushings from the incidence tabs (that touch F-28). You can heat them up with a soldering iron and twist them out. 5) Elongate the holes (upward) where the incidence bushings were installed. My guess is that this would have to be about 1/8 inch. 6) Grease the incidence pins, slide the canard incidence bushings on the incidence pins and reinstall the canard. 7) Push the trailing edge of the canard down until the new (newsletter #80) template is level when your longerons are level. 8) When everything is okay, slide the canard forward enough so you can apply flox to the bushings, and then slide the canard back, and install the bolts thru the lift tabs. Hold the canard in place until the flox cures. 9) Reinstall the canard cover with micro. The only visibile evidence that you made this change should be along the hacksaw blade cut over the top of the canard. Fill that with micro, prime, and touch up. Best regards, Nat Date: Tue, 24 Dec 2002 18:06:44 -0500 From: "Marc J. Zeitlin" Subject: COZY: Latest newsletter templates - canard incidence Mark Knaebe writes; >In flight, the elevator with trailing edge down results in a virtual >canard incidence greater than the actual incidence. "Incidence" is the angle that the airfoil makes with respect to the fuselage - I believe that what you're trying to say is that the effective Angle of Attack is higher with the elevator deflected downward than with it "in trail". >The greater the elevator is out of level (zero) the more drag. Maybe, but not necessarily. It would all depend upon the "lift/drag polar" of the airfoil - it's possible (although unlikely) that a slight deflection of the elevator (either up or down) would cause the airfoil shape to be such as to lower drag. Unlikely, but possible. >By design, the canard has greater wing loading than the main wing >and will therefore stall at a higher velocity than the main wing. That's part of the reason for the canard stalling first, but not all of it. Other factors are the incidence angle and airfoil shapes. >.....I would think this would be the case no matter what (within >reason) the incidence of the canard is. Correct. This is totally a function of the CG position. >By moving the cg back you reduce wing loading on the canard reducing >drag but at the horrific potential of main wing stalling. Let's not get melodramatic :-). As long as the CG is ahead of the "neutral point", which for COZY MKIV's built to plans seems to be about 2" BEHIND the rearmost CG position in the envelope (per Nat's testing), there's no danger of a main wing stall. >Given the above I would think you would want to install the canard >so that at cruise the elevator is at zero; where the virtual >incidence = actual incidence. Again, you're confusing AOA and incidence. The most important thing is to ensure that you do NOT have enough elevator authority to raise the nose high enough to cause a main wing stall. Don't conflate drag reduction with safety - they're really not related in this case. >2nd issue - One way to increase the canard wing loading is the >mandatory span reduction of the canard but wouldn't a forward >movement of the CG limits have accomplished the same thing while >maintaining a slightly slower stall speed? It is very possible that one other solution to the original deep stall issue with the COZY MKIV would have been a CG position change, rather than a canard shortening, as you point out. You know, it just struck me that (I believe) the original COZY MKIV incidence angle was determined BEFORE the canard was cut 6". If we've had this discussion before, someone please stop me, but maybe the reason that many people seem to have a need to modify the incidence angle is that their canards are shorter than the original one....... -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://marc.zeitlin.home.attbi.com/ http://www.cozybuilders.org/ Copyright (c) 2002 From ???@??? Tue Dec 24 18:20:20 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by sccrgwc03.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021224232011.BJVI10343.sccrgwc03.attbi.com@alum.mit.edu>; Tue, 24 Dec 2002 23:20:11 +0000 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id SAA17414; Tue, 24 Dec 2002 18:20:10 -0500 (EST) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id gBONBSf00793 for cozy_builders-outgoing; Tue, 24 Dec 2002 23:11:28 GMT X-Authentication-Warning: twctex.lidar.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from twctex.lidar.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id gBONBRi00788 for ; Tue, 24 Dec 2002 23:11:27 GMT X-ClientAddr: 204.127.202.62 Received: from sccrmhc02.attbi.com (sccrmhc02.attbi.com [204.127.202.62]) by twctex.lidar.net (8.11.6/8.11.6) with ESMTP id gBONBRv00783 for ; Tue, 24 Dec 2002 23:11:27 GMT Received: from ZEITLIN-2.attbi.com (c-24-63-4-80.ne.client2.attbi.com[24.63.4.80]) by sccrmhc02.attbi.com (sccrmhc02) with SMTP id <20021224231642002000f96je>; Tue, 24 Dec 2002 23:16:42 +0000 Message-Id: <5.1.0.14.2.20021224181553.00a04d50@mail.attbi.com> X-Sender: marc.zeitlin@mail.attbi.com X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 24 Dec 2002 18:16:13 -0500 To: Cozy Builders Mailing List From: "Marc J. Zeitlin" Subject: COZY: Canard Incidence Angle Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Marc J. Zeitlin" Kevin Funk tried to send this to the list, but a bizarre characteristic of the mailing list software kept it from going through: I had to adjust the canard incidence on my plane. I found that the plane was not stable in flight where a bump upward would increasing climb until stall and a bump down would increase until redline (or more). Nat rode with me at Copperstate 2000 to see this actually happen. The canard was exactly to template for pitch but a lillte too big for the template that should be able to surround the canard. This is because I got no foam burn back and my canard cores are precisely to template. As an example, check the elevator torque tube template and see that it is 7/8" and the tube is 1". Burn/Melt back is supposed to create a 1" hole for the tube to fit down. I had to sand out my cores to fit the tube. I used a broom handle with 1 and then 2 pieces of sand paper to create the proper diameter. I heated and then removed the rear lift tab bushing inserts. I filled the holes with flox and redrilled the holes at 1/4 inch above the original site. This was calculated to be 1.4 degrees. I guessed that I might need 1-2 degrees. The front edge of the canard cover lifted up and I lost my precision fit. The trailing edge of the canard cover required a lot of grinding and refitting. The canard was placed and replaced at least 15 times using carbon paper to find the contact points. I needed a little trimming on the fuselage sides, especially near the torque tube exit. I finished the job in 3 hours in the hanger. White electrical tape was used to sucessfully hide the 2 new joints that were now ugly. Flight is extremely better. The plane is now stable at all speeds and much easier to fly. I hope to redo the canard top this winter during my annual for cosmetics. Kevin Funk MD Cozy Mark 4 #90 N871F Flying since June 2000 -- Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu http://marc.zeitlin.home.attbi.com/ http://www.cozybuilders.org/ Copyright (c) 2002 From ???@??? Sun Dec 29 21:38:18 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by rwcrgwc56.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021229145325.PHVG12821.rwcrgwc56.attbi.com@alum.mit.edu>; Sun, 29 Dec 2002 14:53:25 +0000 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id JAA22791; Sun, 29 Dec 2002 09:53:24 -0500 (EST) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id gBTEjwF31219 for cozy_builders-outgoing; Sun, 29 Dec 2002 14:45:58 GMT X-Authentication-Warning: twctex.lidar.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from twctex.lidar.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id gBTEjvg31214 for ; Sun, 29 Dec 2002 14:45:57 GMT X-ClientAddr: 206.46.170.133 Received: from out010.verizon.net (out010pub.verizon.net [206.46.170.133]) by twctex.lidar.net (8.11.6/8.11.6) with ESMTP id gBTEjvv31209 for ; Sun, 29 Dec 2002 14:45:57 GMT Received: from livingroom ([4.47.223.38]) by out010.verizon.net (InterMail vM.5.01.05.20 201-253-122-126-120-20021101) with SMTP id <20021229145121.IXJR6251.out010.verizon.net@livingroom> for ; Sun, 29 Dec 2002 08:51:21 -0600 From: "Mike Pollock" To: "Cozy Builders List" Subject: RE: COZY: canard template Date: Sun, 29 Dec 2002 08:51:23 -0600 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0002_01C2AF17.76FE2170" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Importance: Normal In-Reply-To: <000a01c2af02$3ebd8b80$437f7e18@we1.client2.attbi.com> Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Mike Pollock" Dick Rohaly writes: >Does anybody know much increase in incidence Nat added to the old template Dick, I calculated it to be between 1.1 - 1.2 degrees of increased incidence. The benefit of increasing the incidence is that the trailing edge of the elevators will fair in trail properly at cruise and mid cg. I believe the increase in incidence needed may be due to the amount of canard tip removal that Nat did (3" per side removed) to ensure that the Cozy will not get into a deep stall. I will have to redo my canard as well. I still have not completed the canard cover at this time, so it will be easier. Regards, Michael Pollock Flying Velocity N173DT Building Cozy MKIV #643 EAA #411862 EAA Chapter #1246 Technical Counselor #4357 Based at TKI / NE Dallas Metroplex From ???@??? Mon Dec 30 23:26:49 2002 Return-Path: Received: from alum.mit.edu ([18.7.21.81]) by rwcrgwc52.attbi.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with ESMTP id <20021231031606.WEWC26331.rwcrgwc52.attbi.com@alum.mit.edu>; Tue, 31 Dec 2002 03:16:06 +0000 Received: from canard.com (lidar.net [64.246.36.7]) by alum.mit.edu (8.9.2/8.9.3) with ESMTP id WAA00414; Mon, 30 Dec 2002 22:15:55 -0500 (EST) Received: (from wright@localhost) by canard.com (8.11.6/8.11.6) id gBV37IA08140 for cozy_builders-outgoing; Tue, 31 Dec 2002 03:07:18 GMT X-Authentication-Warning: twctex.lidar.net: wright set sender to owner-cozy_builders@canard.com using -f Received: from twctex.lidar.net (root@localhost) by canard.com (8.11.6/8.11.6) with ESMTP id gBV37Cp08135 for ; Tue, 31 Dec 2002 03:07:18 GMT X-ClientAddr: 208.129.255.5 Received: from goinpostal.extremezone.com (enterprise.extremezone.com [208.129.255.5]) by twctex.lidar.net (8.11.6/8.11.6) with ESMTP id gBV37Cv08130 for ; Tue, 31 Dec 2002 03:07:12 GMT Received: from 0022765262 (i184-2.phx.extremezone.com [208.152.73.184]) by goinpostal.extremezone.com (8.11.3/8.11.3) with SMTP id gBV3BmL15875; Mon, 30 Dec 2002 20:11:48 -0700 (MST) X-Spam-Filter: check_local@goinpostal.extremezone.com by digitalanswers.org Message-ID: <011501c2b07b$da8dfe80$b84998d0@0022765262> From: "Nathan D. Puffer" To: "Nick U" , "'Cozy Builders Mailing List'" References: <000201c2ac2d$123d53b0$6900a8c0@office> Subject: Re: COZY: Latest newsletter templates - canard incidence Date: Mon, 30 Dec 2002 19:10:18 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-cozy_builders@canard.com Precedence: bulk Reply-To: "Nathan D. Puffer" Dear Nick, Vance Atkinson installed and tested the Roncz canard on the 3-place, I did not. So I refer all these questions to Vance. I know he increased the angle of incidence over what was used in the Long EZ, and he determined the span. Best regards, Nat