Date: Thu, 13 Apr 1995 16:08:08 -0400 From: CozyBldr@aol.com Subject: Attaching canard Recently I was asked the following question by another builder. My response follows but I would enjoy hearing any other possible solutions. >How did you attach the canard in chapter 12. If you mount the >holding pins straight you can't slide the canard in, because of >the angle of incident the wing is at. I know of two builders that plan >to angle the pins. I responded that I mounted the pins in straight as I didn't really see how I c ould do otherwise since the alignment bushings in the attach tabs would be difficult to insert at an angle. Attaching the canard requires inserting the elevator hinge pins after the canard is in place on the fuselage. Any comments would be appreciated and passed on to this builder. Paul ; Thu, 13 Apr 1995 16:44:35 -0400 Date: Thu, 13 Apr 95 15:42:25 CDT From: qtdalls!ken%qtdalls@uunet.uu.net (Ken Reiter) Subject: Re: Attaching canard Hello Guys, I would NOT change the angle of the attach pins!! Part of the lift load IS through the pins. Yes, it is a tight fix. But I strongly suggest not to change this angle. That's my input. Ken Date: Mon, 17 Apr 95 13:22:15 est From: "Phillip Johnson" Subject: Re: Attaching canard Hi all, I came across the problem of the canard attachment points a couple of years ago and after a real panic because I could not remove my canard following installation of the tabs. I decided to modify my attachment and I came up with a good solution. I was going to publish my solution in the news letter but I find Nat difficult to converse with so I let it slide. The tabs on the rear of the canard are not highly loaded unlike the main lift tabs however, if the pins are angled it might be possible, in a sloppy installation, for these pins to slip out of the retaining holes, the result being catastrophic. In my installation I eventually removed the pins, re-drilled the longeron doubler with a 3/8 inch drill all the way along the length of the doubler. I then inserted, using a flox cement, a steel tube 3/8" OD x 3/16" ID into the newly drilled hole and along the full length of the doubler plus some protrusion from the rear end. The steel insert was configured to be flush with the insert of the rear tab and co-aligned using a 3/16" dia greased rod. After cure I made a small 2024 Al plate with an AN3 nut plate attached. This plate was then cemented, using flox, to the front face of the tabs. A long AN3 bolt, about 4 inches in length (size to fit) is then used from behind F28 to pass along the length of the doubler, through the tab and screwed into the nut plate. If all of the alignment is done correctly, tightening the AN3 will cause the main lift tabs to locate flush and correctly positioned against F22. Removal of the canard now requires the removal of the two AN3's, from the rear tabs, and the two AN4's from the main lift tabs, followed by a simple vertical movement of the canard, i.e. there is no juggling. My belief is that, since the canard is secured in this way, even a sloppy installation would not cause fatigue to the main lift tabs since there can be no bending component on these tabs. Additionally, in the unlikely event of a failure to the main lift tabs, some support my be given through these more secure attach points. One of the areas that has given me cause for concern, and this is not peculiar to my installation, is the region of high torsional compliance between F22 and F28. If you hold, on the completed aircraft, F28 in one hand and push and pull F22 with the other hand, you will notice that some differential movement occurs. Now when you attach the canard, this region stiffens up significantly which indicated that the stiffening path is through the canard lift tabs and alignment pins/AN3's. Since the reaction between the canard and the main wing is the primary source of torsional strain in the aircraft this imposes considerable loads on the four attach points weather pins or AN3's. The main lift tabs are more than adequate to do the job but the rear tabs were not designed for this type of load. Since the Cozy is a derivative of the Long-eze I tried this same experiment on a Long-eze and found this to be absolutely ridged. In this region the Long-eze is a composite made from 1" foam at this point and uses the same lay-up schedule as the Cozy. The Cozy is only 3/8". I have tested my measurement on a couple of additional Cozy's and found that they exhibit the same torsional strain as mine so I can assume that mine is representative of the design. As far as I know there have been no incidents recorded where the rear tabs have given way on the Cozy, but it is an area giving me some concern. I am considering strengthening the region using either carbon or adding some extra foam and glass thickness locally. Has anyone else noticed this apparent weakness? Phillip Johnson Date: Wed, 19 Apr 1995 11:52:36 -0400 From: CCady@aol.com Subject: Canard Hinge Pin On the Roncz canard, I've noticed that some builders have apparently microed the end of the hinge pin inside the canard tip. In the plans this is accessable for removal. When I built mine I wanted an easy way to remove it without a hassle. I threaded the end of the hinge pin close to the elevator tip hinge line. I use a separate rod with a threaded tube on the tip and chuck it on a cordless drill to move it in and out. But I still have a slot in the lower tip to get access to the hinge pin which I think I'll leave so that in the event that I need to lubricate the pin I can remove it. What do others do to make it easy to remove the hinge pin? I noticed that the Velocity uses the external hinges like the GU canard used, which I like for ease of installation. It seems like the internal hinge pin can't find the hole without several tries. Cliff in Tampa