John, Looks like Wicks still sells the 1 1/4 x 1 1/4 that is called for in the plans.
http://aircraftproducts.wicksaircraft.com/viewitems/aircraft-aluminum-metals/6061-t6-aluminum-c-channel Thanks, Rob Schmitt -----Original Message----- From: KRnet <krnet-boun...@list.krnet.org> On Behalf Of Mark Langford via KRnet Sent: Friday, March 22, 2019 1:48 AM To: Oscar via <krnet@list.krnet.org> Cc: m...@n56ml.com Subject: Re: KR> Bent Rudder Horn John Bouyea wrote: > I’m looking for help in finding real “aviation-grade” 1” OD 1/8” thick > U-channel with radiused inner corners. Is there such a thing anymore? > Where do you get it? I don't know that I have an answer either, but will throw out a couple of options. I was going to point out that the sharp inside corner channel is almost always the much weaker architectural 6063 aluminum, but it looks like you've done your homework on that also. One would think nvAero would be a source of this channel now, so maybe Steve will chime in on this, unless he can't buy it either. Aircraft Spruce has some 1" square 60601-T6 tubing (see https://www.aircraftspruce.com/catalog/mepages/alumtubing-sq.php), but it's 1/4" rather than 1/8" wall. Of course there's the "minor" detail of having to mill out one side to make the box into a channel, but that's quick work for a guy with a mill. I was going to point you to onlinesmetals.com, but they don't have the channel either. They do have some "rounded corner" box cross-section material, which should work assuming there's no interference to rotation. See https://www.onlinemetals.com/merchant.cfm?id=1761&step=2&top_cat=60 to see what I mean by that. It has an outside radius as well as an inside radius. I probably haven't told you anything you didn't already know, and there are other options as well, (larger channel with spacers, etc), but I'll spare your time with that. For others, as a general rule, the sharp internal radius angle and channel is 6063, which is not nearly as strong as 6061-T6, and the sharp corner exacerbates the weakness, depending on how it's loaded. If you're not sure what you have, but have some known 6061-T6, drill a hole in it, and then try the mystery metal. 6063 drills like butter by comparison! 6063 is a bit more shiny than 6061 also. Worst case though would be to use 6063 and make sure you inspect it every year, or to be absolutely sure, just use steel. That's not a huge amount of steel, although the moment arm is long, and the change in CG direction is usually not preferable. For 6063 in both 1" channel and 1.25" channel, see https://www.onlinemetals.com/merchant.cfm?id=297&step=2&top_cat=6 . That's probably the simplest option, but not the best. There are probably a lot of KRs flying exactly this setup though.... Mark Langford, Huntsville, AL ML "at" N56ML.com www.N56ML.com MMV Gathering CoHost _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
