From: "Steve Campbell" Subject: COZY: Building Tip Date: Thu, 5 Feb 1998 15:00:12 Dear Fellow Builders, I recently discovered something kind of nice, particularly for the builders at the earlier stages. Most of the metal parts that you build consist of rather small pieces. I have found that, due to my ineptitude, I often wind up educating myself on the building of these parts several times. Wick's sells 10# boxes of Al sheet, Al tubing, and steel tubing. For $15 you get a nice assortment of pieces. I got the sheet and will probably get the Al tubing as well. It's great knowing that you've got a whole box of aircraft grade material in your shop and you're not going to have to stop what you're doing and wait to get another 6" piece in the mail. Keep on building, Steve ************************************************ Stephen A. Campbell, Associate Professor, ECE University of Minnesota 200 Union Street Minneapolis 55455 (612) 625-5876 phone / (612) 625-4583 fax Campbell@ee.umn.edu ************************************************* From: SBLANKDDS@aol.com Date: Thu, 5 Feb 1998 19:44:01 EST Subject: Re: COZY: Building Tip I found an easier way to get the metal parts bent and fitted well. I recruited an RV-6 builder to make them!!!! He was glad to ask me for help with the vertical fin faring and other glass parts for the RV-6..... Another plus....he got it right the first time! Same reason I did not mold my own tires from a rubber plant !!!! Steve Blank Date: Thu, 20 Nov 1997 02:47:45 +0100 From: Jean-Jacques CLAUS Subject: COZY: Re: [canard-aviators] Throttle Bracket Arthur K Armani wrote: > > [The Canard Aviators's Mailing list] > Hello Everyone: > I have a great question for everyone. My brother in law is currently > building a new throttle bracket for my Long-eze. (upgrading to an O-320) > According to the plans it requires 2023 T-3 .063 Alum. We were wondering > why they chose heat-treated alum? I was wondering if it really needs to > be heat treated? We are trying to bend it, but can't. For safety reasons > we will stick to the plans, but for educational experience I had to ask. > Art I put myself the same question that you. Concerning bending of aluminum sheets, I can give here an "alchemist's secret". Unfortunately, it doesn't permit to transform the 2024-T3 in gold. Here is the process: Take the soap of MARSEILLE (or an equivalent chemical formula) in cuttings or shabby as of gruyere cheese; Put it of aluminum on the place to bend; Let heat the piece but not directly on soap; When soap will have burnt and will have become black, the good temperature will be reached; To this moment, throw the piece in the cold water; The piece will be able to be bent easily; After some hours, the alu part will take its original toughness. It can be a solution to adapt the KEN BROCK step (COZY) to the radius of the fuselage. Happy building, Jean-Jacques CLAUS French Cosy Builder From: cdenk@ix.netcom.com Date: Wed, 19 Aug 1998 12:56:32 -0500 (CDT) Subject: Re: COZY: Re: [canard-aviators] Throttle Bracket Remember when bending material (steel and aluminum included) the bend must be perpendicular to the grain (rolling direction) i.e. imagine bending about the roll that was used to determine the thickness, but your radius. Usually if you look closely, the grain is noticeable. If there is a printed label on the material, it is the grain direction. All this info is from publications like accepted practices, etc. every builder should have a library about 5 inches thick, and browsed thorough, noting whats there, for future use. From: "Nat Puffer" Subject: COZY: Rudder pedals & engine mounts Date: Thu, 27 Aug 1998 09:41:47 -0500 Cozy builders, The rudder pedals provide directional control both in flight and on the ground. We therefore consider them to be critical to safety. The rudder pedals supplied by Brock Mfg. are welded by an expert craftsman, Mike Youngblood, to make sure the welds are sound, they are then stress relieved to remove any stresses due to welding (stress relieving is more closely controlled than flame annealing). They are then cadmium plated in accordance with military specification QQP416 and baked to prevent hydrogen embrittlement. The baking has to be started within 4 hours of plating. The spec. requires that the parts be held at 375 deg. F +-25 deg. for 8 hours. Brock maintains records for 10 years showing that these specifications have been met. If you make these parts yourself or purchase them from an unauthorized supplier, you should make sure these specifications are followed (we have no influence over unauthorized suppliers and some are unreliable). Engine mounts are also critical to safety. The engine mounts supplied by Brock are also welded by Mike Youngblood in a jig to ensure they are identical to the one we approved, and then they are stress relieved, also in a jig, to ensure that the dimensional accuracy is maintained. The engine mount is painted on the outside with zinc chromate and each member is drilled (#51 drill .067" dia.) so that the inside can be treated with boiled linseed oil (by the builder) in accordance with accepted practice to prevent corrosion. Following linseed oil treatment, the holes are plugged with -0-4 drive screws (available from Aircraft Spruce or Wicks. We cannot guarantee the dimensional correctness or structural integrity of engine mounts from unauthorized suppliers (we've had several complaints in the past). Regards, Nat Date: Mon, 14 Sep 1998 12:13:51 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: 304 Stainless Steel Tubing/Stock Al Wick said: >When machining it, make sure you don't get the material hot, it gets hard >real quick. As I recall, I ended up overheating a piece, wiping out the >drill. Lotsa coolant needed, particularly for band saw. >It was fun making the bushings, not difficult holding the i.d. tolerance, >and lot of satisfaction in eliminating another Brock part. If you know >what I mean (30% price increase in one year %#$). I couldn't agree with you more, Al. This creates even MORE than the usual amount of satisfaction with building something yourself. About machining Stainless... We do a LOT of that, here at work, so I picked up some tips from our machinists. It certainly is good to keep it cool, but the main culprit that makes it difficult to machine is: work hardening. Whether drilling, cutting, lathe-turning, or whatever, it pays to bring the cutting tool against the material briskly and firmly, then feed it steadily, without hesitation. The worst thing you can do is to stop cutting pressure, while the tool is still in contact with the work. It hardens instantly. Just bear down on it and keep it moving through the material. Fairly slow RPM, and, of course, plenty of coolant. It is kind of hard to take a tiny little cut to just shave a couple of mils off, but it can be done, if the previous cut was made well, according to the above reccomendations, with a nice sharp tool. High speed steel works very well, when it's good and sharp. I enjoy making these types of parts, too. On my Long, I made custom bushings for the wing-attatch points (out of aluminum, of course). After all the fitting and alignment, I made each bushing with a custom-thickness flange, so that I can use a single, thin washer between each one. If all that careful alignment pays off as I think it will, I'll never have to keep track of how many washers go under which bolts. It was EZ to do. -Howard Rogers From: Epplin John A Subject: RE: COZY: 304 Stainless Steel Tubing/Stock Date: Mon, 14 Sep 1998 14:46:50 -0500 > Al Wick said: > >When machining it, make sure you don't get the material hot, it gets hard > >real quick. As I recall, I ended up overheating a piece, wiping out the > >drill. Lotsa coolant needed, particularly for band saw. > >It was fun making the bushings, not difficult holding the i.d. tolerance, > >and lot of satisfaction in eliminating another Brock part. If you know > >what I mean (30% price increase in one year %#$). > Howard Rogers adds: > I enjoy making these types of parts, too. On my > Long, I made custom bushings for the wing-attatch points (out of aluminum, > of course). After all the fitting and alignment, I made each bushing with > a custom-thickness flange, so that I can use a single, thin washer between > each one. If all that careful alignment pays off as I think it will, I'll > never have to keep track of how many washers go under which bolts. It was > EZ to do. > [Epplin John A] I made most all my parts also. 304 stainless is fairly easy to machine. I use ceramic inserts for every cut I can, but do not have a small boring bar so the bore us usually drilled and reamed. I use a cutting fluid from LPS that works very well. Also did the same thing Howard did with the wing bushings. I am just finishing the strake skins at the moment, one thing I did, believe I got the hint from Howard, was mount the wings and build a rib next to the wing, at the end of the center spar. I trimmed the outer surface down 3/8 in and built the strake skin to that edge. The point here is that when I mounted the wings, after they had been carefully mounted with my custom bushings, they came out with a little error. I use a machinists level for my reference, which may be an overkill. I had to add a .010 shim under one bolt to come to the same point that I had previously. When I get finished with the strake skins, another couple of weeks, I will mount the wings again and hope for the best. John Epplin Mk4 #467