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Post by schines on Sept 3, 2011 21:27:44 GMT -5
Hi all, I'm starting to build my tail feathers and I see that the plans call for the hinge bushing to be shimmed out 1/16" to allow for fabric. I don't understand why the hinges need to be shimmed out- it seems that there would be enough room for the fabric between the tubes from the width of the hinge alone. Am I missing something? Thanks, Scott
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Post by soneraifred on Sept 3, 2011 22:00:25 GMT -5
There are two reasons for shimming the hinges out. The first, like you said, is to provide clearance for the fabric. The second is related to that, and that is by shimming the hinges on both sides of the joint, the hinges don't rub on the mating piece. In other words, if you didn't shim both the elevator and horizontal stabilizer hinge bushings, the elevator bushing would rub on the horizontal stab, and the stab bushing would rub on the elevator.
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Post by schines on Sept 4, 2011 12:12:10 GMT -5
OOOHH! That makes sense. Thanks Fred!
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Sept 7, 2011 8:49:20 GMT -5
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Post by schines on Sept 9, 2011 20:45:19 GMT -5
So Pete, is that a problem for you? I plan to use Fred's advice, but I am curious. -Scott
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Post by shanenothdurft on Sept 9, 2011 21:07:08 GMT -5
does anyone know how much throw you need for the elevator
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Sept 10, 2011 9:26:56 GMT -5
So Pete, is that a problem for you? I plan to use Fred's advice, but I am curious. -Scott Don't know yet....they travel free and clear now, but when I add fabric it looks now like there will no clearance at the bushings. I will cut around them, but that may make a rougher cut. -Pete
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Sept 10, 2011 9:30:40 GMT -5
does anyone know how much throw you need for the elevator It should be in the archive of Sonerai.net. Off the top of my head it is enough to make 15 dg up elevator 15 dg down. Anyone correct my numbers please. -Pete
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ncam
New Member
Posts: 4
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Post by ncam on Sept 12, 2011 23:31:18 GMT -5
There is a beautiful S2 midwing featured in Sport Aviation,some time ago, the owner hit some wires. (Ray Burgner) The thing that interested me was that he used strap hinges which close up the gaps between the control surfaces and look better as well as working well. It takes a little more forward planning but worth it. You don't need fairings or gap seals. Regards Neville
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Post by jondorb1 on Sept 15, 2011 20:29:18 GMT -5
I too have elevator and rudder bushings that are not shimmed out 1/16". I had to file down the outside of the bushings so they would not rub or touch the tubes on the opposing control surface. The thinnest of these bushings has a wall thickness of .045", down .02" from .065". Is this acceptable or should I have new bushings with 1/16" welded on? -JondorB1
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Post by n3480h on Sept 16, 2011 17:13:01 GMT -5
If I did that, I would constantly think (worry) about it every time I flew it, but that's just me.
Tom
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Post by jondorb1 on Sept 16, 2011 20:59:11 GMT -5
Yes, I agree; I've decided to have new bushings with standoff welded on.
Jon
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Post by jondorb1 on Sept 17, 2011 21:09:35 GMT -5
I've decided to shim my bushings but I'd like to know where it's stated in the plans to shim the bushings out. Am I missing some notes? I have the Sonerai 2LS plans and sheet 13 specifies 1 3/8" distance between centerlines of the horizontal stab tube and the elevator tube. The stab tube is 1 1/8" OD, the elevator tube is 1" OD, and the bushings are 3/8" OD. By my calculations, even if the bushings were flush with the tubes, the distance between centerlines of stab and elevator tubes would be 1 7/16" or 1/16" greater than the 1 3/8" shown in the plans. Were corrections made to the plans? -Jon
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Post by n3480h on Sept 17, 2011 22:14:36 GMT -5
Jon, I just went through my plans and found no mention of shimming hinge bushings. I would not have known but for Sonerai.net postings. I do not have my builder's manual here, but I don't think its in there either.
I used short vertical sections of 1/16" RG45 welding rod for spacers. I elected to go with 3 hinges on each side of the stab/elevator, and 3 on the rudder. I slid the three sets of three pieces of 1/4" bushing stock onto a 3 foot piece of 1/4-20 threaded rod (hardware store - cheap). Then I positioned the bushings on the stab rear spar with cheap spring clamps on the threaded rod, and tacked the outside two bushings of each set. Don't weld the center pieces of bushing onto the stab - they will go onto the elevator or rudder. Once tacked, I removed the spacers and final welded, filling in the 1/16" gaps as I went, with all bushings still on the threaded rod. This maintains alignment. After it cools, number the center bushing (not welded) in each set and put the same number on one of the adjacent bushings in each set so you will know which center bushing goes with each set of outter bushings when you weld the center bushings to the rudder or elevators. Tap the threaded rod out with an 1/8" punch or piece of 3/16" rod. It'll take a little work, but the threaded rod will come out. Use the threaded rod again to align all bushings when you position and weld the center bushings to the elevator and rudder. This prevents any binding of the hinges. I slowly cleaned out the bores of the hinge bushings with a 1/4" drill bit welded to the end of a mild steel 3/16" rod (allows a little flex). After all bushings are welded to the stab and elevators, drill a 1/16" hole in the topside of the center bushings for oil, and you're done.
Tom
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Sept 18, 2011 0:16:27 GMT -5
Jon, I just went through my plans and found no mention of shimming hinge bushings. I would not have known but for Sonerai.net postings. I do not have my builder's manual here, but I don't think its in there either. I used short vertical sections of 1/16" RG45 welding rod for spacers. I elected to go with 3 hinges on each side of the stab/elevator, and 3 on the rudder. I slid the three sets of three pieces of 1/4" bushing stock onto a 3 foot piece of 1/4-20 threaded rod (hardware store - cheap). Then I positioned the bushings on the stab rear spar with cheap spring clamps on the threaded rod, and tacked the outside two bushings of each set. Don't weld the center pieces of bushing onto the stab - they will go onto the elevator or rudder. Once tacked, I removed the spacers and final welded, filling in the 1/16" gaps as I went, with all bushings still on the threaded rod. This maintains alignment. After it cools, number the center bushing (not welded) in each set and put the same number on one of the adjacent bushings in each set so you will know which center bushing goes with each set of outter bushings when you weld the center bushings to the rudder or elevators. Tap the threaded rod out with an 1/8" punch or piece of 3/16" rod. It'll take a little work, but the threaded rod will come out. Use the threaded rod again to align all bushings when you position and weld the center bushings to the elevator and rudder. This prevents any binding of the hinges. I slowly cleaned out the bores of the hinge bushings with a 1/4" drill bit welded to the end of a mild steel 3/16" rod (allows a little flex). After all bushings are welded to the stab and elevators, drill a 1/16" hole in the topside of the center bushings for oil, and you're done. Tom Very nice narrative Tom, that may have been what my 1st builder did. My elevator and rudder have free and full range travel. They also can be removed and replaced easily, i.e the bushing line up well. It's good to know "How to" should I have to replace or repair what I have. -Pete
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