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Thought I'd start another thread on this, as the original is way long.
I've got all the ribs cut, and the right wing panel begun. I decided to build the wing as an evenly tapered structure, root to tip. If the wing is built as per the instructions (ribs flat on the board) one ends up with a left and a right wing, both flat on the bottom and tapered on the top. I don't think Laddie intended that to happen, as the front view of the airplane on the plans shows an evenly tapered wing section. So....
I determined that the centerline of the W1 rib is exactly 15/16" from the widest part of the rib at the bottom. Thus all the alignment tabs you see are 15/16" down from the centerline of each rib. (I learned this trick from Sig and Lanier. Many of their kits use alignment tabs. You just cut em off after the upper part of the wing is finished.)
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I've built a couple of swept wings that had swept spars, and learned that it's better not to cut the spar notches in the ribs until they are pinned in place and ready for the spar to be installed. I lay the spar on top of the ribs over its location on the plans, and use a felt tip to mark both sides of it on top of the ribs. It's then fairly easy to use a razor saw and a hobby knife to cut out the notches. This results in a very tightly fitting spar with good glue joints.
< Message edited by Mustang Fever -- 4/1/2008 3:30:33 AM >
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I've thought about it twice : what you will achieve through this is having a no washout wing... I am now wondering what the original way to build the wing (I've re-read RCM's article about it, and indeed ribs have to lay flat on the trailing edge and front sheeting). I'm having a hard time figuring out what kind of washout that would yield (if any).
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OK. Returned from visiting and flying in NJ, and made a bit more progress.
The leading and trailing edge pieces are glued on and shaped, as is the trailing edge sheeting, and the spruce main spar.
After experimenting for a bit, I discovered that ordinary round, cedar pencils fit the ID of the carbon tubing perfectly. Cut up eight pieces and epoxied them in as plugs, as per instructions, to keep water from getting into the wings.
The tubing I got is from dragonplate.com It's .375 OD and .290 ID, a bit thicker in the wall than Laddie specifies, which is OK by me. (I think about 0.08" vs 0.06" Very consistent OD/ID, very smooth, very rigid. $18.20 for a 48" piece, including shipping. They have a wide range of CF products.
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Bob, go for it. I now have some motivation to get back to mine, I would be ashamed to have you get yours done and in the air given how long ago I started mine However, in my defense I will say I have done a kit bash of a Rascal, a Seawind, half a pylon seaplane to use the wing from the crashed Seawind, and a second Seawind (as I say, I do get sidetracked). Also did a Splash 3D, but now really need to get back onto the Arrow...Pete
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I dunno, Pete. My build rate is going to depend on when I can scrape the $$ for the various components. I'll be lucky to get her done before the snow flies this fall.
Got the carbon spars all epoxied in today. The 3/8 holes in each of the three ribs did not quite line up correctly, it was necessary to "hog" out the #2 and #3 holes a little so as to get the CF spars 90 degrees to the #1 rib. (I'm leaving the #1 holes on both panels alone, so the alignment will be the same for both.) To insure good strength, I made some plywood versions of the little "paper rectums" that are used to strengthen pages in a binder. They're epoxied on the outboard side of the ribs where you can't see em, but there's one laying in the foreground.
Tomorrow I'll do the leading edge and center section sheeting, then she'll be ready to come off the board for the other side.
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Was goofing off down at the field, flying my Wonder, so didn't make a lot of progress.
Here's the first piece of leading edge sheeting. Every time I sheet a wing it seems I'm trying something different. This time, because the wing is up off the board like it would be with a jig, I TiteBonded the first piece to the LE only, using clamps in four places and mucho pins elswhere. Looking in from the back side, I can see no gap, and squeezing the sheeting against the LE causes no glue to run out. Should work ok. Tomorrow AM, I'll soak the top of the sheeting with water and then thick CA it to the ribs in front of the spar, Poly it (Gorilla) to the spar, and thick CA it to the ribs aft of the spar.
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I know now why Laddie hasn't chimed in on the "tapered wing, alignment tabs" issue. He can't stop laughing. The wing comes out the same regardless. After I got it sheeted on one side and took it up off the board, and removed the tabs, it laid perfectly flat on either side. I guess it's because of the constant trailing edge thickness, and the fact that all the rib bottoms are flat up to where the LE sheeting ends at the spars.
Live and learn, eh? Anyway, here's one panel complete with CF spars.
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quote:
He can't stop laughing. The wing comes out the same regardless.
Hi Bob !
Actually this wouldn't be the case with a different wing section along the wing (dfifferent ribs). This looks like a particular case. I haven't checked the ribs myself. Your panel looks good
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This is probably something that is a lot simpler than it appears to me, but I've been sweating this step:
Making the two 1/8 ply boxes that go in the fuse to accept the wing tubes. I made the pieces and did a dry run, trying to get them all aligned properly around a piece of the carbon fiber tube. Kinda like wrestling snakes. Gluing them all at once would be really tough.
Maybe this will get it started. I clamped one of the pieces to a square, while both items were sitting flat on the building board, and pinned the other piece up against it. When the Gorilla glue sets, I'll try the next step.
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Laddie M's Arrow - 2nd Attempt - 
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However, in my defense I will say I have done a kit bash of a Rascal, a Seawind, half a pylon seaplane to use the wing from the crashed Seawind, and a second Seawind (as I say, I do get sidetracked). Also did a Splash 3D, but now really need to get back onto the Arrow...Pete
