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General control line discussion => Open Forum => Topic started by: Chris Fretz on March 24, 2020, 02:08:22 PM
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Curious to know your system to align a wing in a full fuselage airplane. Especially when you're dealing with a outboard wing that is 3/4in shorter.
Thanks
Chris
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The system I use is described in this video:
https://www.youtube.com/watch?v=iX2kIn9Brns
https://www.youtube.com/watch?v=TZldHVxz0MI&list=PLg0IjwkivQPBu_O_knQ5bRXkG2ba4gq1e&index=2
https://www.youtube.com/watch?v=x_2z1nsQo3w
It involves buying jigs from Walter Umland of "builtrightflyright.com" in the vendors section below. The jigs work regardless of whether the wing panels are the same length or not.
Joe Ed Pederson
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If you really want proper alignment you have to build jigs to align all of the components. It is worth any amount of time and will pay off with a model that flies with minimal trim. This jig uses a 4 foot by 5 foot piece of MDF as a base that is then trued to dead flat level. Laser alignment units are also used. Look at the pictures will show that both wing and tail are jigged along the leading and trailing edges for the wing and flat base pieces for the horizontal tail.
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Not only is Alan's jig system spot on, but I see a fancy new wing! ;D
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Not only is Alan's jig system spot on, but I see a fancy new wing! ;D
Ir looks like a Bearcat.
Keith
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I just draw lines on the fuselage for motor, wing and tail. Then when I make the cut out for the wing the line is still there front and back. You need lines on the wing LE and TE too.
Motorman 8)
That might result in satisfactory results, but missing even a portion of the width of the pencil lines on the wing and tail can lead to a significant misalignment, nose to tail, with respect to the wing and also the tail. A jig of some kind, and there can many variations that do the job, is almost mandatory for a seriously built, competitive stunt ship. At least with most "standard" CL stunt configurations where the wing TE and the horizontal stabilizer TE are straight, as in no sweep and dihedral in either, these respective TE's can be kept parallel with careful measuring when attaching the horizontal stab without resorting to jigs even if the wing is not mounted true to the fuselage..
Keith
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Not only is Alan's jig system spot on, but I see a fancy new wing! ;D
I see Chris' shop with Alan's plane and jig in it! But I'll wager they share the jig. y1 Steve
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It is one of three new wings (composite) that are close to flying this season. The new Rare Bear is waiting for clear to gas off so buffing can start. Chris Cox should be buffing his new ship in a day or two. It isn't a Hellcat this year. Arkady also has a new ship that is in the painting process.
The assembly jig is a shared item.
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This is what I did on my last plane. Two incidence meters on each side of the wing, plus I traced off a rib from the lost foam jig and cut it out that was the exact height From the wing centerline to the top of the fuselage which is a straight line. I also make a mark about 25 or so inches out from the center of the wing towards each tip and measure the each mark to a pin I put in on the rear of the fuselage. Most of the trim I had to do with this particular plane was level the wings and get the CG correct. Other than that it flew pretty much perfectly right out of the gate
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Curious to know your system to align a wing in a full fuselage airplane. Especially when you're dealing with a outboard wing that is 3/4in shorter.
Thanks
Chris
Even with offset wings, the wing still has a center line. The trailing edge, which is usually straight with no sweep, needs to be straight and can be checked with a straight edge. Measure out a convenient distance from the center line and ,make an accurate mark on each wing. That can be used to center the wing in the fuselage. The horizontal stab is marked up in the same way. I don't have the room for an elaborate jig, I just have to use the tools I have to the best advantage. After I have the wing and stab marked up like I mentioned, I rig up the fuselage in an old Black and Decker Benchmate plastic vice on a solid table in the middle of my garage. I use three Robart incidence meters. One on the engine ( which is bolted in place at this point,) one for the wing, and one for the stab. I go by the Whitely method of bench trimming, and set the engine up at 1 degree down thrust, wing at zero to the center line, and the stab at 1 degree negative incidence. I use a good metal ruler/straight edge to square the wing up to the fuselage by the triangle method, and then line up the stab to the wing by measuring wing T.E to the stab T.E. Having everything as fine fitting as possible, slow cure epoxy, and all required tools at the ready is important because once I start this procedure I don't want to stop until I'm finished. I double and triple check everything as I go. This works well enough for me in that knowing what the balance, approximate tip weight, line length, prop and such is supposed to be for a model, the last three airplanes that I have built from scratch, plus any ARF's, I have been able to do the pattern on the first or second flight on each airplane. All this requires is good measuring tools, a solid work surface and fine, accurate marks. I have done a lot of large, jig and fixture work in my time, the type of stuff that requires an accuracy of .015" or so over a long distance, like 60 feet or so. You have to read the rulers and protractors and such by knowing where you want the dimension, front of the line, on the line, or back of the line. The line on most rulers and tape measures is about .015' wide, so you take that into account from the first measurement you take. Like anything else in this hobby, it just takes practice and some thought, but very doable. This method works with just about any model, full fuse or profile, but the fuselage shape can present some challenges as far as holding it goes, you just have to figure it out.
Type at you later,
Dan McEntee
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Chris:
If you have a table saw, get some welding magnets and use them to help align your components with the miter slot and the edge of the table. Align the trailing edge with the edge of the table and the fuselage with the miter slot. The picture shows a profile that we jigged up to glue the wing in place, but it is easy enough to do this with a full fuselage plane also.
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Also, get some line levels and make sure your table to dead level before using it.
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Just curious - does anyone check the accuracy of their spirit levels? Most of the ones I've checked are always off a bit with no means of correcting the error.
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Just curious - does anyone check the accuracy of their spirit levels? Most of the ones I've checked are always off a bit with no means of correcting the error.
I set my line levels on the top of one of my construction levels to check it. Since they are plastic, I can adjust by sanding their base.
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Thanks for all the comments. It's nice to see how everyone does it. I've been using a piece of glass gluing balsa triangles to make a jig, like Sparky showed in one of his videos.
Chris
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Thanks for all the comments. It's nice to see how everyone does it. I've been using a piece of glass gluing balsa triangles to make a jig, like Sparky showed in one of his videos.
Chris
Chris,
It's a good thing you didn't want your fuselage offset a degree.
CB
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Chris,
It's a good thing you didn't want your fuselage offset a degree.
CB
It's a good thing you don't fly any of yours!
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It's a good thing you don't fly any of yours!
"Give a man enough time and he'll ruin everything."
Plato
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For any smartphone you can get a leveling app. Very sensitive, same results every time.
Regards,
Wolfgang
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I set my line levels on the top of one of my construction levels to check it. Since they are plastic, I can adjust by sanding their base.
You can check a level against itself just by swapping ends. If it doesn't change, you're good. If it does, the level is off. Not many surfaces in an average house hold that you can check a level on. If you have a really good level that you know is correct and accurate, use it to level your clothes washer and drier. The tops of those have a nice, hard, slick surface that you can use to check level on your lesser quality stuff. Where I used to work, the flat bed cutters in the bindery were as solid as anything could be, and once those were leveled, triple checked and locked down, I used that to check my stuff from home when needed. Check your construction level against a known surface, and swap ends when you do it to be sure of that level. Especially if you have had it a while and you have never checked it out. It will only read as good as the surface you have it on.
When setting up a model like I described, I always triple check stuff to be sure of readings. Robart meters have a jeweled movement in them, but they can stick a bit, and the more you use them the better. I take them off the model and reapply them, and even rotate them to a different location to check my readings. Practice makes perfect.
Type at you later,
Dan McEntee
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Hey, I'm just glad to see someone uses my videos with Walter's jigs from Joe Ed's post above. I see a bunch of others I need to make time to read about too.
Rusty