Wing Alignment

[Chris Fretz]

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

[Joe Ed Pederson]

The system I use is described in this video:







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

[Alan Resinger]

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.

[tom brightbill]

Not only is Alan's jig system spot on, but I see a fancy new wing!

[Trostle]

Not only is Alan's jig system spot on, but I see a fancy new wing!

Ir looks like a Bearcat.

Keith

[Trostle]

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

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

[Steve Helmick]

Not only is Alan's jig system spot on, but I see a fancy new wing!

I see Chris' shop with Alan's plane and jig in it! But I'll wager they share the jig.  Steve

[Alan Resinger]

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. 

[Matt Colan]

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

[Dan McEntee]

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

[Bob Hunt]

I have a method for installing and aligning the wing to fuselage that has worked perfectly for me and the many who build at my shop for many years. I briefly outlined this method in the text for the book I wrote about my Caprice model. Here's an excerpt from that text that deals with the method I used and still use to this day:

This component assembly is where most potentially great stunt ships are ruined, and it’s also where the really great flying ones are for the most part made! The accuracy of the wing/fuselage and the stabilizer/fuselage joints are of supreme importance.

Each model builder will have pet methods of achieving this accuracy of component joining. Use whatever method works best for you. I’ll give you a brief rundown of a method that I’ve developed that actually allows me to not even have to check the alignment.

The actual opening that needs to be cut in the fuselage sides for the wing is not the airfoil section at the center. It’s not even close. So how do we determine the wing’s exact shape where it will pass through the fuselage sides? The wing tapers in both planform and thickness to a point about 1 1/8-inches out from center before it passes through the sides. I reasoned out that the exact fuselage opening shape was easily available. I cut an extra foam wing panel and covered it with 1/16-inch sheeting only a few inches out on the panel, and then figured out the exact position of the fuselage where it passed over the wing. I marked this position and then band sawed the extra wing panel chordwise at that point. That cut yielded a perfect wing-opening template, and that is what I used to draw the wing opening on the plan.

I actually use the airfoiled piece of sheeted foam as a “plug gauge” to fit the wing perfectly to the sides when I’m preparing them. If positioned perfectly on the wing’s
centerline on the fuse side, then when the wing is installed it should fit the opening perfectly and also have no incidence. Seems reasonable, don’t you think?
I can supply this accurate wing-opening gauge on request. If you opt to use this gauge, do not outline the opening of the wing with pin punches when you are laying out the fuselage sides. Instead, make an accurate centerline in the wing cutout area and use the gauge to mark out and fit the wing opening.

It further dawned on me that if I were to trace the tip shape onto pieces of sheet balsa, and maintain the same centerline to bench measurement as at the fuselage, I could hold the tips in exact alignment. This would give me four points at which the wing is being aligned automatically. I know this is a bit hard to visualize, so take a quick look at the photo of this line-up procedure. That should explain the concept better than the proverbial 1,000 words it replaces.



The above method works exactly the same way with built up wings that are constructed in the Lost-Foam system. I simply design the wing so that it has the first ribs on either side out from the center positioned directly under where the fuse sides will pass over the wing. When I make the ribs foe the wing I make an extra rib at that point, and then cover it with the same thickness sheeting that will be used on the wing. That gives me a plug gauge to use to open the fuselage sides to the exact shape of the wing. The only critical thing at that point is to align the plug gauge precisely on the enter line of the wing on the fuse sides.

When installing the wing - foam or built up - you will need an absolutely flat surface. I use a piece of 6-inch thick foam that was very accurately cut to yield a flat surface. I draw center lines for the fuselage on that piece of foam, and also a line that is 90 degrees to that line to allow me to adjust the skew (top view alignment) perfectly. I don't even bother to check the incidence alignment because it has to be perfect due to the nature of the system.
   
Larter - Bob Hunt

 

[Scott Richlen]

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.

[Scott Richlen]

Also, get some line levels and make sure your table to dead level before using it.

[CircuitFlyer]

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.

[Bob Hunt]

One reason I came up with my method is that it does not employ an incidence gauge. In my experience they are not at all accurate. You can put them on and get one reading, then remove them and reapply and get a totally different reading. Some my not agree with this, and that's okay; I'm using a method that insures accuracy without any measuring devices that rely on a bubble being used to assemble the parts.

I do use a Johnson Angle Finder for one operation, and I've found that device to be accurate no matter how many times I remove and replace it. And I do remove and replace it several times just to be sure, but that device  is not used to check the wing to fuselage alignment in my method; it is used to level the fuselage/wing assembly when installing the tail. And even then it is just a double check to my scale measurements.

Later - Bob

[Scott Richlen]

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.

[Chris Fretz]

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

[Avaiojet]

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

[Chris Fretz]

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!

[Avaiojet]

It's a good thing you don't fly any of yours!

"Give a man enough time and he'll ruin everything."

                                                                     Plato

[Wolfgang Nieuwkamp]

For any smartphone you can get a leveling app. Very sensitive, same results every time.
Regards,
Wolfgang

[Dan McEntee]

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

[RknRusty]

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