Another Wing Jig

A while back, some were asking about wing jigs. This is part of the one I just finished. As pictured, it's just for framing up the wing. There is a larger board that allows putting together the entire plane in one jig for alignment. Should work pretty well.

Where did you get the 90deg pieces for your supports. If the full jig is as nice I'm sure it will do a great job.

Do you have a photo of the full set up?

Well, I made them. They are made from aluminum angle stock, 6x4 inches. I'm just building the wing. The stab jig isn't set up and I didn't think to take a pic of the fuse portion. The fuse is finished. Well, the box, anyway.

I'll take a shot of the whole thing when I start framing up the whole plane.

Here's a pic of the fuse. I thought the hatch was particularly tricky.

>Where did you get the 90deg pieces for your supports. If
>the full jig is as nice I'm sure it will do a great job.
>
>Do you have a photo of the full set up?

I have seen similar angles with the groove already cut up, but don't remember where. I think they are used to aling canopies over window blinds:+
Fernando

Nice set-up and very impressive work Randy. You might think about doing an article on this set-up for Stunt News. Thanks for sharing it.

Larry,

Yea, I might do that. I've already had a couple of emails asking if I was in the jig selling business now. Yikes! I did these on a mill, but unless I had a CNC mill with CAM, I wouldn't even think of it. Way, way too much work. Took me a month to do this one.

But I think the concept is instructive and the theory. Once the jig is set up (which takes quite awhile to get right), actually building the wing is sort of anti-climatic. Actually building the wing took about 4 hours total. And I can say it's the straightest wing I've personally ever built.

Gosh, I love elliptical shapes. I'll post a pic when I finish up the sanding.

For those interested:

Here's the completed wing. 7.84oz as it sits there.

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Below is the same jig applied to the stab.

Beautiful work, Randy!

I too dearly love these elliptical shapes.

You've inspired me to get back to work on StuntRib-X, the Excel spreadsheet version. This version is planned to do elliptical wings as well, and both elliptical and "compound" elliptical thickness tapers, plus ribs for elliptical tips.

I know, I'm promising the moon. Like going to the moon, it may take me 10 years, but I'm not bad mouthing Microsoft Basic or Excel so much, now that I'm learning a few things.

I'll probably be bouncing some things off you soon.

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"Great minds discuss ideas. Average minds discuss events. Small minds discuss people."

Larry,

No problem. I'm glad to help any way I can. I'm having an awful lot of fun with this. I couldn't have even gotten close without some trial and error on StuntRib and the unfinished spreadsheet program. There was a lot of cutting a rib and referring to the spreadsheet to check the thick the thickness and such, but it worked pretty well.

Randy,

The stab is interesting. How do you apply the top and bottom skins?

I have those aluminum bars, but I have no idea how to set it up for a taper. How did you drill those slots? What is holding them in place.
Jay

>It's done sorta like an I-Beam wing. The idea for the jig is
>based on Tom Morris' Millenium Wing jig...sorta. The wing
>rib shape was done largely with StuntRib. I actually used an
>I-Beam rib template and check the final against the patterns
>generated by StuntRib. The went pretty close to on, so I
>didn't mess with it further.
>

Randy;

Neat.

Two additional questions:

Did you use the same template for both the straight center and diagonal ribs?

Did you keep the angle the same between the ribs as you go towards the TE, or the distance? (Can't tell for sure here).

>Neat.
>
>Two additional questions:
>
>Did you use the same template for both the straight center
>and diagonal ribs?

Caught that, did you?

I figured out pretty early that the original template wasn't going to work for the diagonal ribs. Sigh... I used the StuntRib program to generate 2 rib templates. The diagonal ribs have a slight longer, flater section just aft of the high point as it turns out. I messed with Larry's program quite a bit along with his Excel spreadsheet before I got tempates that gave a consistent, elliptical taper. That was fun.

>Did you keep the angle the same between the ribs as you go
>towards the TE, or the distance? (Can't tell for sure
>here).

Mostly. I had to change the angle slightly as you move torward the tip to maintain the correct taper. I cut a sort of a vertical taper template. A guide, really. I used that to place the ribs. Seems to have worked out. The only part I really miscalculated was the spar taper. As I have discovered with this sort of wing construction method. You have to allow the ribs and the guide dictate the taper. I designed a spar that, it was planed, would force a more severe taper. Just didn't work that way and I had to split the spar to keep the designed taper shape (hope that's clear). Anyway, if you look close, you'll see some vertical bracing on the spar. That was boo-boo repair. Actually made for a stronger spar, I suppose, but cost me about a half ounce in weight.

I may make another run at this wing, depending on the final weight and boo-boo repair. Once the jig is set, it's pretty easy to crank out wings with it.

When using the laser level, do you find the spot size or line width to be fine enough and similar width from close to far targets to get the heights well. Or do you have to go back with something like a straightedge to get them all colinear?

Curt (messing with the laser level procedure)

Cap,

For the distance (65" or so), I think it's negligible. The instructions for the one I bought (from a local tool dealer) says that dispersion is less than .002" for a distance of 20 feet, so I think 65" is fine. I do initially use "set" blocks. I calculate, from the plans, the distance from an arbitrary spot below the wing to the centerline and make some blocks for the LE and TE. I set the lower jig clamps with these then check with the laser level. For this, you really need the base to be flat and level. Mine is. But in the end, as long as yhou have a flat reference point, it probably doesn't matter. Also helps to have a back plate on the opposite side from the laser level. I just set up a piece of melamine (spelled right now?) as a sort of reflector. Not sure, but it seems that the beam is more, I guess, what, tight? with this. Probably just my imagination. Maybe I can just see the beam better with the white backdrop.

>>Did you use the same template for both the straight center
>>and diagonal ribs?
>
>Caught that, did you?

Been playing with the concept of diagonal ribs myself of late. It caught my eye.

>I figured out pretty early that the original template wasn't
>going to work for the diagonal ribs. Sigh... I used the
>StuntRib program to generate 2 rib templates. The diagonal
>ribs have a slight longer, flater section just aft of the
>high point as it turns out. I messed with Larry's program
>quite a bit along with his Excel spreadsheet before I got
>tempates that gave a consistent, elliptical taper. That was
>fun.

Interesting. I am trying a different approach, but using some of the same products you are. Using rib and tip templates done in CAD and placed along the Z-Axis, I am rendering a surface between them. Where I am failing on this is then slicing this surface at the rib locations and extracting 2D ribs. If I can figure this out, then getting diagonal ribs for a given wing design laser cut would be a snap, and one would not have to go through the mess of a lost foam system or the "by guess and by gosh" I often resort to.

The real problem is my ignorance of CAD and 3D rendering programs such as Solidworks and Rhinocerous.

Of course, I look at your "barn swallow" type LE, and realize that doing that in CAD would really make one's head hurt...

You guys have a **LASER**?!!

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"Paper clip: The larval stage of coat hangers"

>You guys have a **LASER**?!!
>
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>
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>
>"Paper clip: The larval stage of coat hangers"

Larry,

You have a talent to annoy me!

That's surprising to me, considering I'm a fan of your joke and your ability to take life lightly not to mention your brains and that Stunt Rib!

The only explanation I can find is that you sure can sense the moment when guys are all dead serious to come up with your wisecracks.]

For instance, my ears perked up whrn i read about that laser level tool, started getting ready to do a google research on it and next thing I see is that joker by the name of Larry Cuningham making me feel like an idiot!! ..

I'll finish this posting with two "quotes", à la Larry...

1 - "Don't take life too seroiusly. you ain't gonna get out of it alive, anyhow"

Unknown:(to me )

2 - Get outta here. Larry, you old monkey!!" LOL (Laughing Out Loud)

Ion Muniz

God bless you!

In Christ,

Ion

PS. I never forgot that picture of a V-8 engine from a GM car you posted as a repply to a serious (!) question I made about 4 cyclin'.

I swore revenge, and I'm doing like the folks from the State of Bahia do:

If you are unfortunate enough to get a "Bahiano" pissed (*) at you he just says, in a very relaxed way: "Just wait, I'm writing this down...".

It might take a week, a month or a year, but one fine day you find yourselk as sorry as you could be for messin' around with a Bahiano...

I'm a friend of this pop star from Bahia, Caetano Velloso, and every once in a while I tell him "Caetano, I wanna die as your friend!"

Bad business to have that Bahiano as an enemy!

Singer João Gilberto, the "Father of Bossa Nova" is also from Bahia, but he's worse; It doesn't help being his friend, he'll badmouth you anyhow.

Not even Antonio Carlos Jobim managed to escape unruffled from his fiery tongue!

But, since some of us Brazilian musicians know better, we learned to just ignore João's ramblings.I like him and cherish his friendship, knowing that as soon as I'm gone from his presence he might just say to the other guys around: "You know, that Ion is a nice fella, but his flute playing stinks" or whatever he decides to throw at me.

I've heard stories of João being with some friends, and nobobody wanting to be the first guy to leave...

I know that even if you're the last one to leave, it won't do you any good. He can just pick up the phone and "do the job" via voice...

So Lary Cuningham, you better fear and tremble, the curse from Bahia will seek thee...

(please, Larry, do not get abny wrong ideas, I just felt like throwin' in some cultural aspects of Brazil. I hope you enjoy it. and it's all true!

(*) I sincerely hope that the word "pissed" is within the limits of decency in the US, or at least at Stuka Stunt. If it's not, please let me know, so that I can quickly edit this posting~

Curt,

>>One of these days I'm going to score a 5' granite surface plate! Then I'll need to figure out how to get it into the basement.<<

I've thought about that. My shop is over the garage. When it was built, I told the contractor that shop a would be upstairs so the floor needed to be re-inforced. There are 2 10x12 support posts and cross beams in the garage. I suspect I could put a full sized Bridgeport mill up there without problem. Does make getting out of the cars interesting. Takes a certain amount of technique.

There is a much larger melamine plate that I will use when I get ready to put the plane together that will allow me to jig up the entire plane in one shot. I initially got the idea from Paul's Impact article. It's why I made 38 of the risers. Sheesh! Between that, 2 incidence gauges, a laser level and a thrust incidence gauge, the darned thing better at least be straight!!

Randy,Curt, Larry (putting baby finger to lips here ),

I picked up a trio of cheap laser levels about two weeks ago at a truck load tool sale. Idea was to use them in or with model construction jigs,..or for anything else that I could think of. Like Curt mentions, the actual beam width seems a little heavy/wide for model work in stock form in my opinion. So I spun a few "beam reducers" to take the edge off the spots. See the photo's. What seems to work is a extremely small hole centered in the beam aperture. I might make three more reducers of smaller size and see what effect this has on the beam produced. Not sure as to what use I'll be putting these units (besides the finish on the basement renovations) but I get a warm (red) glow just thinking about the possibilities. For any one interested: I paid $14.95 cand. dollars (plus tax) each for these units. Lee Valley Tools carries a near identical unit for $22.00cand and change which includes a tripod threaded mounting boss on the underside (mine do not have this feature). Both include a bubble level on board for set up use and are powered by AAA cells. For the price I thought I could not pass them up.(was the only reason I went to the sale in fact)
Photo's: One is of the units. Second one shows the business end, ... one with reducer,... one with out,... and the reducer sitting in front. Third one shows the laser dot stock and reduced, against white paper. With a level building surface and a means to lock one of these at a set height, it could be very easy to slide it around to check pin point alignment of the model,..or use it to transfer ref points for paint finish striping and the like as you might use a surface gauge. And of course you can always tease the cat with one.

Interesting, but why build parts in a very complex and expensive jig if there is no practical way to complete the parts in the jig. I don't know of any jiging method of building complete stabs in a jig. I build a very straight and strong spruce/balsa "I" beam for a stab main spar, but from that point on, my airfoiled stabs are mostly built up in the air, which isn't to say they aren't straight. It just means I haven't found a pratical metho of jigging them. Without using the complex sheeting method you describe, it seems pointless to build a very flexible structure in a precision jig and then have to take it out to finish it. This exposes its weak structure to all of the problems I experience with building stabs without jigs.

I'd concur with Al. (Who is not going to?)

Although all I've done so far is straight and moderately tapered wings on a thin rod Adjusto-jig, I leave the wing on the jig until I literally cannot add another piece of sheeting without taking it out. Once all the sheeting is in place and the glue long dried then I take the wing out and immediately add the final sheet to the underside where the ribs are held by the little red plastic do-hickeys.

Biggest problem I have (diverging the thread) is drilling the two holes in the rib stacks for the small rods that position the ribs.

Any wisdom on drill speed, pressure and technique to get a clean small hole drilled in a stack of ribs of soft balsa?

Use a "sharpened edge" piece of brass tubing for your "drill". Mark the holes very accurately with a circle template and use the tubing "by hand" to cut the hole.

I never cared for the Adjusto-Jig. Too much hassle to use it. I like the Morris Lincoln Log method, which supports leading and trailing edges. If you make the support blocks accurately, you can do all planking with the wing properly supported.

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If the leading edge and trailing edge are straight, the wing comes out straight.

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"Character is what you are. Reputation is what people THINK you are."

Hi, Larry-

As you know, I have jigged up a wing just this way - except that it's flapless (Oh, NO - I hear it coming from Texas already! The NEXT one will be a flapped stunter, I swear. I know I need one, and it'll be built. But I did say I was building this one). Anyway, it's sort of a cross between "New Millenium" and original "Lincoln-Log" structures - resembles what I've seen of Tom Morris' more recent types, with rib slices cut to computer-generated shapes and pre-assembled with cross bracing. The main spar is open with diagonal braces creating a truss work, and thus I think will form the equivalent to a D-tube structure, with l.e. sheeting. There are 21 full ribs and 20 l.e. stub ribs. Jigged and glued without sheeting or bellcrank mounting, and before significant wood removal for l.e. and t.e. shaping, it weighs around 2 1/2 oz. so far. Now, bear with me...

It turns out that this flapless wing is more complex than a lot of flapped wings. To get the strength and stiffness I wanted in my high-aspect-ratio experiment, I designed it so that the 3-piece t.e. spar is actually the 1/4"-thick front wall of a triangular spanwise tube consisting of it and the upper and lower 1/16" t.e. sheeting, all glued also to the triangular aft rib sections. The 3-piece aft spar must be tapered, so that the t.e. sheeting can be glued to its upper and lower surfaces.

My friends feel that the wing will be subject to warpage, if it does not remain jigged during the aft sheeting process, but of course the "trailing edge" jig blocks must be removed to taper the spar and make room for sheeting.

Here's the question:

Would you agree that I will need to make jig block inserts to clamp onto the 1/16" aft-spar's front-facing "tongue" (from the front) to stay warp free? Any other ideas? Thanks.

Work has slowed on this, while I get some season ending air time and ponder the approach.

SK

I know people say that it can't be done, but I find that using a fresh drill bit and running it at the highest speed you have on your drill press, you can drill nice holes. Or if the stack is not too thick, use sharpened brass tubing in the drill press.

Cy,
When you leave off the last piece of sheeting and remove the jig rods you are subject still to twisting and warping. The wing doesn't become a monocoque (where skins bear most of the load) unit until all of the skins are in place. Then you have a very warp resistant structure. this also makes the point that, no matter how accurately open bay wings are built they are not monocoque structures and are subject to deformation from many forces as innocent as paint shrinkage. Fully sheeted wings (including foam) are the most likely to maintain precision alignment.

As for jig holes, make a plastic template and use sharpened brass tubing.

Yes you can fully sheet wings in a Morris type jig. I have a Millennium with a number of spanwise cracks where the sheeting meets the leading edge to prove it. Those are butt joints in highly stressed locations. The only butt joints I now tolerate are laminating joints to make wide sheets. all the other joints, leading edge, spars and trailing edge are lap joints. The Millennium wing turned out to be a disaster with spanwise cracks at the leading edge and insufficient flap travel. I considered replacing just the removable wing but decided, instead, to just build a new Millennium with improved, lighter structure.

>Cy,
>When you leave off the last piece of sheeting and remove the
>jig rods you are subject still to twisting and warping. The
>wing doesn't become a monocoque (where skins bear most of
>the load) unit until all of the skins are in place.

Yeah, I know that. With the Adjusto-jig, however there are these red plastic thingies holding the ribs in position that preclude sheeting the whole thing.

I'm very pleased with the wings I've build with the Adjusto-jig--they are way better than anything I ever did on a table top as a kid.

But the jig fixture is a hassle and the two rod system seems way better.

I hate to give up on something I've learned, but then all life is change and progress, right?

Maybe the next ship I'll go get a couple of rods and some 2X4's and build a jig and use the bid round rod scheme.

Al,

Well, my original intent was to use a set of machined aluminum sort of long clamps that fits in the jig displayed. They would clamp the sheeting to the substructure in the jig. I built something that would have worked, but may have been problematic due to this particular stab's complex elliptical curves. A normal, tapered stab wouldn't be a problem. It is essentially 3 long aluminum bars that attach to the uprights and would hold the sheeting tightly to the substructure.

Works for me. The way I ended up doing it (with the cradle)was just an interesting experiment. As I noted, it was a one time deal. Next time with a normal, tapered stab, I'll use the clamp setup.

Randy,
Even if you devise a way to add sheeting by clamping in the jig at the leading and trailing edges you still have the problem of making sure the rest of the ribs are in full contact as the adhesive dries. I CA the top skin in full contact. With one side fully glued the stab is still very flexible. I then attach the bottom skin to the rear spar with CA. The rest of the sheeting is glued with water thinned Tightbond and held with about 50 pieces of masking tape around the leading edge and tips. As the masking tape strips are applied the surface may easily be straightened by eye. the masking tape will tolerate a fair amount of twisting for alignment, stiffening as more tape is applied. Finally, the surface is weighted to insure rib contact as the Tightbond dries. this isn't precision alignment, but it is very good, and, as far as I can tell, as good as anybody else's method of building airfoiled stabs.

Al,

That's exactly right. That's why I machined wide pieces from aluminum that have horizontal arms with attachments to the uprights. A little messing around with it insures that the sheeting has full contact with the substructure. But as you note, you really need to use CA for one side and some sort of slow cure glue for the other side to close it up.

This was why I wasn't all that happy with the system for the elliptical structure. With a double elliptical taper, it meant making a series of curved clamp pieces to insure that the sheeting was in contact at all points. I wasn't all that interested in spending hours on end making these for one project. I suppose if I had a CNC mill with CAD and CAM hookup, I could make the pieces precisely enough. But doing it by hand would mean a lot of small cuts with constant removal from the mill and checking followed by resetting the piece in the mill and more small cuts. Not a fun proposition.

The other option was to set up a frame with adjustable pieces along what would be the surface of the stab, but again. setting up a frame with maybe 40 separate adjustment stations didn't seem like fun.

In reality, a certain amount of shiming is necessary to insure that the sheeting is in contact with the substructure at all points.

I really need to take a picture of this process to make it clear.