Wing Construction, Old and New

LAST EDITED ON Jul-22-03 AT 04:00 PM (CDT)
 
Remember the good 'ole days, how we used to build wings?

First, We had to make a template for the root and tip templates. I used .032 aluminum.

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Then we had to shape a bunch of rib blanks.

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Then we had to index them for dihedral and punch jig holes.

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We did all this work just to get a set of usably good, but not perfect, ribs.

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Now, time and technology gives us more and better options. Here is a computer generation of the ribs of my latest project, "Saggletooth 2". Lightening holes are omitted for clarity.

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Here is a laser cut set of ribs for the BBQB Bearcat. I must admit, I'm spoiled. Now I don't like to build without laser cut parts. Thankfully, We've got Kyle at Tanks-hangar.com, (817)759-1740.

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My first I-beamer. Juno-like model from winter 1980.

And here is new foam wing with almost unlimited dihedral and sweepback possibilities for semiscale stunters like this Zlin 526 AFS with little dihedral and LOT of sweepback.

Al,

I never could see how you could end up with the beautiful stack of ribs after slapping balsa blanks between two end plates. At least not for the steep angles and complex wing like you are building. I used the sanded stack to make up thicker templates for individual ribs. (Maybe that is what you did?)

But the laser cut parts sure are fine, aren't they?

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"Energizer Bunny arrested, charged with battery."

LAST EDITED ON Jul-22-03 AT 06:38 PM (CDT)
 
>Al,
>
>I never could see how you could end up with the beautiful
>stack of ribs after slapping balsa blanks between two end
>plates. At least not for the steep angles and complex wing
>like you are building. I used the sanded stack to make up
>thicker templates for individual ribs. (Maybe that is what
>you did?)

Larry;

I always thought that the concern about the angle on the ribs was overplayed. I usually made the rib templates about 1/32" "fatter" than what I wanted, giving me 1/64" on each side. After the ribs were stacked and trimmed, I broke the stack apart, and "trued" the ribs. The was accomplished by placing the rib on a flat, smooth surface (like a cutting board. I then trued up the sides by a couple of strokes with a sanding block and 220 grit that was perpendicular to the board.. About two strokes was all it took. Cap strip joints were smooth and level. Assembly was as perfect as I could imagine. My C and D tube wings came out just fine.

Yes, laser is probably more precise, but not all of us have a laser cutter near by. The stack and trim method has served builders well for two generations. The angle induced can easilly be compensated for without a lot of balsa wastage.

Al - I would be interested to see how you generate those individual rib profiles.

ADDED LATER - Al, so your reply as to how the ribs are generated after I posted.

Nicely annoted post, Al!

What I'd like to know is what program to use on the Mac that generates airfoils and what not for DFX, and how you correlate Jig holes, dihederal and what not in the various airfoil sections for the ribs so that the jig tubes end up holding the ribs correctly.

I can get by drilling a pair of holes in a match stack of constant chord ribs for a flat wing for my venerable adjustajig, but I'd probably switch over to your larger jig tube format if I had software that would allow me to do the design work.

Cy.

LAST EDITED ON Jul-22-03 AT 06:23 PM (CDT)
 
Cy,

Why fight it. Let Kyle do the work. Send him a root and tip rib, or just the top halves if you want perfectly symmetrical ribs. Also show the vertical relationship of the root and tip ribs and where you want the jig tubes. Kyle will "blend" the root and tip ribs creating as many intervening ribs as desired. He generally includes a BBQB bellcrank mount, gear block cutouts and reinforcements, and some custom fine tuning of the lightening holes to reduce interference with the jig tubes where possible.

If you just have to do it yourself, call Kyle for software information. As for rib profiles, I do not generate them with any software program as I think all that I have seen are inappropriate for full flap stunt ships operating at Reynolds nrs of less than 500,000. The outline of my left shoe sole still works as well as any design process that I know of.

Refering to my original post, I gave Kyle the root and tip rib shown in the multi-colored diagram which also showed where the jig tubes should be and Kyle generated the rest.

The outline of my left
>shoe sole still works as well as any design process that I
>know of.

Al,

Pretty cool in this day of computer generated everything! (Uh, I don't suppose that your shoe sole outline happened to be generated by a "ModelCad" program...?)

I understand that a major athletic shoe manufacturer uses a modified nobler rib profile for their soles

>Nicely annoted post, Al!
>
>
>
>What I'd like to know is what program to use on the Mac that
>generates airfoils and what not for DFX, and how you
>correlate Jig holes, dihederal and what not in the various
>airfoil sections for the ribs so that the jig tubes end up
>holding the ribs correctly.
Cyber,

If by "generates" airfoils you mean the ribs between the root and the tip you need, in 1st place, to be able to draw the two ribs, and it takes some time to get he hold of it.

I was using an old version of "Canvas", and after the two ribs are drawn you jus select both and give a "blend" effect, speccifiyng how many shapes you want to generate .

If you want it all, you'1l gave to get a Windows emulator installed on your Mac and use..is it compufoil?

Well, get the Windows emulator software (your Mac will run just like a PC) and assk John Miller about Compufoil.

BTW, Canvas is/was available in both Windows and MAC versions. I learned it on a MAC and have it on my Windows PC. Nice program.