Question about planking

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NeedHelp12

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Hi , I have no experience in planking but have a question about it nonetheless:

How does one make sure that the wing planking is firmly attached to the underlying ribs especially if the wing profile is interpolated from root to tip?

Thanks in advance
 

BJC

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Could you provide some additional information?

What airplane design are you building?

By “planking”, do you mean the spar, or are you referring to planking like on the hull of a wooden boat?

What aviation experience (designer, builder, pilot, mechanic, engine specialist, etc.) do you have?

Those will help HBAers provide meaningful answers.

Welcome to HBA.


BJC
 

proppastie

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wing planking is firmly attached
Given the question as posted I would suggest that you look at a set of plans for an aircraft in the material you are talking about. If you build a known aircraft the designer will have designed it so it stays together. (assuming you build it correctly) If you have trust issues you can static load test the finished product.

You might join a local EAA chapter or go to some "Sport Air" workshops and learn some aircraft skills.
 

TFF

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The answer is craftsmanship. For a joint to work, the parts have to meet. That takes practice and time and good measurements.

Sounds like more of an RC project than a real plane. There are better places like RC groups and RC Universe that use those techniques that fit better a RC plane. Scale planes RC Scale Builder is superb. You can also get away with more with an RC airplane in many ways. Not as heavy and not carrying a person.
 

Pilot-34

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I have never heard of a planked wing.
But There are lots of things I haven’t heard of ,can anyone suggest an example?
 

Tench745

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Hi , I have no experience in planking but have a question about it nonetheless:

How does one make sure that the wing planking is firmly attached to the underlying ribs especially if the wing profile is interpolated from root to tip?

Thanks in advance
What I'm picturing, based on your question, is skinning a wooden wing with plywood. I do not have any experience doing this, but as I understand it you butter the mating surfaces with the appropriate glue, lay the plywood in place, and secure it temporarily to each rip, spar, etc with a nailing strip (a piece of wood to spread clamping pressure and held in place temporarily with nails.

If this is not what you're referring to, I'm at a loss.
 

Tiger Tim

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How does one make sure that the wing planking is firmly attached to the underlying ribs especially if the wing profile is interpolated from root to tip?
It just takes a lot of checking and fitting before you commit to glue.

As an aside, your post history implies that you may be asking because you’re building models. If that’s the case I suggest a forum like rcgroups.com or hippocketaeronautics.com. Because of size differences there are often model building techniques that would be unsafe or impractical on a full-scale aircraft and full-scale building techniques that would be too heavy, too labour intensive, or not strong enough when scaled to model size.

In other words, some context for what you’re up to would help a bunch.
 

NeedHelp12

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What I actually mean is :

How is an airplane wing covered with wood so that the wood follows the shape of the underlying ribs?
 

BJC

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Plywood is used. It bends easily to the shape of the airfoil, except, for the leading edge. Some leading edges are shaped from solid wood. Some are molded from two or more layers of very thin plywood.

Search for a build thread by Tantrum1, to see examples. Snoshoo SR-1 Reno Formula 1 Racer


BJC
 

Ed Waldrep

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Many wings with taper a surface that is only curved in on direction, along the airflow or chordwise, but in the other direction they are flat on both the top and bottom surface. Take for instance the wing on an Extra 300S. If you lay a long straight-edge on it in a particular spanwise direction like at the thickest part, the straightedge will touch the surface from root to tip. If you build a model of one using hot wired foam cores, you only need two templates at either end of the foam block, for the root and tip. This makes sheeting the core easier since there's only a bend in one direction.

If the wing is built out of wooden spars and multiple ribs, it can still be sheeted with balsa sheet or plywood. The shapes of the ribs in between is determined usually these days by a airfoil plotting program like Wingmaster or Profili or other traditional methods. When you sheet the wing you can use a long stratight-edge to press down on the sheeting as the glue dries. This helps to ensure that the wing surface is flat and that any gaps that may exist don't distort the sheeting. When I built a Goldberg Chipmunk I used my triangular shaped drafting rulers or a metal yardstick and pressed down on the sheeting as I sprayed CA kicker on the joints. I build quite a few wood ribbed wings and turtledecks and it always seemed that there was a gap here and there. Variability in cutting accuracy with a scroll saw was likely the cause. Even now that I laser cut, things are aren't always as accurate as I'd like, but thick CA glue makes up for a lot.

When I get around to building an ultralight I'll have to get a longer, stronger straight-edge like some angle iron or square aluminum tube. But hopefully a 1/16th inch variation in dimensions will have a lot less impact at the sizes of a full scale airplane. The straight edge may not be necessary, laser cutting will help a lot in the regard.

Oh and I didn't get into complex wing shapes with compound curves, like a Spitfire or a modern airliner like the 747 or A380. There's some straightness there but also a lot of curves.
 

wsimpso1

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One thing that requires a lot of care in execution is holding the skin down everywhere. Frequently these thin plywood skins are clamped using strap clamps and nailing strips make the skin conform to the underlying structure and glue up solid. But the final insult is that when you bend a skin one way, it tries to get a curve the other way so that it looks saddle shaped. Think on this a moment, you bend it one way and inner surface must get shorter around the curve while the outer surface must get longer. Materials will not do only this. Where the inner layer is shorter along the curve, it is also trying to get longer in the direction perpendicular to the curve. The other surface is getting longer around the curve, and trying to get shorter perpendicular to the curve, so it gets slightly saddle shaped. The edges want to lift, and you need to hold down the edges of the pieces of plywood extra hard. Nailing strips may only be needed at panel edges...

Billski
 

TFF

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In the model airplane world it’s called sheeting. Planking in the model world is taking strips of wood and running them length wise and dealing with the gaps after. There are all sorts of tricks from ammonia baths to steam to aid in bending wood. Takes practice and picking the right method for what you got.
 

Riggerrob

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Planking was fashionable for building speed boats and early airplanes (e.g. Albatross and Curtiss flying boats) before marine-grade plywood was available.
Basically, you start with thin, narrow strips of wood, trim them to shape and glue them onto ribs. The thinner the strips, they easier they curve. Sometimes, you need to steam wood before curving it. Then start trimming the next strip. Once the first layer is complete, start trimming and gluing the second layer to lay at 45 degrees to the first. It is a complex, labor-intensive process.
For tutorials, read "Wooden Boat" magazine and similar tutorials on YouTube. Also consider attending classes in wooden boat-building.
 
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