Tutorial : Crafting articulated wings
Define the need
To build my Guardian of Kings costume, I HAD to have wings; and for good measure, they HAD to open.
The biggest challenge was to give a “Woah” effect to the costume, like a peacock showing off his plumage. To achieve that, the motion of the mechanism imitates a real eagle wing, which looks pretty close to what people picture in their head when they think about angel wings.
I had the choice to automate the wings so they would open with a remote trigger or create a system to open them by hand.
For automated systems, there were two possibilities: use electrical motors or a pneumatic system.
Electrical motors allow for total control over the speed of the wings as well as different angles while opening the wings to give a natural feeling of a bird movement.
The main drawback of this solution is the combined weight of motors, batteries and all the steel elements used in the system. If the wings were the only prop on the costume it would have been okay-ish, but if you add to this a full armor and a sword, it becomes a bit too heavy to wear.
The pneumatic system on the other hand allows for a quick opening of the wings. The portability and autonomy of the system are rather good. But the required pieces were hard to find, so they would not have been cheap for me. Additionally I had my doubts that the security checks would let me through while I had air tanks attached to my waist.
Because no automatic solution was good enough, I went to see what was possible on the side of manual systems.
I quickly realized that with a manual system, all you need is figure out one thing: which one of your joints will power up your great invention!
Generally the most practical solution is to use an arm, preferably a free one. Of course it would be possible to use a leg, a foot, your neck and so on, but that would be looking for trouble!
In my case, I wanted a length of course small enough so I didn’t have to move my arm too far to open the wings. For this, I drew an unfolding mechanism and attached a cord and pulleys to it. And there I have to be honest and admit that I got very lucky: the course was almost perfectly right at the first try :p .
Research, drawings and prototypes
Before building our wing, we have to figure out what we’re building.
In the beginning, a pivot/slide system seemed like a good solution, but the practical build of this would have been quite the difficult task. To be sure not to mess up, I cut some cardboard pieces and put them together with metal wire.
I then tried a system with pieces put end-to-end, maintained parallel by doubling the middle piece.
The movement is limited but good enough.
The best would have been a secondary course angle for the back and forth, but it was too complicated to implement. So I let the movement free and put simple minimum-maximum stops to set the course (see further below).
I then looked for a way to attach the feathers. There is pretty much an infinity of possibilities when tackling this step. The one that seemed the most practical and also the most common was using a wire connecting all the feather of a same row, that will let you set precisely the angle between each of them when the wing is open (visible on Mashayahana’s tutorial photo on DeviantArt).
So when the wing is at rest, the wire is not stretched and the feathers just drop naturally toward the floor. When the mechanism is activated, the first feather, tightly fixed to the structure will pull the wire, which will then pull on the second feather, which will then pull on the next and so on until all the feathers of the row are unfolded.
Another question was the back anchor point. The most obvious solution was using a harness, or a backpack. In the end I chose a backpack that I pretty much turned into a harness…
The last problem to solve was finding the right material for the feathers, and how to make them. Once again, a lot of possibilities, from fabric to foam, even real feathers. But the price fluctuated a lot between each of them…
I went for the “foam, wood, wire, glue” solution to get a feather that is flexible and light. The painting was a bit harder to figure out because of said flexibility, but we got pretty good results using “Dip”, a flexible and waterproof paint.
To figure out the length of each feather, I drew a prototype on SolidWorks in an articulated assembly. It proved quite hard to set all the lengths right so that the wings would fold back on themselves nicely and still have a good look when they were open.
The first prototype was made out of bamboo. I thought it was light, and robust enough to hold all the feathers, but it turned out to be brittle and not very durable.
It was still useful. It confirmed that the general mechanism was good. And that with some adjustments to the length of the wood pieces, the feel was the right one.
For the backpack, it was initially supposed to keep the “carry objects” function, but when the costume was on, the width of the backpack made me look crooked and kinda weird. So we removed the extra width, and just cut pretty much all the pockets, since they were just useless in the end.
List of necessary materials:
- 1x Bag
- 4m of wood (4×4 in my case). Can be replaced by plexiglas for exemple
- 1x thin plywood plank (~5mm) for the dorsal plate
- 2x large washers with 6mm internal diameter
- 1x large washer with a big internal diameter
- 20x bolts or screws 6mm
- 20x self locked nuts 6mm
- 20x 6mm washers
- 3x small pulleys
- 40x “closed” pitons
- 2x wood screws (small)
- 2x small screwable plastic stops
- Very durable string
- Hot glue
- Hot glue gun
- Drill (pillar drill prefered)
- 6mm spanners
- A large screwdriver
- A metal saw
The bag was bought at a sports shop for 10€. It is basic but efficient because the straps are padded and comfortable for the shoulders, and it has two straps on the front for stabilization, which is very practical.
A wooden plank the same height as the bag’s is attached to the back. It will be the base on which the whole wing mechanism will be fastened. It is screwed in with very large washers so it doesn’t tear the fabric.
On top of the plank, two wooden cleats are screwed: one at the top, one at the bottom. On each of them we place two pivot. You just have to put a wood piece between them now and they will be able to pivot back and forth, just like we saw in the “research” section.
It’s on this wood piece that the whole wing will come on each side. So we pierce two holes in each of them.
Now we go for the wings. To do this, simply cut the wooden bars (in my case oak 20mm wide, very solid) to the length that has been defined on SolidWorks, drill the holes (preferably with a pillar drill for better accuracy), and assemble these pieces together with screws / washers / nuts (SWN).
The nuts must not be tightened otherwise the entire mechanism is fixed; Therefore, in order to prevent them from being unscrewed and go for a walk while you are showing off, locknuts are used, which remain in place even when they are not tightened.
Tip: if like me you are fumbling with your system and often have to disassemble / reassemble, first use regular nuts which are much easier to screw / unscrew than the locknuts. Locknuts need to be screwed with a wrench from the beginning, which wastes a lot of time in the long run. Also, the plastic ring gets damaged and becomes almost ineffective.
The wings can now be attached to the bag using SWNs. These screws are very long because they will serve as the “stops” on the wooden plate at the base of the bag and thus stop the course from the wings to the front.
Now that the skeleton is in place, we will install all the mechanism to open the wings with the arm.
Three hooks are driven into the wooden cleats, two at the top and one at the bottom. There will be a pulley attached on each, and through each a string will pass.
This string is first attached to the lowest point of the wing (a simple wooden screw is enough), it then passes into the pulley which is on its side, and is tied to a ring. Another string does the same on the other side. A third one goes from the ring and passes into the lower pulley, it then becomes the handle to unfold the wings. These two strings are therefore driven by a single handle. They must be perfectly adjusted to trigger the opening of their respective wing at the same time. The slightest shift will be felt when pulling the string by an unpleasant jerk.
Good, our wing bag is now functional. We must now prepare him to receive our innumerable feathers. They are arranged in superimposed rows, with the main row in the middle, surrounded by two secondary rows, one on each side.
For the main row, 14 holes are drilled vertically into the wooden skeleton, one for each feather, uniformly distributed along the wing.
For the secondary rows it’s a little different. The mechanism being on two layers of wood, I hooked laterally to shift the base of the feathers when necessary. Otherwise, I used simple wood screws. Again, it is necessary to distribute the holes along the length of the wing and to be symmetrical.
The bag is ready to receive the feathers, which will constitute our next step and is also the most tedious part.
What you need:
- Foam Sheets
- 30cm skewers
- Hot glue
- String (thick)
- Flexible paint
For the material I decided to use foam sheets because it is inexpensive, easy to work with and quite rigid.
I cut a sheet of foam to the right size. I then cut a column of about 2mm in its center to put the wooden skewer in as the central axis for the feather.
All that remains is to fix the string by wrapping it around the skewer and pouring a good amount of glue over it.
To the painting now; Just apply two coats of flexible paint (to avoid cracking when the feathers twist) then two layers of classic paint the color you want.
Now repeat the process a hundred times.
The first thing is to attach the wings to the wooden base of the backpack. It will be easier to put the feathers on the wings then. It is enough to fix them with two SWNs, by the holes of the two ends of wood.
To keep the wings open, you can tighten both SWNs temporarily.
The longest task now is to fix the feathers well, and for the threads connecting each row of feathers, I must say it is all in how you feel it. You have to choose the angle that you think looks best between each feather so you will have a harmonious effect at the end. To avoid this thread from moving along the skewer, I put a point of hot glue each time.
Once each wing is assembled, the mechanisms must be hidden. This I made non removable: large sheets of rounded foam, over the whole, fixed with hot glue again. So be sure that your mechanism works great!
On this sheet of white foam are fixed the non-articulated feathers, those do not require too much effort: a good amount of glue and it is done. But be careful to adjust the position and the angle to keep the effect!
Now connect the two strings of the bag to the bottom of the arms of each wing and your wings are finished!
Although the mechanism is generally strong and functional, there are still some improvements that could be made:
- Some feathers near the joints remain trapped during the folding of the wings and are therefore damaged by using the bag repeatedly.
- I think a more rigid fixation of the feathers would allow a better movement of the wings and less likely to prevent the feathers from returning to the right place.
- Speaking of the feathers, I would advise you to use foam sheets of a color close to your desired color. Because even if I have tripled the layer of “Dip”, the cracks are inevitable and become visible when it is bright pink that comes out just underneath!
- If you have the necessary resources and / or motivation, it would be interesting to look again at the opening movement, because I think the effect could be improved, with a render even closer to a natural wing.