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Steampunk auto-folding wings

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I have made for my daughter steampunk wings which can fold open and closed with the help of Lego Technic parts.

I was running out of time for the "make it real" contest, so I posted this instructable before I am all done, with the intent to improve/expand as I go... I have not yet been able to do the fabric on the wings, but the rest is done and working.

This is my first instructable, so bear with me as I tweak my style...

So where do you start? You find wings you like that fit the style... Leonardo DaVinci was a prolific drawer and researcher of wings, so I started with looking for images by him, and found one that my daughter liked and looked doable...

Finally, what would I do with the printer? It'd print the parts I used and make them look more Steam Punk and less Lego... And then more, obviously.
I'd also like to start a little 3D printing workshop to allow others access to affordable 3D printing...
 
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Step 1: Design the mechanism

Picture of Design the mechanism
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I then designed the mechanism for the wings in Lego Digital Designer, and subsequently built it for real to test whether it actually worked...

Step 2: Transfer the design to the wings image

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Satisfied the mechanism worked I took the measurements of the Lego mechanism and transferred it to the image from DaVinci and then I printed it on 1:1 scale. After that I drew the actual shapes on the drawing and then transferred those to foamboard to create a real size prototype.

Step 3:

With a working prototype in my hands, it was time to go for the real thing: multiplex.

I had the straight parts sawed to measurements and the long, curved spines were jigsawed. After that I drilled all the holes and connected all the identical parts for left and right to eachother and finished them with a belt-sander. I rounded the square ends of the straight parts and made certain all parts for left and right were smooth and identical.
I also created a 2nd set of long spines in 1mm thick balsa wood, so I can cover the fabric (and coach-bolt heads) once it is attached...

To connect the parts I used coach-bolts, metal washers (for behind the nuts), nylon washers (between the parts so the joints move smoothly) and self-locking (nylon) nuts. When everything aligned and worked, I took it apart again to stain, and reassembled. Then it was time for the lego mechanism for the movement...

Step 4: Movement plate

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I made a movement plate, with two slots that move over a pair of coach-bolts as the basis for the mush/pull mechanism that folds and unfolds the wings. On one end I attached the ends of the push-rods, on the other end the Lego mechanism would be attached.

The main mechanism is a rack and pinion system to change the rotation in to a linear motion, and I made it double for stability and strength. The rest is simply a reduction gear system, topped off by a PowerFunction motor with a slip gear (to prevent overheating when the extremes of the mechanism's motion range are reached).

Step 5: Almost done!

And this is how far I've gotten so far... Everything works, I've attached 2 belts and 2 metal supports to it so she can carry it on her back. On the other side I used a wooden wine (gift) box which looks the part and is covered with travel/airmail stickers instead of a simple mounting plate. It hides the Lego motor and reduction gears, and supplies a spot for the powerbox.
The 2nd bottle slot can be used to carry something... A bottle of water for instance...



Next step is to attach the fabric to actually make it look like wings.

Step 6:

I first intended to make the wings two layers of fabric with the ribs in between, but that proved to be unsuccessful, so I went for a single layer of fabric with bias-tape (bias binding) to make tunnels for the ribs.

The detail images show how I've done this. I aligned the tape to the fabric's cut out points as much as possible. I also made a double zigzag at the top of each tunnel, and folded about 1cm of the bias-tape for even more strength.

When all tunnels are done, take 5x5mm Balsa wood rods, and cut them to size (Balsa is soft enough to cut with scissors, light enough to add virtually no weight, and strong enough to build airplane wings from!) but do not insert them yet.
After they're all the right size, stick the fabric to the main rib with contact glue. As you may recall, I also made those in 1mm balsa wood. Stick that on the other side of the fabric, making sure both pieces of wood align perfectly. Then you can use some carpenters upholstery nails to make it look more authentic.
Once the main rib is reattached to the mechanism, you can insert the balsa ribs to see how it looks... It may be difficult to get the balsa to slide in the folded bit at the end of each tunnel. You can use pins to guide it. Insert the pin through the fabric just below where the folded bit end, but make sure it does not go through the bias-tape as well, then - making side to side motions - slide it's point between the folded bit of tape and the main tunnel part of the tape. Once it is in there, push it in further and make it come out again at the fabric side. Now the balsa rod cannot catch on the folded part and goes where you want it!

Repeat on the other side!

Step 7: Final touches and wrap-up

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When everything looks the way you want it, it is time to stain the balsa, insert them permanently (and fix them in place with a binding of thread) while tensing the wing fabric.
Finally I added 2 pairs of elastic ties (to at the top, 2 at the bottom) between the free center flaps of the two wings so they're under tension when extended...

As you can see in the last picture, they are pretty impressive when unfolded, and the only drawback I found so far is that the batteries drain pretty fast.

If you fold/unfold them a few times in a row, you can tell they're starting to slow down... I may modify the batterypack so it takes 6 14500 LiPol batteries in pairs (they do about 3.7V each) or triplets (11.1V, tests on the web show that these motors work fine on 12V, and it'll increase the speed too, which could be a bonus). That way I have 3 or 2 sets of rechargeable batteries with a good capacity. If they last a single day, I'm happy... We can recharge them over night! ;)

Step 8: Finished!

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And this is the finished product...



In the end I modified the Lego Powerfunctions battery box so that it takes 2x 3 14500 LiPol batteries (nominal 11.1V) as these deliver higher voltage (nominal 3.7V pp) and have a higher discharge capacity, so the motor gets more power to turn and drive the gears.
(I had to dremel through a metal connector pad inside the box so I could separate the 6 slots in 2 sets of 3 and then soldered in extra wires to connect those up to the orginal points. Double the capacity, higher voltage and rechargeable, better all round!)

This results in the wings folding and unfolding faster, which looks better and makes the movement smoother, as it has less tendency to stall...
(Applied mechanics trivia: Friction of moving objects is lower than the friction of stationary objects, so keeping them moving is good!)
megaduty1 year ago
Pretty cool Cesco, I voted for you!
And thanks for uploading the vid.
CescoAiel (author)  megaduty1 year ago
You're welcome! Thx for the constructive criticism and for the vote! (I can definitely use more of the latter! )

And hey, it got an email telling me it's featured in the Technology section! Flabbergasted! Esp. as it is my very first Instructable, and not even finished yet!
Is there a website one could go on to get the lego pieces?
do you think it would be possible to use springs and a latch to make the wings jump open rather than using electronics? or is the system too delicate for that kind of jolt
CescoAiel (author)  captainjazzhands1 year ago
As long as you don't use springs that are too powerful and tighten the nuts accordingly it should work... (I think!)
eduard811 year ago
Hmm, for some reason i can't seem to reply on your post... So I'll just repost.

OK, thanks.
That might be a bit small for me, so i'll probably add an extra foot. To bad the engine won't hold up, it was an nice solution (everybody has easy acces to lego's).

I also thought about using gas pistons and then linked to the small 12gr co2 canisters. I haven't found an affordable piston though.
CescoAiel (author)  eduard811 year ago
I think it also depends what you want to use for the wings... Wood is relatively heavy... So is cotton fabric...

If you were to use lighter materials (aluminium, fiber/resin spines, nylon fabric, etc.) you might still be able to get away with using the Lego... Perhaps adding springs to take some of the load (esp. when extending the wings, which is clearly the heaviest task for the motor) may help as well...
CescoAiel (author)  CescoAiel1 year ago
PS: The main problem is not the motor (and if it were, Lego also has a bigger one, although that is a bit slower too), but the strength of the plastic cogs, esp. the really small ones, as well as the cohesion of the frame they're mounted in (the 'bricks' come apart which cause the cogs to slip).
I chose to not glue anything together, so it can be repurposed... I think that using glue and resin to reinforce the cogs and stick the 'bricks' of the framework together would also increase the load they can take!
buzzthud1 year ago
oh my gosh i LOVE this!! i want to make one but can you please post a little more on the motor and how you attached it?
CescoAiel (author)  buzzthud1 year ago
Sorry for not replying sooner, but I have been (and still am) too busy to do any crafting or instructables updating!

I have pictures for another instructable (a steampunk reactor/powersource) ready, but no time to make it...

I'll try to make pictures and post them though... Not giving an ETA tho!
eduard811 year ago
I love this build! (consider it stolen for my own set of wings).
One question though (well 2 actually). What was your wingspan, and do you recon the little motor could handle more (and thus a heavier weight)?

CescoAiel (author)  eduard811 year ago
Wingspan is approx 5' / 150 cm when expanded... And the Lego already struggles (already replaced some broken cogs!) with these, so bigger wingspan would very likely not work with Lego.

I have looked at using either pistons (but that requires a source of pressurized gas/vapor), which would be more true to the theme, or electric linear actuators, but the (10V-12V) ones that have sufficient range (IIRC approx 14cm or 7") of movement are very expensive...
nerd74731 year ago
Cool
nerd74731 year ago
Coll I may build this
A very nice project! The idea and the combination of the LEGO Software, the LEGO itself and the DaVinci Wings are great. Looking forward to see more...
Very cool, excited to see the completed project
CescoAiel (author)  iminthebathroom1 year ago
So am I.... So am I! ;)
CescoAiel (author)  CescoAiel1 year ago
Almost done now!

A few more pictures and a videoclip to be added, but over all, the project itself is finished!
Kiteman1 year ago
It's a shame the photos are so dark, but what we really need is a video of them operating!
+1 on video!
CescoAiel (author)  megaduty1 year ago
As I mentioned, I had to work with the pictures I had on my PC and iPad. I will definitely get better pictures (and a video) as soon as I get back home end of this week...
CescoAiel (author)  CescoAiel1 year ago
Better pics and video added...
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