Steampunk Auto-folding Wings





Introduction: Steampunk Auto-folding Wings

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...

Step 1: Design the Mechanism

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

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

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

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!

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!)



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    35 Discussions

    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!


    2 years ago

    This is great! I have a 7 year old who will be thrilled to help me work on this. I might not make it battery operated and figure out a manual way to make them open a rest and then release.- and make it a bit more durable so his 4 yr old brother can have a set too.

    1 reply

    You can take the push-rods off of the back-plate and extend them a little, then make a handle/knob at the end and 'hooks' on the back-plate to fix them in the up/open position.

    Grab the handles/knobs, and lift them up and hook them on the back-plate to open the wings. Unhook and lower then to fold the wings

    There is a lego e-bay type website for your legoing needs: Super sweet, or, and don't quote me on this, I believe you can order individual legos from

    One option for potentially stronger gears (I don't know if they would actually be stronger) would be clock gears. If you can find a clock shop that makes *real* clocks (with metal gears and not battery powered), ask if they have a spare parts bin. If a gear isn't quite right, or somehow won't work for a clock, it might get chucked in bin and the owners might let you take some. Either way, clock shops are fun to explore.

    Super Cool! Thanks for sharing, you did a fantastic Job! Very creative and live how the open with battery!

    You could be like batman if you paint it black

    I might be able to build it if I knew what a good alternative to buying online would be.

    1 reply

    Most wood (multiplex) can be bought almost anywhere, as can the nuts and bolts. (If you want to use balsa (like I did) you may have to go to specialist shops for model-plane building) Lego Technic (if you want to go that way, see my reliability remark in the other comment) can be bought in many toy stores, or you can go to a Lego shop to just get the required parts ordered. The wine box can be gotten at many deco shops (Just saw them on my vacation trip to Florida in the Hobby Lobby for instance)
    For fabric, try JoAnn's or Michael's if you're in the USA...

    I have a question. How much would you charge to build one of these? I would like one but don't have acess to internet often enough. Could it be built for 100$ or less?

    1 reply

    I really don't have the time to build another one of these. We've discontinued use of the wings because it was - after repeated use - unreliable. The small gears (the really small ones) kept breaking...
    ​​My daughter thinks they're too heavy too, so I won't try to remedy the problem either... If I were to try remedying it, I'd probably use a high speed linear actuator (which I tried to replicate with the Lego Technic, which in itself was successful, just had issues with the reliability/quality of the small gears ), and those aren't cheap.
    Finally the shipping would be prohibitively expensive, due to the total weight!

    Sorry I cannot help you any further!

    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

    1 reply

    As long as you don't use springs that are too powerful and tighten the nuts accordingly it should work... (I think!)

    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.

    1 reply

    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...