HowTo: WinDIY - Build wind turbine blades

An important component of WinDIY are certainly the wings. They absorb the energy of the wind and convert it into a rotary motion, which in turn feeds the generator and thus produces energy.

Of course, the wings should be as light as possible. At the same time, however, stable enough to withstand the forces even in stronger winds.

On the way to a suitable design I have therefore experimented a bit. Info about these experiments can be found here:

In the following article you will find the tips to rebuild the wing. You will need three copies of this wing (of course).

Important: The wind turbine is currently (11.10.2020) not yet running perfectly. The blades still need to be adjusted and also the generator does not quite fit the characteristics of the wind turbine. So there is still some work ahead of me. But maybe the shown components are a suggestion for everyone who is working on his own design of a 3D printed wind turbine 🙂 .

Safety instructions

I know the following notes are always kind of annoying and seem unnecessary. Unfortunately, many people who knew "better" have lost eyes, fingers or other things due to carelessness or injured themselves. Data loss is almost negligible in comparison, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Because even the coolest project is not worth injury or other trouble.

Affiliate links/advertising links

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Required tool:

Hot glue gun
3D Printer
Allen wrench
Cordless drill
(long) 3mm drill bit

Required material:

You will need the materials listed here for a Wings. So keep in mind to order enough parts for three wings 🙂 .

1xrafters tip
1xAluminum rod 10x10mm 67cm long
1xShrink hose approx. 1m long and 140mm wide
1xM6x100mm hexagon head screw
1xM6 Self-locking nut
5xM3 nut
3xM3x20 cylinder head screw
2xM3x8 cylinder head screw
2xM5x75 cylinder head screw

In the following list you will find all the parts you need to implement this article.

Wing profile info

The design of the wing is based on the NACA4412 profile with a chord length of 120mm.

On the following page you will find info and configurable templates for this and other wing profiles:

Collect required parts

Before you can start building the wing, you must of course have all the necessary parts together. A complete list of the required materials and tools can be found above in the material and tool list.

The plastic parts can be easily created with a 3D printer. All parts are designed so that they can be printed on a normal FMD printer.

The required STL files for printing can be found here:

I printed the parts with the following settings.


  • Perimeter: 3
  • Infill: 10%

Wing base(both parts):

  • Perimeter: 5
  • Infill: 50%

Wing end part:

  • Perimeter: 3
  • Infill: 30%

The screws in the sash should preferably be made of stainless steel so that they do not rust due to moisture.

Mount end part

Somewhat untypically, we start with the end. Namely, the end part of the wing.

You will need the parts shown for this.

Now insert the aluminum profile into the sash end part.

This should be pushed into the sash end part as far as it will go.

Because now you first need to drill a hole in the aluminum profile.

To do this, use the wing end part as a template. By drilling through the hole (which is actually intended for the screw) in the aluminum profile, you have directly the correct position for the drill hole.

Important: When drilling, make sure that you only drill through one outer side of the aluminum profile. You should not drill completely through!

After drilling, your aluminum profile should look something like this.

Now the prepared aluminum profile must be connected to the sash end part. To do this, insert an M3 screw into the sash end part as shown.

This should then project into the recess for the aluminum profile as shown.

Now it gets a little tricky.

Through the opening in which the aluminum profile will later be inserted into the wing end part, you must now screw an M3 nut onto the previously inserted M3 screw.

The finished M3 nut could then look something like this.

Now you can insert the aluminum profile into the sash end part as shown and screw it with the prepared screw.

Mount the first five rafters

After the wing end part is mounted, you can now mount the first five rafters on the wing.

To do this, push the first four Rafters as shown on the aluminum profile.

Now you have to prepare the fifth spar a little bit.

This is namely - similar to the wing end part - fixed to the aluminum profile with a screw.

To do this, insert the M3 bolt into the hole in the rafter as shown and screw on the M3 nut on the inside as shown.

You can then pull the M3 nut into the recess in the rafter with the help of the screw.

Prepared in this way, you can now push the fifth spar loosely onto the aluminum profile.

Before the individual rafters are now pushed together, you should coat the connectors with a little glue.

This is not absolutely necessary, as the wing parts will most likely hold together without glue. But I recommend it 🙂

To do this, brush the positioning aid on the ...

...trailing edge of wing ...

... of each individual spar...

... as well as on the front of the wing with a small drop of glue.

Have you prepared all the rafters with the glue.... can now put them together.

View of the first rafters put together.

Close-up view of the hole at the front edge of the rafters into which the positioning aid must be inserted.

Close-up view of the hole at the rear edge of the rafters into which the positioning aid must be inserted.

Now prepare the fifth rafter so that the nut, which sits on the bolt, is pulled into the recess in the rafter.

Then you can slide the spar on the aluminum profile.

Once you have assembled the first five rafters, you can screw the fifth rafter (previously prepared with the screw) tightly to the aluminum profile with the screw.

Make sure that the screw is tightened but not too tight to pull.

Mount the rafters six to ten

In principle, rafters six to ten are mounted in the same way as the previous five rafters.

You will now need another five rafters.

You can slide four of them onto the aluminum profile as usual.

You should prepare the fifth with a screw as before. This can be used to secure the fifth spar to the aluminum profile as before.

All five prepared rafters would then look like this.

Now you can coat the connectors with some glue as before and...

... put the individual rafters together.

When everything is neatly put together, you can also tighten the screw of the last rafter and secure the attached rafters this way.

Mount the rafters eleven to 15

By now you've had practice installing more rafters. Now it's time to install the last five rafters before mounting the connector for the sash.

Here you can see the wing built up so far and the five rafters not yet installed.

Other view.

Prepare the fifth spar again as before so that you can fix it to the aluminum profile later with a screw.

Now pushes the five rafters back onto the aluminum profile, prepared the connectors with glue...

...and pushes the rafters or their connectors together.

Using the screw in the last rafter, you can then secure the rafters back onto the aluminum profile.

Assemble the wing side part of the wing base

So that the wing can be easily assembled or disassembled later, you can now mount the first part of the connector on the aluminum profl.

For this you need the upper part of the connector shown and a M3 bolt incl. nut.

As with the sash end part, you now need to put the upper part of the connector onto the aluminum profile and drill through the screw hole of the connector with a 3mm drill bit.

The aim here is to drill a hole in one side of the aluminum profile (as with the sash end section).

Once you have drilled the hole, you can now reinsert the screw into the connector.

This should then look something like this.

Now you can push the connector onto the aluminum profile and clamp it with the prepared screw on the aluminum profile.

Now the wing looks almost finished.

Assemble the hub side part of the wing

Of course, it must be possible to plug in the connector that has just been mounted somewhere. To do this, you should now prepare the part of the wing connector on the hub side. This will then be mounted on the hub later when the hub is assembled.

You will now need the parts shown.

Another view

Now slide the M6x100 screw as shown...

...into the connector...

...and place the self-locking M6 nut on the M6x100 bolt as shown.

Ready screwed on...

...this should then look like this.

Make sure that the head of the M6x100 screw is correctly inserted into the recess provided.

Now you can test the connector for the first time.

The parts should fit together as shown.

You can now secure the plug connection with the M5 screw.

To do this, push them completely through the two parts of the connector...

... and screw them together with the matching M5 nut so that the connector is held together by the M5 screw.

Fixes the screw on the upper and...

... underside of the wing.

Other view.

Now the structure for your wing is ready. The only thing missing is the wing surface.

Other view.

Other view.

Prepare shrinking of the heat shrink tubing

In order for the wing to offer resistance to the wind and for its aerodynamic shape to generate lift, it is important that the skeleton of the wing is covered with a film. The easiest way to do this is to place the wing in an appropriately sized shrink tube.

You will need the parts shown for this.

Important: Of course, you should remove the lower part of the connector now. It is not enclosed by the heat shrink tubing.

Other view.

Now check again that the shrink tubing is at least as long as the whole wing.

If so, you can now insert the wing into the heat shrink tubing.

Since you are about to shrink the shrink tubing onto the wing with hot air, you should now store the wing slightly away from the base.

In this way, you avoid damaging the base from the hot air.

This could then look like this, for example.

I simply used two empty boxes.

Close-up view of the wing in the shrink tube.

Close-up view of the wing in the shrink tube.

Close-up view of the wing in the shrink tube.

Close-up view of the wing in the shrink tube.

Close-up view of the wing in the shrink tube.

Shrink on the middle part of the wing

You will need a little patience to shrink the shrink tubing. Here you have to be careful that the hose does not get too hot, because then holes will appear. In the video below you can see how I did it. To shrink the heat shrink tubing I used a hot air station, which I set to 150°C have set.

The aim when shrinking the shrink sleeve is for it to fit the wing skeleton evenly all over, with as few wrinkles as possible.

Important: During this shrinking process, you should not yet shrink the ends of the wing! These will be prepared with glue in the next step to "seal" them.

A few tips:

  • never direct the hot air to one spot for too long
  • do not set the temperature too hot
  • in case of doubt, let the affected area cool down first and work on it again later on

Shrink the ends of the heat shrink tubing

The ends of your wing must now be prepared with glue. This way, the ends can be secured against water penetration.

This is what your wing should look like now. Most of the shrink tubing fits snugly against the skeleton of the wing.

The ends are still loose and not shrunk on.

View of loose (unshrunk) wingtip.

View of loose (unshrunk) wingtip.

View of loose (unshrunk) wingtip.

View of loose (unshrunk) wingtip.

The aim now is to seal the ends against water penetration. To do this, you should now coat the space between the wing skeleton and the shrink tube with glue.

A cotton swab can be particularly helpful in the corners. This allows the applied adhesive to be distributed better.

You should do the same at the other end of the wing.

Make sure that the glue is spread around the entire wing.

When the shrink tubing is later shrunk on, it automatically lays on the wing and thus comes into contact with the adhesive over a large area.

In the following again two videos how I proceeded with the shrinking of the wing tips.


If everything went well, your wing should now be fully assembled. For a complete assembly you will of course need three wings.

View of the assembled wings on WinDIY

Have fun with the project

I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂

PS Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂

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  1. Hello,
    a very interesting project, I will continue to pursue it, maybe even try it myself.
    Haven't read everything yet though.
    There may be an alternative to the shrink tubing used,
    We use iron-on foil on our model airplanes to cover the wings and fuselage. The underside of the iron-on film is coated with hot-melt adhesive. The iron-on foil is applied to the component with an iron, the hot-melt adhesive becomes active. Any creases or loose iron-on film will then shrink and become tight. Unfortunately I don't know if the hot glue will hold on the plastic. But it's definitely worth a try. Just google iron-on foil for model flights or model making.
    Greetings Reimund

    1. Hello Reimund,
      thank you very much 🙂
      That sounds like a cool option too. Do you know what temperatures arise during the ironing process?
      3D printer filament becomes soft (depending on the filament) from approx. 70°C. There are also filaments that are a little more temperature stable.
      I'm also a bit worried about the construction that or whether the wing is really waterproof. I had tried to glue the ends together, but whether that really works (permanently) would have to be checked with the help of a long-term test.
      How is that done with model airplanes with the wingtips? Are they also glued to this film?
      Thanks for the hint 🙂
      Best regards

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