HowTo: WinDIY – Build the hub including mechanics

At one point or another I have probably already mentioned that it was important to me to be able to control WinDIY safely and to be able to limit its speed in an emergency.

This is why I developed a mechanism which allows to adjust the angle of attack of the wings. So the wings can be adjusted to the current wind and rotation speed. In addition they can be turned out of the wind in strong winds.

In this way the speed and the load of WinDIY can be controlled.

I have written down some additional information here:

In the following article you will find the instructions to rebuild the mechanism for adjusting the wing’s angle of attack.

Safety instructions

I know the following hints are always a bit annoying and seem unnecessary. But unfortunately, many people who knew it "better" from carelessness lost their eyes, fingers or other things or hurt themselves. In comparison, a loss of data is almost not worth mentioning, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Even the coolest project is worth no injury or other annoyance.

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Required tools:

Hot glue gun
3D printer
Allen key
Cordless drill
3mm drill bit

Required material:

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

9x603ZZ Bearing
6x606ZZ Bearing
5xM6 self-securing nut
6xM6 nut
3xM3x20 Cylinderhead screw
3xM3 self-securing nut
15xM3 nut
3xM3x30 Countersunk screw
3xM3x16 Countersunk screw
6xM3x40 Countersunk screw
3xPrepared wing slot
1xM6 Threaded rod 60cm long

Collect needed parts

Before you can start building the hub and its mechanics, you will of course need to 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

On this picture you can see all parts needed to build the hub mechanism.

The required STL files for printing can be found here:

I have printed the parts with the following settings.

  • Perimeter: 5
  • Infill: 50%

The screws should preferably be made of stainless steel so that they do not rust through moisture.

Mount the hub base on the axle

First the hub base must be connected to the axle. This actually makes further assembly a bit more complicated. Unfortunately, this has to be done right at the beginning, because the screw holes which are used during the assembly are difficult to reach later on.

For this you first need the shown parts.

The axle, the hub base, 3x M3 nuts and 3x M3x50 countersunk screws.

In order for the screws to hold the axle in place, you must first insert an M3 nut into the axle as shown.

Depending on the print quality of your printer, you may have to “force” the nut to go into the correct position.

Now you can put the first M3x50 screw through the hole in the hub base.

Another view of the inserted screw.

The inserted screw should then …

… be inserted into the axis as shown and screwed together with the previously inserted nut.

Now that you have provisionally fixed the axle with a screw, you can insert the other nuts…

…into the recesses in the axle.

Then you can insert the remaining screws into the hub base and screw them into the axle with the nuts.

The axle should now be bolted to the hub base with three M3x50 countersunk screws.

Mount the first wing slot

The blades are not directly connected to the hub. First only the slots are connected to the hub. The wings can then be plugged into it later.

Insert the first 606ZZ ball bearing from the outside into the recess of the hub base as shown.

On the opposite inner side…

..the second ball bearing is then inserted.

Now you can plug in the first wing slot.

You should have already prepared this wing slot during the construction of the wing.

This should look like this.

The first securing of the wing consists of a self-locking M6 nut, which is screwed onto the M6x100 screw of the wing slot.

When screwed on, it should look like this.

The nut should be so tight that the wing slot cannot be moved in the direction of the screw. At the same time, it should of course still be possible to turn it.

The next ball bearing is now inserted on the inside of the hub.

Push the 606ZZ ball bearing over the M6x100 screw into the recess on the inside of the hub base…

…and secure it again with a (normal) M6 nut.

Another view of the screwed on M6 nut on the M6x100 screw of the wing slot.

Attach lever and adjust correctly

Now comes a somewhat critical step where you should work as precisely as possible. To be honest I am not really satisfied with the mounting of the lever on the M6x100 screw of the wing slot yet. This is because the lever is secured on the screw by clamping it between two nuts. Theoretically this should hold. Practically, it does too. However, it would be safer to put a split pin through the M6x100 screw. There is certainly room for future improvements. 🙂

For correct adjustment of the lever you should now raise the hub base a bit higher. For example, I have placed it on two boxes.

The goal is that the trailing edge of the wing slot is at exactly the same height as the back of the hub base.

Once you have adjusted the wing slot correctly, you can now put the lever on the axle and on the M6 nut that was screwed on before. The nut should fit as close as possible to the ball bearing, but the whole wing slot should still be able to rotate freely.

As soon as the lever is correctly attached…

…you can temporarily secure its alignment in the hub base with an M3 screw (the screw is removed again later). (see picture)

View of the secured and aligned lever.

Install guide ball bearing

In this step, the ball bearing is installed, which allows the push rod to adjust the wing’s angle of attack. Actually this step could have been done before the installation of the wing lever.

Insert the 606ZZ ball bearing…

…into the recess in the hub base.

The ball bearing is then clamped in the hub base with the shown clamp.

Close-up view.

The screw for clamping the ball bearing is secured in the axle with a nut.

Now repeat this two more times…

..until the ball bearing is jammed with a total of three clamps.

Another view of the jammed ball bearing.

Top view of the jammed ball bearing and a mounted lever.

Mount the remaining two blades to the hub

After the ball bearing for guiding the push rod is mounted in the hub base, you can continue with the mounting of the remaining two wing slots. These are mounted in exactly the same way as the first wing slot.

Once all three wing slots are installed, your previous setup should now look like this.

Close-up view of the three assembled wing slots including lever.

Close-up view of the three assembled wing slots including lever.

Close-up view of the three assembled wing slots including lever.

Close-up view of the three assembled wing slots including lever.

Attach the nut lock

As already mentioned above, the levers for adjusting the wing’s angle of attack are clamped on the M6x100 screw of the respective wing slot. To prevent the inner nut from loosening afterwards (which would cause the lever to no longer have any effect on the rotation of the wing) you should urgently secure this nut against rotation.

Before you secure the nut, again make sure that the inner nut is tightened as tight as possible.

But of course the setting of the lever should not be changed.

So first check that the angle of the lever to the wing slot is correct and then tighten the nut as tight as possible.

” Tight as possible” here means so tight that you can’t get it tighter “by hand” using a wrench.

Now you need a M3x20 cylinder head screw, a M3 nut and the 3D printed plastic part to secure the lever.

Now place the fuse over the M6 nut as shown…

…and secure it with the M3x10 screw by …

…screwing it to the M3 nut on the back of the lever.

Now repeat this again for all three wing slots.

Close-up view of the levers including attached fuses.

Close-up view of the levers including attached fuses.

Now you can also check that the levers have the correct angle to the wing slots.

If the wing slots are straight (as shown in the picture)…

…the levers should hit the stops of the hub base. So the angle of rotation of the wing slots is limited in one direction.

Additional view.

Attach the “lever extender”

(Btw: Sometimes not easy to find suitable names for the individual parts. 🙂 )

This section is about attaching the “lever extender” to the previously mounted levers. This is part of the mechanism which turns the back and forth movements of the push rod into a turning movement for the wing.

First you need a 3D printed lever extender, a M3x20 cylinder head screw and a self-locking M3 nut.

Now mount the lever extender on the first lever as shown.

Another view of the mounted lever extender.

Another view of the mounted lever extender.

If you have mounted the first lever extender, you can repeat this for the other two levers.

Close-up view of the mounted (and folded) lever extenders on the levers.

Close-up view of the mounted (and unfolded) lever extenders on the levers.

Attach the lever plate

Here comes the next important part for the mechanics to adjust the angle of attack: The “lever plate”.

For this you need the lever plate, three M3 nuts and three M3x30 countersunk screws.

Now mount the lever plate as shown on the first lever extender…

…and fix it by inserting the M3x30 screw from outside into the lever plate.

To fix the screw you have to put a M3 nut into the recess on top of the lever plate.

Completely plugged in you should not be able to see much of the M3 nut.

Now you can screw the M3x30 countersunk screw into the nut.

Repeat this for the remaining two lever extenders.

If you now move the lever plate back and forth you should already notice that the wings can be adjusted according to the distance of the lever plate.

View of the folded lever plate.

Insert ball bearing at anchor point

So far we have used a ball bearing which is intended to guide the push rod.

Now the ball bearing is mounted, via which the thrust movement of the push rod is transmitted to the lever plate.

You will need the ball bearing securing plate, a 606ZZ ball bearing, three M3x16 cylinder screws and three M3 nuts.

Now insert the 606Zz ball bearing into the recess in the lever plate.

Close-up view of the inserted ball bearing.

Now secure the ball bearing in its position by mounting the ball bearing securing plate including the three M3x16 cylinder head screws on the lever plate.

The screws are secured by inserting them into the recesses on the bottom of the lever plate.

Additional view.

Attach the stabilizing ring

To give the hub base a little more stability a stabilizing ring is now mounted on the hub base.

You will need the 3D printed stabilizing ring, six M3 nuts and six M3x40 countersunk screws.

The stabilizing ring is now placed on the hub base from above…

…and screwed into the hub base with the M3x40 countersunk screws as shown.

To do this, screw the M3x40 screws into the nuts, which are inserted into the recesses on the bottom of the hub base.

Close view of the inserted M3 nuts.

Close view of the inserted M3 nuts.

Mount push rod

The push rod consists of a M6 threaded rod. It will later transfer the thrust movement generated by the pitch actuator to the mechanism in the hub.

At this point you need the previously prepared hub base including attachments as well as two self-locking M6 nuts and an M6 threaded rod.

Now push the threaded rod through the first and second ball bearing in the hub as shown.

Then pull the push rod back a little and screw the first self-locking nut onto the push rod as shown.

The nut is unfortunately not visible but is located in the socket wrench, which makes assembly much easier.

It is also helpful if you clamp the threaded rod in a cordless screwdriver as shown. So you can easily screw the threaded rod into the M6 nut.

If everything worked, the M6 nut should sit on the threaded rod as shown.

Now you can put the threaded rod back into the upper ball bearing.

Close-up view of the inserted threaded rod in the upper ball bearing.

To keep the push rod in the upper ball bearing you have to screw the other M6 nut onto the push rod as shown.

The push rod should now sit tight in the ball bearing.

Additional view.

Additional view.

Additional view.

Now it is time for a first test.

This video shows how the mechanics should work now. (Don’t be put off by the changed design. This is a video I took during the development of the mechanics 🙂

Fasten the cover

Last but not least the hub now gets a cover. This covers the mechanics and should protect them from moisture and rain. Additionally it makes the hub slightly more aerodynamic.

You will need the 3D printed cover, three M3 nuts and three M3x16 countersunk screws.

Close-up view of the required parts.

Insert the M3 nut into the recess provided in the hub base…

… and fix the M3x16 countersunk screw in it.

Now you secure the M3 nut again with some hot glue in the frame of the hub base…

… and remove the screw.

Now you can put on the cover and screw it into…

…the frame of the hub base using the prepared screws.

View of the attached and screwed cover.

View of the attached and screwed cover.

View of the attached and screwed cover.

Have fun with the project

I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂

P.S. 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 appreciate it that I share these information with you, I would be happy about a small donation to the coffee box. 🙂

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  1. Von den 606ZZ Kugellagern werden insgesamt 6 Stück benötigt. In der Materialliste sind nur 2 Stück erwähnt.

  2. Kleine Korrektur. 😀 Es werden insgesamt sogar 8 Kugellager vom Typ 606ZZ benötigt. Zwei zusätzliche für die Gewindestange, die durch die Achse geht.

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