Now that you have your blades made, it’s time to build a wind turbine hub. The hub will be used to attach all the blades together so they can be attached to the body. If you haven’t got you blades together check out our blade design post here.
We hope you have got your generator ready to go. If not, don’t worry you can still start this part of the project. First, though check out this free resource list. It’ll show you the best generators you can purchase from Amazon and have it delivered to you by the time you finish constructing the hub. Or you can check out how to build your own generator in our free PDF guide here.
Types of hub design
The conventional design for a wind turbine hub is to have 3 blades. But you can have more than 3 if you want. The more blades there are on a wind turbine, the more torque (rotational force) produced and the slower the rotational speed of the hub, this is because more blades cause increased drag caused by wind flow resistance. Wind turbines used for generating electricity need to operate at high speeds and actually, don’t need a lot of torque. So, the fewer the number of blades, the better suited the system is for producing power.
But wait! Why don’t we see more wind turbines with 1 or 2 blades instead? Well while theoretically, one-bladed wind turbines are the most aerodynamically efficient designs, they are not very practical because they are very unstable at higher speeds. Two-bladed designs are theoretically the next best design. But they are affected by a wobbling during operation. The image below shows the efficiency of different hub designs.
The image above shows that the 3 blade design is the most power efficient design. It’s no surprise that’s why 90% of turbines are designed like this and it’s the design we suggest you use.
Building the hub
The hub of your wind turbine is going to be the easiest part of the build to construct. Although this doesn’t mean it isn’t a crucial component. If this part of your turbine breaks due to the rotational forces acting on it during operation the whole thing can come crashing down. So you will want to get this part right for the sake of the structural integrity of your wind turbine. It can be as basic as a piece of wood, but you will ensure it is a hardwood. One that’s appropriately treated so it can survive outdoors in wind and rain for years.
Your hub needs to hold the 3 blades on one side and connect to the generator on the other side. To do this we suggest you split the hub into two different components; the face and the connector. First, let’s look at the face the design below can be used for the face.
The face is a simple disk design the will have the 3 blades mounted to it. If you’re more comfortable with metal working or have an aluminium disk lying around that’s even better. The figure below shows a simple wooden hub with the 3 blades screwed to it. The wood used was ash which is a common hardwood and a good substitute for aluminium.
And that is pretty much it for the face. All you have to do now is screw or bolt your blades to the circular face and you have the first part. The second part is the hub. This is the part that will attach your blades and face to the shaft of your generator. This is the part that transfers the energy from the wind into your generator which then turns it into electricity.
In the resource list, we showed you a part you can buy on Amazon. It’s a perfect part to use for your hub. Just make sure you buy a hub who’s inner diameter matches that of your generators’ shaft diameter or it won’t work. Again we are an Amazon associate so clicking the link below helps support the website.
It’s a great little hub because it comes with already threaded holes that can be easily and simply bolted to the face. It also comes with an Allen key and bolt kit to mount the hub directly onto the shaft of your generator. Again, just make sure you get one that matched to shaft diameter of your generator.
So there you have it that’s all you need to build a wind turbine hub. Now you can attach your wind turbines to a working hub that you can then attach to your generator. So once you have them all attached, get a volt meter out and hook it up to the output wires of your generator and test out how many volts your turbine can output from just one simple hand spin. You’re not well on your way to creating free electricity. Keep an eye out for next weeks email where we will talk about the body and how to attached your newly made blade and hub part to it.
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