Introduction: Aerofoil Lift Wind Turbine
This is a step by step guide detailing how to build a wind turbine, using aerofoils to create lift, and turn the turbine.
The design has been tested and optimised.
Step 1: Materials
The following materials were used in creating the turbine;
Acrylic (5mm sheets)
Styrene (1mm sheets)
Acrylic (3D printing material)
Silicon (mould making material)
Resin (casting material)
Step 2: Step 1: Making the Blades
Firstly, you need to find a curve template for an aerofoil. The website we used for this was www.worldofkrauss.com and the aerofoil we selected was the MH 32 as this had a good lift to drag co-efficient, and also is used in low speed gliders, so we felt it was ideal for our application.
We then imported the curve into Solidworks and created a 3D model of the aerofoil, with a chord length of 100mm, and 250mm high.
This model was then 3D printed, to create a solid blade. We then sanded the blade to create a smooth surface, and we gave it a coat of primer.
Next, we made a box from 1mm styrene, of dimensions 40x130x280mm, but we left one of the 40x280 sides clear to allow us to make a mould.
To do this, we placed the aerofoil into the box, and then filled it with a silicon moulding material. This mould was then left to dry overnight.
Once the mould was dry, we removed the origional blade, and then we used a resin to cast another 11 blades, meaning that we had 12 in total.
Step 3: Step 2: Making the Turbine Body
To make the body of the turbine, we used CAD to create 4 circles, all of diameter 360mm, with a central hole of 12mm to insert an axle into the turbine. Two of the circles also had slots for the 12 aerofoils to be inserted into them.
We then exported these as a .dxf file, and then laser cut the pieces from 5mm sheets of acrylic.
Using Di-Clo, we glued two (one of each) circles together, making sure the holes in the centre were aligned.
Then, using super glue, we stuck the aerofoils into one of the assembled end plates.
Once they had dried, we stuck them into the other end plate, giving us the assembled turbine.
We then machined a metal axle, which was of the following dimensions;
20mm @ 9mm diameter
290mm @ 12 mm diameter
20mm @ 9mm diameter
10mm @ 4mm diameter
This shaft was then inserted into the turbine (ours was tight enough to not need further securing, but arrodite welding would work)
Step 4: Step 3: Making a Frame
To make a frame to hold the turbine, we used MDF.
We firstly cut a base plate from 12mm MDF, 300x450mm, as this was the size we had avaliable inside our wind tunnel.
We then cut 2 x 190x250mm sides, which we then added side supports onto for added stability.
Next, we drilled a hole into each one at 210mm high, of a diameter that would hold the bearings firmly in place (24mm for us)
After insering the bearings into the holes, we then placed the shaft into the bearings, and then used PVA wood glue and nails to attach it to the base.
Once this had dried, we then attached a gear onto the end of the shaft and secured it with a grub screw.
We then attached a gear onto the output shaft of the generator (we went for a 1:6 ratio).
Finally, a mount was build for the generator to hold it in place at the correct height, so that the gears were meshing properly.
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