Step 1: The Hub
80mm length of wood 50mm*50mm
65mm length steel rod 8mm
1 inexpensive had held drill
To create the blade hub we took an 80mm piece of wood, and used the lathe to create an 80mm cylinder witch was rounded at one end with a diameter of 40mm. We then drilled a 50mm deep hole with an 8mm diameter into the flat end and inserted a 65mm steel bar such that it would protrude at the end. We then need to drill 6 more holes around the outside of the hub, 2 lines of three 6mm holes; these will be used to attach the blades.
Step 2: The Gear Box
An inexpensive hand held drill
a small motor
In order to convert our rotational energy to electrical energy we must link the motor to the blades, and use it as a generator.
To do this we me must remove the main body of the screwdriver and take the head off.
Inside you will find a 2 layer planetary gearbox. The ratio of this gearbox is 1:36 so we need to adjust this if we want the turbine to spin. In order to lower the ratio we will remove one layer of the gears. the new layer will be 6:1.
Using a metal rotary saw we were able to cut the outer gearing in half, this allowed for the shaft of the motor to connect with the central gear.
Clean, lubricate and reattach the gear box to the chuck, we will use this to attach the hub.
We now have the gear box and blade attachment for our turbine.
Step 3: Adjusting the Motor and Housing
A 90mm length of 65mm aluminium circular bar
We milled through the centre of the aluminium creating a hole big enough to snugly fit the motor. Before drilling through the whole cylinder stop and change to a smaller drill bit, this hole should be big enough to allow the motor axil to protrude from the closed end.
we sanded part of the cylinder down to create a face which will be useful when attaching the housing to the turbines stand.
In order to fit the central gear of the planetary gearbox to the motor we must file one edge of the axil down to a semi circle, fit the axil into the central gear and the gear back into the planetary system. The motor will now generate when the chuck is turned.
Step 4: The Stand
2* 50mm*80mm pieces of wood 240mm long
10*280mm piece of plywood
500mm x 500mm x 10mm MDF board
Cut a wedge out of the plywood wide enough to firmly hold the chuck in place the other pieces of wood should be fastened directly to one side of this plywood, these will hold the motor and housing.
Using screws fasten all three bits of wood to the 500mm*500mm base.
Step 5: Blades
you will need:
Sheet of card bored
12 pieces of dowel 120mm long diameter 5mm
Simply cut 6 blade shapes out of the card bored and cover in PVA glue.
Once dry use a glue gun to stick them to dowelling and insert dowel into the holes drilled into the hub. Blades should be at a 30 degree angle.
Using CAD software we created the design of our Blade.
Using a 3D printer we created one hard copy of the blade.
After sanding we encased the 3d printed blade in latex to create a mould.
using this mould we were able to create 2 more blades exactly the same.
We drilled 2 holes into each blade and inserted dowelling, then attached to the hub.
Although type 2 was much more impressive looking we found the cardboard blades worked far better. Not to mention cheaper, 3D printing used our whole budget.
Step 6: Assembly
Large Jubilee clamp
2*piece of sheet metal 10mm*240mm
Arrange all the mechanical pieces of the turbine in order from Blades, Chuck, Gear box, Motor &casing. in order to hold these together, and to stop the gears slipping we will clamp the assembly together with one of the metal strips. Drill a hole in the middle of the strip to allow for the motor to spin freely.
Wrap the strip around the outside of the assembly and secure with the jubilee clamp. Make sure the gears are able to spin freely under the forces applied but the clamp.
Step 7: Completion
You can change the wings by unscrewing the chuck. This allows for very easy blade prototyping. Using our Cardbored blades we are able to generate 19 Volts.
Sometimes we had to make the assembly more secure, excessive use of masking tape came a quick answer on the final day of testing.