This is a step by step guide on how to build a wind turbine by maximizing the wind speed using a nozzle/diffuser approach.
This approach was considered through various testing and prototyping to try and increase the efficiency of the wind turbine.
NOTE****Test video at step six****

Step 1: Materials

two buckets (bought from Tesco)
MDF(Medium Density Fibreboard)
safety blade/scalpel
handsaw
PVA Glue 'polyvinyl acetate'(any preferable adhesive)
electric handdrill
PVC pipe(poly-vinyl chloride)
coupling(preferably oldham coupling or any good chosen connection)
Generator
U-pol(or some kind of filler)
multimeter and variable resistor

Step 2: Making the Nozzle/diffuser

the nozzle or diffuser can be made from a funnel or a conical bucket.
in this case a bucket was used by cutting the base out.
from testing it was found that having a lip converging to the nozzle increases the wind intake, and having one diverging from the diffuser draws the wind out by increasing the pressure.
the lip was made by vacuum forming around a wooden base( if vacuuum forming is out of the question try using a bucket that you can bend to create the shape).
the lip is then glued onto the bucket ,using upol fill and sand off to smooth the lip over the bucket

Step 3: Making the Frame

the frame can be made with a varied type of materials(but most importantly the chosen material should be sturdy and strong enough to withstand the wind pressure.
in this case Mdf was used.
using PVA 'polyvinyl acetate ',glue stacks of mdf to the required depth necessary to support both the nozzle and diffuser.
saw off the ends and inside to shape creating a support in the middle of the frame(for the gear and blade aasembly)

Step 4: Making the Blades and Hub

The blades and hub was made with a PVC Pipe and MDF respectively( again material choice is dependent on availabilty and properties).
PVC pipe was used because the curve inside the pipe makes it possible to pitch the blades at a desirable angle and also it strong and haevy enough to withstand wind pressure and at the same time produce more torque.
The blade shape is dependent on the direction you want it to rotate(clockwise or anticlockwise), this shape ensures the wind blows the blades in a clockwise direction.
the hub
the hub was created in such away that the blades are slanted at 30 degree angle(again through testing it was found that having more blades produced more voltage but with this setup the maximum blade the hub could hold was six)

Step 5: Making the Gear Connection(using Planetry Gears)

we wanted to have blade,hub and gears in one axis so our obvious choice was to go for a planetry gear system.
Using the gear assembly of an electric hand drill we were able to have the correct size and shape for our turbine,and the chuck too was suitable for supporting the blade shaft.
using planetry gears can be a challenge because the gear ratio can be too high or low, in our case the ratio was too high so we removed the secondary layer of gears.
the generator shaft was used as the sun gear by coupling it onto the gear assembly.the wooden frame insert is to support the generator and keep it aligned to the gears

Step 6: Testing

the turbine was tested in a purposefully built wind tunnel so as to have a constant source of wind.
during the test the highest voltage were got was 16V with a resistance of 47 ohms but with a bit more tweeking we expect to get up to about 20V