For this build I am building my own super powerful ducted fan. I am using a 18V drill motor, an RC plane propeller and laptop batteries to run the fan. It is nice and windy at 4 volts and not too loud. At 12V it super powerful and loud and slides across the table.
I was thinking of mounting it to my bike and running it at 16V to see if it will push me a little but now I am building a larger one for that.
Step 1: Parts Required
DC drill motor (or another motor)
Laptop batteries (or others)
Fan blades (I used a plastic propeller)
1/8" plywood for duct wall
Plywood and 2x1 for motor mount arms
Switch (I used a 2P2T switch for 2 speed)
Step 2: Testing Motor and Batteries
The the motor with different voltage and test the current and wind power you would like.
In my test 4V was about 1.5A which is a good low power setting. 8V used about 3A which was a perfect high power setting.
I will used 4 batteries, 4 in parallel for 4V and 2 sets of 2 parallel batteries in series for 8V. So on low power it will last around 5 hour and on high power for about 1.5 hours.
I wired up a 2P2T switch to change between series and parallel. Please find the wire at the instructable below.
Step 3: Building Duct and Motor Mount
After gluing to pieces together I carve the edges to make them more aerodynamic.
I glued two triangle of wood to old the motor.
I soaked a piece of 1/8" plywood in water and then bent it and let it dry. I cut 3 strips that were 3.5" with the wood grain perpendicular to the strip so its easier to bend. I used the T as a guide and glued the 3 pieces together with overlap joints and leaving one joint open. I glued the 3 T ends to the plywood duct. It is important to mount the motor and rotate the prop to make sure the clearance is enough all the way around.
I then cut two pieces 1/4" plywood about 4.5 by 1.5 to form the top duct support. I used two pieces to go around and hold the motor. I glued these supports to the duct and to the T.
I glued a piece of wood to the T to stop the motor from sliding backwards. The motor pushes the air forwards so the motor is then pushed back.
I also used 2 zip ties to hold the motor down.
Step 4: Battery Pack
As a cooling fan 4V or 8V is more than enough power.
Step 5: Wires to the Motor
I taped the wires to the support arm so it would not move and get sucked into the prop.
Step 6: Testing
At over 47 Watts this is one crazy powerful little fan.
I think at 16V this fan could push my bike some decent thrust and it would sound really cool.
Step 7: Adding Protection
I used some wire cutters and cut a circle out of protective grate from a larger fan that was about half an inch larger then the duct. I bent the wire around the duct. I then used hot glue to glue protection on the front and back.
Step 8: Adding a Switch
This is just temporary as I want to use the 2T2P switch so I can have two speeds.