why go outside to find some natural wind when you can make your own wind in the comfort of your own home!
for this very purpose I proudly present 'the Gale'
it's a right dandy little(ish) desktop USB fan.
it's not currently working at full capacity as I'm having a wee spot of bother with the fan bit at the mo. but I can confirm that it does indeed puff out a slight; but very distinct breeze. result!
please let me know how well it works for you
right, i was thinking to myself one day and decided that my best course of action would be to get an existing fan with a DC brush-less motor and a working fan in it already. this would solve my issue of the model motor getting really hot and the printed fans falling off the shaft, which is no good to anyone. and also hopefully gain sufficient airflow through this contraption.
subsequently i have bought said fan (http://www.amazon.co.uk/SAVFY-Portable-Retro-Mini-Plastic/dp/B00JUK0UDS/ref=sr_1_1?ie=UTF8&qid=1438632685&sr=8-1&keywords=usb+fan) and hacked it up so i was left with about 5-10mm of the black housing poking out the back of the wee circuit board (see picture for clarity). this makes for a dandy mounting solution and just pushes into the 'motor mounting plate v2' which you need to print to replace the first one. if you do go down this road, you will also need to print the 'ring mount retrofit' and eventually glue this into the top of 'casing_pt1' in order to screw the main ring assembly onto the bottom.
also, the usb fan comes with an on/off switch that can be made to fit in place of the speed controller by making the round hole rectangular with a file or something. the air flow out of this thing doesn't really warrant turning down, maximum is just fine.
After receiving a couple of requests for a smaller version of the fan, i have finally given in to the pressure and made a smaller version. in the included zip file you will find all the ring parts that now makes a 140mm diameter fan outlet and a base with a 95mm internal diameter. you will however need to design your own motor mounting plate to hold whatever motor you are planning to use.
you will need (well I needed at any rate):
a Speed controller
an unwanted USB cable (i bought one from the pound shop)
and 11 off M3x10 cap screws
then just wire up and assemble as per the delightful pictograms above (note: you may wish the thread the usb wire through the housing before wiring it up)
also you should make sure that your printer is printing slap bang bobby in the middle of the build plate because the big rings are 200mm diameter and may fall off the edge (i have a flat on the side of mine for this very reason)
i have gone with a fan fan as i couldn't get the impeller to work. i don't know why, maybe it's not spinning fast enough, i don't know but the fan seems to be doing something all-be it poorly.
ignore most of the items required to build this that are listed above.
at the time of this edit, all you currently need is as follows:
1 off USB desk fan (LOL - a fan to make a fan)
10 off M3x10 cap screws (maybe only 5, depending how tightly stuff fits together)
print out the bits:
ring_1, ring_2, ring_3, casing_pt1, ring mount retrofit, motor mounting plate v2.
then make the round hole in 'ring_3' rectangular to fit the switch from the fan you just bought.
now make a mockery of the USB fans warranty by cutting away the plastic cage, so that you are left with about 10mm or so of the stand off attached to the back of the motor (see picture). then insert this 'stump' into the printed motor mounting plate and assemble. it's fairly straight forwards.
i found it easier to assemble if you remove the tiny clip that holds the fan blades onto the motor, you can the remove the blades while faffing around :)