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Help with a Hand Held Fan Design Answered

So I am making my own hand-held fan. I do not know what type of design for the fan I can attach to the motor. It is battery powered, and my motor has a long metal rod on the end. I am thinking of using cardboard (if anyone can think of anything better to use, suggestions are welcome). I just don't know how to make the cardboard, so that it is easily fit onto the fan. Any special designs, or platforms I could put it on, to attach to the motor? Thanks! Brenn

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This is what i use to create simple propeller, use the natural curve of the soda bottle to obtain the propeller pitch (it's twist). Use harder bottles for stronger props. Note that the prop blades are cut at an angle (i prefer 7 degrees), How many degrees they're cut and the blade's shape is actually up to you. If you want to reduce drag (but weight will increase) , use round wood pieces rather than rectangular. I've also used corks in place of wood. Sorry if my drawing is not that clear, hope it helps

propeller.png

. Wow! Fantastic idea. Does this actually create an airfoil, or just something close enough to move a little air?

Well if you stick the propeller on a thin stick, and twist it between your palms, it has enough lift to fly 8 - 10 feet up.. The drawing doesn't do much justice, since i find it hard to draw the actual twist in the blade. But honestly, in sense of airfoil, it's not as good as a carefully carved propeller, but close..

. Neat. I'd be interested in knowing how close it is, but don't know enough about what's going on to come up with a search string. Just curious, not that I need to know. . If it was that close, I guess amateur prop makers would use tubing to fab their props. It's still a ingenious method of making a DIY prop, especially for proof-of-concept models. Thanks for posting it - it's something I might actually use one day.

And oh.. soda bottle prop is quite commonly used by amature (beginners in prop making)..it is by no means a new thing..

If you have A LOT of patience, and want to try some more real.. then this is the best option (do check out the calculations on the spreadsheet). I carved my first prop using these instructions (discovered that it's actually way harder than it seems) :)

Carve balsa propeller

Well I got it working. I am not sure if it is exactly like gyromild's but it definitely works well. It gives me some nice air.

Dude, (dudette?) GREAT idea for source of alreaady curved blade material. Love it. You should post just that as a n instructable, it's so useful. (Well, maybe add in how to make a handheld fan from it)

I'm an old dude..much older than the knex folks at least.. :) On the instructable, i might just do that..thanks

Thanks, I will try different materials and see which one works the best!

I found a variation to the water bottle design. I just cut off "wings" on the curve, and glued it to the cap, and the screw-on spot. Then I drilled a hole in the cap, and glued the motor head to the cap. It works great. An Instructable on this will be coming soon!

I'm definitely looking forward to it!

Is there a good shape I should cut the foam?

I would imagine a shape similar to a boat prop would work. Pretty much any design in which the "fins" are slightly twisted would push the air better.

Thanks! I will go looking for that! I was thinking of using hotglue to attach it to the motor.

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Bran

10 years ago

Craft foam (it is thin, and comes in many colors) would be good for the "propellers" if you will. In fact, it's the same stuff that the propellers on store-bought fans use. You can buy it at Wal-Mart, or if they don't carry it at yours, try a craft store such as Hobby Lobby or Michaels. To attach the foam to the motor, I would probably just use tape, but I'm not sure how well that would hold up. I think that if you could find a toy car big enough for your motor, that would be very unique.