ataripirate

Hand Powered LEGO Fan Recreation Project

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I am trying to replicate the fan that is in the video at this link, it seems that the things that look the easiest to do, can be the trickiest.

Here is a still shot.

lego%20fan%20parts%20small.jpg

It doesn't seem that hard to make, but with a lot going on, I seem to be missing something and cannot get it to function properly.

wondering if anyone could do a parts list, minus the fan blades of course, of what they see, assembly seems to be straight forward, but again, maybe I am missing something.

any comments and ideas are welcome, improvements, other versions, concepts are appreciated.

thanks to any and all that provide assistance in any way

Bobby

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The fan acts as a flywheel, if you have made the mechanism as it is on the photo,you first must rotate the blades by hand to start it .

The principle of this is the same as a single cylinder pneumatic engine, you have one cylinder that goes up & down, and the flywheel maintains the motor running.

Just look at the wheel at the start

Edited by LXF

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It's like a single-cylinder engine. The crank mechanism has dead-zones, so you need to manually turn the blades to give the system enough momentum to get it through the deadzones.

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thanks for the suggestions, and input, I will give it a look and try some things as soon as I can.

if anyone has any other ways to make a simple "fan" that works by the same or similar pumping motion, please share.

thanks

Bobby

Edited by ataripirate

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It's a matter of timing, too. If you just squeeze it, it won't spin. You'd have to squeeze and release so the wheel can stay in motion.

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what would I use to make the blade free spinning, when the gear is not powering it? thanks

you're looking for ratchet type mechanisms. I think there was one recently - try to find some ideas from here: http://www.eurobrick...showtopic=76983

No, a ratchet is not your solution here - the blades are never free-spinning (it's an easy mistake to make - I made it myself until I read LXFs post about the flywheel).

To operate this fan, you need to give enough of a squeeze on the handle that the momentum of the fan blades carries the 40t gear around so that it's in a position for the next squeeze to keep the fan blades moving.

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No, a ratchet is not your solution here - the blades are never free-spinning (it's an easy mistake to make - I made it myself until I read LXFs post about the flywheel).

To operate this fan, you need to give enough of a squeeze on the handle that the momentum of the fan blades carries the 40t gear around so that it's in a position for the next squeeze to keep the fan blades moving.

I was under the impression that post #7 was "how to I make it spin freely when you aren't squeezing the trigger", and not "how do I make it work". You say the blades are never free spinning, but in post #7 I replied to, the question is "how do i make it free spinning?". In that scenario, you are actually looking for a ratchet mechanism if using a trigger style approach, otherwise you're looking for a ratchet equivalent like the centrifugal clutch you find in a lawn mower starter ring or an inertial 'bendix spring' arrangement like a car starter motor.

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I was under the impression that post #7 was "how to I make it spin freely when you aren't squeezing the trigger", and not "how do I make it work". You say the blades are never free spinning, but in post #7 I replied to, the question is "how do i make it free spinning?". In that scenario, you are actually looking for a ratchet mechanism if using a trigger style approach, otherwise you're looking for a ratchet equivalent like the centrifugal clutch you find in a lawn mower starter ring or an inertial 'bendix spring' arrangement like a car starter motor.

Ah yes, that's probably a better interpretation of that post - how to improve on the current design, rather than how to implement it. In which case you're right and I retract my objection :-)

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You could try a rack and pinion mechanism too: replace the pushrod (between the fan and the hand-operated lever) with a rack, and put a gear on the axle of the fan.

Advantages:

*no need to hand-start the fan

*the fan can spin faster, and even you can make several gear-ratios by exhanging the gear at the fan

*the ratcheting mechanism could easily be solved, but I'm not near my Legos at the time to try t. Maybe just a week rubber band that's pulling the rack against the gear would suffice. If the movement of the level pushes the rack in a line (no perpendicular motion of the rack's joint at the lever), the rack will rotate the gear when it's pushed, and will slide off the teeth when pulled.

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Using a xl-motor to power a s-motor could work?

generator.jpg

done this to make a lego torch.... don't see why not

also does the effort involved in the OP overcome the cooling effect on the person?

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I'm pretty sure that doesn't work. I think you are confused with Mindstorms motors, which can do that.

I've never tested one motor to another but if you manually turn the 9398's wheels it will power the others via the wires, you might have to connect everything via the battery box and switch it off to generate power?

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I'm pretty sure that doesn't work. I think you are confused with Mindstorms motors, which can do that.

I tried this recently and it definitely works. It's not quick so it's not much use for this fan, and the motor from the Renewable Energy set is a much better fit, but the M-motor can be back-driven with an XL.

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