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I get the assignment is to use rubber bands, but to twist rubber bands in a spiral, or to roll them up is actually a really inefficient way to store rubber band energy. Their energy is far better served with being extended out freely. While yes, this will create a lot of force and short movement, its the ideal way to power something with an escapement mechanism like a weight would, that swings a pendulum or spins up a large wheel. If you really want to stick to the windup, add a rope to the rubber bands and wind up the rope, stretching out the rubber band, As you wind up rubber bands it will bind and the inner spool isnt as stretched out as the last winds.
Agree, getting a good long stretch definitely feels like the best way to do it. That was the idea behind the pulley concept - to stretch the rubber linearly over a significant distance. Admittedly, I did a pretty crap job of designing it, so I'd love to revisit that idea in another design at some point!
You should probably come up with a flywheel and some kind of wind up mechanism which would allow you to simultaneously crank up the weight and still be able to power the load.
Holy shit dude, this is awesome!! I hope to see a video with a gigantic generator using the slingshot rubber, maybe you could try doing it like the slingshot works? I also cannot wait to see the gravity video!
I'd like to see the hand crank replaced with a well geared foot pedal, charging your phone while being anxious seems like a good use of that state of mind.
I think you could try to use a bunch of small rubber bands in parallel and then just stretch them linearly, no winding then up. then gear up the output massively. That way you use a small amount of space to store the energy and it allows for easier expansion of storage by just adding more small bands
You can also use rubber bands for (super inefficient) refrigeration. No, I am not kidding you, stretch a rubber band and feel it with your lips, it gets noticeably hotter as you stretch it. Then hold it stretched for a few seconds to let it cool to ambient temperature, and let it go back to its relaxed state, it will be noticeably colder than ambient.
Rubber springs are definitely not even close to an ideal power storage medium. Friction between the elastomers turns quite a lot of this stored energy into heat. A coil spring or, as mentioned, gravity driven mechanics, will perform much better.
11:39 I realize you're a lego channel, but lego is the limiting factor when you've got massive forces like elastic band or *twisted rope*. Use fitness bands. Scale up. Lose the plastic. Increase the gear ratio even further so it takes at least a minute. Figure a lever for a human to stand on every minute that resets the internal rubber band. Boohoo, you have to take a step once a minute to charge your phone and run safety lights when the power goes out :P
You're 100% right, Lego is a major limiting factor. I've made a great many generators, and Lego always turns out to have severe limitations on how much torque can be handled - both on the input, and the rotor. Though I'd like to experiment more with some aluminium Lego pieces 😉 Then we can put it under much more stress
