Moving models

**Bonzo** · #1 09-23-2014, 06:40 AM

Here are a few of my models that maybe of interest. The paper ones are powered by an elastic band.

**elliott** · #2 09-23-2014, 06:59 AM

Ummm... Got a link or some pics? Looking forward to seeing them.

**Bonzo** · #3 09-23-2014, 07:52 AM

Here is the link to Youtube:-

https://www.youtube.com/user/MrDalgoma

**Miles Linnabery** · #4 09-23-2014, 08:32 AM

Dear Bonzo:
The Helix with the marble is very clever it must drive cats wild.
Thanks for sharing,
Miles

**Vermin_King** · #5 09-23-2014, 10:40 AM

I hope you are a Physics teacher. Things like these stir the imagination

**SCEtoAUX** · #6 10-05-2014, 10:27 AM

Built the Helix. Works pretty good. Something kind of amusing is you suggest an 80mm cocktail stick and a 60mm elastic band. Looking around I saw that I had a 60mm cocktail stick and an 80mm elastic band. I tried them and the machine worked OK. The elastic band broke (I had a spare in that same length that also broke) but it is unclear if it was because of the age of the elastic band or if it was the extra length that got all bound up when winding it that caused the failure.

Since the Motor is around 60mm in length I decided to make my own 60mm elastic band to more closely match that length. That was accomplished by cutting a long elastic band and gluing an overlap to close the circle and get the 60mm length needed. It worked good. I then whittled down a 100mm length of bamboo skewer to match the diameter of a cocktail stick then cut it to 80mm. Worked good, too. So far no failure of the elastic band and the 80mm length of the skewer seems to add a slight more stability.

There is some antici...................................pation in waiting for the marble to drop once it has reached the top of the helix.

It is also kind of calming to wind the machine and let it rotate with no marble in it. It sits upright without the marble and rotates in a slow, stately manner.

30 winds or so seems to give a good performance for one cycle of the machine. That is just a ballpark figure since it depends on the type of elastic band used. Too much winding could collapse the machine or snap the elastic band. You need to wind the elastic band in a clockwise direction when looking at the cocktail stick on the bottom of the machine in order for the helix to rotate in the correct direction to get the marble to travel up the ramp.

Anywho, nice machine model. Thanks for offering it.

**Bonzo** · #7 10-07-2014, 03:15 AM

Thanks for making it and for your comments.

If you ensure that the slice of candle is no more than about 6mm thick there should be no tendency for it to overturn.
Regarding the elastic bands, You can always double up on the square section ones.
For interest, it is based on the principle of the Archimedean screw, considered to be a method that could have been used to water the plants of the Hanging Gardens of Babylon.