Looking back I see I wrote something along the lines of this post back in 2009, 2012, 2019 and 2022! Why am I so hooked on making working models, after all a working model can be simmed and will be if one ever materialises?
But a suggestion on the Bessler wheel forum yesterday prompted me to re-examine my model and I saw a simple but crucial error that I might have missed on a sim.
Anthony (a newbie) has this signature “it’s not where you see the weights on the wheel that matters, its where the wheel (FEELS) the weights thats important”. Now that is a fact I learned so long ago that I almost forgot how important it is.
Imagine you place pendulum on a wheel with its pivot just below the axle, so the weight hangs downwards. If you rotate the wheel a few degrees clockwise, the pendulum rotates anti-clockwise relative to the wheel. The pivot bears the weight of the pendulum and as long as the pendulum moves relative to the wheel, the weight is pulling down on the pivot.
But if you place a stop in the path of the pendulum forcing it to stop and remain motionless, the weight is no longer felt on the pivot, but rather where the weight actually is, resting against the stop.
As soon as the pendulum is free to move again the weight is again felt at the pivot.
The error I found was a simple mistake. A supporting rod I had fitted into the mechanism was too short, meaning the part it was supporting did not have its pivot close enough to the axle to gain a big enough advantage? Unless you keep the fact mentioned in Antony’s signature in mind you might not even realise you’ve overlooked it. Like I did!
Actually I didn’t forget about it, but I was so intent on correcting what I saw as an unnecessarily long lever in a drawing, I shortened it too much.
JC
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