So he tried rubber in tension. He figured the
rubber of the day had 1500-2000 ft lb/lb of energy in tension. In the first
of these models he seems to have tried to overcome the dwindling pull of
the rubber with a pair of fusees, the rubber motors pulling
cords that were wrapped around the fusees marked G in the second photo.
So what's a fusee?
A fusee is a more or less conical spool around which the cord is wound.. As the rubber unstretches and looses tension, the cord winds down to the end of the fusee with the higher diameter, allowing the torsion on the prop shaft to remain constant. I don't think I'm being clear. Here's one in an ancient clock where, as the spring in the spring box D unwinds, the chain climbs down the fusee . Therefore the load on the escapement remains more or less constant. |
He doesn't say much about these models in his book other than printing these intriguing pictures. In any case he soon realized that the extra weight of the machinery and especially a frame strong enough to support the rubber in tension made the whole idea impractical. And he moved on to steam.
But these models have such a strange, alien beauty
that it is very tempting to try again.
