eccentrically1 wrote:I think the fact that they accelerated to their final speed so quickly with such a small push is just as important as starting from any position.
Yup, agreed .. just as important. The two things together suggest a good amount of forward drive force.
However, B. says that it is like an OOB wheel, which we know has torque symmetry, and is not self-moving, and WILL FIND PQ ! So the excess impetus runs it on by the PQ with greater velocity than it would have without the assistance, imo. And that is why it can never again find PQ because it is getting more and more wheel momentum as it rolls thru each sector gathering more and more speed.
But .. the wheel itself must have some appreciable mass to it - which acts as a bit of a flywheel - else we'd have reports of it "hunting" as it sped up. By all accounts it was a near uniform acceleration, or at least no reports of variable acceleration to operating rpm. And within 1 to 2 turns was at full speed.
eccentrically1 wrote:A two finger (?) push would indicate they weren't very massive, same logic for stopping them.
"His assistant who didn't weigh a hundredweight stopped them by grasping the axle twice" (paraphrased).
I tend to agree. They were massive enough to smooth out acceleration somewhat. But not super-massive as to be very difficult to hand-stop, or cause a very slow start time which would have been noted by the witnesses and wasn't. This suggests to me that whilst wheel momentum aided the load tests (stampers, lifting, water screw), only in a minor way. And excess impetus drive was what kept the wheel speed near constant, even under load conditions as the witnesses observed. The only time the speed variation was notable was the Kassel water-screw test down from 26 to 20 rpm.
eccentrically1 wrote:I also think the fact that they did have a terminal velocity is a clue, but I haven't seen any suggestions here?
Eta: the clue is it shows they weren’t PM? A true PM wheel wouldn’t have a terminal velocity. Wouldn’t they accelerate forever?
If we assume the wheel internal arrangements had a similarity to an ordinary OOB wheel where objects changed radius etc, then it takes TIME for transitions to occur. What's called lag, or latency. And it gets larger and larger with the further an object moves in distance, frictions, and the relative speed of the wheel compared to gravity's acceleration. If we take an extreme case of a wheel doing 100 rpm then not only will CF's be effecting the lag but also little time available for a gravity induced transition to occur. And that why they have terminal velocity, and don't accelerate forever, imo (notwithstanding structural failure).
Since B's. one-way wheels did have a good clip then I speculate the transition distances were relatively small, so that the drive could be engaged quicker, and act for longer, time wise.