Are we coming to the closing end of this thread?
Bob, where are you?
Not even close to the end, there is a lot of people still working on the concept. Keep in mind, it much easier to comment, then to do actual testing.
@All,
My next step to creating a Bob machine replication, would have been to add the pneumatic setup. But since this seemed a rather expensive addition, I decided to determine just how much addition force is coming from the Centrifugal slam capture. For those that don’t know, that is the impact force resulting when the connected weights are at the 12+1†point and CF slings them out to the end. After all, it is the only force that could make the machine a self-runner.
So I setup a unit mainly to test CF sling capture force.
The Cf rotor is shown in the Cf test bed rotor comments picture. It is relatively simple, the twine with a swivel and thread thru the center eye and is attached to the weight box. The stop block keeps it at 12+1â€. The unit is brought up to 50 rpm (as Bob stated) and released at 12:00. then it slams into the Irwin clamp with the bungee. Then the digital scale is used to determine how much force it takes to get the bungee to that position. I also attached the weight box to the Irwin clamp and brought it up to 50 rpm to see how much force occurs without the slam.
With 2.7 lbs for each weight box:
CF slam 15 10 lbs/ounces
CF static 5 5 lbs/ounces
With 4.7 lbs for each weight box:
CF slam 25 4 lbs/ounces
CF static 7 3 lbs/ounces
The CF static values are very close to my previous post of the CF 1-2 spreadsheet calculations. Of course using a hand held digital fish scale is not the most accurate, but close enough to see the advantage of the slam and the increase with weight.
However the slam didn’t occur unit the 5:00 O'clock position give or take a half-hour.
Why is the slam so late? This is to late for much gravity assist.
I think you have to go back to my previous analysis post of Bob's older machine with only the air cylinders and in his movie where the weights are up at the top when starting and don't sloppily pop up to the top again until it slows down at the end. He has the extra air pressure push on the weights that I don't, which would cause it to go out earlier at 50 rpm, hopefully at 2-3, otherwise you would get very little gravity assist.
Bob’s statement: ‘The air cylinders I use as a shock absorber, similar to that in a car and it also stores a bit of energy that locks the 2 weights together almost at the bottom’ (or top).
Then, I tried a test using a very long bungee to simulate the air cylinder and with 4.7lbs weights it slammed at 2:00, great. The bungee was not the same as Bob's air cylinder power curve, but probably within 50% and the best I can do at this time. At rest, the bungee overrode gravity to within 2 inches of where it would have hit the Irwin clamp.
The CF test 1 picture shows my first test attempt with an AC induction motor. It did not have enough torque at low rpm’s to turn the rotor. Just showing the failures to help others.
So in CF test 3 picture I am using a Ryobi battery powered drill motor to rotate the unit to 50 rpm’s. It has more than enough torque. The drill attachment structure looks terrible, but worked great,
get er done. It is connected to a full wave bridge to convert to DC and the Variac.
Regards, Larry