The one way bearings in the pendulum arms cause the second sections to rotate clockwise.
The wheel of flails also rotate clockwise.
The location of the mass at the end of the flails is closer on the left than the right.
There are other dynamics aspects present so the wheel does not lift the weights to the top or bottom.
There is a compound angle at the pendulum joint.
It is in the dymanics
Last edited by agor95 on Tue Jan 28, 2025 1:37 pm, edited 2 times in total.
[MP] Mobiles that perpetuate - external energy allowed
The device [aka Claireon] was presented to a selected group of people.
A high speed rotation did cause the centrifugal pinning we all know about.
When the rotation speed reduced the top flail on left dropped to a position on the right.
Also the desired effect happened. As the flail's second arm section is a pendulum and it overshoots.
Then as the arm before it exerts torque the one above it pushed further out as a secondary bonus.
I was expecting a similar action by the bottom left flail. So it drops closer to the centre line and moves inwards.
There was lass overshoot than expected.
I am looking at increasing the masses at the end of the secondary arms. That should help trigger that effect.
The only option after that would be to build a version with a different compound pivot angle.
Regards
[MP] Mobiles that perpetuate - external energy allowed
I do not blame you. That is why I created this demo device.
When showing the device one can show in slow motion the key steps to it's movement.
Also the affect of fast, optimal and slow rotation rates.
It was interesting starting the device at fast and then watch it slow into optimal rotation rate.
Like always it takes time for me to create animations; However I have a physical model to compare with the other development paths of maths and simulators.
In the picture the secondary arms are pointing down. If I were to move them into position against the one way bearings. Then the 'Claireon' device starts rotating.
And that will never do :)
I wonder if any other members has built a 5-flail device before me with compound angle pivots?
The main key dynamics are :-
The arms on the right are further out from the hub than the left.
The arms transition on the left side. In effect reducing their torque contribution.
The arms while transitioning also get an extra boost to reach a more favourable position than gravity alone.
The arms when transitioning in effect reduce their inertial resistance to the frame rotation.
P.S.
I think your best hope to understand this tread is by getting your hands dirty.
Build a hand flail with a compound angle with a one way pivot.
Then rotate it around an imaginary hub pivot.
Regards
Last edited by agor95 on Mon Feb 10, 2025 1:27 pm, edited 1 time in total.
[MP] Mobiles that perpetuate - external energy allowed
I have not seen anyone show this novel pivot variant which is combined with one way bearings.
This also exploits the difference in inertia between a mass under translation and rotation.
When the primary arm is rotated at speed the mass at the end of the secondary can lag behind.
That was hinted about with regards a chimney falling over some years ago.
The lag is used to prevent inertial resistance to the main frame's rotation and the angle caused the lag to
move the mass further out to the rim. This happens on the downward arch.
Taking the inverted top hint - There is another lag assist to flail the mass closer to the hub.
Taking this arm in / arm out is similar to a crab eating with two limbs and moving sideways with the others.
In this case flailing two arms and rotating the frame sideways.
I am Looking forward to see quick developers playing with the concept with small hand help demo examples.
Regards
[MP] Mobiles that perpetuate - external energy allowed
