MT 24 and MT 25

[zoelra]

Alan,

In the attached picture, the yellow dots represent the fixed pivot points, and the orange dots the connection points to the arms. Obviously I could have used better colors - you have to open the picture to see it more clearly. If this is what you are saying then it makes sense. Thanks for catching this.

[ruggerodk]

@Zoelra:
It's a 'compound' illustration showing both states of the mech...including the z-plane.

regards
ruggero ;-)

[Nobody]

Thanks a lot for your answers and for marking the pivot points in that MT 40 drawing.

Of course there is a lot of personal interpretation and speculation in Besslers words and drawings.....
Guess the more one gets in harmony with his words, thoughts and superior wisdom the closer he is
to recover the working principle.

In this case my personal interpretation is, that the storks bill on the right side is more about showing
correct application with more than two pairs of rods (links) on one side, rather than showing the Z-plane
of that MT 40 drawing. Please correct me if you think this thought is a complete incorrect assumption.

Thank you and with best regards,
Nobody

[ruggerodk]

@Nobody:
Your assumption are just as correct (or incorrect) as mine ;-)

What I see is a drawing showing different states: A) Rod in, storkbill expanded and B) Rod out, storkbill contracted.
I don't see a mech that has a rod in and a rod out at the same time (as drawn) - rather, both rods are either in or out at the same time.
As to the z-plane: That's the plane of the storkbills....in the direction of the wheel's axle. Perhaps even inside the axle?

regards
Ruggero ;-)

[Nobody]

@ruggerodk,

it is good to have different interpretations, often the trueness sits somewhere in between:-).
The reason why I thought the storks bill on the right side is more about showing correct application
is simply that the main MT 40 drawing would have become quite elaborate with that design in it.

Anyway coming back to that invention it seems no member in this forum has made a practical
test experience with a model?

To my understanding there is also another benefit in that MT 40 drawing:
It seems to be one of the (fewer) designs that would either work in both directions and
therefore an aspirant for the dual-directional wheel mechanism.

Best regards,
Nobody

[Ed]

Anyway coming back to that invention it seems no member in this forum has made a practical test experience with a model?

Why do you say this? Have you not done a forum search?

[MrVibrating]

Hi everybody (and Nobody!)..

I've been trying to take a (much needed) break from all this, and this is my first read here in weeks..

I'm tested many scissorjack systems. For the last week i've been contemplating three of them sitting on my desk - a single scissor pair, a double and a triple, trying to find 'something special' behind them. As Jim says, they obey the same laws of leverage as a balance beam... it's just a linear, if beguiling, lever, and its efficiency is determined only by the relative mass displacements - ie. you have to look through the scissorjack, as if it wasn't there, and only consider the masses and distances for input and output.

Quite by coincidence though, i've spent the last two weeks focused on MT24 and 25..

What draws me to them is this 'knee lever' mechanism - it has a number of consistencies with various other clues:

- the peacock's tail alluded to in AP

- a weight is heard to land on the descending side of the wheel

- the wheel is under torque as soon as an internal weight is heard to begin falling (as opposed to after it has fallen)

- it would emit a sound of parts or poles moving or being dragged over each other (poles & long metal beams have distinctive acoustic properties)

- a freely-opening knee lever landing on a rim-stop would allow the full weight to be applied to the wheel; presumably then the mechanism allows a reduced force when lifting / resetting

NB: There's a key difference between MT24 and 25 - in 24 the poles are hinged to the hub, and each of the 8 mechanisms has an independent middle pole.

In 25 though, these 'poles' pass through the hub and each mechanism shares one end of a 'pole' with an opposite mechanism - and as emphasised in the accompanying text, this is why they must be longer and curve inwards... ie. a better word for 'poles' here would be 'leaf springs' - they have to be flexible enough to bend, and rigid enough to act as pushrods. This combination of rigidity and flexibility thus implies elasticity.

This last point leads us to another important distinction between 24 and 25:

MT 24 and 25 have a further distinguishing feature - they trade axial tranlsations for radial ones; the outer weights maintain their radial distance, levering the pole weights radially to cause an overbalancing force. But this also creates an axial gap - an underbalancing force that counters the OB torque.

Hence, MT 25 is an improvement over 24 in that the interconnecting leaf springs synchronise the axial & radial translations in opposite quadrants, cancelling out this axial underbalancing force, and leaving the remaining radial OB force.

Furthermore, the leaf springs also exert an axial force on the outer weight poles because they're being bent, and the degree and direction of this sprung force alternates as the mechanism cycles.

There's a good 3D sim of MT 25 here, however it lacks any implementation of inter-connecting leaf-springs.. i currently reserve judgement on whether this axial elasticity would make any significant difference to the outcome, however it is clear that it will alternately work with, then against, the opening and closing of the axially-moving outer weight poles. In short, Bessler is intimating that the interconnecting leaf spring is kinked, and the effect of this kink as the leaf spring moves radially through the hub is to advance and retard the motion of the outer weight poles..

Final thought on scissorjacks - the only significant aspect i've found concerns the relative input-to-output accelerations - as more scissor pairs are added to the jack's length, the relative I/O accelerations increase linearly. This is why a long jack seems to open and close surprisingly rapidly when the handles are pumped (like a linear whiplash effect). However i doubt this is the useful property Bessler hints at, and the power requirements remain a straightforward function of mass, distance and time.

Still, my current hunch is that scissor / knee lever -type mechanisms operating with leaf springs may be a worthwile lead...

[ruggerodk]

Anyway coming back to that invention it seems no member in this forum has made a practical test experience with a model?

Why do you say this? Have you not done a forum search?

Ed - I think Nobody refer to a test model of MT40.
I couldn't find any in my forum search....perhaps you could help providing a link..?
regards
ruggero ;-)

[Ed]

Sorry, one forum no longer exists and I think I was referring to info posted there. In any case, I have built many versions of MT40 in the past, including one that works as a balanced motion wheel.

[AB Hammer]

Ed

I have also built several versions of MT40 and I know that balanced motion wheel all to well. LOL ouch!

Alan

[ruggerodk]

... I have built many versions of MT40 in the past, including one that works as a balanced motion wheel.

That sounds very interesting - could you please alaborate on your experience?

[Ed]

Sure. Could you specify what aspect you'd like me to elaborate on?

[bluesgtr44]

I did a WM2D model of MT25 a good while back ago. Here's the link to the old thread......

http://besslerwheel.com/forum/viewtopic ... 5586#45586


Steve

[ruggerodk]

I don't know Ed - really, anything on rotation speed, the set-up, force applied to storkbill vs RPM, rod mass/weight, you name it....

[Ed]

Keep in mind that it didn't work, so no "rotational speed" or "force applied to storkbill vs RPM"

I built most models out of meccano with a few custom parts, except for one I built out of regular hardware and bigger (about 2 ft. dia.).

None of these exists anymore, as I built all of these models back in 2005/06 and have since recycled everything.

I do still have some spreadsheets, sims, etc. so I can show images of setups from those, and maybe even a video or two?

I can describe how it behaved, but you'll have to ask questions that don't include assuming it turned by itself.

Also, it makes a poor flywheel. Unless it's the motion wheel. :-)