Improbability Drive MkII

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Ken I

Project of the Month Winner!!!
Project of the Month Winner
Oct 31, 2010
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Cape Town, South Africa
I built the original as a proof of concept and to confound the curious :-

I have exhibited this every year at our local modeling club as a curiosity.
However it's always been pug-ugly and I figured I needed to tart it up some.

Top Left - Beginning to look old.
Top Right - I normally use an old turntable as a flywheel - even more ugly.
so I figured I would give it a flywheel and a presentation base.

Unfortunately every time I looked at it I was remined of the old adage that you can't put lipstick on a pig - so I set about giving it a facelift as well as adding a few new confounding wrinkles :-


So now the whole thing rotates vertically, can be reversed by changing the "timing" on the ball bearing and the addition of a pair of black granite gears (water-jet cut) which I jest are from Fred Flintstone's car.

A short video of it running.

Note: What makes it "improbable" is that the pistons go up and down twice per revolution - so its not a simple eccentric mechanism.

If you've seen it before keep it under wraps while others have a go at figuring out how the thing works. Regards, Ken I
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Stan, I'm glad someone has finally commented.

Here's a slo-mo of the business end - note the stub ends of the levers are moving in and out twice per revolution (see gap between lever and clearance holes in the plate)
Clue the low points are opposite the keyslot in the hub and the high points at 90° from that. (under the forward/reverse timing lever & opposite).

That said its still near impossible to figure out what's going on.
Right click and select loop to get an endless repeat of the single revolution.
In its prior configuration this was somewhat easier to see when the shaft turned and the body and levers stood still.
You can cheat by going to the orignal post of 11 years back.
I get asked "what practical purpose does it have" - none really, I don't do practical, I prefer oddball engines. and this is probaly the odest motor I've ever built.

Regards, Ken I
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Thank you kindly! Never having played with the mechanism you used I can say there is no way I would have figured it out on my own.

Very clever gizmo you created there!

I like your approach to doing things for the heck of it, it's a lot more fun to do something just because it pleases you that to do something that just has to be done. Now that I'm retired I'm doing my best to enjoy my third and final childhood :) Second was called "being such a good dad", only my wife caught on that I was just having fun and enjoying taking the kids along for the ride!

You're confusing Ken's improbability drive with the infinite improbability drive.
What Ken had built is a finite improbability drive.
It's easy to tell. Ken's engine does not require a really hot cup of tea to start.

I noticed that Ken's engine is the MkII and believed this newer version no longer required the really hot cup of tea :)
The likelihood of all those odds and ends, including some bits that are on the rare end of the spectrum, all being in the same place (Kens shop), at the same time, are completely improbable. Just some random added energy from a passing truck / lorry or a large horse fly introduced a slight vibration in the quantum field and the darn thing just assembled itself. It was so completely improbable that it had no choice but to exist. :)

Think I've remembered my Douglas Adams reasonably well on this one, and he was the ultimate authority...

Stan (who always has a towel handy)
Starting with all the frequently used excuses relating to ignorance (i.e. my background is not engineering, this is just a hobby) and the fact that I may use words incorrectly. I will give it a go.

I believe the levers are pressing on the top bearing and the energy moving any tolerance in the bearing to the opposite side,also possibly adding energy to the top of the shaft. Which appears to not be in contact with the fixed surface as it rises above its bearing. As both the bearing and the shaft "release" the imparted energy and return to their normal state it results in motion through the bearing therefore rotation. By applying the levers in sequence it maintains the rotation. I have no idea how the levers on top result in changing direction as they do not seem to be impacting the valve sequence. Unless they preposition the "flex" of the shaft to one direction or the other.

Well that is my guess it is likely the result of too much beer and a vivid imagination.
You might win the pot of petunias award for lateral thinking - but no.

I'm putting together a post to add here explaining where it all comes from - a commonly used device which for some strange reason is not very well known at all.

Regards, Ken I
that's a great "puzzle motor" - I wonder, if you were to double the length of the rods holding the pistons, leaving the pivot where it was, you would have a series of outward moving pistons that could move in and out of a larger ring which could be a pump, a second source of power, or just an added point of counfoundment.

If the upper part were to pump some warm colored liquid, you could assert that it is producing an ancient beverage that isn't completely unrelated to somethig which might have been called tea.
O.K. The explanation as promised.

The bearing at the business end is a flexible "wave generating" ball bearing from a harmonic drive - see video :-

Disclaimer - I have no commercial interest in AG Harmonics but they have made a really good video explanation.
The following is my own demo :-

I am demonstrating a 50:1 harmonic drive but they do go to as much as 200:1 in a very small space with high torque carrying capacity.
In the first video they point out that these are zero backlash - and they do mean zero - what they don't mention is that this device which looks distinctly Heath Robinson would likely be very inefficient.
These devices are in fact extraordinarily efficient, generally in the 70-80% range which allows them to be reversible.

My improbability drive (which improbably does two strokes per "crank" revolution) simply uses the levers to squeeze the outer ring of the bearing causing it to rotate.

Improbable yes but it does work.

Time for that pan galactic gargle blaster.

Regards Ken I
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Today at 2:45 AM
If that engine is to pump anything, it should be the ingredients for a pan-galactic gargle blaster.
Anyway, you can't use an improbability drive to make tea - that would be perpetual motion.

Pete Twissell,
Engine builder, motorcyclist and general machine botherer.

if we were to have that discussion via the time wormhole, say in 1955, would that be "pre-Petula" motion?

..... ducking and running for cover ......
Mmm.. well as zaphod beeblebrox once thought to me ... "the higher it flys the much" and don't you forget it earth boy.

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