Quantitative Analysis of Diabolo Acceleration Techniques

[Sharpes]

Hey Everyone!  I had the amazing opportunity to do a term project on the subject of my liking this semester, and also was able to use a $60,000 high speed video camera and some really expensive analysis software.  After many hours, I've got some interesting results that I thought I'd share with the diaboloing community.  You can find the final paper and presentation, both in .pdf format, here: http://web.mit.edu/nsharpe/Public/Diabolo%20Analysis/.  The presentation has all the pretty pictures and dumbed down results for those that don't want to read the whole paper.

Here's how the various acceleration techniques stacked up against each other in terms of maximum speed:


The maximum recorded angular velocity we found was 5771.5 rpm, using the circular acceleration technique and the bearing diabolo.  This correlates to a rim speed of 83.7 mph or 134.7 kph for you metric minded folk.  This explains why diabolos going really fast give friction burns so easily.  Some interesting tidbits from the report:

- While circular accelerations give the highest max speed, chinese whips accelerate the diabolo the quickest.
- We recorded a maximum throw height of 69 ft!
- For the most part it seems that the bearing can achieve higher speeds and accelerates quicker than the fixed axle, as would be expected.
- Here's what the velocity of the diabolo looks like when it's being accelerated from a standstill using chinese whips, with representative frames from the video shown:


Anywho, that's what we got.  Unfortunately the class is now over, but I should be able to borrow the equipment in the future, so perhaps we'll have some more interesting stuff to report next year.

-Nate

[Dracodragon]

Wow this is really interesting! Good job nate and others who put the time into analyzing this; I am definately going to try and read the whole paper when I find the time.

[monkiatzu]

that is beyond interesting!
i was hoping someone could give us statistics like this
thank you very much for that
i can tell you put alot of effort into this project.

One thing i think you can try if you want to do something similar, is test different brads of fixed axles.
acceleration speeds would be different, i hypothesise, as the diameter of teh axles changes slightly.
the greater the circumference, the more string wrapped around, and thus a faster rate of acceleration.
thats what i think anyway, might be wrong, but it woul be interesting to test.

Well done

[Mop]

Amazing! I've been wondering about this quite a lot recently. Thank you for providing a interesting and accurate insight. 

[mike.]

we have some smart cookies here .

BTW. i'm going to start showing up at MIT juggling club after x-mas. should be fun.

[Ethan]

really cool stuff, thanks alot for the different technique analysis

[Janey]

thats very interesting, i read it all. nice work!

[Jakob]

Hey That is very Interesting, I might show it to my Physics Teacher. I've discussed some diabolo physics with him, and as a surprise for last lecture, I got to juggle in front of everyone in the auditorium, speaking about the physics

a fun thing: he borrowed a pair of Henry's aluminium sticks and my purple Circus. And tried the string greased up with rosin (what you would use on a violin to optimize friction)

[Sharpes]

And what was the result?
-Nate

[Hathaway]

If you get a chance it would be interesting to see how multiple wraps on bearing effect the speed/acceleration!

[Hector 641]

This is some really interesting stuff guys. Really really well done. 
Up to Frontpage shouldn´t it???

[-Leo-]

Finally someone got around to doing something like this! Impressive stuff, much better than anything that has been done/spoken of before on the forum in this area!

[Martijn]

Very interesting indeed! Thanks for sharing, I hope you can investigate some more interesting areas!

[Chiok]

You know, I've not read enough research papers this year.  I'll read this and assess your rigor (33 pages later).  Thank the lord for the summary.

Chiok

[Sean]

That's just awesome Nate. It's great when you get to incorporate one thing you find interesting into another, isn't it?

One of the big future questions I'd have is: What's the difference in rotational inertia between the diabolos? That's mostly what it's all about after all. I guess it gets a bit more complicated since the width can also affect the lateral stability. Rotational inertia would be a good place to start.

[Midoryu]

Wow.  Good thing your prof. decided to do that, 'cause this is ground-breaking research.  What I mean by ground-breaking is you could do research like this and publish this, or sell it off to manufacturing companies, or designers like William Ling or Ryo Yabe (assuming they have not done the exact same thing already).  Not only will this bring mass fame, this useful information will be publicized and used extensively and can be applied to practically anything that needs to be applied to.

That's just my evil gene talking.

Anyways, good job on the research, Sharpes.  This is extremely important for all the diaboloists out there, because the equations you developed (however inaccurate it may possibly be) will be needed like a crack addict going into withdrawl.  For example, your equation for the maximum height achieved by a spinning diabolo can be used for siteswap, where in order to determing what a 5 is you can calculate the velocity needed for a 5 to be pulled off cleanly.  Actually, I can't do that right now, 'cause I'm a siteswap idiot, but I'm sure if another member of this forum knows what I'm talking about, he/she would have come up with the heights already somewhere on notepad.  Or something like that.

[Final Note]:  Actually, I WAS going to do the relationship between string length and velocity, but if anybody cares to do so after reading this awesome research report by the Sharpes, I shall be eagerly awaiting the results ^_^.
Either that or I go get my Taibolos and my MB string right now.

[The Void]

...you could do research like this and publish this, or sell it off to manufacturing companies, or designers...

You know, someone once designed a diabolo having done all their maths/physics analysis first on what would make the best kind of diabolo.

They came up with the Radical Fish diabolo, and we all know what a b*stard child of a fruitbat trumpet surgeon that was.

The Void
..................
...remembers the Yomega RPM

[Jakob]

And what was the result?
-Nate

More static friction, less kinetic friction.
The sting tangled more frequent than a new one without rosin.
It didn't improve anything, was funny to try though.

- Jakob

[Midoryu]

You know, someone once designed a diabolo having done all their maths/physics analysis first on what would make the best kind of diabolo.

They came up with the Radical Fish diabolo, and we all know what a b*stard child of a fruitbat trumpet surgeon that was.

The Void

Ok, so you mean to say that they've done more research than the Sharpes have done?  (This statement is intended to be completely non-biased, of course)

But either way, the Sharpes actually PUBLICIZED this without asking money from the moderators before posting this.  What I'm trying to get at (to rectify my statement from the previous post so that it reflects exactly what my thoughts are, so as to create less confusion) is this type of research, when compiled as much as possible, could be sold WITHOUT withholding anything from the general public, and as such, what I meant to say was in a book that Penguin can sell or something, but not so much SELL IT OFF TO COMPANIES OR DESIGNERS (which, in my opinion, are not likely to publish the research so readily), per se.  Otherwise, there'd be a book titled "The Physics And Quantitative Analysis Of the Diabolo"...or something along that line.  Either there's no such book describing the subject in discussion or I have a lot more to learn.  In the case of my ignorance, I'd like to be enlightened with an image of any books that have already been published with the research in question.

(High on turkey when I typed this)

[Donald the Trekky]

Really interesting. Thank you.