# Is there any mechanism to accelerate a flywheel with no max speed? **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2012, 9:38am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862 "2012-08-18T09:38:22Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![kyogi](https://avatars.discourse-cdn.com/v4/letter/k/51bf81/32.png) [@kyogi](https://boards.straightdope.com/u/kyogi)\ **Post date:** [August 21, 2012, 5:30am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/21 "2012-08-21T05:30:53Z")
> [@AaronX](#): > > Hypothetical situation: I have a free source of energy, like a rotating drive, piston or moving water. I want to store this in a flywheel. The amount of energy I can store is limited by the max speed of the flywheel. But if I use, say, gears, the max speed is determined by the max gear ratio. Is there any mechanism with no max speed? > > I was thinking if the energy source were a jet of air, I could use a turbine, and maybe change the angle of the blades as it sped up, but the speed would be limited when the speed of the air equalled the speed of the surface of the blades, no? If I correctly grasp the gist of the question, my answer is this: think magnetic suspension in place of a spindle. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 21, 2012, 5:49am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/22 "2012-08-21T05:49:17Z")
> [@Little\_Nemo](#): > > That leads to a theoretical possibility. Suppose you could design a flywheel that always moves at a constant speed? But you could add energy to the flywheel by increasing its mass. Double the mass at a constant speed and you’ve doubled the energy. And you could presumably withdraw energy by the same means - remove mass while keeping the rotation at a constant speed. > > It’s obviously a theoretical system - I don’t know how you’d add and subtract mass from a constantly rotating object. But if you could build it, you’d avoid some of the problems of the variable speed flywheel. No light speed concerns anyway. By moving the center of mass on a rotating flywheel it would have the same effect as adding mass. It would require more energy to maintain the speed and conversely store more kinetic energy. If the poster is speaking of energy storage as he stated he made one very important wrong statement. He feels the energy storage is limited by the speed of the flywheel, it is more limited by the mass of the flywheel. Or mass and speed. I hear this logic all the time when guys think putting bigger tires or higher geared trans will speed up their cars top end. You simply cant get any more power out than what you put in. ---
**Author:** ![kyogi](https://avatars.discourse-cdn.com/v4/letter/k/51bf81/32.png) [@kyogi](https://boards.straightdope.com/u/kyogi)\ **Post date:** [August 21, 2012, 6:03am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/23 "2012-08-21T06:03:13Z")
Badger, you’re spot on, but I was taking a pot shot at the true intent of the OP question. Wasn’t bothering with details until some OP feedback. When that comes, we may, twixt us, have a real answer for him. Which is kinda depressing, because as this thread continues, I find more & more to think about that I haven’t in years. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 21, 2012, 7:02am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/24 "2012-08-21T07:02:10Z")
Actually I’m wondering more about transmissions than flywheels. Another way to phrase the question might be: can you get an infinite gear ratio with a finite number of gears (and no electrical motors)? ---
**Author:** ![kyogi](https://avatars.discourse-cdn.com/v4/letter/k/51bf81/32.png) [@kyogi](https://boards.straightdope.com/u/kyogi)\ **Post date:** [August 21, 2012, 7:16am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/25 "2012-08-21T07:16:11Z")
> [@AaronX](#): > > Actually I’m wondering more about transmissions than flywheels. Another way to phrase the question might be: can you get an infinite gear ratio with a finite number of gears (and no electrical motors)? OK. That’s a different game. Gonna go have a smoke & think about that. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2012, 7:38am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/26 "2012-08-21T07:38:24Z")
> [@AaronX](#): > > Actually I’m wondering more about transmissions than flywheels. Another way to phrase the question might be: can you get an infinite gear ratio with a finite number of gears (and no electrical motors)? The answer is no. Apart from maybe exotic things like black holes, there isn’t anything physical/real that scales from finite to infinite. Infinite isn’t a synonym for ‘very large’. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 21, 2012, 7:46am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/27 "2012-08-21T07:46:49Z")
I don’t know. That’s what I would have said about an infinite number of gear ratios, until I heard about CVT. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [August 21, 2012, 8:26am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/28 "2012-08-21T08:26:59Z")
> [@AaronX](#): > > I don’t know. That’s what I would have said about an infinite number of gear ratios, until I heard about CVT. No you are confusing an infinite number of ratios with an infinite range of ratios. A theoretical perfect CVT is infinitely variable within its maximum and minimum ratios, but does not have an infinite range. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2012, 12:37pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/29 "2012-08-21T12:37:30Z")
You can’t have something that is real, starts with a measurable value, then increases to infinity. There is no numeric amount you can add to X to increase it to infinity. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 21, 2012, 1:08pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/30 "2012-08-21T13:08:49Z")
How about conductivity of a superconductor? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2012, 1:15pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/31 "2012-08-21T13:15:06Z")
> [@AaronX](#): > > How about conductivity of a superconductor? ‘Infinite conductivity’ doesn’t mean anything. A superconductor has zero resistance, or I suppose you could say it’s 100% conductive. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 21, 2012, 4:09pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/32 "2012-08-21T16:09:20Z")
I don’t think that infinite and ratio belong in the same sentence. Several false asumptions in the OP need to be addressed as they are the basis for the question. If you were to attach air nozzles to a spinning flywheel that would spin it using thrust the flywheel could never attain the speed of the air comming out of the nozzles, the more nozzles you added the closer it would get or the lighter you made the flywheel the faster it would go but no combination would bring it to the speed of the air comming out of the nozzles, or blowing across blades regardless of pitch on the blades. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2012, 6:50pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/33 "2012-08-21T18:50:15Z")
> [@badger5149](#): > > If you were to attach air nozzles to a spinning flywheel that would spin it using thrust the flywheel could never attain the speed of the air comming out of the nozzles, the more nozzles you added the closer it would get or the lighter you made the flywheel the faster it would go but no combination would bring it to the speed of the air comming out of the nozzles, or blowing across blades regardless of pitch on the blades. This is incorrect for fan-type turbine - the physics here is that of the inclined plane, which is itself a machine, where mechanical advantage can increase speed. A yacht can sail faster than the wind, and a turbine can move faster than the jets of air driving it, for the same reasons in both cases. What you say is true for a Pelton Wheel turbine - where the vanes have a cup on the end, and the jets squirt into the cups in the same plane as that of rotation. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [August 21, 2012, 6:57pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/34 "2012-08-21T18:57:24Z")
> [@Der\_Trihs](#): > > So use a rotating black hole instead; they can be spun up to near lightspeed. I’m not sure if that counts as a “flywheel” though. Actually, you can overspin a black hole: the location of the horizon is determined by the ratio of the BH’s mass to its angular momentum; eventually, when the angular momentum gets too large, there won’t be any horizon anymore, leaving you instead with a naked singularity. Though maybe that’ll still work as a flywheel… ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [August 21, 2012, 7:01pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/35 "2012-08-21T19:01:55Z")
> [@Mangetout](#): > > You can’t have something that is real, starts with a measurable value, then increases to infinity. There is no numeric amount you can add to X to increase it to infinity. But you can have something that is real, starts with a measurable value, and can increase past whatever measure you can come up with. Which is a pretty good rigorous description of infinity, in my book. So I don’t think asking whether a physical thing can go to infinity is meaningless or ridiculous. I mean, for instance, the answer to ‘how fast can a shadow move?’ is “it’s only limited by how strong your light source is and how big a thing you have to cast a shadow on” which can be summarized as ‘Infinitely fast’. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2012, 7:07pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/36 "2012-08-21T19:07:30Z")
> [@Quercus](#): > > But you can have something that is real, starts with a measurable value, and can increase past whatever measure you can come up with. Which is a pretty good rigorous description of infinity, in my book. > > So I don’t think asking whether a physical thing can go to infinity is meaningless or ridiculous. I mean, for instance, the answer to ‘how fast can a shadow move?’ is “it’s only limited by how strong your light source is and how big a thing you have to cast a shadow on” which can be summarized as ‘Infinitely fast’. That’s just another way of saying “there’s no such thing as the biggest number” - it’s not the same as finite things being able to transition to infinite. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 22, 2012, 1:37am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/37 "2012-08-22T01:37:56Z")
> [@Mangetout](#): > > ‘Infinite conductivity’ doesn’t mean anything. > > A superconductor has zero resistance, or I suppose you could say it’s 100% conductive. You say infinite conductivity doesn’t mean anything, yet zero resistance does? In any case, that proves you can start from a finite conductivity reach infinity. So I’ll just ask: can I get a gear ratio of 1:0 or 1:epsilon, epsilon arbitrarily small? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 22, 2012, 7:06am UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/38 "2012-08-22T07:06:48Z")
> [@AaronX](#): > > You say infinite conductivity doesn’t mean anything, yet zero resistance does? Yes. In the same sort of way that a cup can be \*empty \*or _full_, but not \*infinitely \*empty or \*infinitely \*full. > [@](#): > > In any case, that proves you can start from a finite conductivity reach infinity. No, it doesn’t. That’s the opposite of what I said. You can’t progress a finite value to infinity (at least not in finite time) - a population of rabbits that doubles every week will get _really big_, but will never become _infinite_ in any finite period of time. > [@](#): > > So I’ll just ask: can I get a gear ratio of 1:0 For zero turns of the input shaft, you want the output shaft to turn once. Obviously not - this is similar to the problems encountered if you try to divide by zero. > [@](#): > > or 1:epsilon, epsilon arbitrarily small? There are physical limits to what will actually work, but if you’re ignoring physics and talking mathematics only then yes; for any given gear ratio, you can devise another ratio that is higher or lower (proof: just couple two of them together). ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [August 22, 2012, 12:34pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/39 "2012-08-22T12:34:04Z")
> [@Mangetout](#): > > That’s just another way of saying “there’s no such thing as the biggest number” - it’s not the same as finite things being able to transition to infinite. Well, I think we’re getting to the point where I have to ask “What do you mean by infinite?”, you’ll wave your hands and say “You know, _infinite_, forever, without limit” and I say “But I just gave an example of something without limit, and you said that wasn’t what you meant by infinite.” then you say “OK, scratch the without limit part” and I say “Then what do you mean?” then you say “Infinite!” and I say “So you define ‘infinite’ as that thing which no finite number can ever reach by increasing?” and you say “Sure” then I say “But that makes your statement kind of boring true by definition, right?” and around here someone derails the thread by talking about how Cantor was crazy; there can’t be more than one infinity, and things are never resolved. There, did I save us both some time? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 22, 2012, 12:41pm UTC](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862/40 "2012-08-22T12:41:02Z")
> [@Quercus](#): > > There, did I save us both some time? Not really, because the question here is not “is there any such thing as a valid concept of infinity?”, but rather: “can I actually make or design something with an attribute that is infinite, by just making that attribute bigger or something?” [Previous page](https://boards.straightdope.com/t/is-there-any-mechanism-to-accelerate-a-flywheel-with-no-max-speed/631862.md?page=1)