There is an interesting and potentially useful property to do with the procession of Gyroscopes, as well as devices like the "Powerball" toy.


When the gyroscope is rotating (Ws) and then force is applied to increase the procession (Wp) the Ws rotation increases.

Experiments with the Powerball show that a small increase in Wp results in a very large increase in both Ws and the resistance to an increase of rotational velocity in Wp.

More intuitively, imagine the dynamics here as being like a variable gear that increases in gear ratio at an accelerating rate as the speed of the input increases.

Would it be practical to design a vehicle such as a human powered bike or a motorised car that used this property of a gyroscope instead of a conventional gearing system.

Bike Gears and Chain

  • $\begingroup$ TINSTAAFL. You can't get energy from nowhere, and gyroscopes have the annoying ability to precess, which is really not what you want happening to your bicycle. $\endgroup$ Jan 3, 2019 at 19:50
  • $\begingroup$ TANSTAAFL (Ain't) if this is a Heinlein reference. $\endgroup$
    – fred_dot_u
    Jan 3, 2019 at 22:56
  • $\begingroup$ The whole post above is about incurring work by encouraging precession in order to increase the spinning of the gyroscope. The extra angular velocity is not free, it's happening as a result of pushing. With the giroscope/powerball this is with the muscles in your forearms and hands (powerball requires pushing really hard when at speed). With a bicycle it's by pushing peddles and things being geared up. With my bicycle like design it's by some mechanism that changes peddling into a precession like circular tilting movement at approximately the same rate, but with no toothed gears. $\endgroup$
    – alan2here
    Jan 4, 2019 at 2:42
  • $\begingroup$ @fred_dot_u I was using the "Economics 101" version :-) $\endgroup$ Jan 4, 2019 at 16:07

1 Answer 1


Naively, this looks as if it would be rather efficient, as there are few obvious mechanisms for heat loss. However, I'm unsure as to how make such a mechanism reliable. What if the wheel starts turning in the wrong direction?

Gearing would probably still be required, given the rotational speeds required for the exploited gyroscopic effects, so heat would be lost there. But the lack of chain makes for one fewer mode of failure.

If one make the gyroscopic effect reliable, such an engine might be reliable, perhaps more so than the traditional cog & chain, but given the need to step down the rotation speed to drive the wheel, there's not likely to be a noticeable energy saving compared to your traditional bike.

Overall, a nice idea. It would be worth building such a thing to investigate further.


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