Flywheel Bicycle with NuVinci Hub and Regenerative Braking
Inventor Maxwell von Stein has created a bicycle using a NuVinci 360 hub with a chain ring adapter connecting the power output of the hub to a flywheel. This allows the rider to aid in braking by first shifting so that power is transferred from the bicycle wheel’s motion and transferred to the flywheel. Then when a boost is desired (when trudging uphill perhaps?) shifting in the other direction will transfer the power from the flywheel to the rear wheel. Cool!
Using the NuVinci continuously variable transmission, the rider is able to smoothly transfer energy to and from the flywheel by shifting up or down.
Check out the video here:
http://www.sciencefriday.com/program/archives/201108126
Source: http://www.notechmagazine.com/2011/08/flywheel-bicycle.html
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August 29, 2011 at 2:19 pm
Interesting, but he ruined a nice Bridgestone!
Also, no chain tensioner on the human chain left side drive
August 30, 2011 at 10:08 am
Once that flywheel is spinning, it’s going to be hard to turn the bike thru corners. The solution to this is to have the flywheel mounted like a gyroscope within 2 further degrees of freedom – thus making it very complex to add or claw back power. This is the reason inertia braking has never caught on (in anything but trams running along straight tracks).
October 3, 2011 at 3:00 pm
Great point Jake but I wonder though if that gyroscopic effect of the flywheel could be seen as a feature instead of a bug say in the case of riders that don’t have the best balance. But then if it makes it difficult to turn effectively, that could trump any positive balance gain.
Also Aaron, why would a chain tensioner be necessary there? Because of the vertical dropouts?
November 20, 2011 at 1:16 pm
The most obvious problem with this “invention” (very similar things have been done many times before) is that it presumes that one can get something for nothing.
Any flywheel produces energy relative to its mass and its momentum. Both of those factors depend upon a bicycle’s biggest enemy: weight. In other words, the only way that a flywheel could produce any useful power for pushing a 25 pound bike and its 175 pound rider forward is if it has enough weight to overcome inertia and keep working under load.
If the flywheel weighed say, 100 pounds, it could probably do some good in propelling the bike and rider when needed. But that would come at a serious cost of having to haul along an additional 100 pounds when pedaling the rest of the time.
If the flywheel weighed say, 10 pounds, it would expend its momentum very quickly, since it’s having to work at such a huge disadvantage of *it’s* mass+momentum to the bike and rider’s mass+inertia.
To put it another way, this device can only either be pretty much useless in actually moving its rider forward, due to its LOW weight, or it would be more of a human energy waster, due to its HIGH weight, and the increased human energy required to move along when it’s *not* “helping”.
November 23, 2011 at 10:45 pm
I remember years ago reading a discussion of flywheels as energy-storage devices. IIRC, a flywheel of relatively small mass could store large amounts of energy but only if the rotational speed is very high. At such high speeds, air resistance would sap energy from the flywheel, so the housing would need to be evacuated of air. Probably too complicated for use on a bicycle.
Steve