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A Bike That Uses Its Brakes for a Speed Boost (and Other Student Engineer Inventions) [Video]

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For more than 150 years New York City’s Cooper Union for the Advancement of Science and Art (more commonly called The Cooper Union) has finished its school years with an annual event  showcasing student projects in the areas of art, architecture and engineering. Of the more than 300 projects on display this year were several inventions designed and built by students demonstrating a firm grasp of what society will want and need from technology moving forward. Such inventions included a bicycle that features a flywheel, a wave energy converter and a mobile mini-robot.

flywheel, bicycle,energyThe school awarded its Nicholas Stefano Prize for an outstanding mechanical engineering senior project to Maxwell von Stein for his flywheel bicycle. The bike (see the video below) uses a spinning flywheel to recover energy lost during braking so it can be later reclaimed to boost speed. A flywheel can temporarily store the kinetic energy from the bicycle when the rider needs to slow down, according to von Stein. The energy stored in the flywheel can be used to bring the cyclist back up to cruising speed. In this way the cyclist recovers the energy normally lost during braking. In addition to increased energy efficiency, the flywheel-equipped bicycle is more fun to ride since the rider has the ability to boost speed, he adds.

Von Stein’s invention features a 6.8-kilogram flywheel from an automobile engine mounted to a bicycle frame. The flywheel is driven through a continuously variable transmission in the rear wheel. During charge, the transmission is shifted to increase the ratio of flywheel speed to bike speed.  During boost, it’s shifted to decrease the ratio of flywheel speed to bike speed. The rider can charge the flywheel when slowing or descending a hill and boost the bike when accelerating or climbing a hill. The flywheel increases maximum acceleration and nets 10 percent pedal energy savings during a ride where speeds are between 20 and 24 kilometers per hour.


wave, power, energyThe Harold S. Goldberg Award for technical leadership in engineering went to Charles Canepa for an ocean wave energy converter. Canepa, who also won the school’s William C. and Esther Hoffman Beller Prize for civil engineering, worked with fellow Cooper Union engineering students Matias Garibalid, Daniel Nash and Jacob Presky to design their wave energy converter so that the flap pushed by the waves is kept orthogonal to the waves’ forward direction. This way, maximum torque is constantly transmitted to the device’s drive shaft and maximum power is captured.

Canepa and his team are one of many groups in academia and industry developing technology that can convert wave power into renewable energy to decrease the world’s dependence on fossil fuels. For example, the U.S. Energy Department is funding a project led by Ocean Power Technologies to use the company’s buoys to capture wave energy off the coast of Oregon. Likewise, Edinburgh-based Pelamis Wave Power is working with Swedish utility Vattenfall to install Pelamis serpentine-like wave energy converters near Scotland’s Shetland Islands to deliver power to 26,000 homes there.

robotNicholas Wong and Hadi Jammal won the Wilson G. Hunt Award given to a graduating mechanical engineering student based on general engineering excellence in his studies. Wong worked with fellow Cooper Union students Lili Ehrlich and David Isele to design and build the Mojo-Robo tank robot, an autonomous device that specializes in launching ping-pong balls. Wong was also part of the Cooper Union’s Interactive Light Room project, where he was the primary designer of electronic "firefly" devices that educate and entertain children—in particular those who are deaf and hard of hearing. Each firefly is a self-contained circuit board that achieves synchrony of flashing with other fireflies in its proximity as arranged on a magnetic wall.manufacture,mold

Jammal worked with classmate Saman Farid to develop a reconfigurable mold they hope will help inventors and industry rapidly produce small quantities of customized parts used when building prototype devices. The reconfigurable mold is akin to the PinArt toy, which uses small pins that move in and out to create a cavity to fit a predefined shape, such as one’s hand. Instead of pins, Jammal and Farid’s mold uses pegs that can be adjusted in and out (using software) according to an inventor’s needs.

Images of flywheel bicycle courtesy of Maxwell von Stein, wave energy converter courtesy of Charles Canepa, robot courtesy of Nicholas Wong and reconfigurable mold courtesy of Hadi Jammal

Video courtesy of Maxwell von Stein


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  1. 1. Penguin59 9:09 am 06/24/2011

    To Maxwell von Stein, about his flywheel bicycle: congratulations on a clever and straightforward design. I would be interested in learning more about the testing and calibration that you had to go through since you built the first prototype.
    Also, does the added weight negatively affect the bicycle’s dynamic handling in a noticeable way?
    Have you considered storing the energy with compressed air instead? I acknowledge that the complexity of the design would be much greater, but you won’t have the weight penalty and even more the bicycle frame could double as air tank.
    Good luck.

    Link to this
  2. 2. alexdrudi 10:17 am 06/24/2011

    Adding a flywheel to something which has as its main design goal that of being as lightweight as possible sounds weird.

    I guess a spring would make more sense as the energy storage unit.
    6.8 kg are not negligible even on the slightest climb. Unless you manage to spin the passenger kid on the backseat somehow.

    Link to this
  3. 3. brerlou 2:14 pm 06/24/2011

    I suspect that there is an equation somewhere that would show that the energy required to push this heavier than normal bike during normal operation over time is about equal to the energy to be gained from the flywheel storage system.

    Link to this
  4. 4. slidda 5:16 pm 06/24/2011

    I believe no such (straightforward) equation exists. The flywheel makes the bike frame heavier, yes, but the energy is stored as angular momentum, (r) X m(v). All else being equal, if the flywheel were lighter, it could still store the same amount of energy and spin faster, provided the bearings were extra-low friction and the moving air around the frame didn’t take it’s cut in the friction game. That’s the energy trade-off, minimizing losses, and not weight per se.

    The energy is not gained from the flywheel, just not lost by the system as a whole. I actually think in stop and go urban biking scenarios, this setup might work nicely.

    Link to this
  5. 5. myavataractually 12:25 am 06/25/2011

    The flywheel bicycle is a simplified application of one of the variations of kinetic energy recovery systems (KERS) being used in automotive engineering (e.g. Formula One race cars).

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  6. 6. R.Blakely 4:23 am 06/26/2011

    Riding my own bike I realize that a big factor is speed. When I go faster I waste much more energy. This means air friction is the biggest problem in bicycle riding. I think a big advantage is a variable speed transmission, to maximize the small amount of energy that a person can deliver to the bicycle. A flywheel is just a frill.
    A better frill is an air-friction drag-reduction-type frill.

    Link to this
  7. 7. PGracey 1:24 am 08/17/2011

    Two points: One; His system doesn’t seem to have a clutch to allow it to be stopped completely, only slowed substantially. two; The kinetic energy of the bike/rider in motion is a form of storage and recovery when long periods of coasting are utilized. Both methods seem to need a great deal of anticipatory planning when approaching a possible red light. One to account for the amount of slow rolling before it turns green, and the other to begin using coasting early so that minimum braking is needed.

    I used coasting with my aerodynamic faired recumbent to great advantage on a coast to coast trip years ago which was aided partly by the weight of the gear I was carrying. I believe I did about one third fewer turns of the pedals than I might have using a standard touring bike.

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  8. 8. Johnny Payphone 8:44 pm 09/8/2011

    That flywheel bike is eighty years old! They’re handin’ out awards for completing assignments from Popular Mechanics’ “The Boy Mechanic Builds Toys”!!!!! Haw haw haw

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  9. 9. ungun 5:39 pm 12/3/2011

    There was an article about this idea a couple of years ago. Porsche uses a hydraulically powered unit. I pointed out that I used the idea in a story first published ’94, still available at Penguin59, good point, there was a dragracing car in the sixties that used compressed air. Remarkably quiet, for drag race.

    Link to this
  10. 10. virtualend 6:12 pm 02/6/2014

    I realize this article and comments are more then 2 years old – but I just stumbled across it when doing a Google search for something else.

    I also saw a very similar photo of a bike from many many years ago. The article it was posted on did not know what the purpose of the flywheel was, and dismissed it as an apparent lost cause.

    “Moustachioed gent on fly-wheel equipped bicycle
    This image from the Bike Culture archives has us scratching our heads.”

    Looks like the revival of this idea finally paid off for someone after all.

    Link to this

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