COSMOS bicycle
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Richo 18
Likes Bikes and Dirt
Please correct me if I'm wrong, because I'm pretty sure I am, but I thought...
It's hard to get the right wording for it, I know there's an theorem for it.. but basically,
the amount of energy you put in is proportional to the movement/distance travelled. Like, it doesn't matter what gear you are in, it takes the same energy to go 100 meters from a static start regardless?
If that is incorrect, then is it something to do with the whole.. work=distance travelled against gravity... (or something to that effect)
????
Educate me
Cheers
It's hard to get the right wording for it, I know there's an theorem for it.. but basically,
the amount of energy you put in is proportional to the movement/distance travelled. Like, it doesn't matter what gear you are in, it takes the same energy to go 100 meters from a static start regardless?
If that is incorrect, then is it something to do with the whole.. work=distance travelled against gravity... (or something to that effect)
????
Educate me
Cheers
tu plang
knob
yeah basically work done (or energy used) is the integral of force over the trip. that means if you use a small gear you have a small force integrated over a large number of revolutions through which you apply that force. inversely for a large gear you apply a large force but require fewer revolutions. in the end you use the same energy if all else is equal.
you loose energy through friction primarily, that in bearings and that with the ground and due to wind. hence thin tires and tight clothing to reduce the latter and now we are seeing ceramic bearings for the former.
you loose energy through friction primarily, that in bearings and that with the ground and due to wind. hence thin tires and tight clothing to reduce the latter and now we are seeing ceramic bearings for the former.
Dumbellina
Likes Dirt
No you're kind of right:
work = force x displacement (distance moved) (Newton.metres)
force = mass x acceleration (Newton's second law) (Newtons)
acceleration = change in velocity/change in time (or it can be gravitational acceleration, 9.8 m/s^2 )
work = mass x change in velocity/change in time x displacement
= mass x change in velocity squared
which is simplified to:
energy (kinetic) = 1/2 x mass x velocity^2 (Joules)
--------------------------------------------------------------------------------
Ceramic bearings save friction by staying rounder longer than steel balls, because they are materially much stronger. Steel balls get deformed under stress loads which means they don't rotate smoothly in the cup/cone. Deformed balls loose energy by having to use energy to overcome the "flat" spots. Similarly ceramic linings in cups/cone prevent pitting which affects smoothness.
As to how much energy they save. I think that's moot because most riders replace steel balls regularly before they rob too much energy (well most riders should!), ceramic balls last a lot longer. So its in the long term reliability and savings department that ceramic balls glow.
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tu plang
knob
hmmm theres figures out there somewhere, for anything but time trials and maybe tri its a pretty trivial saving. having spoken to people runing them though, the superficial difference is meant to be very noticable (ie smoothness of BBs and wheels.)
aah while that is right dumbellina, what he said wasnt really anything to do with instantaneous kinetic energy,
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Dumbellina
Likes Dirt
It is kinetic energy - the potential energy (chemical) in the muscles leading to muscle extension/contraction (kinetic), which is transmitted through the pedals to the cranks, into the chain, into the rear wheel, which is then transmitted to the road. The wheel exerts a force on the road, the road applies an opposite and equal force on the bike (and rider), and because of the mass differential the bike move forward, accelerating and increasing velocity (which means their kinetic energy is increased).
The amount of energy used to move forward and increase your velocity is the same, the gears merely mechanical advantage by increasing the torque you are applying on the rear wheel.
Torque (rotational force) = force x distance (from the centre of rotation)
In respect of bike gears - distance is based on the ratio of teeth on the front sprocket and the rear sprocket - or in simple terms the distance one rotation of the chainring causes the rear cluster to rotate. See bike mechanic books that usually have a table of torque "distances" in "gear inches" if from the US.
The energy savings purported in the new pedalling method regarded the efficiency losses in the transmission of energy from cranks to chain. But the "engineer type" was right in saying that the efficiency gains over the standard crank set-up were uncertain.
The old shimano biometric chainrings still used by George Hindcappie (the only one to still use them) offered to increase the efficiency in the same aspect of energy transmission at the "flat spot in the pedal stroke. Other designs allege to offer similar efficiency gains.
But the inventor didn't even say how his invention improved on those anti "flat" spot devices, or that this was the efficiency that he was seeking to gain.
An inventor with an invention that may work, many electrical inventions such as Thomas Edison's many inventions, but no real "benefit" was provided or proven.
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tu plang
knob
yes, i know. the explaination is unnecessery. my point was that he was eluding to the concept that whether you go fast or slow, it still requires the same amount of energy. neither of you explainations explain that very succinctly.
with reference to you last comments, im almost sure he didnt know what problem he had specifically solved or what he had even set out to solve. im surprised it made it onto the show quite honestly.
with reference to you last comments, im almost sure he didnt know what problem he had specifically solved or what he had even set out to solve. im surprised it made it onto the show quite honestly.
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Matt H
Eats Squid
In the '07 dirtworks catalogue there's a company who claims 2-4% more efficiency from ceramic bearings, or as they said "20-40m further every KM" which is a fair amount when you think about it.
chadly1084
Likes Bikes
I watched this show an found it kind of cool, my thoughts were that this bike is either completely ridicules or way ahead of it's time.
Another thought i had was that this guy may be smarter than we think. If he is developing this technology primarily for an internal combustion engine that will improve the engines efficiency by however many percent, Than maybe he just mocked up a silly looking bike with similar technology on it. Put it on the new inventors show to attract interest from car companies and governments so he can get grants and sponsors to develop his idea. If this idea really saves petrol and he already has it patents on it the dude can make lots of money out of the silly bike he has mocked up.
just a thought......
Another thought i had was that this guy may be smarter than we think. If he is developing this technology primarily for an internal combustion engine that will improve the engines efficiency by however many percent, Than maybe he just mocked up a silly looking bike with similar technology on it. Put it on the new inventors show to attract interest from car companies and governments so he can get grants and sponsors to develop his idea. If this idea really saves petrol and he already has it patents on it the dude can make lots of money out of the silly bike he has mocked up.
just a thought......
tu plang
knob
valid thought however, internal combustion engines have been around for a couple of hundred years. as it stands they are limited by thermodynamics, not mechanical design. you can guarantee everything has been tried once. He briefly mentioned some stupidly high compresseion ratio engine they had running but everything has moved away from high compression ratios.I watched this show an found it kind of cool, my thoughts were that this bike is either completely ridicules or way ahead of it's time.
Another thought i had was that this guy may be smarter than we think. If he is developing this technology primarily for an internal combustion engine that will improve the engines efficiency by however many percent, Than maybe he just mocked up a silly looking bike with similar technology on it. Put it on the new inventors show to attract interest from car companies and governments so he can get grants and sponsors to develop his idea. If this idea really saves petrol and he already has it patents on it the dude can make lots of money out of the silly bike he has mocked up.
just a thought......
Pete J
loves his dog
And todays useless science award goes to:
http://www.neodymics.com/
http://www.neodymics.com/
