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Crowd Funding For Crank Physics
BuzzSkyline writes "A new design for bicycle cranks violates basic principles of physics, but that's not stopping the inventor of Z-Torque cranks from trying to raise thousands in start-up capital through crowd funding." The picture looks intriguing for a fleeting moment before it looks silly. Covered in similar style at a site I'm glad to discover exists, the Bicycle Museum of Bad Ideas.
What are examiners for again ? Spelling mistakes ?
You seem to regard science as some kind of dodge... or hustle.
that it cannot be used to extract money from the gullible and hopeful -esp in America where the common man knows so much more than the engineer or the scientist...so in that sense it is a good idea just like all the weight loss and sex aid supplements you see on late night cable
-I'm just sayin'
...can quite comfortably fit outside it.
If computers were people, I'd be a misanthrope.
It's possible that by moving the pedal so the cyclist's legs are in a different position during the pedal cycle, it's possible that his muscles could more effectively power the pedals.
Except no change has been made to the pedal cycle...
One problem with long cranks and a low bottom bracket is the possibility of hitting your pedals on the ground during a turn.
This makes is worse by making it even more likely to hit the crank arm on the ground.
The alternative to limited government is unlimited government.
But the whole point is that as long as the crank is solid, its shape has no influence whatsoever on the transmission of force from the pedals to the gears. If the transmission of force between gears and pedals is identical, in turn, there is no possibility whatsoever of the layout having a physical (read: not "I have these magical cranks so I must pedal differently!") influence on the driver's posture.
Given this comment was made at all and subsequently upvoted, I suppose it's fair to say that even Slashdot is prone to falling for this...
I've seen this before a dozen times or more as an engineering consultant. Some crackpot inventor comes in for a consultation with an engineering idea that "will save the world"*, and they say it works great with the soda-bottle-and-silly-straw model they built of the idea in their bathtub. They have $4 million in investment lined up, and they ask me to work up the numbers to show the feasibility of the idea.
2 minutes later, after trying to explain to them the 0th/1st/2nd Laws of Thermodynamics and how their device can't work because it violates all of them, it degenerates into a shouting match where the inventor (with an on-line PhD in cosmetology or similar) now is trying to tell me how the 0th/1st/2nd Laws of Thermodynamics do not apply to their device. I wish them luck and then send them to the door.
I don't envy them, because their options are 1) somehow continue to snow the investors until they make a major ass out of themselves when demonstration day inevitably comes and/or 2) slowly come to the realization that the 0th/1st/2nd Laws of Thermodynamics DO apply to their invention and that they somehow need to backpedal (pun!) out of the situation.
I'm not against garage inventors, but I wish them the humility to take 30 minutes to get their ideas vetted by a professional in the field before they make asses out of themselves and many others. There are many areas in engineering where the legitimate ideas are getting drowned out by the noise made by the uneducated hucksters.
*actual phrase used.
It's possible that by moving the pedal so the cyclist's legs are in a different position during the pedal cycle
Doesn't work like that. Draw a crank like this on a piece of paper, jab a pen through the point where the crank would connect to the gear and rotate the paper: you'll quickly notice that the thing still follows the exact same circular motion as any old, regular crank does, and therefore the legs don't actually assume any different a position during cycling. If the crank was displaced from the center then there would be a difference as it would no longer follow the same path as a regular crank, but alas, that's not the case here.
An analysis, found on their webpage:
http://www.z-torque.com/Portals/6/DrHuangReport.pdf
Claims that the benefit is from two side effects of the claim:
The increased mass gives a flywheel effect, meaning the pedal goes through top dead center easier.
The long shape bends under pressure, which does slightly increase the length of the arm under pressure.
So, by going to carbon fiber (lighter, and most likely stiffer), they'll most likely negate any benefits!
> so the cyclist's legs are in a different position during the pedal cycle
Only because of the bending. If it were stiffer, position would be exactly the same.
No, it's not possible. During the whole pedal cycle, the wheel is evenly in contact with the ground and the gears are in even contact with the chain. Throwing the angle on there doesn't put the rider's legs in a different position any more than rotating the existing cranks would because the "cycle" still results in the completely circular wheels and gears being in the same place. Simple physics is exactly why this can be dismissed.
"this can't be dismissed just because simple physics says that it has no mechanical advantage."
Are you high?
That's exactly what you can do. The whole point of this is that despite how the bar is shaped the pedal has NOT moved in relation to the crankshaft. If you DID move the pedal, that could make it more effective. It's called "a longer crank". Problem is your pedals tend to hit the ground if you do that.
> have to do more work in order to do a single revolution.
It's inertia. It's not wasted. It'll create a force when the pedal decelerates. Since you always want the pedal spinning, this isn't so bad for cruising. It's only bad for transients, which this would help smooth out.
> related to pedals having 2 moments of inertial.
Would be no different than a straight pedal with more mass on the end.
A variable length crank that grew longer or sorter and avoided ground contact would be a wonderful way to over engineer a bicycle.
You seem to regard science as some kind of dodge... or hustle.
Can I get twice the funding?
Automatically?
I think: "TIME CUBE"!
"Flyin' in just a sweet place,
Never been known to fail..."
but all it does is move TDC 20 degrees along the pedal cycle
No, it doesn't. The forces involved at the peddle and at the crank are identical to those if it were a straight connection. The only difference is the shape of the metal piece connecting them. TDC is in exactly the same place as it would be if there was a straight piece of metal connecting the peddle to the crank.
Who is John Galt?
Manual of Patent Examining Procedure; 706.03(a) Rejections under 35 USC 101 III A rejection on the ground of lack of utility is appropriate when ... (2) an assertion of specific and substantive utility for the invention is not credible. Such a rejection can include the more specific grounds of inoperativeness! Such as inventions involving perpetual motion.
You seem to regard science as some kind of dodge... or hustle.
If this crank extends the diameter of the rotation
Just making the crank longer would do that. The shape bears no effect on the diameter of the rotation as long as the distance between the pedal and the axle stays the same. The shape would only bear an effect if the crank dynamically changed shape during the rotation, but alas, this is a fixed construct.
You decide.
A bicycle is a simple machine. Simple machines work by reducing the force necessary to complete a task. This is mechanical advantage. For a bicycle this mechanical advantages are created by the radius of the pedel and the ratio of the gears, usually with a big gear radius in front, and a smaller gear radius in back. To start the ratios are larger, then can become smaller as the bike accelerates.
There is another thing. The effective force is only the component that is perpendicular to the direction of motion. That why you normally start with the pedals parallel to the ground, and the rider pedaling straight down. With normal pedals, the force is transmitted directly to moving the crank. With this style, some force is always going be expended torquing the z pendal, which will eventually lead to the seam to fail.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
Yeah but the inertial difference would be some infinitesimal amount. Way to small to notice. The real problem is that this design in going to suffer huge stress at the points of the Z so if our intrepid rider is into mountain bikes he's going to break this thing about 4 weeks after he starts using it at precisely the worst possible time to have you crank break (while standing on your peddles on a steep climb.)
All you have to do to blow this out of the water is ask him why there isn't a curlicue wrench to give you more leverage in a tight place... not like we haven't been using wrenches for a while. This is a profound DUH, and no magic fairy dust nor faith in a loving deity will wash the stink of stupid off it. Sorry.
Oh come on. I'm not giving my money to anyone who can't write a sentence.
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Any problem can be made unsolvable if there are enough meetings made to discuss it.
I always slow way down when the guy up front is farting. Don't have to breathe as much of it that way.
Trust me, when you are constantly breaking wind
If you are constantly breaking wind you should either change your diet or go see a doctor.
this can't be dismissed just because simple physics says that it has no mechanical advantage.
Actually, that's exactly why it can be dismissed. It's nonsense.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
If you read one of the papers, from Florida Atlantic University, referenced on the site, the author claims that the advantage comes from an 'intrinsic favorable flexure mode." Basically, he is saying that the flex at the joint of the Z shape creates a smoother ride and higher torque at specific angles (not peak torque however).
While I find it unlikely that the effect is as positive as stated in the article, it is plausible that there is a small second-order effect due to non-rigid behavior of the crank. It is claimed in the article that this effect was tested independently, however I can't see how a flex in the pedal would produce any other effect than to steal energy away from the peddler.
Besides, if you want more torque while biking, just use clip-ins.
Just take a look at those infomercials that try to tell you that 1) for your entire life you've been wobbling around about to fall over
The solution to that is to become a Weeble, because Weebles wobble but they don't fall down.
The Z-crank doesn't work due to basic mechanics. The various warp-drive and wormhole designs are usually not provably impossible, though it is very unlikely that they work (due to quantum effects), and require material (negative energy density matter) that probably can't exist in the required densities, and typically need engineering on a difficult to imagine scale.
One measly zig? That's not going to efficiently couple my torque rotation constant. I want a crank with a minimum of five zigs and, for fuck's sake, a bare minimum of *three* zags... and that will be the "intro" model. The "pro" crank will come with seven zigs and five zags. The "custom" option will end the zigzags with a loop.
Throw in enough, and the bike will basically pedal itself. All I need to figure out now is how to perfect my shake weight handlebars. Still having problems with the braking on those things.
How is this different from alleged gurus claiming that foo-oriented programming is a silver bullet and selling books, seminars, special languages, methodology consultants, and so forth without first having objective evidence?
It's not just bicycles.
Table-ized A.I.
And they go to extreme efforts to reduce it. Muscle strength spent flexing the crank is wasted.
Same thing for crank weight. They go to extreme lengths to shave grams off their bikes, and even more to reduce weights of moving parts.
The idea that this is a great, new, magic crank because it's flexible and heavy is ridiculous!
Prediction for end of Universe #42: Fencepost error in Quantum_bogosort.cpp
The increased mass gives a flywheel effect, meaning the pedal goes through top dead center easier.
[...]
So, by going to carbon fiber (lighter, and most likely stiffer), they'll most likely negate any benefits!
Here's the thing: carbon fiber does not have to be stiff.
You can go out today and buy carbon fiber leaf or coil springs.
carbon fiber cranks are nothing new to the (off)road bicycling word.
And haven't you heard about the amputee athletes who run on carbon fiber legs?
But the main reason for using carbon fiber is lighter weight, and if your system depends on extra rotating mass,
then there's absolutely nothing to be gained by making the crank out of super light carbon fiber.
If Mr. Z-Crank wants springier, he can just choose a different metal alloy and keep the same mass.
[Fuck Beta]
o0t!
Oh, the test was successful. More exactly, the test was successful in proving that it doesn't work. :-)
The Tao of math: The numbers you can count are not the real numbers.
FTL and warp drives are an open problem with no good designs in mind. This pedal is a specific design which obviously does not work.
This inventor has apparently managed to duplicate the invention of medieval alchemists: Transmuting gullibility into gold.
And if he won't listen to his Wyse friends, they should DEC him.
Never answer an anonymous letter. - Yogi Berra