Mando's chainless e-bike is headed for Europe in 2013 (w/ Video)

Oct 11, 2012 by Nancy Owano report

(Phys.org)—Car-choked city streets are inspiring adults to get on a bicycle for local transport. Reasons range from ecology to economy in getting around. Korea-based auto part maker Mando is unleashing the next step up in cycling, a chainless electric bike called Footloose. Sleek minimalist, Apple-evocative design, with technology combined, the Mando is a clear moving target for a mobile, Starbuck-struck generation of twenty-somethings. Mando has been showcasing the bike this year, and its bike is due to hit the marketplace in Europe next year. The company has combined a throttle drive with pedal-assisted technology, This is a chainless bike that trend-watchers are calling the "i-Phone of cycling."

The bike has a hybrid drive system. By pedaling, mechanical energy transforms into electricity. The bike uses a . A key feature about the bike is that it does away with the bike chain; it converts a rider's pedaling to electricity; the rider is the human "generator." can power the bike up to 30 kilometers (18.6 miles) with the motor alone or they can use the pedal for more range. By adding battery energy, the standard range of 30 kilometers can be increased, say enthusiasts, to become a "light e-scooter."

According to the press statement, the Footloose hybrid drive system brings power directly to the drive wheel. When you pedal, transforms into electricity and feeds the e-bike battery. Using a throttle, the motor drive can be controlled.

This video is not supported by your browser at this time.

The Footloose takes cues from with its Electronic Control Unit (ECU), which works with integrated sensors. The sensors recognize speed and slope. The rider can take advantage of an automatic gear changer to monitor terrain and adjust the motor's output as needed. A detachable (HMI) display can go up on the handle bar to display information such as distance traveled, speed and amount of electricity produced.

Another key point being promoted is that it folds up neatly. The bike is a collaborative effort of Mando and Meister. They also called on British designer Mark Sanders and Dutch e-bike expert Han Goes. Sanders describes the look as "clean like the latest smart phones, with powerful technology hidden inside." The resulting design was officially introduced at a show earlier this year and there are plans to have the bike on the European market by 2013.

This video is not supported by your browser at this time.


Explore further: Imaginative ideas for a 'greenlight district' in Amsterdam

More information: www.mandofootloose.com/

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Egleton
1.6 / 5 (14) Oct 11, 2012
Chainless not brainless. About time somebody took bicycles seriously.
Now to make them recumbent and loose the traditional upright hobby horse foolishness.
The hobby horse pose derives from the the original envy of people who could afford a horse.
The recumbent presents a much smaller cross-sectional area to the airflow. Aerodynamics 101.
antialias_physorg
4.5 / 5 (11) Oct 11, 2012
The recumbent presents a much smaller cross-sectional area to the airflow. Aerodynamics 101.

I do love recumbent bikes, but they're not good for most use cases. For everyday use there are other considerations besides aerodynamics.
In cities you need:
1) Stability at low speeds - for you to be able to balance properly you need a significant vertical distance between your center of mass and that of the bike. For recumbent bikes that isn't possible. (alternatively you can add a third wheel but that increases friction, drag and mechanical complexity as well as your horizontal footprint)
2) At intersections your ability to view traffic is extremely bad with recumbent bikes. You have to shove half your body into the intersection before you can see anything (conversely you're much less visible to cars.

Visibility in general: On a normal bike others see your head poking over parked cars befory you reach an intersection. Not so on a recumbent bike.

210
2.3 / 5 (9) Oct 11, 2012
Chainless not brainless. About time somebody took bicycles seriously.
Now to make them recumbent and loose the traditional upright hobby horse foolishness.
The hobby horse pose derives from the the original envy of people who could afford a horse.
The recumbent presents a much smaller cross-sectional area to the airflow. Aerodynamics 101.

The 'old' bike design had and maintains many positives. In traffic a person seated on a reclined bike that you favor, is a lot less visible. Also, their own ability to see, especially in congested traffic suffers greatly. Yes, your favored bike has a small drag coefficient, but, that old style machine U disparage allows the rider to use gravity 2 enhance torque & ones own weight aids the machines power curve. Further, for those suffering lower back ailment, the old style bike offers therapy & is doctor recommended. The seated bike adds stress to the lower back, like sitting always does, but does provide good aerobic depth.
word-
roboferret
5 / 5 (5) Oct 11, 2012
It would be interesting to know how the efficiency of the drive train compares to a traditional chain drive.
Deathclock
2.6 / 5 (10) Oct 11, 2012
There is no way that that is more efficient than a direct drive, you must have to pedal twice as much or more to go the same distance...
ECOnservative
1.6 / 5 (7) Oct 11, 2012
I viewed an almost tragedy recently when a recumbent bike had just crested a hill and a motorist coming from behind didn't see (or understand) his mast with a flag on it. Stopped barely in time. Recumbents are cool - they just have some visibility and low-speed stability issues. I also like the view from my bike being at normal eye level.
El_Nose
3 / 5 (6) Oct 11, 2012
i hat e recumbent bike -- i think they are horrible -- if they were a serious way of travelling their would be recumbent races -- Lance armstrong does not use a recumbent bike
Sonhouse
3.5 / 5 (2) Oct 11, 2012
Anyone hear the price? BTW, Lance is not likely to be riding again any time soon, he is now charged with not only taking steroids, but supplying them as well.
antialias_physorg
3 / 5 (4) Oct 11, 2012
i hat e recumbent bike -- i think they are horrible --

If you have a good bike lane infrastructure (no potholes, long stretches where you can cover largeish distances of a few kilometers at a time without stopping/intersections) they're great. I have a 20km trip to work each way and if I ever find a path that fulfills those criteria I'll splurge for one.

For city traffic they're too dangerous (IMO). For exploring the countryside they're completely unusable. So I'll not get rid of my other bike in any case.
88HUX88
4.6 / 5 (5) Oct 11, 2012
no-one has mentioned conversion efficiency, with a derailleur you get ~98% of the energy from your input at the pedals to the tyre on the road, I wonder what this is? The weight is not mentioned either, you may be able to fold it but it's to go into the boot of a car, you wouldn't lug it around town.
Still anything that gets people on bikes is a good thing.
Scottingham
5 / 5 (2) Oct 11, 2012
I wonder how fast it'd go under pedal power alone...I'm thinking slow to not at all...
HeloMenelo
1 / 5 (7) Oct 11, 2012
This looks like fun, what i'd like to see next is bigger wheels, a more sporty look, however i like the 5 spoke wheels with the mono fork, looks sweet, basically a mountain bike version would be so irresistible. Then spice up the power system somewhat, and you'll have a million happy customers. :)
Jeddy_Mctedder
1.9 / 5 (9) Oct 11, 2012
electric pedal bikes---if you wanna see the future, look at the present, china is making them by the millions. all the delivery guys in nyc use them. this is where the real world applications of pedelecs are heading.

it's beautiful to see new ideas in cycling tech. there must always be a competiiton of ideas and designs for there to be a result that 'wins'. this doesn't mean the losers are bad, just that they didn't get popularized to mass production.

unfortunately it is all too easy to see why this idea won't get mass produced. basic chain and gears work better than any other config for the human power part of the equation.
antialias_physorg
5 / 5 (3) Oct 11, 2012
you wouldn't lug it around town

The point is driving it around town, isn't it?
TrinityComplex
3.7 / 5 (3) Oct 11, 2012
With regard to the efficiency, think about this: You can allow the battery to take you 30 kilometers, pedaling lightly the entire way to go farther, or plugging it in to charge it at the destination. The primary purpose of most e-bikes is transportation, not fitness (go for a conventional bike if fitness is the goal), and rarely are bike commuters going more than 30 kilometers in one direction. I am curious about the conversion efficiency, but I think it would have to be very low indeed to make it undesireable. I also wonder if it has any kind of regenerative braking. The website unfortunately offers no information.
packrat
1.5 / 5 (8) Oct 11, 2012
Just another overpriced piece of crap that can't be repaired without costing an arm and leg. It's nowhere as efficient as a regular bike and never will be. The only positive things about the bike is that it folds up and can easily be put in a car and it is electric so if you don't want to get sweaty riding somewhere you don't have to. There are many other better designs for the same capability already on the market.

@El Nose ...... recumbent bikes are not allowed in races with regular bikes because they are faster than the regular ones. You have much more power using your leg muscles with a recumbent that you get from gravity. Recumbents were banned from regular bike racing early in the 1900's. Most people don't know it but recumbent bikes and trikes have been around as long as the upright two wheel "safety style" (what they were originally known as) bikes that everyone thinks is the standard design now.
tk1
not rated yet Oct 11, 2012
I can't imagine the pedaling part is energy efficient. This is converting mechanical energy to electrical energy then back to mechanical energy.

That being said, I almost want one. I have ridden my bike to work, six miles, well within the range of this bike. The thing is my ride is up hill to work, takes a bit more than 40 minutes to work and about thirty to home.

Would be interested in the price.
VendicarD
1 / 5 (1) Oct 11, 2012
Almost all positive.

Very good. Very good indeed.
ScooterG
1.5 / 5 (8) Oct 12, 2012
I can't imagine the pedaling part is energy efficient. This is converting mechanical energy to electrical energy then back to mechanical energy.


I've always heard you lose at least 25% whenever you convert from one energy to another.

This bike might create a lot of un-necessary CO2 (ie global warming). Typical - solve one problem, create three others.

Sanescience
1 / 5 (4) Oct 12, 2012
I've seen plans for Chinese public induction charging stations for electric assist bicycles. Everyone is afraid that China will have the same car ownership per person numbers and The US. I doubt they would be that dumb.
ScooterG
1 / 5 (8) Oct 12, 2012
Everyone is afraid that China will have the same car ownership per person numbers and The US. I doubt they would be that dumb.


Not everyone is afraid of the Chinese owning cars. The only people who purchase cars are the people who can afford them. Are you against economic prosperity and economic development?
ricarguy
1.6 / 5 (7) Oct 12, 2012
A bike with regen braking and that folds up are nice features, but...
How much does it cost and how much does it weigh?
Oh, and how much are the replacement Li batteries once these go bad in ~5 years?

Chances are I'd be much happier sticking with my 20 year old 10 or 12 speed chain bikes.
Mike_Massen
1 / 5 (6) Oct 12, 2012
ScooterG shows narrow uneducated mindset with
..The only people who purchase cars are the people who can afford them. Are you against economic prosperity and economic development?
The point is considerable amount of resources mostly unsustainable in traffic & putting out more CO2, water vapour, Ozone & SO2. Do you think the Earth can take this load for long without there being effects in an essentially closed climatic system?

We are already close to peak oil, which mostly has higher radioactivity than normal background, are you not able to imagine how much more unpalatable the environment will be with so much more thorium & other radioactive nucleotides should China come close to USA burdened level of car usage ?

So many more people suffering with cancers from radiation from coal, gas/oil not to mention nuclear accidents, how does your deity sustain the universe again - please explain ?

Do you think your deity is going to ameliorate AGW with direct interception - if so how ?
ScooterG
1 / 5 (7) Oct 12, 2012
The point is considerable amount of resources mostly unsustainable in traffic & putting out more CO2, water vapour, Ozone & SO2. Do you think the Earth can take this load for long without there being effects in an essentially closed climatic system?

We are already close to peak oil...


So you would somehow lock down the people of the world so they do nothing that might increase their CO2 output? Should you be denied if you wish to upgrade your car from a 6-cylinder to an 8-cylinder? Should you be denied the right to purchase a car for your daughter's graduation gift?

Or is it a race thing, where you just don't like the Chinese? or would you -say- deny blacks the right to drive any ICE-powered vehicle?

You're a typical, uninformed, angry liberal - Hell bent on controlling other people's lives.

Re peak oil: the sooner we consume the world's reserves of oil, the sooner we'll move on to the next energy source. Burn baby burn!
Mike_Massen
1.1 / 5 (8) Oct 12, 2012
ScooterG mumbled STUPIDLY
..lock down the people of the world so they do nothing that might increase their CO2.. Burn baby burn!
Sigh, please understand:-

1. You have quoting tags back to front & sometimes totally misapplied.
2. You are arguing from against a position you guess I 'might' be taking, that just makes you look immature & foolish.
3. Its not hard to extend your intellect & use my post as a foundation to move forward positively.
4. Never said it would be appropriate to deny anyone.

Obviously declining oil reserves, burning millions of years of fossil fuels in a few centuries is harmful.

The obvious thing to do is:-

a. Before fossil fuels run out, use them to shift to a different energy paradigm
b. Make effort to increase education on a much larger scale

Alternate energy paradigm probably includes:-

i. Biological fuel
ii. Significant Electrical infrastructure
iii. International energy trading scheme

Claimed deities can't educate, only nature & humans can !
Egleton
1.6 / 5 (7) Oct 13, 2012
Hmm. I learned something.
Well, there you go. Thanks fellas.
packrat
1.6 / 5 (7) Oct 13, 2012
A bike with regen braking and that folds up are nice features, but...
How much does it cost and how much does it weigh?
Oh, and how much are the replacement Li batteries once these go bad in ~5 years?

Chances are I'd be much happier sticking with my 20 year old 10 or 12 speed chain bikes.


I hate to tell you this but regen on a bike is almost worthless. The vehicle is not heavy enough to make it work correctly. I've already seen too many people try it. It simply doesn't work.

A good set of modern lithium batteries should last more than 5 years if taken care of properly. You should between 7-10 years use out of them.

Cost for replacing batteries? about $600 at the moment for the range they are talking about

You can take any decent made bike (even walmart versions) add a 500w rear hubmotor and 10amp 36-48 volt lithium battery set for about $1000 to get a nice ebike for about $1500 total with better range capabilities. I bet this bike sells for 2-3 times that much.
packrat
1.5 / 5 (8) Oct 13, 2012
A bike with regen braking and that folds up are nice features, but...
How much does it cost and how much does it weigh?
Oh, and how much are the replacement Li batteries once these go bad in ~5 years?

Chances are I'd be much happier sticking with my 20 year old 10 or 12 speed chain bikes.


I hate to tell you this but regen on a bike is almost worthless. The vehicle is not heavy enough to make it work correctly. I've already tried and seen too many other people try it.

A good set of modern lithium batteries should last more than 5 years if taken care of properly. You should between 7-10 years use out of them.

Cost for new batteries? About $600 at the moment for the range they are talking about

You can take any decent made bike (even walmart versions) add a 500w rear hubmotor and 10amp 36-48 volt lithium battery set for about $1000 to get a nice ebike with better range capabilities. $300 cheaper if you use lead acid batteries but they only last about 2 years in use.
packrat
1 / 5 (5) Oct 13, 2012
The difference between to two messages there on the !500 versus 1000 was I didn't add the cost of the bike in the second message - It wouldn't let me edit the first one.
HeloMenelo
1.5 / 5 (8) Oct 13, 2012
Maybe change the frame shape so one could add more batteries and do away with the peddling, there are motors/esc combination which would make this thing really scoot.

Also by the time batteries need to be replaced, we'll be able to add super caps. If not much better batteries anyway,

And that's when the real fun would start !
Simonsez
5 / 5 (2) Oct 13, 2012
trend-watchers are calling the "i-Phone of cycling."

That's great and all, but based on experience I think I'd rather wait for the superior "Samsung Galaxy of cycling."
Eikka
2 / 5 (4) Oct 14, 2012
It would be interesting to know how the efficiency of the drive train compares to a traditional chain drive.


If you bother to maintain your bike, it's about 95% versus 55% so it's like riding a really really rusty old bicycle without the electric assist on.

The reason why it is that inefficient is because of the low speed and small size of the generator, which cannot be more than 75% efficient over its operating range. The motor controller and the motor itself have similiar issues.
VendicarD
1 / 5 (1) Oct 14, 2012
True. Slugs and worms and other invertebrates seem completely unconcerned by the prospect.

"Not everyone is afraid of the Chinese owning cars." - ScooTard
Mike_Massen
1 / 5 (5) Oct 14, 2012
Tut Tut Eika made yet another generalisation
The reason why it is that inefficient is because of the low speed and small size of the generator, which cannot be more than 75% efficient over its operating range. The motor controller and the motor itself have similiar issues.
Care to explain why a low speed generator cant be more than 75% you sound quite sure ?

Switching electronics these days have quite low losses, from DC conductance losses to less than 0.1 Ohm at 30Amps to AC impedance losses of 5 times still means losses are rather low. What is the source of your claim the motor controller has 'similar' issues which imply similar to an efficiency of only 75% ?
IanC1811
3.7 / 5 (3) Oct 15, 2012
A few comments:-
The power available from the human body is almost (but not quite) independent of things like orientation (upright vs supine) and pedaling cadence. Limiting factors for any individual include ability to dissapate heat, ability to prevent metabolytes building up in muscles and ability to remove CO2. Muscles recover more between contractions if they relax completely between contractions. On an upright (conventional) bike muscles relax each pedal stroke and the power leg lifts the relaxed leg. On a recumbent if the muscles relax totally the knee drops and locks so muscles can never be allowed to relax totally. Power output on a recumbent is slightly lower than on a conventional bike. On flat roads the wind resistance advantage of a recumbent is great enough to more than compensate for the lower power. On long uphills recumbents are at a distinct disadvantage. Continued .....
IanC1811
4 / 5 (2) Oct 15, 2012
... Continued from above.
The ease of balance for a bicycle is proportional to the height of the centre of gravity above the sideways pivot point, (the ground). The higher the easier. (Very tall stilts are very easy to walk on!)
The rules of bicycle racing restrict the design of the bike and the position of the rider for a range reasons including political and commercial reasons. If recumbents were allowed, they would be used in races like time trials on flat ground, but not in the Grand Tours.
A good clean bike chain is about 98% efficient in transferring energy. No other mechanical or electrical arrangement comes close to this. The losses in a generator, battery and motor system will be significant compared to this. A 90% generator, 99% battery and 90% motor is an 80% system. To the best of my knowledge there are no generators and motors that good yet.
packrat
1.1 / 5 (7) Oct 15, 2012
@IanC1811 I'm sorry to tell you this but the only things you got right in those two messages were the fact about the less wind resistance and the electrical parts.

Power output on a recumbent is not less than a conventional bike and a rider in good shape on a recumbent two wheeler or 3 wheeler is going to beat a equivalent rider on a conventional bike. As far as bike races go, recumbents consistently average faster speeds than a regular bike except on something like a dirt track as recumbents are not made for that type riding. It's for good reasons that a recumbent in a fairing is the fastest pedal bike on the planet.
Eikka
2 / 5 (4) Oct 15, 2012
Care to explain why a low speed generator cant be more than 75% you sound quite sure ?


Because generating voltage with a low speed generator is difficult, and because it has to be small it cannot have very large inductors, which means you're drawing out power at low voltage and high current through thin wires. That's a receipe for low efficiency.

Low efficiency is a problem in small electric motors and generators in general. It's incredibly difficult to manufacture one that has both high specific power and high efficiency.

Nevertheless, even if we assume that the motor and generator are each 90% efficient, the system still has 4-5 times the energy loss compared to simply oiling your chain every now and then.

Of course you might use a planetary gearbox to spool the generator up, but that gives you a flywheel effect on the pedals due to its inertia, and the gearbox has to tolerate massive torque from your feet. That's why hub-gears in bikes don't last very long.
Eikka
2.4 / 5 (5) Oct 15, 2012
Care to explain why a low speed generator cant be more than 75% you sound quite sure?


And as for the motor, that too will almost never get run anywhere near its nominal design speed in a bicycle, which means it rarely reaches its peak efficiency. Electric motors aren't the same at all speeds. Even in electric cars, the best you can realistically hope for is around 85% average efficiency, and the smaller the motor, the more problematic it becomes.

Pedaling to drive a generator to charge a battery to drive a motor is just a very silly way to implement a bicycle.
Eikka
2 / 5 (4) Oct 15, 2012
For example: http://solarledwi...tor.html

The nominal speed of that generator is 380 RPM. The nominal efficiency at 380 RPM is stated to be 86% and the nominal power is 200 Watts. A person can temporarily output more than a kilowatt, but such a generator would be even more implausible in a bicycle.

While 380 RPM sounds fast compared to a cyclist at around 60 RPM, this is in fact a low speed generator; it's a disc design which mitigates some of the issues with low shaft speeds by having the magnetics on a larger diameter wheel to get them to move faster.

That's how things are at this scale. 85% for the generator, 85% for the power electronics, 85% for the hub motor, and suddenly you have just 60% of your power left at the wheel - in the ideal case.
Mike_Massen
1 / 5 (5) Oct 15, 2012
Eika as before only offers vague generalisations and nothing definitive.
Because generating voltage with a low speed generator is difficult, and because it has to be small it cannot have very large inductors, which means you're drawing out power at low voltage and high current through thin wires. That's a receipe for low efficiency.
Amazing, it took you 3 full posts and yet you still couldnt get to the point re 75% being some sort of upper limit YOU decided !

Fact is I have seen low speed alternators of > 94% efficiency giving 400W at less than 300rpm, not hard.

There are only 2 things stopping high efficiency in either alternators, generators or motors these are:-

1. Quality of engineering design

in conjunction with

2. Budget

In other words, if your target is high efficiency it can be achieved at a cost subject to quality of engineering design.

As we know from history, once there is a critical mass of demand, costs in a production environment can lower significantly.
packrat
1 / 5 (4) Oct 15, 2012
@Mike_Massen
Just WHERE can you find a 3-4" diameter generator that runs at low speed and puts out >94% efficiency? Me and a whole lot of other people would like to know. If your talking about axial alternators used with wind turbines which are about the only ones I can think of that run at such low speeds you are comparing apples and oranges here. The diameter makes a REALLY BIG difference on those. I've built them from 3-14" inches and anything under about 6" has to turn much faster than that small gen on that bike is going to be able to spin with someone pedaling it even though it's geared up. Eikka is correct in what was posted and neither quality of design or budget can beat the basic laws of physics.
Mike_Massen
1 / 5 (4) Oct 15, 2012
packrat mumbled
Eikka is correct in what was posted and neither quality of design or budget can beat the basic laws of physics.
BULL !

Why are you pretending to be an idiot by twisting (equals lying) the words to argue against an idea I DIDNT propose and Eikka was simply guessing and simply so, nothing definitive !

"Engineering Design" means issues of combinatorial logistics in respect of identifying and managing losses - work out where they are and 'manage' them, please dont be obtuse or pretend to be an idiot, one doesnt have to break the laws of physics to approach good design ugh and GUH, save me from amateurs !
packrat
2.3 / 5 (9) Oct 15, 2012
Well since this amateur is a professional engineer and has been one for about 30 years now and have been building both e-assist bikes and wind turbine alternators of all sizes for the last 15 of those years, I suggest the next time you feel someone is mumbling maybe you should try cleaning your ears out first. I didn't "twist" any of your words. I did ask for where a generator or alternator that small could be got with an efficiency rating that high and instead of answering the question you just start insulting me which is quite typical of of armchair engineer that doesn't have the vaguest idea of what they are talking about....
Mike_Massen
1 / 5 (5) Oct 15, 2012
Packrat claimed
I didn't "twist" any of your words.
Liar, whats this then ?
neither quality of design or budget can beat the basic laws of physics
Implying I must be breaking some laws of physics, Packrat further grumbled
I did ask for where a generator or alternator that small could be got with an efficiency rating that high
And I answered:-
"1. Quality of engineering design
in conjunction with
2. Budget"

But, you want me to spoon feed you, not my job.

Packrat continued grumbling
and instead of answering the question you just start insulting me
So when I said "issues of combinatorial logistics in respect of identifying and managing losses".

Did you take this on board instead of knee jerk reactions ?

Do you know how to:-

i. Identify losses, whether DC or AC ?
ii. Manage losses by changes in materials or topology ?

As I say, I have seen AND tested the alternator as per my earlier post and it came up at just over 94%, not my design unfortunately but, it works.
packrat
1.6 / 5 (7) Oct 15, 2012
Nobody asked you for any spoon feeding.... lol.... the only thing I asked you was to come up with a link or some info on this 'magic' small diameter slow speed alternator of yours which you still haven't done. You also seem to have a problem with reading simple english as I told you I've been an engineer for over 30 years which mean yes I do know how to do measurements and material design. Quite frankly, I really would like to see a small diameter generator that works at 94% at slow speed and puts out enough current to operate a motor on a pedal bicycle. That means it needs to put out at least 250watts at 24,36 volts or higher to even be useful for a bike unless a person only wants to ride at about the same speed or only a bit faster than a mobility scooter.
Mike_Massen
1 / 5 (6) Oct 15, 2012
packrat complained as if to goad me
Nobody asked you for any spoon feeding.... lol.... the only thing I asked you was to come up with a link or some info on this 'magic' small diameter slow speed alternator of yours which you still haven't done.
Surely its obvious to any moderately intelligent engineer there is no link, the person in question has decided not to publish.

In respect of design "All engineers are not created equal", so my best advice is reconsider your implicit assumptions and you might well (independently) arrive at the same design paradigm that allows relatively high efficiency at low speed where cost (of a prototype) is not the primary (limiting) factor.

Cheers

Eikka
2 / 5 (4) Oct 18, 2012
Fact is I have seen low speed alternators of > 94% efficiency giving 400W at less than 300rpm, not hard.


300 RPM is still you pedaling 5 revolutions a second. Way way too fast for a cyclist. The only way I'm willing to believe that claim is if you have a gearbox between the input shaft and the rotor, and even then it's a very very tall order.

packrat complained as if to goad me


You're being an incredibly condescendig twat again. He's only asking you to prove your rather incredible claim, because it seems to me and pretty much everybody that you have the burden of proof when you claim that such things exist.

And even if NASA or someone else can come up with such a device, do you really think it means you could afford to put one in a bicycle? No, the reality of the matter is that small alternators and motors are not all that efficient.
Eikka
2 / 5 (4) Oct 18, 2012
For a typical example of real world low-speed altearnators:
http://www.pmgene...cy-tests

The alternator tested was rated at 750rpm. We required the efficiency not only at the rated speed but also at half speed and the customer's cut-in speed. At the rated rpm, the PMGL alternator achieved 95% efficiency. At 400 rpm it was over 90% efficient and at 200rpm, it was 74%.


Even if you can achieve 94% at 300 RPM, you're not getting it at 60 RPM. It is massively difficult to make a direct-drive generator work at any efficiency with speeds low enough for a bicycle.

In the example, the generator achieved 74% at 27% of the rated speed. Similiarily, if the generator is rated to 300 RPM the speed of 60 RPM is just 20% of the rated speed and thus is likely to do even worse.
Mike_Massen
1 / 5 (4) Oct 18, 2012
Further to my last comments, which people cant seem to read such as my being too subtle with Eg. "..as if to.." ;-)

Surely its obvious to any engineer whether 'professional' or not that if you WANTED to maximise efficiency of an alternator for a specific rpm & power range it would be a straightforward matter but above all, tempered by costs, whether prototype or some production batch size, as well as other standard issues...

So to imply, in any way shape or form, that high efficiency at say 60rpms is somehow not achievable is sheer idiocy UNLESS some have been down that path with a certain minimal amount of focus, intelligence, effort & application in conjunction with the various criteria matched to a goal.

Start with assumptions (but be honest) with diligence, then go on to the methods of identification/testing of losses but, realise these are not trivial exercises & relate that to topology & be prepared to 'think outside the box'.

Thats it, enough from me on this topic.

Cheers
antialias_physorg
1 / 5 (1) Oct 18, 2012
It looks as if they did look at the efficiency issue, with some surprising results

http://www.hupi.o...015.html

(Go to the efficiency section. Important: Read ALL of it before jumping to conclusions. The point about peak and optimal power are interesting and should mirror most people's experience - especially under non-flat terrain conditions and/or variable wind conditions)

For a more in depth analysis this seems to be worth a look:
http://liggecykel...rive.pdf
packrat
2 / 5 (8) Oct 20, 2012
The big problem is people can't put out enough power to make it really worth while without a battery in the middle between those pedals and the motor. You can extend the range by helping to charge the battery but the 200 or less watts most people are capable of won't push a bike very fast by itself. Probably about 10-12 mph max on flat pavement with a lighter weight rider. It's really a manually chargeable fold up electric scooter and not a bike. Mount it on a v stand at home - pedal to charge it up - then scooter along..... It would make a great exercise machine by itself and you could use the power to charge other batteries or to run something else. That would make it a bit more useful.
TrinityComplex
not rated yet Oct 22, 2012
Simply add a USB charging port to the bike to connect other devices? Sounds like a pretty cheap, but useful addition.
antialias_physorg
1 / 5 (1) Oct 22, 2012
You can extend the range by helping to charge the battery but the 200 or less watts most people are capable of won't push a bike very fast by itself

I dunno. On ordinary bikes people put out the same power. And with those 100/200 watts you con go quite fast.

Remember that these bikes can also be recharged at home (i.e. you start off with a lot of energy in the batteries.) They are meant for smallish trips to work or shopping - less than 20km or so each way - not for excessively long biking tours. They are meant as an alternative to taking your car - not as a replacement bike for people who already use bikes.
packrat
2 / 5 (8) Oct 22, 2012
@antialias physorg I've been riding and custom building power assisted recumbent bike and trikes for about 10 years now. 200 watts equals out to the average rider pedaling about as fast as they can go. Almost nobody puts out that amount of power for any time except in racing. The average power is less than 100 watts. A 200 watt motor will push a bike about 10-12 mph and that's it. I know a number of people that use their assisted bike now instead of a car. Some like me no longer even own a car. I use my trike for all my transportation needs and 20Km won't even get me across town and back. My range is over 50 miles and I have a small engine assisted one that has a range over 125 miles.

While you are somewhat correct the many people only use them as an alternative to their cars for short trips there are many of us out here that use them for everything. I have 3 different trailers I use and one is used to haul heavy stuff like appliances which I have moved for people.
TheGhostofOtto1923
3.5 / 5 (19) Oct 22, 2012
BTW, Lance is not likely to be riding again any time soon, he is now charged with not only taking steroids, but supplying them as well.
-And thereby proven spectacularly how steroids can be used to safely extend fitness and performance.

I suggest an Unlimited Olympics, sponsored by some despot on some island nation somewhere, where jacked-up extremophiles can compete with no fear of drug testing. Would Fox air it? They could dedicate it to lyle alzado.

And then we could see what you mere mortals are really afraid of.
TheGhostofOtto1923
3.2 / 5 (20) Oct 22, 2012
Well since this amateur is a professional engineer and has been one for about 30 years now
Yeah mikey seems to have a problem appreciating the value of engineering.
Why are you pretending to be an idiot by twisting (equals lying) the words to argue against an idea I DIDNT propose
-as well as an underdeveloped command of the English language.
Thats it, enough from me on this topic.
-Lost again, eh dude?
If recumbents were allowed, they would be used in races like time trials on flat ground, but not in the Grand Tours.
Recumbents ARE being used for racing with impressive results;

"Over distances recumbent bicycles outperform upright bicycles as evidenced by their dominance in ultra-distance events like 24 hours at Sebring"
antialias_physorg
1 / 5 (1) Oct 22, 2012
many people only use them as an alternative to their cars for short trips

Which, I think, is already a big gain. As cars are pretty bad at burning their fuel for the first few miles until they get up to temperature - and the overwhelming part of trips taken are short range. And the bike in the article is definitely designed with that type of use in mind.

As for hauling freight. I do believe you use them for that, but I hardly think that that kind of use will be a mass market. I can see pizza delivery and the like using assisted bikes
packrat
1 / 5 (5) Oct 22, 2012
I doubt using a bike for hauling anything real heavy would get popular in this country either although it's commonly done over in China and other countries. We do have a company in Raliegh NC that uses Trikes with covered cargo beds for delivery vehicles. Kind of like the messenger bikes used in NY city but capable of packages also. It's going to take a while though before bikes in the USA really get popular for everyday transport because of the suburb situation. Most places are still farther away than many people are willing to go on a bike/trike. I don't think that's going to change until people are forced due to financial reasons. I.E. cars just too costly to operate for casual trips.
antialias_physorg
1 / 5 (1) Oct 23, 2012
The US market is probably not the target (as the heading implies). It's a British/Dutch collaboration designed for the European market (where distances are smaller)
TheGhostofOtto1923
3.3 / 5 (19) Oct 23, 2012
It's going to take a while though before bikes in the USA really get popular for everyday transport because of the suburb situation. Most places are still farther away than many people are willing to go on a bike/trike. I don't think that's going to change until people are forced due to financial reasons.
The divisions among different vehicle types continues to blur. We have I, 2, 3, 4, and more wheels, enclosed, partially enclosed, and open. More efficient and powerful energy sources will increase the trend.

Why pedal when one charge will last weeks? I know because the body needs exercise. I suppose we will fix that one day as well.