What elements of bicycle efficiency have been utilised in other machines?

[mart]

The humble bicycle has been described as the most efficient machine in the world. What aspects of this efficiency (if any) has been replicated in other machines?

There are some interesting stats in the link below. For example, the train is more efficient than a horse. The horse does not require the same level of servicing like a train does, unless you live in Wales.

Horse & rider: 10 Kcal/km per person
Train & riders: 30 Kcal/km per person

The number of riders on the train to make the above calculation is not stated. However, I would imagine that if the train is running at 50% of passenger capacity, then the efficiency figures must reduce.
http://www.exploratorium.edu/cycling/humanpower1.html

 

[slim_boy_fat]

10 Kcal/km per person

Are these figures available for the humble bicycle?

 

[hotrodder]

Figures for a bicycle (at 3 different speeds) are in the link but you need to read the chart properly... horse and rider isn't stated to be 10Kcal/km, it says a horse and rider at 10mph gets through about 275Kcal/km per person. Given they're using both mph and km, don't say how many people are on the train or how weight* effects things i wouldn't put too much faith in their numbers...

I doubt the bicycle is responsible for lending anything particular efficient to other machines? More a case that the bicycle is comprised soley from efficient designs and was got 'right' very early on... the spoked wheel, frame comprised of triangles etc the properties of which were already known about?

* weight of the cyclist (heavier cyclists use more/are less efficient hence all the top climbers being tiny compared to sprinters) or whether the horse rider is a skinny jockey type or an American etc

 

[mart]

I didn`t read the graph correctly . However, putting a line down the graph from train & riders, a train travelling at 30mph uses just over 100 Kcal per person per Km according to this data. I get your point about weight and number of passengers. I imagine they are using averages for the weight. As for number of passaengers, I would guess the train would be at it`s most efficient (in terms of Kcal per person, certainly in terms of £££) when full to capacity.

Although not practical to do, I wonder how mush electricity could be generated from say 6 fit people pedalling stationary trainer bikes in frames with no additional resistance on the wheels other than the generating equipment.

I think the consensus of opinion is that you cannot get more power out of something than what you put in, in terms of energy, be it a power station/ inverter/oil based engine etc. Anyone know otherwise?

 

[wookie]

Apparently, a pro cyclist produces about 500w on a steep climb for a shortish period.

Record over an hour (from what I can find) is 430w/h.

Considering these are pro figures (obtained from bike mounted sensors) I'd say an above average fitness person could do maybe 2/3 of that.

Most people of average fitness will struggle to maintain only 1/3rd of what the pros can do, if you can do better than 1/3rd well done !

Back in the bad old days of the early 90's in the TdF when doping was the norm the elite were capable of sustaining above 500w, but when your blood is 60%+ red blood cells rather than the normal 40% high sustained power outputs are achievable.

But I find it interesting that today's pro-racers need to consume around 8000Kcal each day or more for a hard mountain stage to "fuel" their performance at a grand tour like the TdF and yet they still loose weight over the course of the 3 week race.

 

[wookie]

That's why I said above average fitness...

I know you said above average fitness, from what I've read on the subject they usually divide it up as follows...

Average fitness person = 1/3 of a pro cyclist's output,
Above average fitness = around 1/2 of pro's output,
Seriously fit amateur = 2/3 to 3/4 of pro's output.

All of which just goes to show how "elite" these pro riders really are, back when I was a lot younger and used to clock up a silly amount of miles on my bike (i.e. was proper fit) I could average 23-24mph for extended times (up to an hour), by comparison the top time trialists can achieve around 30mph for up to an hour whilst doing a time trial stage in the middle of riding a grand tour.

 

[wookie]

The cyclists made it faster than we could drive there (ok, we had traffic lights, roundabouts and stuff, but still).

I would've been happy to simply make it there

I know what you mean, I've watched the Tour of Britain go past a few times and each time their speed amazes me. You hang around for ages waiting and then boom in just a matter of seconds and the whole pack has appeared, ridden past and disappeared again, I can see why the mountain stages are so popular with spectators you get to see the whole race pass you slowly and you get to watch the action for an hour or more.

I want to ride up Alpe d'Heuz before I get too old and knackered just to experience a tiny bit of what the TdF is like.

 

[PhillipM]

The mechanical efficiency of a bicycle might be pretty good as all the forces are aligned, but overall efficiency is crap given you're sat up waving your limbs in the air, a good faired recumbant can double sustained speeds you can hold...

 

[Rig Pig]

If one bike is that good then how efficient is this beauty?

 

[wookie]

If one bike is that good then how efficient is this beauty?
View attachment 98475

That would be more impressive if the chain only powered the top bike and then each back wheel powered the next one down until it you get to the ground, no doubt the frictional losses would make it hard to pedal but still....

 

[Omniata]

What about the gears, and belt pulley systems in lathes and pillar drills?