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The world's fastest human-powered vehicle tops 85 mph

engadget.com

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Re: The world's fastest human-powered vehicle tops 85 mph

#101

Post by canistr »

sandworm101 wrote: post #20

Typical Canadians. Their country's flag is smaller than the GMC logo. I hope someone from UofT alumni relations gives them a call. If you are going for a speed record, you need something more like this: http://cdn.rsvlts.com/wp-content/uploads/2014/02/olympics-sk...

I agree. If you read a tech article with MIT/Harvard/Stanford Alumni, you can be sure they'll mention it front and centre.

Meanwhile, whenever I notice something with a Canadian origin, I usually have to dig pretty deep before I figure out which university it's from.

Re: The world's fastest human-powered vehicle tops 85 mph

#102

Post by jacorreia »

x0054 wrote: post #86
sandworm101 wrote: post #28

So my question is now: In terms of aerodynamics, what aren't they doing? Some commentators have noted that the shape of this bike is just about as good as it can get. The rider/engine is also not going to see any vast improvements. So rather than this become a pure athletic event, where can engineers look for improvements? Will they have to start dealing with boundary layer issues? Will the next generation of bike be…

Does it have to be a bike? What about a rowing rig, where you can leverage the powerful muscles in your back and upper body?

Contrary to what it might look like, rowing is almost entirely dependent on your legs, your arms/back merely keep the momentum going at the back of the stroke. Also, the muscles in your back are nowhere near as strong/large as the muscles in your legs, there's nearly a magnitude of difference. Though if you added power from your arms in addition to fully utilizing your legs (it would be much harder to concentrate) then there would be a benefit. But then you run into how to engineer such a thing, especially with respect to aerodynamics.

Re: The world's fastest human-powered vehicle tops 85 mph

#103

Post by Gravityloss »

jdietrich wrote: post #84
sandworm101 wrote: post #28

So my question is now: In terms of aerodynamics, what aren't they doing? Some commentators have noted that the shape of this bike is just about as good as it can get. The rider/engine is also not going to see any vast improvements. So rather than this become a pure athletic event, where can engineers look for improvements? Will they have to start dealing with boundary layer issues? Will the next generation of bike be…

The majority of the drag affecting a modern HPV racer is caused by the wheel aperture. Perfectly fitting the fairing to the tyre isn't practical, due to flex in the wheel and the tyre casing. Managing airflow around this gap is a largely unsolved problem. Some improvements could be made by reducing the rolling resistance of the tyres or the efficiency of the drivetrain, but this will have only a relatively small impa…

this is very interesting. What if the vehicle flew in ground effect (small retractable wheels for takeoff)? You'd also need a propeller for propulsion. You'd drive off the road easily though.

Re: The world's fastest human-powered vehicle tops 85 mph

#104

Post by giarc »

thearn4 wrote: post #100

I've met with some of the guys from Aerovelo and done a little bit of collaboration with them. They're top notch, and an all-around awesome team of engineers. And Todd is a beast (watch the Atlas human-powered helicopter video).

Video https://www.youtube.com/watch?v=syJq10EQkog

Re: The world's fastest human-powered vehicle tops 85 mph

#106

Post by mapt »

mxfh wrote: post #92
mapt wrote: post #76

Earlier quoted context omitted.

You've got it reversed. Weight shouldn't have as much of an impact on acceleration because as muscle mass & power goes up, weight goes up as well. But more weight inside the shell doesn't increase air resistance, while it does increase power. So a heavier rider with greater sustained power output will, in an environment where wheel friction is trivial, go to a considerably faster top speed on flat ground.

Did anything happen to F = m × a in the last 20 years? Acceleration a is heavily dependent on the mass m. Since a = F / m having half the mass would result in double the acceleration with same amount of force F available.

The same amount of force F is not available.

If they're putting athletes into this thing, the bigger the athlete, the more force (okay, the more power) is available for propulsion. They have bigger muscles which store more glycogen and have greater total mitochondrial activity, because there are simply more of these cells available to do the work.

Re: The world's fastest human-powered vehicle tops 85 mph

#107

Post by dasil003 »

Asbostos wrote: post #98
dasil003 wrote: post #10

> The WHPSC is basically where cyclists put their knees where their mouth is, and attempt to beat the record for pedal-powered speed. This is truly an epic pun, I'm duly impressed.

Could have done better using "feet" :P

No, that's the beauty it. When you tuck for aerodynamic efficiency your knees come very close to your mouth.

Re: The world's fastest human-powered vehicle tops 85 mph

#108

Post by tracker1 »

Semiapies wrote: post #17
drpgq wrote: post #8

I wonder why for fastest human-powered they don't use more than one cyclist. I assume with eight humans like in rowing you could get up to a ridiculous speed. Might be a little dangerous though.

This isn't horribly safe, either. Wiping out at 85 MPH would suck . I'm curious what multi-cyclist vehicles could do, now that you suggest it. With the lightness of these vehicles, at what point would you have to add spoilers?

I think the shape would change dramatically for such a thing... it would probably be pretty good at 3-4 cyclists and have a shape closer to the solar car challenges for a more optimum output... There would of course be additional weight to overcome. But it would be interesting.

Re: The world's fastest human-powered vehicle tops 85 mph

#109

Post by QuotedForTruth »

SeanLuke wrote: post #72
QuotedForTruth wrote: post #5

I wonder how much impact a professional track cyclist would have. Im sure the current pilot is a strong rider, but if you got a world record sprinter into the world record bike, how fast could they go?

A professional track cyclist would be quite inferior to these riders. These aren't some average Joe riding here: they're they best high-performance cyclists in the world. For example, this particular record was long held by Sam Whittingham: I invite you to see his Wikipedia entry. https://en.wikipedia.org/wiki/Sam_Whittingham

He's obviously very very strong. I'm sure the riders all the teams select are amazingly strong riders. They aren't, however, gold medal caliber track cyclists. The men with the strongest legs in the world. There is much more prestige and money in winning a track cycling medal than setting a record in human powered vehicles.

Im simply wondering, what happens if they get the best of the best. With proper time to adapt to the vehicle, its probably worth a few mph. Not too significant, but enough to reset the record.

Re: The world's fastest human-powered vehicle tops 85 mph

#110

Post by SeanLuke »

QuotedForTruth wrote: post #109
SeanLuke wrote: post #72

Earlier quoted context omitted.

A professional track cyclist would be quite inferior to these riders. These aren't some average Joe riding here: they're they best high-performance cyclists in the world. For example, this particular record was long held by Sam Whittingham: I invite you to see his Wikipedia entry. https://en.wikipedia.org/wiki/Sam_Whittingham

He's obviously very very strong. I'm sure the riders all the teams select are amazingly strong riders. They aren't, however, gold medal caliber track cyclists. The men with the strongest legs in the world. There is much more prestige and money in winning a track cycling medal than setting a record in human powered vehicles. Im simply wondering, what happens if they get the best of the best. With proper time to adapt…

> They aren't, however, gold medal caliber track cyclists.

Correspondingly, gold medal track cyclists aren't world record setting performance cyclists.

These tasks demand somewhat different skill sets, and at this level, "somewhat" is a big deal. There's a reason why the "top" track cyclists don't hold any of these records.

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