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The world's fastest human-powered vehicle tops 85 mph
- carlhu 11y agoThe video ends with a brief second where the cyclist explains what prevented even higher speed. I make out: "too much vibration...", "knees rubbing...", "unable to continue increasing power output". Would love to hear more about this.
- QuotedForTruth 11y agoNote the video was from last year when they failed to set the record. This year they've done it. They probably will release a video of this year's efforts eventually.
- bjourne 11y agoI believe it is because the vehicle is very aerodynamically unstable. When you ride a normal upright bike, it will fall over unless you actively spend a little effort balancing it. Here is a video of a crash: https://www.youtube.com/watch?v=i5Dapy1xUq0 https://www.youtube.com/watch?v=i5Dapy1xUq0 Note how it wobbles to the right when he pushes the right pedal, then to the left when the left pedal is pushed.
- trevorcreech 11y agoHere's the current video of them actually beating the record: https://www.youtube.com/watch?v=33clAZoaLWs https://www.youtube.com/watch?v=33clAZoaLWs
- irl_zebra 11y agoI'm guessing something can't get much more aerodynamically shaped? I wonder if they used a power meter to measure the driver/rider's power output and whether the driver was an accomplished cyclist. It seems that at this point, it would simply be a matter of getting a stronger cyclist, say someone like Brad Wiggins who can push 430 watts for an hour over an amateur, but still respectable rider, who puts out something more like 250 watts for an hour. The article states that riders have 5 miles to speed up before they cross the speed trap that measures. Assuming the average speed of the whole endeavor is, say, 60mph, you would want a pro time trialist who excels at hard 5-minute efforts. This chart[1] states that a world class cyclist should be able to put out 7.5 watts/kg for 5 minute efforts. Brad Wiggins weighs 77kg, so I guess theoretically he should be able to put out 577 watts, versus a "good" with the same weight who might "only" put out 350 watts in the same 5-minute period. I would be very interested to see what would happen if you simply replaced the 85mph rider in the submission with Brad Wiggins. [1] http://d4nuk0dd6nrma.cloudfront.net/wp-content/uploads/2009/07/powerprofiling.jpg http://d4nuk0dd6nrma.cloudfront.net/wp-content/uploads/2009/...
- luminiferous 11y agoI would imagine that power to weight ratio is more important than just the power. Also the smaller the cyclist, the smaller they can build the aerodynamic shell, thus reducing drag.
- irl_zebra 11y agoActually, on a flat surface with a constant speed or acceleration, weight matters much, much less than frontal area. Weight comes into play much more when many quick accelerations or elevation gains come into play. Because frontal area doesn't increase proportionally with weight, I would argue that power output should be the primary concern and that typically increases substantially with weight. For evidence of this, look at world class time trialists versus world class hill specialists. Fabian Cancellara [1] is considered one of the top time trialists in the world at 181 lbs as he can put out much more absolute consistent power than someone like Nairo Quintana who is considered one of the world class climbers and weighs 128 lbs, [2] even though Nairo Quintana may have a better power:weight ratio. [1] https://en.wikipedia.org/wiki/Fabian_Cancellara https://en.wikipedia.org/wiki/Fabian_Cancellara [2] https://en.wikipedia.org/wiki/Nairo_Quintana https://en.wikipedia.org/wiki/Nairo_Quintana
- QuotedForTruth 11y agoTrack sprinters are even bigger, further showing your point. Chris Hoy is 205 lbs.
- davidw 11y agoExactly. https://en.wikipedia.org/wiki/Tony_Martin_(cyclist) https://en.wikipedia.org/wiki/Tony_Martin_(cyclist) weighs in at 75 kg - lighter than Cancellara - but not that light for a professional cyclist either.
- mxfh 11y agoWas wondering the same since, this is about top speed and not about acceleration the weight shouldn't matter much at all, since it has no direct influence on the air resistance. Would be interested in knowing, if a human powered vehicle on steel rails with steel wheels with the same air resistance could be faster than this just due to the lower rolling resistance.
- QuotedForTruth 11y agoI 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?
- SeanLuke 11y agoA 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 https://en.wikipedia.org/wiki/Sam_Whittingham
- QuotedForTruth 11y agoHe'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.
- SeanLuke 11y ago> 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.
- QuotedForTruth 11y agoWhat I'm saying is that that reason most likely isn't lack of physical ability, but lack of ever trying. Why would they when they are chasing olympic medals and making way more money than would earn setting these obscure records?
- drpgq 11y agoI 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.
- darkstar999 11y agoWould the multiplied power be offset by the multiplied weight and potential loss of aerodynamics?
- davidw 11y agoAs someone wrote above, weight doesn't matter that much, and since the most likely configuration would be one behind the other, the aerodynamics wouldn't suffer that much.
- QuotedForTruth 11y agoMax speed has very little to do with weight as long as you have sufficient room to accelerate. Additional drag would be small if you put one rider in front of the other and both inside of a fairing. The frontal area and shape could stay the same. This is the major source of drag. There would be small amounts of additional drag from the air running along a longer fairing, but doubling the power would more than make up for it. However, the speed would nowhere near double. Power required to overcome drag force is related to velocity cubed. So if you double power, the velocity will increase by a factor of (2)^1/3 or the cube root of 2, 1.259. So if they added another rider of equal power and managed to keep drag the same (it would actually increase a little) they'd go around 25% faster or 107 mph. You may run into other problems like stability and bumpiness first though.
- dasil003 11y ago> 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.
- sandworm101 11y agoTypical 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-skeleton-helmet-pic-2-642x396.jpg http://cdn.rsvlts.com/wp-content/uploads/2014/02/olympics-sk...
- daddykotex 11y agoAs a Canadian, I can relate, but I'm still amazed by all the flags I see when I come down the border!
- darcyparker 11y agoI am a proud Canadian who lives in the USA and have a little Canadian sticker on my car. It's my little shout out to other Canadians on the road. I guess we're quietly showing our pride to others. Being loud about it is not in our nature. But I do like that luge helmet :)
- sandworm101 11y agoIt's not luge. When the idiot goes head-first they call it skeleton.
- darcyparker 11y agoThanks - I never noticed the difference.
- canistr 11y agoI 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.
- sandworm101 11y agoSo 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 covered in golfball-like holes to reduce turbulence?
- deleted 11y ago[deleted]
- Calcite 11y agoI found out they have great Q&A videos on their YouTube channel. They answer here why golf ball dimples are unnecessary for a fin-like shape. https://www.youtube.com/watch?v=ZXpZy_A7mMk https://www.youtube.com/watch?v=ZXpZy_A7mMk
- sandworm101 11y agoGolfball-like dimples are only half my question. In aircraft much work has been done on reducing boundary layer issues with suction holes that actively remove turbulent air. Some aircraft engines, the SR-71's in particular, do this to ensure 'clean' intake air. Subsonic: http://www.dtic.mil/dtic/tr/fulltext/u2/274329.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/274329.pdf Supersonic: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060022120.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2006002...
- Raphmedia 11y agoSpeaking of the SR-71, you guys should all read the heavily reposted stories about it. It's such an amazing plane. While it's not flying in the sky anymore, it deserves to fly in our imagination every time somebody speaks about it. http://oppositelock.kinja.com/favorite-sr-71-story-1079127041 http://oppositelock.kinja.com/favorite-sr-71-story-107912704...
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- tsumnia 11y agoWhile watching this, a thought occurred in my head: for these types of challenges, are the participants tested for PEDs and such?
- zyb09 11y agoPicture on top has new Google logo on it, video at 3:49 shows old Google logo on the vehicle.
- cubix 11y agoThat video is from last year's attempt.
- tangled 11y agoI'm guessing that the rules prohibit using some of the pedal power to charge a battery during the initial part of the run, and then using that stored energy to provide an additional speed boost :D
- sandworm101 11y agoI don't see why not. The initial run is essentially the storing up of momentum. From that, running up a flywheel inside the bike is just storing the same energy in a different place.
- kazinator 11y agoIt stretches the concept of "human powered". Why not just pedal while stationary to charge a battery (take as long as you like), and then ride the course with no additional expenditure of effort.
- tangled 11y agoBecause then you would be bringing additional stored energy into the competition (beyond what's in your body)?
- aninhumer 11y agoWell, the course is a 5mile run up to a 200m speed trap. So if you allow batteries/motors, you could just sit stationary somewhere in that 5 miles pedalling for a while, and then use electrical acceleration to get up to speed for the trap. You're not bringing any additional energy, but its clearly not in the spirit of the challenge.
- jfoutz 11y agoThe d&d fan in me thiks falling is a free action. A human powered plane doing a dive would go faster I'd bet. Not prepared to rules lawyer that case though.
- MrBra 11y agoWhat software solutions are there that could be used to simulate mechanics and physics (including gravity, friction, ...) in order to prototype, say, a human powered heli_thing? :) No, I'm serious.
- trevorcreech 11y agoThey just posted the video where they actually beat the record: https://www.youtube.com/watch?v=33clAZoaLWs https://www.youtube.com/watch?v=33clAZoaLWs
- revelation 11y agoSeems like they could get an extra 10% by simply going to a higher track. Mexico City is popular at 2250m of altitude..
- brandmeyer 11y agoAlso less oxygen for the cyclist.
- revelation 11y agoThe body will naturally produce more red blood cells at altitude so while there is a performance hit, it is mitigated. Also, the crucial power here is anaerobically produced anyway. If must be, I think the rules don't forbid an oxygen tank.
- songgao 11y agoI was gonna say this makes me realized just how aerodynamically inefficient a regular bike is, but then I found out that the world record of cycling on flat surface is actually 83.13 mph [0], which is actually pretty close to this. Assuming the rider is also top notch, I guess the benefit from optimizations done on aero isn't much larger than the weight added. [0] https://en.wikipedia.org/wiki/Cycling_records https://en.wikipedia.org/wiki/Cycling_records
- joe_the_user 11y agowikiepedia doesn't check it's own references. The speed is for a human powered vehicle (fully fared). Edit: All the flat records in the section you're referencing are for hpvs, not tradition bicycles, as a look at the pages of the riders will show. See: https://en.wikipedia.org/wiki/Sebastiaan_Bowier https://en.wikipedia.org/wiki/Sebastiaan_Bowier https://en.wikipedia.org/wiki/Barbara_Buatois https://en.wikipedia.org/wiki/Barbara_Buatois
- songgao 11y agoThanks for pointing that out!
- SeanLuke 11y agoIt's interesting to note that this record was once again set along a very specific stretch of highway in Battle Mountain, Nevada which is prized for its near perfect flatness and is often used for human-powered vehicle record attempts.
- paulgerhardt 11y agoThe course is not perfectly flat, but it is perfect for the contest. The rules for this event stipulate that the track cannot be slopped downhill by more than 0.66%. Conveniently this track averages 0.64% downhill over the entire 5 mile duration. [1] The story about how Raymond Gauge (what an aptronym!) happened to find this particular stretch of road makes for it's own fascinating big data tale. Months of mining away on USGS tables with Celeron processors to get 10 suitable tracks. A documentary made a few years back went into the specifics with plenty of dramatic shots of him driving the lonely stretches of Nevada, New Mexico, Kansas, etc whittling down his choice candidates until he settled on Battle Mountain. The biggest limitation in these events is air resistance. Plenty of other folks have gone significantly faster on bicycles not facing a headwind[2]. Altitude helps. [1] http://www.recumbents.com/wisil/whpsc2015/whpsc_site.htm http://www.recumbents.com/wisil/whpsc2015/whpsc_site.htm [2] 207.9 mph - https://en.wikipedia.org/wiki/Cycling_records#Speed_record_on_a_bicycle https://en.wikipedia.org/wiki/Cycling_records#Speed_record_o...
- mikeryan 11y agoInteresting that for land speed records you generally need to do two passes of a course one in each direction and your speed is an average of the two passes in order to prevent these types of shenanigans ;-) https://en.wikipedia.org/wiki/Land_speed_record https://en.wikipedia.org/wiki/Land_speed_record
- deleted 11y ago[deleted]
- rdlecler1 11y agoSo let me get this straight, WeChat and other major companies are downloading pirated Xcode software which has malware?
- christianmann 11y agoA swing and a miss. You might try again, on a different story. This doesn't seem to fit here.
- nstart 11y agoI'm curious as to how that comment even ended up here :S
- ak39 11y agoThis is probably the few projects in life where you can say you've challenged your mind just as much as you've done your body. And one can see the impact of both of these in these young and beautiful "geeks". What a project it must be to work at - beautiful minds and beautiful bodies. And the happiness shows. :-)
- ohazi 11y agoI'm a little surprised nobody has mentioned the opaque fairing, visibility, or the camera. At first I thought it might be to keep the weight down, as there are plenty of composite materials that are lighter than (even thin) plexiglass. But then there's the weight/complexity of the camera, display, and battery. Then I thought, well, the rider in in such an odd position, maybe he wouldn't be able to see very much even if there was a window. But apparently the actual reason is that the rider produces so much heat that a window would fog up, and it would be too difficult/unsafe for the rider to wipe it. Given the white coloring, I suspect they're also trying to avoid cooking their human power source. Here's part of a Q&A where they discuss visibility: https://youtu.be/mscVAb1VZJw?t=271 https://youtu.be/mscVAb1VZJw?t=271
- PetitPrince 11y agoFor those lazy to convert that's 137.94 km/h . That's just above most of the world's road speed limit.
- ching_wow_ka 11y agoThat's interesting. Any source? I live in the northeastern part of the United States and it's rare for me to see a speed limit above 65 mph.
- Symbiote 11y ago120km/h looks like the typical global speed limit, but I haven't calculated it. It includes China, India, Brazil, several countries in the middle east and Africa. https://en.wikipedia.org/wiki/Speed_limits_by_country https://en.wikipedia.org/wiki/Speed_limits_by_country
- silverlight 11y agoHere in the Midwest we have several highways that are now 75.
- amelius 11y agoThis reminds me of the Flintstones :)
- thearn4 11y agoI'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).
- giarc 11y agoVideo https://www.youtube.com/watch?v=syJq10EQkog https://www.youtube.com/watch?v=syJq10EQkog
- sergers 11y agolast night they broke their own new record, "On Friday evening, Sept 18th, Todd set another record at 86.50 mph"[1] [1] http://www.ihpva.org/home/?view=plink&id=21 http://www.ihpva.org/home/?view=plink&id=21 (the site of the competition that engadget links to)