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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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"There's exactly 2cm of spacers between the top of the HT and my stem."

Which to my mind is a fair bit...



"During the season, I drop the spacers and race right against the top of the HT. I'll just note that the bottle I've designed works with this variation in mind (i.e. it's not 15cm tall). "

OK.

"Some riders will have no stack and others will have 4-5cm. Either way, the stem is still ~3cm tall and your arms are above that. "

Not necessarily.

"The air going around the stem and bars is just as bad (if not worse) than just going around a cylinder. "

Not sure how this is relevent, and your position (minus the fairing) seems to include both...


"Also note that this is a 1" HT (not 1 1/8") and you'd expect a proportional change to the drag given a wider HT. "

Sure. Again, relevence?

"I do plan on testing with the stem/bars in varrying heights due to stack -- I'll let you know when it's done. Should be interesting to see the change, but I really don't expect much of one."

OK - care to expand on this? What do you think is causing the reduction in drag you cite, and how would this be independent of positional changes that have a direct effect on airflow in the area of the bike you are manipulating with your fairing application?

Aren't you, in effect, replicating the design of, eg, a Look style front end, by fairing the stem area of the bike into the top tube?

"Just the way the cable housing bends when you move stuff around changes the drag a ton. It's really incredible. "

Yup.

"Thanks for the note -- I hope to give you more conclusive data in the future. "

You're welcome, and thank you.I look forward to the data.


.

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
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Re: Official MIT information thread. HOPEFULLY [rmur] [ In reply to ]
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-rmur

I hear you entirely -- Too much information often confuses more than it helps, but here you go: Our repeatability in the wind tunnel is very good. The wind tunnel test setup is fairly dialed and the balance gives us results with standard deviations around 1/100 of a lb (.01 lbs). This is after the wind speed is corrected to standard atmospheric conditions. Of course, once you pull a product out, get a rider back on the bike, etc, etc. you have introduced several variables. I got data within .03 lbs between different tests of the bottle (not back to back)...back to back tests were within .01 of a lb. These variations are usually more due to the rider slightly shifting in the wind tunnel. However, testing without an athlete would be completely useless.

I just want to reiterate to everyone reading this post though that wind tunnel time is super expensive and only so much time could be devoted to prototype testing. Once a production model comes out, I'll share more data with you all. That is my focus going forward and I really want to help explain more and more. At this point though, I'm not claiming I can save everyone in the world 2 minutes over 40km....I'm just saying that my prototype does that on my bike :) The final time savings may be more or less, but at least I'm trying to share what I do know. Only a few other people have done this testing on water bottles and it generally agrees with my findings.

One more quick thing too -- this is the only data I can show now, but let me reiterate that I've been testing products and athletes for around 4 years now. Though yaw data explains more about a product, understanding what you'll probably see in that yaw data is just as useful. If I spend 365 days a year testing and post all of that data, it doesn't make better products. I will focus on pulling together data and then using it in the most useful way: sharing it and then developing products that utilize the research time. It'll be a split going forward for sure.

Thanks everyone for reading and asking questions. It's good to see how many people really care about aero these days :)

Mark
markcote@mit.edu

--
Mark Cote
MITAerobike
Specialized Bicycle Components
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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This has been a great thread! Thanks Mark and all those involved for the thoughtful questions and incredible information. Amazing stuff here.

That's all, I'm not going to pretend I have anything to add...

Jim Manton / ERO Sports
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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Quote:
I hear you entirely -- Too much information often confuses more than it helps, but here you go: Our repeatability in the wind tunnel is very good. The wind tunnel test setup is fairly dialed and the balance gives us results with standard deviations around 1/100 of a lb (.01 lbs). This is after the wind speed is corrected to standard atmospheric conditions. Of course, once you pull a product out, get a rider back on the bike, etc, etc. you have introduced several variables. I got data within .03 lbs between different tests of the bottle (not back to back)...back to back tests were within .01 of a lb. These variations are usually more due to the rider slightly shifting in the wind tunnel. However, testing without an athlete would be completely useless.


okay taking 0.03 as the 'accuracy baseline' most of the differences noted were well above that 'noise' level. Speaking loosely here of course :)

thanks for the info ...

BTW, I figure your baseline position Cda is down around 0.225 ... purty slick.
Last edited by: rmur: Jan 29, 07 16:58
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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Mark-
Thanks for sharing some good data. I (and many others) enjoy triathlon as a training / tinkering hobby. I like to workout, and I like to tinker. aerodynamic concepts always seem like part voodoo and part science. I like hearing experience from someone spending time in the tunnel. Good luck with graduation and marketing your ideas.
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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Cool data. It would be interesting to see what happens if you get that Arundel closer to the seat tube. I have heard of people drilling out the carbon cage to get it closer so that its more of a fairing.

Your information has made me into a total aero weenie (ie the homemade front skewer that barely exists) Probably doesnt save me more than a 1/2 second but I like it. See below:




Plus it only weighs 16 grams :)


Dura Ace Baseline:

Jeremy

Want: 58cm Cervelo Soloist. PM me if you have one to sell

Vintage Cervelo: A Resource
Last edited by: jeremyb: Jan 29, 07 19:24
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Re: Official MIT information thread. HOPEFULLY [jeremyb] [ In reply to ]
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Jeremy,

What was the starting point of the skewers. I would like to see what they looked like before and after.

Thanks.
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Re: Official MIT information thread. HOPEFULLY [Bman] [ In reply to ]
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Mark,

Is there a reason you guys don't wear the "Bionic Wings" with your aero helmets?

Just wondering if you have tested to see if they actually make a difference.

Thanks!
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Re: Official MIT information thread. HOPEFULLY [cghebert] [ In reply to ]
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Hahahaha

Two reason:
1. When we got the helmets, we got some of the early ones before the "wings" were available.
2. For team time trial, communication is key and when we've tried ear covers in the past, we can hear each other yelling "On", "Gap", etc.

Aerodynamically, it would make sense that they would help, but I haven't tested them so idk for now.

Mark
markcote@mit.edu

--
Mark Cote
MITAerobike
Specialized Bicycle Components
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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I have a question for you about water bottles on a round seat tube. It has been written that you said it was faster to use a water bottle as to not. My question is, would I be better/faster to use a normal water bottle or an Arundel Crono water bottle?

Thanks for sharing your data with us.
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Re: Official MIT information thread. HOPEFULLY [jeremyb] [ In reply to ]
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I would like to see if someone could do a test to see how much a skewer actually affect the wind. Especially the front one.
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Re: Official MIT information thread. HOPEFULLY [Bman] [ In reply to ]
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...so we've got 4 pages of posting and STILL no pic of this magical freakin' water carrier. Is this a matter of national security of something? It never happened unless there are pictures, right??

________________________________________________________________________
"that which does not destroy me will only make me stronger" Frederick Nietzsche
andrew peabody
http://BREAKAWAYMULTISPORT.COM
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Re: Official MIT information thread. HOPEFULLY [andrew] [ In reply to ]
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You have to read the MIT post within the thread and you will get your answer.
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Re: Official MIT information thread. HOPEFULLY [andrew] [ In reply to ]
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why would he post a pic of something hes still developing until hes got it right and patented. :)
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Re: Official MIT information thread. HOPEFULLY [andrew] [ In reply to ]
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I HAVE read the entire thread, including all of the amazing claims, various descriptions, etc. With the just the info that's been passed around the internet forums, any enterprising person out there with visualizing skills and manufacturing capabilities could easily bring something to market in a minute if they wanted to. I would think that a patent would have been applied for well before building a prototype , or at least before publicizing it so much, and if patent is pending, a photo from the tunnel and some data to back up the claims is not an outrageous request. If I were developing something that could be so revolutionary, I wouldn't be talking so freely if I hadn't taken steps to protect myself.

________________________________________________________________________
"that which does not destroy me will only make me stronger" Frederick Nietzsche
andrew peabody
http://BREAKAWAYMULTISPORT.COM
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Re: Official MIT information thread. HOPEFULLY [andrew] [ In reply to ]
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There is a Patent Pending and I do have legal protection. If anyone would like to discuss this in a more direct manner, please contact me personally.

Mark Cote
markcote@mit.edu

--
Mark Cote
MITAerobike
Specialized Bicycle Components
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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[reply]
There is a Patent Pending and I do have legal protection. If anyone would like to discuss this in a more direct manner, please contact me personally.

Mark Cote
markcote@mit.edu[/reply]
Is this something that is even patentable? Is it novel? Not sure. This place - http://www.twofish.biz/bike.html - sells a bottle holder that can be mounted anywhere, including the top tube. The claim that the bottle improves aerodynamics can be universal. Too much upstream can affect overall rider+bike aerodynamics. While it worked for you, it is conceivable it may be of no aero benefit (or even an aero detriment) for another rider+bike due to completely different configuration changes. Just like some riders are more aero with elbows closer together than other riders, some helmets work better than others, etc.

The location isn't novel. Check the 2006 Marin Mount Vision - http://www.marinbikes.com/bicycles_2006/html/bikes/bike_specs/specs_mt_vision.html. While it's a mountain bike and not a time trial bike, I'd have to wonder if the precedence of that location will affect things.

Good luck with it, but it seems like it could be a difficult sell.


By the way, seems almost obvious which bottle this is (and you have to love the language) -

A sports bottle includes a generally cylindrical hollow vessel having a liquid chamber formed therein and a closed end bottom. The generally cylindrical vessel further defines a reduced diameter neck portion and an upper chamber terminating in an upwardly facing mouth. The upper chamber supports a porous antisplash element preferably formed of a coarse porous foam material plastic or the like. An elongated tubular straw extends from the bottom surface within the vessel upwardly through the neck portion and through the antisplash element and beyond the mouth to form an upwardly extending end which receives a flexible mouth tube which is preferably curved toward the user when the sports bottle is secured to a conventional bicycle. In alternate embodiments, the antisplash element within the upper chamber of the vessel is formed of a plurality of tubular members defining passages therethrough and grouped together to form a generally cylindrical multipassage combination. In still further alternate embodiments, a flexible planar member having a plurality of flexible generally triangular segments is secured to the mouth portion of the vessel to provide an antisplash element. In a still further alternate embodiment, a generally planar valve member is pivotally supported within the mouth portion of the vessel and is pivoted to an open position as liquid is poured into the vessel mouth.
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Re: Official MIT information thread. HOPEFULLY [tigermilk] [ In reply to ]
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Tigermilk, were there not three spoke plastic/composite bmx wheels before Dupont created the trispoke? Your being so picky for no goddamn good reason.

Your little soap box paragraph will unliely sway the U.S. patent office.

Way to go Mark.
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Re: Official MIT information thread. HOPEFULLY [Runless] [ In reply to ]
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Hell, if anything I gave some clues of things that could be similar so that he can build arguments as to why they are unique. As to why DuPont got a patent? Beats the heck out of me unless no similar patent existed or perhaps the novel concept was the process (the patent for the wheel does call out a fairly specific process).
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Re: Official MIT information thread. HOPEFULLY [tigermilk] [ In reply to ]
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Have any test been done on the NeverReach system? if so are the results significant in terms of time savings?
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Re: Official MIT information thread. HOPEFULLY [MITaerobike] [ In reply to ]
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Mark,
Thanks again for joining the thread. With regards to the wheel data. I read this originally in Bicycling magazine and was just amazed that wheels weren't more important. The "aero helmet more important than wheels" stuff just seemed crazy, but heck, I've got an open mind and this is fascinating stuff.
I do see from your data (in this thread anyway) that you compared Zipp 999's to Krysriums, not a traditional 32 hole wheel. Nevertheless, that little of a difference in drag will have us rethinking expensive wheel purchases.

A few important questions though:

1) Did you normalize for wattage output to spin the wheels? This has often been overlooked in testing(at least in the early days). Sure wheels have X lbs of drag compared to a static helmet, but how much faster do you go because of the watts available that you don't have to use to spin the wheel? John Cobb has talked about this and it's significant. It takes very little watts to spin a disk, and quite a few to spin a traditional wheel at 30 MPH through air. When it comes to wheels, we can't just talk lbs of drag and extrapolate to time saved. It's all about the watts. Frontal area at zero yaw and drag on the sensor is just one component.

2) Did you account for different yaw angles? Both drag and wattage to turn a wheel very sharply at yaw angles and this is where surface area wheels excel.


I applaud the research you guys are doing, but I think wheels are much more significant.

Quake
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Re: Official MIT information thread. HOPEFULLY [chewgl] [ In reply to ]
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In Reply To:
A bottle on the seat tube is not a very good place for the bottle (aerodynamically) actually; you're better off putting it on the downtube. It's probably easier to reach too.

- Guo-Liang


This is true. A bottle on the downtube or no bottle at all hardly makes a difference. It's one of those wonderfully inexplicable aero results, but it happens all the time. We did it once again with Frank Schleck in the tunnel, riding with a bottle on the downtube, then tossing it to the side and the drag hardly changes. It does however seem to be important that the bottle is not too close to the rider's feet.

But put one on the seattube and all hell breaks loose. Not a problem in training of course, but in racing keep it on the downtube only, or use a different hydration system altogether (ADS, behind the seat, Camelbak, etc).


Gerard Vroomen
3T.bike
OPEN cycle
Last edited by: gerard: Mar 17, 07 5:17
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Re: Official MIT information thread. HOPEFULLY [gerard] [ In reply to ]
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I've always found this John Cobb test informative:
http://www.profile-design.com/...s/water_bottles.html

The findings agree with your point in that down tube bottles are good, even better than no bottle. But seat tube bottles are also an improvement over no bottle, though not as good as a down tube one. However, he finds both bottles at the same time are worse than no bottles. An aero bar bottle works best, though. So, ideally one downtube bottle ane one aero bar bottle.

He tests the bottles on a QR Tiphoon, but I wonder if things wouldn't change a bit with a round seat tube as I have on my QR PicanTi. In this case, I'm guessing a seat tube bottle would probably trump a down tube bottle, since a vertical, round tube is such a drag.

______________________________________________
Outside of my bike, my running shoes are my favorite things. Inside my bike, it's too cramped to run.
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Re: Official MIT information thread. HOPEFULLY [Roscoe] [ In reply to ]
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In Reply To:
I've always found this John Cobb test informative:
http://www.profile-design.com/...s/water_bottles.html

The findings agree with your point in that down tube bottles are good, even better than no bottle. But seat tube bottles are also an improvement over no bottle, though not as good as a down tube one. However, he finds both bottles at the same time are worse than no bottles. An aero bar bottle works best, though. So, ideally one downtube bottle ane one aero bar bottle.

Our findings aren't quite like that, but it is dependent on the frame (and to some degree the rider).


Gerard Vroomen
3T.bike
OPEN cycle
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