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PostPosted: Wed Nov 15, 2017 6:23 pm 
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Oh boy, here we go! :popcorn:

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PostPosted: Wed Nov 15, 2017 6:51 pm 
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kgt the phd is from 2008 before many of the aero frames we are taking about were on the scene therefore while changing the frame back them may not have made much difference changing it now from a round tubed bike to a madone for example might make a small difference. Difficult to know as the test is not done and if it was someone would say it is not indepedent e.t.c

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Last edited by bm0p700f on Wed Nov 15, 2017 11:28 pm, edited 1 time in total.

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Posted: Wed Nov 15, 2017 6:51 pm 


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PostPosted: Wed Nov 15, 2017 9:53 pm 
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kgt wrote:
Actually Madone is considered as 'the aero king' because some tests say so. Keep in mind, though, that these tests do not follow strict scientific protocols and their results are not actually processed.
In general tests done by manufacturers or cycling magazines are neither rigorous nor independent. Actually the only PhD research on bike aerodynamics ever discussed in this forum has as its main conclusions that the aerodynamics of the frame itself (comparing track frames) do not, practically, matter:

https://ir.canterbury.ac.nz/bitstream/h ... lltext.pdf



That is a thesis. Let's see a peer-reviewed publication instead?


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PostPosted: Wed Nov 15, 2017 10:34 pm 
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Kgt, could you please stop wrecking threads like these?


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PostPosted: Wed Nov 15, 2017 10:50 pm 
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tranzformer wrote:
That is a thesis. Let's see a peer-reviewed publication instead?


Theses are peer-reviewed.

Source: earnt my doctorate.


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PostPosted: Wed Nov 15, 2017 10:55 pm 
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saba wrote:
tranzformer wrote:
That is a thesis. Let's see a peer-reviewed publication instead?


Theses are peer-reviewed.

Source: earnt my doctorate.


Publication. Thesis is different than a publication. Not all theses ever get publication in a scientific journal.

Source: earned two graduate degrees and published in countless journals in my field.

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Last edited by 53x12 on Wed Nov 15, 2017 10:58 pm, edited 1 time in total.

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PostPosted: Wed Nov 15, 2017 10:55 pm 
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kgt wrote:
I am afraid that you misunderstood what you read:

Aren't you a charmer? And not patronizing in the least.

kgt wrote:
"A change to the shape of the bike frame had no significant impact on the drag (<0.3%)" p. 234 a few lines above
So what she says is that the shape of the frame itself does not matter. It matters only when the frame alters the rider's position.

This is a fair point. Underwood's modifications were extensive and groundbreaking, as is appropriate for a serious inquiry into frame aerodynamics:
Attachment:
burrito.jpg
burrito.jpg [ 12.32 KiB | Viewed 339 times ]


You're quite particular about the correct interpretation Dr. Underwood's dissertation. She wrote "a change to the frame shape had no significant impact on drag," and you understand this to mean that "the shape of the frame does not matter." A broader reading might suggest that she meant that she didn't get anywhere with her modifications to two already-aero frames and elected to focus on other areas instead, but you've rejected feeble-minded approaches that indulge in considering the overall context. One must respect a man with such a clear-eyed worldview.

And surely, you're no hypocrite. A man with the courage of his convictions would never complain if others applied to his words the narrow, literal interpretation he himself uses. For example:
kgt wrote:
[This dissertation] has as its main conclusions that the aerodynamics of the frame itself (comparing track frames) do not, practically, matter


Certainly you must mean that there aren't substantial aerodynamic differences between track frames. Round-tubed steel, wind-tunnel-tuned carbon? As long as they're intended for the velodrome, they have pretty much the same drag according to what you wrote. It's an extraordinary claim and it contradicts all the available evidence, but you wouldn't write it if you didn't mean it, I'm sure.

Wait, what? You didn't literally mean that all track frames have the same drag, no matter their shape? You meant something other than what you wrote, perhaps intending to say that similar aero frames have substantially similar drag? Well, I agree: if we read your claim literally, it's incoherent. If we consider the larger context, your argument goes from batshit-insane to a reasonable-sounding (if tautological) position.

If we consider the broader context of Underwood's dissertation, it's fair to say that it's fundamentally about the mathematical modeling of pursuit races and the further modeling of changes to position and their aerodynamic effects. It's kind of weird* that she makes such a weak attempt to modify frames, yes. But looking at the big picture, that seems to have been an effort to justify her decision to ignore the bikes themselves and focus on position and clothing modifications. Here's what Underwood has to say about it:

Lindsey Underwood wrote:
The focus of this thesis was to analyse methods of increasing the speed of track cyclists through changes in position rather than equipment.

I don't know how you decided that one of Underwood's main conclusions was to say that frame aerodynamics "don't practically matter." Chapter 10 contains Underwood's conclusions. Only one sentence mentions frames, and that's just recounting all of the variables she considered. The same sentence mentions putting one's hair in a bun, but I wouldn't draw any sweeping conclusions about hairodynamics or bun drag from this dissertation. It's just not about those things.

kgt wrote:
Anyway it seems that you have done more rigorous research than Dr Underwood. Can you please share it with us? I honestly respect your knowledge and I would like to learn more.


I can tell you're sincere when you describe your sense of honest respect and an earnest desire to learn from me in particular. How could I possibly think anything else?

Since you asked, I have indeed done more rigorous research on frame aerodynamics than Dr. Underwood, but so has my dog. I've also performed much more serious structural analysis than Oprah. Look: if you think this dissertation has anything to say about frame aerodynamics--and that taping a burrito to a stem somehow supported its claims--you're being willfully obtuse. Your tone is disdainful, your story changes constantly and you flat-out walked away from jwfinesse when he politely asked you to clarify an ambiguous point. Just what do you get out of posting this way?


-------------
* I'm not an academic, but I was married to one for twelve years. It's common for dissertators to pass their defenses conditionally: their committee announces that they will have passed as soon as they make certain changes. This is just a guess, but the section on the aerodynamic effects of stem burritos looks to me like it was thrown in to appease a committee member who insisted that Dr. Underwood needed to justify her focus on position and clothing. She also goes on at length about the elastic modulus of different fabrics, a subject that doesn't have much to do with her conclusions. That may be in there for similar reasons, possibly to satisfy a committee member who wanted to see more material analysis. Overall, I think this dissertation is fine, but there are a lot of meanderings down blind alleys.


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PostPosted: Wed Nov 15, 2017 11:00 pm 
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saba wrote:
tranzformer wrote:
That is a thesis. Let's see a peer-reviewed publication instead?


Theses are peer-reviewed.

Source: earnt my doctorate.

I'm with 53x12: theses and dissertations are supervised, not peer-reviewed. Really good dissertations sometimes get rewritten and published as peer-reviewed articles, but most don't. If an unpublished article doesn't count on a CV, a dissertation counts as a publication but not a journal article.

Source: grad school and a 12-year marriage to a rockstar academic at an R1.


Edit: clarity


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PostPosted: Wed Nov 15, 2017 11:40 pm 
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youngs_modulus wrote:
saba wrote:
tranzformer wrote:
That is a thesis. Let's see a peer-reviewed publication instead?


Theses are peer-reviewed.

Source: earnt my doctorate.

I'm with 53x12: theses and dissertations are supervised, not peer-reviewed. Really good dissertations sometimes get rewritten and published as peer-reviewed articles, but most don't. If an unpublished article doesn't count on a CV, a dissertation counts as a publication but not a journal article.

Source: grad school and a 12-year marriage to a rockstar academic at an R1.


Edit: clarity



I'm just curious...what's an R1?


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PostPosted: Thu Nov 16, 2017 12:03 am 
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the thesis cited here has sound methodology. I had a good read and it is applying well worn physics to tease out where the eastiest gains are. It is possible if a search is done that ms underwood has used this data to write up a paper or two.

This obession with evidence being independent and peer reviewed is a fetish here and achieves nothing.

Ms underwoods work is focused on help the aussie track team win medals. her model can be applied to road bikes of course. What i do think is that good aero bikes do encourage a good aero position and there fore good results. We all know that the rider is the least aero part of a bike and there a bike that optimises the postion is doing it what the designers intend - make the rider go faster. The modern tube shapes can only help.

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PostPosted: Thu Nov 16, 2017 12:22 am 
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pyrahna wrote:
I'm just curious...what's an R1?


It's slang for a Research I university. This is an American designation for "full" universities that emphasize research. If you're a research professor in the US (whose focus is on research, not teaching) then you really want to be at an RI. By contrast, professors on a teaching track may work at an RI, but they may also work at, say, a small liberal arts college or something like that.

When non-academics picture a "scientist," like a physicist or chemist or nanotech researcher, they're basically thinking of a professor or post-doc at an R1 (at least if they're picturing this person in the US).

https://en.wikipedia.org/wiki/Research_I_university

I just realized I wrote "post-doc" which also jargon. A post-doc is a post-doctoral researcher: a short-term "contract" researcher who has a Ph.D. (usually granted recently) but has not yet obtained a tenure-track positon. Once they get a tenure-track job, they're called "Assistant Professor." Oh: and they may get a tenure-track job or they may not. Plenty of people don't even get a chance to go up for tenure. If you're denied tenure, that's terrible. You're essentially fired. You typically get to stick around for one year after being denied tenure, and then you're basically done as an academic. You can try to get another tenure-track job, but in many fields those are like hen's teeth anyway, and rarer still once you've been denied tenure.


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PostPosted: Thu Nov 16, 2017 12:35 am 
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Location: Madison, WI USA
bm0p700f wrote:
the thesis cited here has sound methodology. I had a good read and it is applying well worn physics to tease out where the eastiest gains are. It is possible if a search is done that ms underwood has used this data to write up a paper or two.


Yes. I'd like to clarify that I don't think this dissertation is problematic. It does what it sets out to do. I don't think that the dissertation involved serious research on frame aerodynamics; I don't think it claims to. While KGT and I disagree on what the dissertation "means," I don't want to give the impression that I think the work is flawed. It's not. And if I may be so bold as to speak for KGT on this point, I don't think he has a problem with the work either. I have no reason at all to doubt Dr. Underwood's competence to study frame aerodynamics if she chose to.



Edit: swapped a comma for a semicolon


Last edited by youngs_modulus on Thu Nov 16, 2017 3:43 am, edited 1 time in total.

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PostPosted: Thu Nov 16, 2017 12:57 am 
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Location: Madison, WI USA
bm0p700f wrote:
This obession with evidence being independent and peer reviewed is a fetish here and achieves nothing.

I've always thought that non-scientists in general (and bike geeks in particular) like peer-reviewed articles for a really good reason: they know that they're not equipped to evaluate the data themselves. The thought process, one assumes, is that if a researcher's work has undergone peer review, then someone who knows their stuff has signed off on the paper.

That's a good place to start from an epistemological perspective. I mean, I'm fine looking most papers in my field (mechanical engineering) but I'm not equipped to evaluate a journal article on molecular biology or, for that matter, a legal brief.

But it's not like all peer-reviewed research is valid. Reviewers make mistakes too, and a huge proportion of published results cannot be reproduced. (That's a very polite way to say that the research the author did was probably wrong).
https://www.nature.com/news/1-500-scien ... ty-1.19970

Plus, there's a growing problem with the academic equivalent of "fake news:" low-status journals that will publish any paper they get as long as the submission-fee check clears.

bm0p700f has a point: there's nothing automatically "true" about peer-reviewed research. More importantly, the internet brings out a tendency for people to pound the table and demand peer-reviewed information when they don't understand the subject at hand. I'm not saying they're dumb or necessarily wrong; I'm saying that shouting "peer review" can become a cudgel people wield instead of actually thinking.

One reason I write these long-winded and overly technical posts is because I like the idea of de-mystifying these things. I hope to help cyclists outside my field understand all the white papers and engineering jargon that gets tossed around in the bike industry. I know I can go overboard sometimes, but it comes from a good place.


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PostPosted: Thu Nov 16, 2017 2:17 am 
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Image

I literally ate popcorn while reading this.

Great discussion here.


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PostPosted: Thu Nov 16, 2017 2:58 am 
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I think Hambini and Hexsense is right about one thing in particular and it's the handlebar frontal area. It often leaves much to be desired.

I'm looking to put a base bar on the frame I am buying and with that in mind I hope I haven't set myself up with an impossible decision trying to distinguish the madone or s5. (I'm aware a madone is basically impossible to fit other bars on. I'm simply entertaining the option).

As for aero brake calipers. My intuition tells me it's not as important as the bars. Is it worth pursuing, good question. I've found that it often adds a lot of weight. (Sure weight is not everything but I like to do a fair trade between weight and aero. Saving a couple of watts is worth a moderate increase in weight. But save half a watt for 200-300gr is pushing it.)

Changing subject to the Trek Speed Concept 9 I noticed the down tube is very slim with a completely different tube profile than the madone. The fork frontal area is quite big with a quite wide stance of the fork legs. Not like the Cervelo P5x at all.

The youtube user Ronald Kuba did some tests between his Madone 9 and Speed Concept 9 and came up with around 2.5km/h average speed difference between them at equal power. I think wheels and clothing were kept the same. Yes the difference comes a lot from the rider position but it's interesting how the "Aero king" can so easily be improved upon by relatively traditional tube shapes that seem to be on the Speed Concept 9.

Maybe an oval cross sectioned down tube is faster than a kammtail, as long as no bottles are mounted, or? Thanks for commenting.

/a


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Posted: Thu Nov 16, 2017 2:58 am 


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