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You guys know I love me some aero goodness.....
Last Post 10/04/2016 05:05 PM by Frederick Jones. 25 Replies.
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79pmooney

Posts:1757

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09/30/2016 04:14 PM
CK, I've been wondering about the styling of that Diamondback. Finally got it. It was a challenge. Protoype got cut clean by a garage door. But the photos had to be out next week. No time. So the bike was cut to a clean line at the break. Seatpost and HBs photoshopped in. Now that the photo is out, production has to make them. Funny how great innovations come to be if you know the inside story!

Ben
Cosmic Kid

Posts:2187

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10/01/2016 08:41 AM
Updated pic of the new Cervelo....

Just say "NO!" to WCP!!!!
Nick A

Posts:525

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10/03/2016 10:18 AM
Wow, interesting analysis. What blows my mind are aero bars. What I mean by that is that for decades nobody figured this out. There's no technology involved, just the shape of some handlebars. I even, will occasionally put my forearms on the tops of my road bars, and can instantly feel the difference. I'm surprised nobody stumbled upon this pre-LeMond.

Aerodynamics is a fascinating field, but sooo complex. I've had a couple careers, and one was designing bridges as a civil engineer. Except, they were just your boring highway overpass variety. Simple static wind load. No aerodynamics required. But I do know from being peripherally involved with one suspension bridge, that the aero can get interesting. At one time they widened the bridge, and used an open steel grate deck, not for weight but for aero. It purposely killed the lift caused by the new profile. There was a cable stayed bridge somewhere that worked well in the wind tunnel, but then in practice they found that when water droplets formed on the cables, they began to "sing" during a steady breeze. As I recall, it was more of an embarrassment, than a safety issue.

Nick
79pmooney

Posts:1757

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10/03/2016 12:53 PM
Nick, a little off topic but following your lead. I lived in Seattle during the '90s; the years of bridge and other civil engineering failures. Of course, this is the city a couple dozen miles north of the famous Galloping Gerdie, the suspension bridge in Tacoma, WA that went into resonance and self destructed in a storm. While I was there, the Hood Canal floating bridge tore loose during a storm, Seattle's I-90 floating bridge sank, the traffic stop on the 520 floating bridge raised unexpectedly (and as I recalled, killed a driver) and about a mile north of that bridge, the new construction in the UW Husky stadium fell down.

The sinking of the I-90 bridge was the one that really got me. I was working at MARCO at the time, doing stability tests and writing the reports for fishing boats operating in the Bering Sea winter where adhering to those reports and not overloading the boats was life and death. I was using the latest versions of the high end stability software created right there in Seattle. (I would hit impasses trying to model in the boats in our shipyard, talk to the creator on the phone, he would make up a script that would work and I would run over to his house and get the new program.) The I-90 bridge sections were hollow concrete blocks that floated with the roadway above. The roadway was being torn down and the debris temporarily stored inside the section. (They had cut access holes in the sides. No one paid attention to the fact that the holes were on the south side of the sections and that winter storms in the northwest usually come from the south; that waves could well be several feet high. Before the storm, they had loaded the sections with so much debris that the cutouts were just 10" above the water!

This being Seattle, all anyone had to do to save that bridge was - go to UW's department of Naval Architecture and ask a professor there if a student could be borrowed to model the bridge into BHS (Basic HydroStatics - the ship modeling and stability program). The would have cost the State, contractors and everybody else exactly zero $$s. The student spends a week (as a raw beginner) to model the program and in week more will be able to tell everyone exactly how much water is allowed in the section if it is loaded to "here" before it sinks. Rocket science? No this is Archimedes 2000 years ago. The student could have done the calculations faster by hand but the model would have had real long term value. (There is a patent I share with that university. I approached a mechanical engineering professor with an idea, he put four students on it and it happened.)

I could have modeled and run cases for that bridge in an (easy) afternoon, but I would have demanded $20/hour. To lose a bridge to the cost of millions in the most naval architect heavy city in this country for violating the most basic principle? Really? (The math involved is far simpler than Newton's falling apple.)

Rant, rant. I haven't thought about those bridges in years!

A bridge singing in the rain? I like it!

Ben
Cosmic Kid

Posts:2187

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10/03/2016 02:22 PM
Posted By Nicholas Arenella on 10/03/2016 10:18 AM
Wow, interesting analysis. What blows my mind are aero bars. What I mean by that is that for decades nobody figured this out. There's no technology involved, just the shape of some handlebars. I even, will occasionally put my forearms on the tops of my road bars, and can instantly feel the difference. I'm surprised nobody stumbled upon this pre-LeMond.


They did....they were called "triathletes".
Just say "NO!" to WCP!!!!
longslowdistance

Posts:1499

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10/03/2016 07:38 PM
We have a winner!

Cycling was so hidebound.
Merckx's hour record bike had narrow drop bars, they did have a clue.
Nick A

Posts:525

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10/04/2016 11:10 AM
LSD: But the narrow drop bars are hardly the forearms a few inches apart position. Did they know about this position, and it just wasn't legal? I mean, you could have adopted this position pretty early on in the development of the bicycle, yet nobody did? Or if they did, I'm ignorant. As I recall, at least with any widespread usage, it started with cow horns then "aero bars" in the '80's. Google shows varying dates, but it looks like the first usage of forearms close together was in a 1984 in a RAAM race.

CK: LOL. True.

79: I hear ya. I did some bridge inspections in NYC. Oy. How about this. We flagged a bridge because a subway car in a rail yard under the bridge had taken out a column. So the cops thought, lets let the heavy trucks over the weight limit drive onto the bridge, get a few of them stopped in the middle, and then ticket them...instead of not letting them on the bridge in the first place.

N

Nick A

Posts:525

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10/04/2016 11:40 AM
Hmm, edit button now showing up? So, anyway: edit...

LSD, I wasn't trying to say cycling was hidebound. I was just marveling at how sometimes something so simple takes so long to get discovered. Complex rim and frame shapes take more recent technology, but just from personal experience, just putting the forearms (very) close together makes an instant and noticeable difference as compared to deep in the drops, even with narrower bars. I just think it's cool to think about,how nobody "accidentally" put there arms like this in the '60's, '50's, 40's, and noticed this as well, or if they did, nothing seemed to have come of it that I can find until the '80's.

N
79pmooney

Posts:1757

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10/04/2016 12:29 PM
Nick, with non-aero brake cables, you better know you will never need the brakes! You will have to sit up. pull your hands behind the cables then reach forward should you need to slow. So there was more disincentive to do the forearms on the tops.

Ben
Cosmic Kid

Posts:2187

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10/04/2016 03:05 PM
OK, leaving aside the overall design of the bike, this is some REALLY impressive engineering....wow. Would love to see Cervelo bring that kind of adjustability to a road bike!

https://player.vimeo.com/video/184688849
Just say "NO!" to WCP!!!!
longslowdistance

Posts:1499

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10/04/2016 05:05 PM
Nick, but it was hidebound! I was one of those hairnet wearing traditionalists. I know the animal. Very un-accepting of the nontraditional.
It took triathletes thinking outside the box to substantially move the technology forward, and an American embracing the tech in such a spectacular way (winning the Tour when it seemed lost) to help accelerate acceptance of new tech.
(As for doping tech, cycling has always been open to new ideas.)
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