General Discussion Triathlon Talk » Ask me about A2 Wind Tunnel! Rss Feed  
Moderators: k9car363, alicefoeller Reply
 
 
of 2
 
 
2012-06-18 6:56 PM

User image

Champion
7136
5000200010025
Knoxville area
Subject: Ask me about A2 Wind Tunnel!

Going in: Drag grams - 2981


Coming Out: Drag grams - 2811

 

Fire away some questions. Gotta get some sleep now, but I'll throw out some tidbits...

- Didn't test race wheels (per John Cobbs advice)

- Mantis at 25degree rise was my fastest hand position... everything below did not make any effect at all, and 30degree was worse than flat... so be careful messing with raising your hands.

- A Torpedo bottle tested about neutral with flat bars... tested way way worse than anything else in mantis position.

- Frame Virtue bottle tested almost neutral, and faster at 10degree yaw.

- HEAD POSITION MATTERS A LOT!!!!



Edited by Leegoocrap 2012-06-18 6:57 PM


2012-06-18 7:04 PM
in reply to: #4268086

User image

Elite
7783
50002000500100100252525
PEI, Canada
Subject: RE: Ask me about A2 Wind Tunnel!
Interesting, I would have thought your starting head position was better!
2012-06-18 7:07 PM
in reply to: #4268086

User image

Subject: RE: Ask me about A2 Wind Tunnel!

I would have liked to see you post this as a multiple choice, i.e. which one was going in, which coming out?  Excellent info in any event.

Any chance you tested a stem mount torpedo bottle?



Edited by ChrisM 2012-06-18 7:07 PM
2012-06-18 7:24 PM
in reply to: #4268086

User image

Subject: RE: Ask me about A2 Wind Tunnel!
Regarding the differences in torpedo mount flat vs mantis, and your head position...how many grams of drag difference are we talking about?
2012-06-18 8:17 PM
in reply to: #4268086

User image

Elite
3779
20001000500100100252525
Ontario
Subject: RE: Ask me about A2 Wind Tunnel!

so what does a 170 grams of drag buy you in terms of watts or speed?

Oh, and that mantis position does not look comfortable - just saying.

2012-06-18 10:14 PM
in reply to: #4268086

Master
10208
50005000100100
Northern IL
Subject: RE: Ask me about A2 Wind Tunnel!

Did you do anything with the seat? It looks kind of high.

Ok, but really, what did John Cobb say about using race wheels? Don't bother testing between them for this round or that the basic set would show you more?



2012-06-18 10:21 PM
in reply to: #4268197

User image

Extreme Veteran
494
100100100100252525
Olympia, WA
Subject: RE: Ask me about A2 Wind Tunnel!
GoFaster - 2012-06-18 6:17 PM

so what does a 170 grams of drag buy you in terms of watts or speed?

Oh, and that mantis position does not look comfortable - just saying.

x2 on both the question and comment.

2012-06-18 10:44 PM
in reply to: #4268086

Extreme Veteran
502
500
Washington
Subject: RE: Ask me about A2 Wind Tunnel!
did you get cold with all that air blowing on you?
2012-06-18 11:26 PM
in reply to: #4268086

User image

Extreme Veteran
1136
100010025
Subject: RE: Ask me about A2 Wind Tunnel!
Leegoocrap - 2012-06-18 6:56 PM

- HEAD POSITION MATTERS A LOT!!!!

Tell us more about this!  Tail touching your back, tail just slightly off your back, tail straight up in the air, tail turned sideways when you check your 6... we need the details!

You look too upright on your aero bars... maybe you could lower them a little?

I would also like to know what kind of benefit (even if it was small) the torpedo mount made on the "regular style" aero position.  Did you test a regular bottle mounted on the frame or just aero bottle?

2012-06-18 11:57 PM
in reply to: #4268086

User image

Elite
6387
50001000100100100252525
Subject: RE: Ask me about A2 Wind Tunnel!
Hey... so what about A2 Wind Tunnel?
2012-06-19 2:55 AM
in reply to: #4268397

User image

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!
citaltfort - 2012-06-18 11:21 PM
GoFaster - 2012-06-18 6:17 PM

so what does a 170 grams of drag buy you in terms of watts or speed?

Oh, and that mantis position does not look comfortable - just saying.

x2 on both the question and comment.

The position isn't all that bad. Different, but not painful or anything. Now how it effects handling is yet to be seen.

From Dr. Coggan (at 25mph it would be closer to 4.2w instead of 5)

Memorize this (I did):

0.1 lbs (50 g) of drag (at 30 mph) = 0.5 s/km = 5 W = 0.005 m^2 CdA = 0.0005 Crr

 



2012-06-19 2:57 AM
in reply to: #4268392

User image

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!
brigby1 - 2012-06-18 11:14 PM

Did you do anything with the seat? It looks kind of high.

Ok, but really, what did John Cobb say about using race wheels? Don't bother testing between them for this round or that the basic set would show you more?

"I would suggest not testing with the rear disc because air breaks off of them at different yaw points, they are not consistent, and it makes it hard to pin point real improvements."

2012-06-19 3:12 AM
in reply to: #4268441

User image

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!
wbattaile - 2012-06-19 12:26 AM
Leegoocrap - 2012-06-18 6:56 PM

- HEAD POSITION MATTERS A LOT!!!!

Tell us more about this!  Tail touching your back, tail just slightly off your back, tail straight up in the air, tail turned sideways when you check your 6... we need the details!

You look too upright on your aero bars... maybe you could lower them a little?

I would also like to know what kind of benefit (even if it was small) the torpedo mount made on the "regular style" aero position.  Did you test a regular bottle mounted on the frame or just aero bottle?

Tri808 -  Regarding the differences in torpedo mount flat vs mantis, and your head position...how many grams of drag difference are we talking about?

about 50g - 70g difference between the tail hanging up a bit and sitting flush against my back.

Turtling (very tough to hold correctly for longer than a minute or so at a time) was worth almost another 100g difference. - fastest run @ 2738g

 

Run w/ hands flat + torpedo was about a 3-5g difference on my setup.

Run w/ hands in mantis + torpedo was 2811g (no bottle) - 3043g (bottle) ! Which tested worse than every other bottle setup we tried, including two bottles behind the saddle.

2012-06-19 3:17 AM
in reply to: #4268086

User image

Member
325
10010010025
Groningen, Netherlands
Subject: RE: Ask me about A2 Wind Tunnel!
Cool beans. So where are you planning on putting your hydration setup now?
2012-06-19 4:20 AM
in reply to: #4268086


5

Subject: RE: Ask me about A2 Wind Tunnel!
Were you surprised at how fast time flies by when testing in the wind tunnel?
2012-06-19 5:35 AM
in reply to: #4268521

User image

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!

John Cobb - 2012-06-19 5:20 AM Were you surprised at how fast time flies by when testing in the wind tunnel?

Unbelievable. I got in 28 runs total and felt like about 5-10 minutes before time was over was about when I could start asking the right questions of what to test.



2012-06-19 5:38 AM
in reply to: #4268504

User image

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!

Snaaijer - 2012-06-19 4:17 AM Cool beans. So where are you planning on putting your hydration setup now?

 

Virtue Bottle on the frame for sprints and Oly's

Virtue Bottle on the frame + Bottle Tucked under saddle (Lieto style) and/or in Jersey for Halfs

Virtue Bottle on frame + Cages behind saddle for Full distance if/when I decide to do another one.

2012-06-19 6:28 AM
in reply to: #4268086

User image

Master
1770
10005001001002525
Bedford, MA
Subject: RE: Ask me about A2 Wind Tunnel!

Sounds cool! I have 'free' time there because of my bike purchase (Blue, which is based in Atlanta), but living in MA, it's a bit of a drive.

As others have said, what is your hydration storage plan? Downtube sounds best, but for longer races you generally need two bottles on the bike.

2012-06-19 7:57 AM
in reply to: #4268498

User image

Elite
3779
20001000500100100252525
Ontario
Subject: RE: Ask me about A2 Wind Tunnel!
Leegoocrap - 2012-06-19 3:55 AM
citaltfort - 2012-06-18 11:21 PM
GoFaster - 2012-06-18 6:17 PM

so what does a 170 grams of drag buy you in terms of watts or speed?

Oh, and that mantis position does not look comfortable - just saying.

x2 on both the question and comment.

The position isn't all that bad. Different, but not painful or anything. Now how it effects handling is yet to be seen.

From Dr. Coggan (at 25mph it would be closer to 4.2w instead of 5)

Memorize this (I did):

0.1 lbs (50 g) of drag (at 30 mph) = 0.5 s/km = 5 W = 0.005 m^2 CdA = 0.0005 Crr

 

So, at regular arce speed would you say the new position will save approx 10 watts?

2012-06-19 8:15 AM
in reply to: #4268086

User image

Elite
7783
50002000500100100252525
PEI, Canada
Subject: RE: Ask me about A2 Wind Tunnel!

- Mantis at 25degree rise was my fastest hand position... everything below did not make any effect at all, and 30degree was worse than flat... so be careful messing with raising your hands.

What happened between flat and 25 degrees?  No change at all and then something changed drastically at 25 degrees or was there a gradual alteration?  I know my bars aren't perfectly flat - probably 5 degrees (or less) up.

If you were given the chance to go back in a few months once you are fully comfortable with the changes, what would you test next?

2012-06-19 8:17 AM
in reply to: #4268568

Subject: ...
This user's post has been ignored.


2012-06-19 8:22 AM
in reply to: #4268790

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!
FoggyGoggles - 2012-06-19 9:17 AM

Did you take out any spacers on the neck when going to the mantis position? Your elbows are dropped, blocking the view of the neck.

Also, do you feel additional pressure / fatigue on your shoulders or middle back in the mantis position?

ahh good catch, I forgot. The first thing we did that made any change to drag at all was remove the dust cap from the stem (lowered the cockpit about 7mm) it had a positive effect, but not enough to warrant NOT having a dust cover. I'm looking for a zero stack now actually.

I actually feel a bit of relief on my (broken/plated) collarbone in the mantis position.  I think it has to do with the slight shift in where my forearms hit the pads.

2012-06-19 8:42 AM
in reply to: #4268785

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!
axteraa - 2012-06-19 9:15 AM

- Mantis at 25degree rise was my fastest hand position... everything below did not make any effect at all, and 30degree was worse than flat... so be careful messing with raising your hands.

What happened between flat and 25 degrees?  No change at all and then something changed drastically at 25 degrees or was there a gradual alteration?  I know my bars aren't perfectly flat - probably 5 degrees (or less) up.

For me it was not gradual. 0-20° was almost straight across the board, 25 was a huge improvement, and 30 was considerably worse than 0. Of course, If this testing has shown me anything at all it's that you can't base much on what somebody else tested. I expected closing my elbows (like Zabriskie) would make a huge impact... turns out it almost nothing for me... nor did moving mine out farther than I started with.

If you were given the chance to go back in a few months once you are fully comfortable with the changes, what would you test next?

How much time would I have? Every little change you make eats up time... changing wheels/bikes/suits eats up the most time, since you have to get off the bike (and re-calibrate the computrainer if you switch wheels)

If I had a short amount of time I'd go back, test what I had at as many yaw angles as possible, then set everything back up to when I started and do the same thing to get a full range of differences. Then with time left over I'd throw on my race wheels/hydration and see just exactly what my drag was decked out.

With more time there's a ton of things I would love to learn about what equipment worked best for me (that is, brakes, levers, crank covers, other aero bottles on the frame, some kind of "fairing" type deal - think Tollaksons Triceratops hydration system - on the front of the mantis type position, more suits, which front wheel works best with my fork at different yaw sweeps, a better frame...)

 

 You come out with more questions than you go in with.

2012-06-19 8:55 AM
in reply to: #4268852

Elite
7783
50002000500100100252525
PEI, Canada
Subject: RE: Ask me about A2 Wind Tunnel!
Leegoocrap - 2012-06-19 10:42 AM 

 You come out with more questions than you go in with.

That's what I'd be afraid of.  

How close together are your arms?  ie. when you have an aero bottle mounted between them, do you arms touch it or is there some gap? With my setup, I have a bit of a gap on either side of the bottle and I wonder how much that hurts me (if at all).  I've tried going narrower but my massive broad swimmer shoulders don't let me get comfortable like that.

2012-06-19 8:59 AM
in reply to: #4268086

Champion
7136
5000200010025
Knoxville area
Subject: RE: Ask me about A2 Wind Tunnel!

18cm center of pad to center of pad when I left, a bit tighter when I went in.

 

- and although you come out with more questions than you go in with, I'd add that the answer's you do get are huge. Just think, buying bikes from this point forward I know exactly where I need to have my contact points at!



Edited by Leegoocrap 2012-06-19 9:02 AM
New Thread
General Discussion Triathlon Talk » Ask me about A2 Wind Tunnel! Rss Feed  
 
 
of 2