A grainy still pic of one of the monitors at the TAMU wind tunnel, showing the P3C from above:
Forgive my ignorance, but what units are the drag number?
the units used for drag are AWESOMENESS
so it is only 1.5 awesome
.
Carbon fiber or alloy basebar on there?
Have you ever seen any wind tunnel data for continually varied speed and direction?
Reason I’m curious is after talking with a colleague that in the past worked at the GM wind tunnel. He witnessed tests for a number of vehicles, from standard cars, bikes, to dragsters and F1 racers. For each vehicle stabilization of air flow and drag occurred at different times after the required speed was achieved. Some vehicles like the dragsters never had a constant stable condition due to the huge tires spinning the drag would constantly change.
This stabilization period means that results can be different by just waiting varying amounts of time when a data capture is performed.
Also if the stabilization of air flow in a tunnel takes time, wouldn’t this mean that in real conditions of constantly varying direction, speed and cyclist movement that wind tunnel data could be very far from what actually occurs?
if the stabilization of air flow in a tunnel takes time, wouldn’t this mean that in real conditions of constantly varying direction, speed and cyclist movement that wind tunnel data could be very far from what actually occurs?
If that were true, then you wouldn’t be able to predict the power requirements of cycling outdoors in gusty winds to w/in, on average, ~2 W. We’ve shown, however, that you can, which makes your hypothetical objection seem rather moot.
My guess is 0.061 +/- 0.001 m2 at zero yaw.
Oh yea of little faith. 
My guess is 0.061 +/- 0.001 m2 at zero yaw.
Oh yea of little faith.
I’m with Rick if the drag number represents lbs…but since IIRC A&M claims an uncertainty of +/- 0.05 lbs on their balance, the uncertainty on the CdA would work out to be +/- .002 m^2.
My guess is 0.061 +/- 0.001 m2 at zero yaw.
Oh yea of little faith.
I’m with Rick if the drag number represents lbs…but since IIRC A&M claims an uncertainty of +/- 0.05 lbs on their balance, the uncertainty on the CdA would work out to be +/- .002 m^2.
In 1990 or 1991, Kyle reported in Cycling Science that drag force measurements for bare bikes in the TAMU tunnel (as it was configured/equipped back then) were reproducible to w/in +/- 0.03 lbs.
Oh yeah…were the cranks horizontal and the pedals removed? If not, that would be the equivalent of the Hooker, right?
Oh yeah…were the cranks horizontal and the pedals removed? If not, that would be the equivalent of the Hooker, right?
http://forum.slowtwitch.com/...oker%20drag;#1109749
You mean that I haven’t posted any side pics of the bike being tested by itself yet? Shame on me…
(BTW, I think if you look carefully you might be able to answer your own question…well, sort of.)
Oh yeah…were the cranks horizontal and the pedals removed? If not, that would be the equivalent of the Hooker, right?
http://forum.slowtwitch.com/...oker%20drag;#1109749
You mean that I haven’t posted any side pics of the bike being tested by itself yet? Shame on me…
(BTW, I think if you look carefully you might be able to answer your own question…well, sort of.)
I can’t see diddly-squat from that so-called “picture”…ya big friggin’ TEASE!
I can’t see diddly-squat from that so-called “picture”…ya big friggin’ TEASE!
I don’t think that you’re trying hard enough…after all, you’re the guy who spotted the Blackwells based on their “marbled carbon”, aren’t you?
I can’t see diddly-squat from that so-called “picture”…ya big friggin’ TEASE!
I don’t think that you’re trying hard enough…after all, you’re the guy who spotted the Blackwells based on their “marbled carbon”, aren’t you?
Yeah…but after I let that one loose, now I think you’re just playin’ with me 
What is the value in testing a bike without a rider riding on it?
Are the correlations between rider and riderless bikes well enough understood that this tells us something?
Do bikes exist with great drag numbers alone but that suck once a rider is on them?
What is the value in testing a bike without a rider riding on it?
It results in more reproducible data (according to Kyle, +/- 0.03 lbs w/o a rider vs. +/- 0.1 lbs w/ a rider…but the data we collected on Friday were actually much tighter than that, possibly due to improvements that have been made in the wind tunnel and/or testing procedures over the last ~20 y).
Are the correlations between rider and riderless bikes well enough understood that this tells us something?
Yes.
Do bikes exist with great drag numbers alone but that suck once a rider is on them?
Only one of which I am aware: the Trimble.
The hooker was 22mm wide. Nothing MUST be faster than that, and if fact, it’s taken this long to get anything even close in the double diamond design.
Chris
http://forum.slowtwitch.com/...post=1362315#1362315
according to this post the P3C package exhibits less drag than the Hooker … or at least that’s what I read into it …
You’re reading that post correctly: with cranks vertical and pedals attached, the Cervelo P3C had less drag at 0 to 10 deg of yaw than my old Hooker. This was not a head-to-head comparison of bare frames, so I would not consider it the definitive word on the subject, but given the results and the way they were obtained I think* the P3C is more aero.
*I once attended a scientific presentation in which the presenter differentiated between “I know”, “I think”, “I believe”, and “I feel” as used by a scientist by comparing them to a modern steel-and-concrete suspension bridge, a stone-and-wood bridge, a rope-and-wood catwalk, and a tightrope, respectively.
How Frank Day balances on his tightrope without falling off I have no idea
.
No, the P3T exhibits less drag than the Hooker Eliter maybe.
The insinuation was there. Add on the rest of the crap that you have to hang off of a bike, and then see if it still beats it.
Chris