Wanted to move this into its own thread, it is pretty interesting and this may go on a while.
Anyway the basic question is, can an out and back, or loop TT be faster with wind in some cases than with no wind at all. As we know from various wind tunnel results, drag can be a good deal less at medium and high yaw than at zero yaw.
But any wind will also mean more apparent wind speed when riding, at least some of the time.
So can you be net faster? I mentioned that we seemed to notice faster times at one of our local TTs that used to occur monthly in Austin when there was moderate wind at certain directions. So here is are the results from best bike split I ran on that course:
Out and Back
8.09 miles
250 watts normalized power limiter
cda - yaw
0 - .21
5 - .2082
10 - .1972
15 - .1948
20 - .1875
0mph wind
time 18:56
5mph wind 180 degrees 18:52
8mph wind 180 degrees: 18:46
Of course bestbikesplit's physics could be wrong, the CdA vs yaw numbers could be unrealistic. But I believe analytic cycling's dynamic wind page will get you similar results if you set it up using their wheel drag vs yaw inputs. I haven't done it in a while because it is cumbersome to set it up.
Discus!
Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
Anyway the basic question is, can an out and back, or loop TT be faster with wind in some cases than with no wind at all. As we know from various wind tunnel results, drag can be a good deal less at medium and high yaw than at zero yaw.
But any wind will also mean more apparent wind speed when riding, at least some of the time.
So can you be net faster? I mentioned that we seemed to notice faster times at one of our local TTs that used to occur monthly in Austin when there was moderate wind at certain directions. So here is are the results from best bike split I ran on that course:
Out and Back
8.09 miles
250 watts normalized power limiter
cda - yaw
0 - .21
5 - .2082
10 - .1972
15 - .1948
20 - .1875
0mph wind
time 18:56
5mph wind 180 degrees 18:52
8mph wind 180 degrees: 18:46
Of course bestbikesplit's physics could be wrong, the CdA vs yaw numbers could be unrealistic. But I believe analytic cycling's dynamic wind page will get you similar results if you set it up using their wheel drag vs yaw inputs. I haven't done it in a while because it is cumbersome to set it up.
Discus!
Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter