Do you know your recumbent's CdA?
#27
Senior Member
Coastdowns have been a mainstay of recumbents for years. The problems with them are, you have to normalize weight and there's always a difference of opinion on the validity of the details - what speed to start, do you measure acceleration, top speed, total roll-out, etc. When adding fairings, the weight thing can be important. And I'm not sure how any of them would be turned into a magical CdA number. Measuring power at the hub would seem to be more reliable, but few non-racers are willing to buy a PowerTap hub or similar equipment. (I know a few are, but they don't talk about it.)
Even 'aerodynamic' TT uprights seem to get more benefit from drafting than a typical lowracer. That tells me something, even without knowing numbers. I've been in a 5-bike lowracer paceline and the benefit is barely noticeable - certainly not the kind of help it gives the uprights.
Even 'aerodynamic' TT uprights seem to get more benefit from drafting than a typical lowracer. That tells me something, even without knowing numbers. I've been in a 5-bike lowracer paceline and the benefit is barely noticeable - certainly not the kind of help it gives the uprights.
#28
Perceptual Dullard
Thread Starter
Join Date: Sep 2009
Posts: 2,420
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 1,156 Times
in
494 Posts
Coastdowns have been a mainstay of recumbents for years. The problems with them are, you have to normalize weight and there's always a difference of opinion on the validity of the details - what speed to start, do you measure acceleration, top speed, total roll-out, etc.
Measuring power at the hub would seem to be more reliable, but few non-racers are willing to buy a PowerTap hub or similar equipment. (I know a few are, but they don't talk about it.)
[Edit:] BTW, someone just pointed me to this, which appeared today.
Last edited by RChung; 11-03-09 at 02:34 PM.
#30
Newbie
Join Date: Nov 2009
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
You might be entertained by my efforts at measuring drag. Go to https://mysite.verizon.net/resob0n9/bicycle_performance/
If you wish you can email me at
foxconner@verizon.net
If you wish you can email me at
foxconner@verizon.net
#31
Perceptual Dullard
Thread Starter
Join Date: Sep 2009
Posts: 2,420
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 1,156 Times
in
494 Posts
You might be entertained by my efforts at measuring drag. Go to https://mysite.verizon.net/resob0n9/bicycle_performance/
#32
Perceptual Dullard
Thread Starter
Join Date: Sep 2009
Posts: 2,420
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 1,156 Times
in
494 Posts
I was searching for something and came across this thread from nearly a decade ago. Reading through it again was nostalgic. Man, you guys were suspicious back then.
#33
Senior Member
I wasn't suspicious so much as I was unable to add anything useful.
Likes For BlazingPedals:
Likes For Steamer:
Likes For RChung:
#36
Zircon Encrusted Tweezers
Join Date: Nov 2008
Location: high ground
Posts: 1,347
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 261 Post(s)
Liked 131 Times
in
83 Posts
Although I do stand by my one old statement:
Consider that if you are a college professor who ponders questions like this for a living, then it is likely you are much more suited to answering your own question than anyone here.
#37
Senior Member
IIRC, weren't you doing something with leaning trikes a long time ago? I remember they looked pretty interesting, whoever was working with them.
#41
Senior Member
#42
rebmeM roineS
Join Date: Jan 2006
Location: Metro Indy, IN
Posts: 16,216
Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked 347 Times
in
226 Posts
Still have not measured the CdA of my bikes.
But do have a general idea of what CdA means.
But do have a general idea of what CdA means.
__________________
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Likes For JanMM: