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an oldie but goodie

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Recently, it was pointed out to me that a Ph.D. in Mechanical and Aerospace Engineering from Rutgers University reported that he has measured the lead rider in a paceline to receive an 8-10% reduction in CxA. FWIW, I looked at this NASCAR effect about 10 years ago (dueling it out with Jobst Brandt on rbt, nonetheless!). Here is a BTR forum link with additional info regarding (cliff's notes is that I estimated the effect using race car data at around 2-5% at the time IIRC...but even that might be a generous estimation):

biketechreview.com/index.php/forum/1-general-discussion/3573-blast-from-the-past

...here's some inviscid analysis to also help ballpark the expected effect (figure 5 is the one of merit, remembering velocity is related to pressure):

http://biketechreview.com/index.php/performance/demand/478-flow-stagnation-ideal-fluids-and-you

..and here's some reported data off of velonews from over 10 years ago regarding the topic of "lead rider in a paceline" aerodynamics:

http://velonews.competitor.com/2002/12/bikes-and-tech/technical-qa-with-lennard-zinn-the-aerodynamics-of-drafting_3330

I'm not quite sure what is going on with the previously mentioned Ph.D's methods/instrumentaion, but it is at odds with multiple independent lines of inquiry. A 10% reduction in CxA is quite significant, and really wouldn't require anything fancy in order to detect this kind of effect at track pursuit speeds...so, it's surprising that it hasn't been reported more frequently...

 

 

 

Last Updated on Saturday, 12 September 2015 14:25  

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