So, with the test rig sorted out, it was time to head out to the test course and do some runs! To minimize wind and traffic effects, I prefer to head out to the course early on a Saturday or Sunday morning.before the small neighborhood that the course road services begins to wake up and starts moving around. That helps to minimize any power meter drift during the runs.
turning the pedals slowly while freewheeling) down the descents of the course at least once per lap.
#Goldencheetah half pipe method plus#
I prefer to use a PT for my aero field testing since it eliminates the uncertainty of variations in drivetrain resistance across the gearing, plus the PT's "coasting zero" feature allows me to have the power meter zero while soft-pedaling (i.e.
#Goldencheetah half pipe method pro#
The hole in each sphere ended up being a nice friction fit, so swapping between spheres was a very simple process.Īll runs were recorded with my trusty old yellow-cap PT Pro wheel mounted on the rear, with a cover in place to turn it into a de facto disc. I took a quick trip to the nearby Michael's craft store and acquired some styrofoam spheres, 2", 3", and 4" in diameter. Using Andy's setup as a guide, I set about figuring out what sorts of objects I could use for the test. Since identifying the new course, and having done just a few tests on it, one thing I wanted to do was to repeat the type of testing that Andy did and attempt to characterize the potential "sensitivity" of the course using the VE method. Both of these courses are best described as a sort of "extended halfpipe", an "out and back" course having a U-shaped elevation profile that allows for turnarounds to be taken at low speeds and thus avoid braking. So, I started scouting around for an alternative course and luckily found one that is much closer to my home (I can ride there in just a few minutes) and that has laps that are significantly shorter than the old course (shorter laps = shorter test run time). Well, last year I discovered that my preferred field testing venue for VE runs had suffered some "traffic rerouting" that had made it much less appealing for the purpose (part of that "discovery" occurred when Andy sent his test setup to me to try and the results from my first course were very mixed due to excess vehicle interference after the nearby roads had been modified). In short, it's an effort using known geometric shapes to try to determine the "sensitivity" of the aerodynamic field testing method.
Andrew Coggan published a blog post titled " A Challenge to Cycling Aerodynamicists" in which he described a field test he undertook to take up something he coined the "Tom Compton Challenge". Using the tool to make evaluations at zero yaw still can hold a significant benefit for someone interested in improving/testing bicycle aerodynamics.Ī couple years ago, Dr. So, the question with this type of testing usually comes down to just how sensitive can it really be.especially as compared to something like a wind tunnel? Admittedly, there are some limitations to this type of testing, the main one being (at present time) that the results are mostly limited to zero yaw conditions, but as we saw in one of my previous blog posts, the most common yaw angles a TT'er or triathlete encounters are usually centered around zero yaw. Of course, since I wrote that spreadsheet for my own use, it's not exactly the most "user friendly" (Hey, I know what I'm supposed to do, I wrote it! -).but, don't worry, everyone else is in luck since Andy Froncioni (the main tech guy behind Alphamantis and the ERO facility that recently opened at the indoor track in Carson) added a version of the same calculations (called "Aerolab") to the freeware power meter analysis software, Golden Cheetah. When I first read Robert's info, I wrote up a spreadsheet that I've used since then to analyze everything from position changes to tire air pressure effects. My method of choice is Robert Chung's "Virtual Elevation", or VE protocol, sometimes known as the "Chung Method". As some of you may know, I've been field testing bike stuff and positioning with a power meter for 4 or 5 years now.
0 kommentar(er)
