Hi Marcag- I'm super busy with work so I don't have time to comment in detail but I would say two things really stand out to me after skimming your posts:
I absolutely appreciate that protocols allow to get more accurate data, especially when no accurate sensor exists. The same start/end point gives a delta Elevation = 0, no need for altimeter. Out and back averages wind out, I get it......
(1) This part above really stands out. I totally understand that it would be great to have detailed and accurate enough sensor data to get real time CdA just riding along, but... it just doesn't exist right now. Lots of people are trying and failing. And it's not just bikes. It's Formula 1 too, and there's real money there, not just the play money here. In the absence of accurate sensor data for elevation and wind, protocols are key for testing. To get precise results you need to pay extreme attention to detail, and follow a detailed protocol. It's really not that hard, and it can be done as part of regular training rides, but it really is that important.
(2) The second thing that stands out is that you seem very focused on getting the elevation profile to fit / make sense. This is actually totally unimportant. What you need is a good estimate of CdA, period. You don't need a good estimate of the elevation profile. You also don't need a good estimate of what the wind actually was. Furthermore, trying to estimate these things does not seem to help in estimating CdA. I have tried going down the path you are going down (spent lots of hours on it maybe five years ago) and I found it did not work well. What works is following the right protocol, testing on a day when the wind isn't massive, and then using the math to average out the wind and elevation changes. The elevation charts that result often look bad and the great thing is it doesn't matter. I don't even look at them.
marcag wrote:
First of all, I don't like protocols. I like to ride, do my workouts and if I can get aero data, great. I absolutely appreciate that protocols allow to get more accurate data, especially when no accurate sensor exists. The same start/end point gives a delta Elevation = 0, no need for altimeter. Out and back averages wind out, I get it......
(1) This part above really stands out. I totally understand that it would be great to have detailed and accurate enough sensor data to get real time CdA just riding along, but... it just doesn't exist right now. Lots of people are trying and failing. And it's not just bikes. It's Formula 1 too, and there's real money there, not just the play money here. In the absence of accurate sensor data for elevation and wind, protocols are key for testing. To get precise results you need to pay extreme attention to detail, and follow a detailed protocol. It's really not that hard, and it can be done as part of regular training rides, but it really is that important.
(2) The second thing that stands out is that you seem very focused on getting the elevation profile to fit / make sense. This is actually totally unimportant. What you need is a good estimate of CdA, period. You don't need a good estimate of the elevation profile. You also don't need a good estimate of what the wind actually was. Furthermore, trying to estimate these things does not seem to help in estimating CdA. I have tried going down the path you are going down (spent lots of hours on it maybe five years ago) and I found it did not work well. What works is following the right protocol, testing on a day when the wind isn't massive, and then using the math to average out the wind and elevation changes. The elevation charts that result often look bad and the great thing is it doesn't matter. I don't even look at them.