neal@druxv.UUCP (Neal D. McBurnett) (07/10/84)
I agree that Bike Tech is an interesting publication, and I recommend it, but it seems to me that the article on the effects of wind is really butchered. The author says that the net effect of a slight tail wind can slow you down! For example, he claims that a wind with a true heading of 100 degrees off of your direction of motion will slow you down if it has a true strength of 1.5 times your true velocity. As I see it, your drag is determined only by your forward velocity and the component of the true wind which is in the direction of your motion: cos alpha. I think his mistake starts with equation 3. He says drag is proportional to w^2 cos beta where w is the magnitude of the apparent wind velocity, and beta is the angle of the apparent wind (apparent wind = true wind plus bicycle-induced wind). I say that eq. 3 should read (w cos beta) ^ 2 or, equivalently, (u + (v cos alpha)) ^ 2 where u is bicycle ground velocity, and v is true wind speed. This makes all the rest of his equations and figures needlessly complicated and counter-intuitive. What do you think? -Neal McBurnett, ihnp4!druny!neal, DR x4852