Talk:Drag coefficient
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"streamlined" goes to a page that doesn't discuss "streamlining" ...
Sports cars not terribly aerodynamic
Hi
Although the article _does_ mention that sports cars sometimes tend to sacrifice lower Cd values for negative lift at higher speed, it is misleading to represent normal family cars as having such poor aerodynamic values. Modern sedans, such as many Lexus models, BMWs and Mercedes-Benzs all have Cd values of around 0.26 and 0.27. Additionally, I think a discussion of drag needs to take frontal area into account, as it is the product of these two figures that produces an indicator to the vehicle's true aerodynamic efficiency. Looking at either one in isolation is not particularly useful.
- Perhaps the article on the drag equation might be a better place to add this discussion, since that brings in all the contributing factors. However it's still not the full story since without knowing the power of a vehicle's engine it still doen't give you much of an indication of performance. Given enough power, even the most brick-like of vehicles can be made to perform well, at least in terms of speed/acceleration, if not economy. My feeling is that since car frontal areas are more or less of the same order (certainly within a reasonable range, since frontal area derives ultimately from the size of the human body), Cd gives you some relative measure of a car's "draginess", without saying anything about how this affects performance. In fact it's like a lot of figures - they tend to get picked up by marketers and used rather disingenuously, i.e. the try to blind the public with science. Witness the commercials for the 80s model Audi 100, which strongly featured its drag coefficient, as if the average person had a clue what it meant. They even put a decal "Cd 0.3" on the C pillars! So, while I agree with you and think the article could be expanded to include these points, it should also point out the meaninglessness of it, given that it's not a predictor of performance. Graham 00:51, 2 Jun 2004 (UTC)
- I was just about to query the absence of frontal area, which is very important to aerodynamic efficiency. A blocky Jaguar XJ40 might not have a great Cd, but it can be efficient as its frontal area is not great. I'm sure mpg figures with more "slippery" rivals such as the Mercedes S-class would bear this out. I'll try to work something in as without it, the discussion of efficiency is incomplete. Stombs 11:56, Jan 28, 2005 (UTC)