why do people think they know that some wing (or whatever) "is the same as used in X"? We know that aero performance can come down to minor things, teams seem to be directing air flow with a precision of a few centimeters.
Or am I missing something?
No, you are not missing anything, that is a valid question. It's just my second job to be tech analyst and I have large gallery with pictures which I can compare. Hence, I can almost certainly tell whether something new has been introduced. Small changes, which are not visible to the human eye are unlikely to bring large difference in performance, especially when it comes to front wing, which is usually a part with couple of elements whose primary workload is to divert air to a very known places.
Back on what @boldhakka says above: ground clearance (ride height) is something that affects the car's performance quite a lot, but this is again something that's not easily visible from the track, especially when we have different shooting angles. 30 mm front ride height is a good ballpark number, so in that department millimeters count.
It also helps to have seen both wind tunnel smoke plume visualizations, as well as CFD turbulent models for open-wheel race car.
Next we have production time frames plus packing and logistics, which definitely reduces the time to create new front wing, test it and send it on the track - Mclaren did that on the last YDT that has taken place at Yas Marina. Today, they are bolting the wing onto the pylons.
Whether or not certain team decides to race a particular wing is something that I can't tell for sure. You can't, however, be that much certain about other parts of the car, such as suspension geometry, diffuser and exhaust placement. What I can't really agree with is remarks regarding the angles of attack on both the front and the rear wing - these changes are very hard to spot, as I write about it in my blog
Here's a picture showing the changes done for the AoA on a front wing main plane:
Cars usually arrive with 0 AoA setup.
Again, good question, it's just the front wing really small millimeter changes do not bring large effect.
Edited by kvarbanov, 15 November 2012 - 15:58.