Originally Posted by
Pandian
How many professional aerodynamic engineers, or anyone with detailed knowledge of this field are on this site? The McLaren front wing is a puzzle.
Starting on the straight, the center of the front wing is high. It takes a certain speed before it dips almost out of sight. Now, the car is very fast.
As soon as the braking starts, it pops up fast. It is the position for all corners, at all speeds.
Questions:
1 - Are the flow patterns at the different heights significantly enough ?
2 - What does the movement occur on? Torsion on the end plates is obvious answer - is that correct?
3 - The end plates are wide front to back - needed for down force at front. Do they get enough torsion from the mobile mid-section to reduce drag on the straights?
4 - A significant force keeps the mid-section down. That is gone at the corners, the mid- section is in the highest level, different flow pattern. Is that enough to follow another car at the corners, without losing much grip?
5 - Does this mean the car has different front wings for the fastest segments and the slowest speeds?
6 - Do these changes give racing advantage? Canada, USA and Monza.
7 - What do the F1 people think the up and down movement of the mid-section occurs on - springs? That carbon fiber is very strong - it has to move on something.
So, any thoughts people - experts or not in the field of aerodynamics!
The wing deflects due to aero load. Same idea you see on airplane. The movement are more likely to be caused by the main planes(not endplates) of the wing. As the wing is only supported at the center struts, as the speed increases the aeroload increases, and the 2 sides(left and right of the center support) assumes a condition not too dissimilar to a cantilever beam under distributed load. With F1 car's wing made of composite material, specific sections of the wing can be lay-up to different structure and assumes different property(read, amount of deflection, unlike a uniform, homogeneous material). All the process obiviously have been studied in windtunnel and CFD/Aeroelasticity simulation. While material like carbon fiber is very strong, they can be engineered to specific need of the team, as the loading we are talking about is very high at speed(>1000lb is my guess). The bending is not the only movement occurs, the wing profile is most likely changing as well, as it may trim itself out at speed(reduce angle of attack, makes less downforce, and kills drag), while the slot-gap between planes reduces as well, achieving the same effect. This is effectively movable aero, only it is not disallowed by the wording of the rule as any engineer will tell you, everything will deflect under load, so the rule book builds in a static test criteria for deflection, which can be engineered to pass(a la floor spring of Ferrari and BMW), and the test are a poor representation of on track actual aero load(pointload vs distributed load, and cannot test individual axis of deflection).
University of Toronto Formula SAE Alumni 2003-2007
Formula Student Championship 2003, 2005, 2006
www.fsae.utoronto.ca
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