Tuesday, February 28, 2012

Aero rake in F1, RB8

A short article on what is aero rake (as usual, an attempt with simple words) and how it's being used in F1, for example Red Bull Racing and their front wing. The following picture is from Barcelona testing 2012, day 2, and is originally located here, at http://f1.f-e-n.net

Red Bull Racing (RB8, Barcelona 2012, day 2).
Photo credit: f1.f-e-n.net
Shown picture scaled down, larger image available (click)

Above you can see the setup of RB8 done at the front wing.
The idea is simple: through controlled setup to find out and understand wing's behavior in different airflows.
This is a useful data when you plan to use different wing ride height parameters, and in general to measure how the flow works out around the wing.

First, there are cables holding the wing and preventing the usual plunge. This is done in order to achieve constant results, usually used in conjunction with straight line permanent speed run.

Then, we have laser ride height sensors, which I can't spot on that picture, should be on endplates (if any at all) which are used to measure the ride height at the end of the wing. Usually, there's a third sensor in the middle, under the nose, who's a benchmark and the deviation would be your amount of flexibility.
I.E. the tips of the wing are measured to maintain max clearance of 10mm, whereas the center sensor shows
15mm, so the wing flexes at the tips up to 5mm compared to the center line. This way you can monitor and adjust your wing parameters.

The aero rake itself could be used for measuring air speed, angle flow, pressure (Pitot-Static probe) and even temperature. Since the cables are holding the wing and the lasers are measuring just how much exactly does it flex, the sensors on this two-row aero rake are collecting data on wing's wake and thus creating effective and data-rich info sheet.

What is really a Pitot tube?
It's a thin tube that has two holes - the front hole is located to face the airstream for measuring the stagnation pressure. For incompressible flow (where the material density is constant) it is a sum of the dynamic pressure and static pressureThe side hole measures the static pressure and the difference between these two is dynamic pressure, which can be used to calculate fluid flow and speed, in our case that's the air.

Another point of installment of aero rake could often be seen in front of the tires, or right behind the sidepods, for example, just like Red Bull did in Canada FP. That's a custom shaped 34 sensors grid mounted on a bulge, above the sidepod.
Image credit: formula1.com