http://scarbsf1.wordpress.com/category/f1-2012/ (I probably should have guessed Scarbs would have something on this!)
Maybe not the easiest read, but some nice pictures showing where exits are allowed and some analysis of the various options. If I may briefly try and summarise, using his drawings (hope he doesn't mind hotlinks!)
- The yellow boxes are where the exits can be. The last 100mm of pipe must be within this section.
- The last 100mm of pipe must also be round and be of 75mm internal diameter, with no obstructions (to stop people trying to manage the airflow)
- The angle of the exit is also defined:between 10 and 30 degrees from the horizontal axis (where the hour hand is on your watch between 2 o'clock and 2:40) and plus or minus 10 degrees from the car's centreline
- Crucially, there are also rules that say that you cannot blow onto any sprung element of the car between the exit and the rear axle line. This stops the idea I had to blow the engine cover or other bits for example and to use that to manage the airflow. This is looked at by drawing a cone from the exit extending 3 degrees outwards to the rear axle line. No sprung element can be in this cone.
- No other gasses can enter or exit the exhaust along any point in its length (which seems to address cold blowing)
Scarbs has a load more drawings on this, as well as an analysis of the elements that could be blown. He suggests a range of options which I will again summarise, but you should visit his site for the drawings.
- aero neutral - aim at the gap below the rear wing
- beam wing - unlikely he says
- suspension elements - these can be blown in front of the axle line as they are not sprung, but there are 5 degree limits the the angle of these components
- inner rear wing endplates - could create downforce but also a lot of drag
- rear wing underside - perhaps the most beneficial
- rear wing top - more downforce with less incremental drag
- outside rear wing endplates - may reduce drag while on throttle
- brake ducts - no sprung so again can be blown in front of axle, adding downforce directly onto the tyres
Although he doesn't mention it specifically, I think that blowing the DRS slot may also be a twist on 6.
It certainly seems that there are a lot of different avenues for the teams to explore...! No wonder Williams are getting started early. Comparing the pictures with Scarbs' drawings, it looks like the Williams position is about as close the the centreline and the rear of the car as they are allowed and is also seems they are close to maxing the angles (10 deg towards the centre and 30 deg up from the horizontal). Looking at their lap times, it certainly doesn't look like they are going to suffer greatly compared the the EBD, does it?
There is so much more innovation to come in this area over the winter, and what I like about it is how much more visible and obvious the exits now are and how much easier it will be to understand the effects. If I was betting, my money would be on a drag reduction system to supercharge the DRS, but I have no technical basis for that - ie. it's a wild guess
