Renault’s radical R31 exhaust system

By: Sam
Article Source: http://www.racecar-engineering.com/articles/f1/renaults-radical-r31-exhaust-system/

Renault’s engineers were given a short simple design brief with the R31, “be daring, try to innovate, take risks.” They have taken this to heart with the exhaust system design, during the very brief car reveal it quickly became clear that the car had no obvious exhaust outlets. Instead the rear bodywork is continuous aside from the exit duct for the gearbox oil cooler.

It is thought that the exhausts run forward from the engine bay and exit near the side pod inlets though there are no obvious apertures or heat shielding was evident at the launch they were revealed during the cars first runs.

This is because the exhausts were blanked off by a triangular plate (see above), compare to the below with plate removed.

Note the outlet behind the turning vale, the exhaust pipe is oval in section and split in two. A metal heat shield protects the carbon fibre floor ahead of the outlet, whilst a ceramic thermal barrier coating protects the areas to the rear. Heat management is critical in 2011 and no more so in the sidepods of the R31!

The exact benefit of this is unclear though Renault Technical Director James Allison did allude to it during the launch event. “It’s true to say that the car has been designed in an ambitious manner and a quick glance at the layout will confirm that its entire concept differs considerably, not just from last year’s car, but from any car this team has ever produced” explains Allison. “Those changes represent our attempt to extract the absolute maximum aerodynamic performance from the regulations, which have changed quite significantly for this year, and to further develop the concept of using the exhausts to blow the floor.”

A look at the RS27-2011 engine reveals a little more, with the four exhaust pipes merging into one as usual but this pipe the loops back and downwards. This is a significant departure from previous layouts, though where the gasses travel from there is yet to be established. It has been both hinted at and speculated that the gasses exit further forward than in any other design and possibly driving the car floor from much further ahead than is conventional. Allison is not letting on much yet but another team source added “the exhausts are not at the back, I’m not sure what can be said about them but you will only see them if you know where to look.”

Allison’s contribution added background information but few specifics “we set out to try ad to and conceive a car that wasn’t just smaller, lighter and stiffer, but one that would jump us up the grid. The guys up top said to us that they were ok with us taking some risks to have a go at something that was different that will hopefully bring us an advantage. The risk is that the layout of a Formula 1 car has been settled for some while and it's quite tricky to package all of the stuff you need into the space that is available. You make much of a change to that and you are in virgin territory, you find out as you go along what happens. We have gone with a layout that is different, different to last year, different to any year I can remember.  It is one which I think has a lot of promise and it is one which I think is going to deliver what we want and I hope we have done enough basic engineering on it to keep it sensible and reliable.”