Renaults Front exit exhaust

voxpop

Seems like a innovative idea from Renault - could be this years F-duct

link

Scarbsf1's Blog

Everything technical in F1
Renault R31 Front Exit Exhausts (FEE) – Explained

Renault have found a new solution to the blown diffuser concept. In fact they’ve turned it on its head. With an exhaust that exits at the front of the sidepods.

Last years teams reintroduced the blown diffuser concept, either by blowing exhaust gasses over the top of the diffuser, or by creating an opening into the diffuser to blow inside the diffuser. Both solutions created more downforce. With the latter solution now banned, it seemed the less effective over-blown solutions are all that’s left to race. However LRGP have found another way, blowing the front edge of the floor.

For a diffuser to create downforce it needs as much flow to pass through the venturi as possible. Teams arrange bargeboards and other aero devices to build up a high pressure region ahead of the floor to ensure the greatest mass flow underneath. Its then down to the expansion ratio of the diffuser to pull that flow through. Last years blown diffusers improved the expansion ratio, but not the flow ahead of the floor. What Renault have done in to lead the exhausts forward through the sidepods (about 1 meter) in-between the chassis and the radiators, then turn the exhaust 90-degrees to point it down towards the leading edge of the floor. The exhausts gasses follow the curved leading edge and round underneath the floor. This accelerates the flow under the floor for more mass flow and hence more downforce.

Problems with this solution are mainly to do with heat and engine mapping. With exhaust temperatures of 6-800c some clever insulation solutions are needed to keep hits heat from the fuel tank, radiators and a electronics. Then the Renault engine team lead by Rob White need to design exhaust tuning to deal with a far longer secondary pipe. typically longer pipes are better for low revs, somewhat contrary to the needs of an engine running at 18000rpm. Renault placed their KERS MGU and Battery underneath eh fuel tank, this was clearly to allow the packaging of the FEE. Unlike the McLaren F-duct, it is possible for this solution to be copied as no monocoque alterations are required.

voxpop

Ficus wrote: »

Its very clever thinking alright by the Lotus-renault boys indeed. But i suppose the most important thing from that write up is the last line "Unlike the McLaren F-duct, it is possible for this solution to be copied as no monocoque alterations are required."

Would it be that easy to copy? - even with the Renault car, its unclear whether they will have heat issues and the side pods are bigger than most others. Trying to shoe horn the setup into a car that wasnt designed for it during the season would be risky enough imo.

Cookie_Monster

Anyone care to guess how long before its banned then?

RayM

LIGHTNING wrote: »

I think its a brilliant piece of work by the Lotus boys, Chapman would be pleased.

It's very clever and innovative (and hopefully not too easy for the other teams to copy), but I doubt that Chapman would be very impressed at the idea of Toleman... Benetton... Renault trying to pass itself off as 'Lotus'. The car is a 'Lotus' in the same way as the Ferrari is a 'Marlboro'.

Ghost Train

Will be interesting to see if it works

still bit of time before start of season if other teams want to look into it,

Sounds tricky enough to design in

EvilMonkey

No point in trying to copy it until we see if it gives a significant advantage and doesn't overheat underside of the car or if the engine looses some performance. The Renault had one of the best engine for accelerating out of a corner last season.

McLaren are rumoured to be doing something similar, but i haven't seen any pics yet.

voxpop

seems redbull have their own take on getting around the banning of the blown diffuser - by channelling the exhaust gasses along the inner edge of the diffuser.




link

EvilMonkey

The Blown diffuser isn't banned everyone has one of some sort, double diffusers are banned.

voxpop

I thought they had new regs in regards to blowing exhaust gasses through the diffuser - i.e. the diffuser had to be solid bar a small hole for the starter,etc

EvilMonkey

I could be wrong but my understanding is the rear diffuser has to be a single piece with no holes(except the starter hole) in it and they cant have a hole in the floor to drive air through it. But their is no rule against driving the diffuser with exhaust gases.

They have banned the blown rear wing(made redundant by the adjustable rear wing anyway), and double diffusers.

Red Bull are getting round having no hole in the floor in the pic you posted, i think!

Ghost Train

http://scarbsf1.wordpress.com/2011/02/02/red-bull-rb7-open-fronted-exhaust-blown-diffuser/

According to the above there is still an area in the outer 5cm of the diffuser that can have openings

Renault put in fastest time today on the final day of the test today

Ghost Train

Good discussion here

http://www.f1technical.net/forum/viewtopic.php?f=6&t=9450

looks like it diverts some of the air hitting the leading edge of the floor out sideways, less air getting under the floor

don't really see it accelerating the air under the floor

Charlie-Bravo

Ghost Train wrote: »

Good discussion here

http://www.f1technical.net/forum/viewtopic.php?f=6&t=9450

looks like it diverts some of the air hitting the leading edge of the floor out sideways, less air getting under the floor

don't really see it accelerating the air under the floor

Less air getting under the car providing negative pressure, sucking the car down - more downforce.

But how much air is it diverting, is the whole design package banking on this innovation!!? Yesterday's testing times may indicate so, but until the first quali session we won't know...