Renault R31

[Blackout]

Renault couldve made the exits out the bodywork like redbulls big hole out the back in order to create a better "undercut" sidepod but they didnt... They shaped the exits flat and smooth to direct air over the diffuser and they did it for a very good reason.

Yeah. Or they could do what they did with the R29; 'cut' the rear bodywork just in front of the Gbox/rear suspensions and let the air exit from there



I think the RB7 has simmilar but smaller outlets extended to the diffuser...

[Shafto]

Marcush the design of the bodywork seems to show otherwise and honestly i think your only guessing as to what the friction of the radiator is with no facts at all. This is Renault F1 not Daewoo, they can design a radiator with less drag if they want to and make them a little bigger to make up for the lost cooling (which definately looks plausible because the radiators look huge). For all i know they couldve had big bob in the boonies making these radiators by hand for the last year... nobody knows

And even if the radiators have high friction it shouldnt matter because were talking about air being rammed through a sidepod here... Im not talking about a freestream of uninterupted air. Air isnt gonna just bounce off the radiators, the air is gonna be forced through via constant pressure, and that air is gonna go somewhere. That "Somewhere" is a much smaller hole out the back which will result in a higher velocity well shaped flow of air over the diffuser. Your claim is like saying that you cant have a air ram intake because the airfilter creates some friction which we know in the 21st cetury is untrue. Why? because air ram has constant air pressure. Except the volume of air intake to the hole where it exits on the sidepods is an even greater ratio then a ram air intake. Which infact makes my theory very plausible and most likely true.

Renault couldve made the exits out the bodywork like redbulls big hole out the back in order to create a better "undercut" sidepod but they didnt... They shaped the exits flat and smooth to direct air over the diffuser and they did it for a very good reason.

Please dont make me whip out the crayons my drawing skills are terrible

Dude, you may be on to something here. I want to contribute a tad!

So we know by law, that if we constrict the duct that air is passing through, it will speed up. LAW. given that fact, we can say that with the R31, the air passing through the side pods will accelerate IF they exit where we are assuming.

BUT we have radiators in the way of our beautiful flowing duct. So whatever velocity we will lose through the radiator the question is will it be gained in the energy absorbed by heat? Then what velocity do we gain with the exit being smaller than the inlet? And for those of you saying that it will slow, that is impossible, if that is the case, less air is coming out than coming in and that would mean choke and huge drag problems! The SAME amount of air comes out the back as what goes in, just faster!

HAVING said that, I am not sure if that is what is going on.... but I would like to think so.

bed time

[manchild]

Sidepod is split in two. There is a tunnel between radiator section and chassis - heading backward, cools the exhaust and reduces the drag. Splitter is a vertical plate at certain angle to be parallel with the chassis that widens in the area of cockpit and further to fuel tank.

It has identical purpose as undercut, only this is better way to do it, since air doesn't have to go that much around the sidepods, but almost without being forced to change direction it passes trough the car with no obstacles, and can be used at exit as pleased for the benefit of diffuser.

Result is much harrow overall stream, which is also a benefit for getting the most out of exhaust blown virtual skirts.

I've been suggesting a tunnel between radiator and chassis more than 5 years ago - the day I've joined the forum.

viewtopic.php?f=6&t=1341

Unfortunately the images are gone, but the explanation stays.

[marcush.]

right ,some time ago this was discussed on this very site.Cool the xhaust but also create a largely unrestricted path to the difusser.Now thats making sense.

[Lindz]

Last year, RBR had long, multi-pass high fin count radiators layed at fairly extreme angles and packaged as tight as possible to the engine. Renault had smaller, more upright (maybe single-pass) rads. Both had the same engine. That is also a reason why they can fit those ducts in there. The shaping of the Renault sidepods exits all that air down low to blow the floor, and the air over the top to blow the beam wing.

For the sake of this theory I'll say that the drag induced by each car's radiators is roughly equal. The RBR has less air flow into the sidepod and uses this air only for cooling, thus why it expels it into a more neutral area. The Renault lets more air into the sidepod but it's radiators are less restrictive and they duct some more air around to cool the exhaust and blow the floor.

The Renault car is looking very progressive in this regard. They are blowing the front of the flor with the FEE, the rear of the floor with the sidepod cooling air, and the beam wing over the top of the sidepods/engine cover (similar to McLaren's theory with their L-shaped sidepods). They are betting that instead of 'wasting' that cooling air, they can re-use it at some sacrifice of the airflow around the body. RBR are betting that they can slim everything down to a minimum and optimize external airflow.

VERY interesting stuff!

[Boost]

right ,some time ago this was discussed on this very site.Cool the xhaust but also create a largely unrestricted path to the difusser.Now thats making sense.

Very similar design philosophy to that used by Audi on the R15 LMP car.

[Blackout]

right ,some time ago this was discussed on this very site.Cool the xhaust but also create a largely unrestricted path to the difusser.Now thats making sense.

Very similar design philosophy to that used by Audi on the R15 LMP car.

Have you more informations/photos about it ?

You can see heat sensors here on the floor. That could mean that the exhaust alsow blow above the floor !?

[horse]

You can see heat sensors here on the floor. That could mean that the exhaust alsow blow above the floor !?

I think it would give them an indication of what proportion of the exhaust gas is flowing above the floor - it's likely that at least some of it is. Useful for validation mainly, I suspect.

[Blackout]

Ok.

Look at the rear left wheel...

[SLC]

...and RF1 joins the world of full size pitot rakes

[horse]

Hmm, pitot tube array at the rear wheel. Would corroborate Ringo's CFD, which seems to indicate that a lot of the exhaust ends up there (although I still don't think the above/below split is right in his simulation).

Ringo's R31 CFD Study

[Lindz]

So I did a quick little illustration showing the theory we were discussing a bit...

The radiators were 'mocked up' based on last year's cars and photos of this year's cars that look into the sidepod inlets. *This is just to illustrate the theory, I'm not claiming to have some insider info*.

Note also that in the maily side view perspective, you don't get a full idea of how wide each car's radiators and thus sidepod flow is. For the sake of arguing, assume that the surface areas of the rads are almost the same, this is just showing how a larger flow through the sidepod (Renault) aided by the green slot duct can in theory be blown over the floor. This is possible because of the FEE.

The RB7 also blows it's floor/diffuser as well, but I'm only illustrating cooling differences between the cars. These are well and truly opposide ideas, quite cool!

[Lindz]

Also seems like Renault were trying this concept last year as well, but it was too compromised by having the exhaust pipes back there. Now with the FEE, they can slim the rear down so the beam wing has good flow, plus they have much more evenly dispersed air coming out of the sidepod to blow the floor with. This makes sense why they've been 'boasting' about the FEE so much... it may be very possible that's not the real innovation with this car, but the more people they convince it is, the better for them.

Other teams have said that they've tried the FEE, but it wasn't a real benefit to their car. Of course with Renault designing their floor around it from the get-go, their FEE is quite good but I suspect that teams might be thrown off as to why the R31 REALLY has a FEE.

We could all be talking a load of pants and the car could be a dog. Or, like last year and the F-Duct, we (F1 Technical) could be well on to something before most others. (I've been lurking the site for something like 4 years, just finally registered yesterday).

[horse]

(I've been lurking the site for something like 4 years, just finally registered yesterday).

Welcome! Great contribution. This car really is the "dark horse" of the pack. It will be very interesting to see if the team can turn all of this innovation into reliable pace.

[FrukostScones]