Renault R31

[NormalChris]

The fact that the inlet to the sidepods is larger than the outlet on most the cars could mean that there is some acceleration of the flow although I would think it negligible. On smaller formula car design you typically want the area to be the same. To expect a usable pressure increase through radiators, oil coolers, then through the exhaust manifold around the transmission and suspension is a little far fetched. Wouldn't there have to be some plumbing in there for it to feasible, or else every other car is wasting this opportunity? I think its just an additional area to exit the flow (besides the engine cover) that might be influential to the surrounding area. Possibly helping the discharge from the FEE? Gurneys on a diffuser are also very common.

[Twaddle]

The fact that the inlet to the sidepods is larger than the outlet on most the cars could mean that there is some acceleration of the flow although I would think it negligible. On smaller formula car design you typically want the area to be the same. To expect a usable pressure increase through radiators, oil coolers, then through the exhaust manifold around the transmission and suspension is a little far fetched. Wouldn't there have to be some plumbing in there for it to feasible, or else every other car is wasting this opportunity? I think its just an additional area to exit the flow (besides the engine cover) that might be influential to the surrounding area. Possibly helping the discharge from the FEE? Gurneys on a diffuser are also very common.

If my following assumption is incorrect, could you explain a bit more about the part I've bolded?

I'm assuming you mis-typed and are talking about velocity increase, rather than pressure, since getting heated by all those things combined with being in an enclosed space is what's likely to cause the pressure increase. While you would expect significant turbulence to be generatd by passing over all the cooling surfaces, the fact that sidepod exits appear to be so much smaller than the inlets suggests that there is an appreciable velocity increase. If there isn't then surely there must either be some other exits that we aren't seeing? That or they've built themselves a car with a couple of drag generating ovens strapped to the side.

[NormalChris]

I'm assuming you mis-typed and are talking about velocity increase, rather than pressure, since getting heated by all those things combined with being in an enclosed space is what's likely to cause the pressure increase. While you would expect significant turbulence to be generatd by passing over all the cooling surfaces, the fact that sidepod exits appear to be so much smaller than the inlets suggests that there is an appreciable velocity increase. If there isn't then surely there must either be some other exits that we aren't seeing? That or they've built themselves a car with a couple of drag generating ovens strapped to the side.

Im not sure whats going on, im saying that I dont think that the velocity of the air coming out at the back above the diffuser is blowing the diffuser.It really seems that the exits are smaller than the inlets but if combined with all possible venting it might match up closer than what it appears. Sidpods are drag inducing ovens yes? You can try to negate that in different ways to translate it into an advantage but I dont think "blowing" is whats going on at the back of the renault, but it could be. If it is I dont understand why other teams haven't used this in a more advantageous way.

[adrianjordan]

Could it just be that with the exhausts exiting where they do, Renault are being overly cautious in terms of cooling initially and we might see slimmed down openings once they better understand the requirements of their car with the FEE??

[Twaddle]

I don't understand how it works without choking up, but the difference in the size of the inlets and exits that we see so far suggest that it is.

I guess it could also be that it is actually choking up, but they're ramming enough air through it anyway to get sufficient cooling while also coping with the additional drag and finding a way to deal with the turbulence from the overspill. Maybe that's one of the functions of the FEE. I'm not sure how this would work either though and it's all starting to sound a little too far fetched.

Redbull have obviously been directing hot air (and not just via CH ) at the beam wing for a while, and others are looking more closely at what they're doing with it now too. There's evidence to suggest that Renault are trying something more extreme, but I'm really not seeing how it works so far without coming up with insane ideas like the one in the paragraph above. I guees that would answer your question about why the other teams aren't doing it too; they still have their sanity.

Adrian's post above is starting to seem more likely again, and was what I originally thought before noticing how small the apparent exits were. It still doesn't answer to what happens to all the air entering those huge sidepods in the current configuration though.

[AbbaleRacing77]

Like i said its not a unobstructed free flowing stream of air (we know this). But the air is still being pushed through. The air has to go somewhere especially at 200mph. And if its not... Then i would think theres gonna be some major cooling issues. Like i said... If it didnt work, it would be pretty unintelligent to design sidepods that big... And dont even try to tell me that its because its to make room for the forward routed exhausts. Its a 4 or 5 inch pipe not a sewage drain.

Ringo... that huge opening in the front of the side pod + 200mph = your mass flow for ya

***Perfect example--- Ever look at a super trap exhaust or a muffler in general? Would you agree that its turbulent? Now what has a more powerful flow... a muffler setup or straight pipes? Your answer... theyre exactly the same.. yes the muffler has more resistance and turbulence (nobody denies this) but under pressure theyre gonna flow the same amount of air because the same amout of air is coming out of the motor and being forced out the end of the exhaust. Your turbulence theory is irrelevent when under alot of pressure.

Now add a nozzle to the end of that muffler for a higher velocity (Nozzle= r31 tiny sidepod exits)... this is what renault is doing in theory

Im getting tired... can someone that understands take the night shift to explain this once again to the next person that tells me its
turbulent under the engine cover... Thanks

Renault radiator is equivalent to the muffler in the example.

The radiators are simply not restrictive enough to prevent large quantities of air being forced through the sidepods just like a muffler doesn't stop exhaust flow but only makes it a little more restricted.


For those of you still in doubt please reade my muffler example again...

[AbbaleRacing77]

If any of you have old radiators or even better high quality racing radiators like I do I suggest take your mouth and blow through it to see what kind of resistance you get. You'll find that it's very minimal and more turbulent but my muffler theory already rules out turbulence under constant pressure as way to stop airflow

[zgred]

They're wheel force sensors for building up their tyre simulation models...

see:
http://www.kistler.com/LI_en-ch/13_Prod ... -cars.html

[Blackout]

Ok, Normalchris. If blowing the diffuser is not the aim, why are these outlets shaped that way ? why are they very low placed and scarifying valuable space on the floor ?
Correct me if I'm wrong, but there is no air flowing directly on the diffuser and touching it, except the air that exits those outlets.

If the only purpose of the outlets was cooling, why Renault did not cut the bodywork somewhere near the blue line, for example, exactly like on the R30 and late version of the R29, and opened a big path toward the diffuser ? they could easily place the outlets there, just in front of the suspensions, like in the cars I mentioned.
They also had the possibility to tighten the coke bottle shape a lot and use a big outlet a la RedBull...



]

[NormalChris]

You know I dont know why it is they've designed it that way. Maybe they didnt want the end of the engine cover too bulbous and this is a new area to be exploited because of how tidy the rears are now. It looks like Williams is using the same area but with the driveshaft obscuring it. http://www.gpupdate.net/en/f1-photos/64 ... 78/#168978I dont know what its for I just know what came to mind when the idea was brought up. It's possible that it is blowing the diffuser. Its a new concept to keep the rear end really clean and chimneys ect. are banned so maybe this opportunity hasn't been available before and thats why its only come out now.

[Lindz]

Just speculation, but it did seem a few pages ago that there was a possible duct on the inside of the sidepod, close to the tub. This would be fed by 'clean air' and it would be able to 'blow' the floor (and help with the turbulent post-radiator air). I think both of these streams together are what exit the duct and blow the floor.

The sidepods are very oversize and the radiators are placed well outboard, leaving tons of room on the inside for a. exhaust pipes down low, and b. some sort of duct for this theory.

[Robbobnob]

Ok, Normalchris. If blowing the diffuser is not the aim, why are these outlets shaped that way ? why are they very low placed and scarifying valuable space on the floor ?
Correct me if I'm wrong, but there is no air flowing directly on the diffuser and touching it, except the air that exits those outlets.

If the only purpose of the outlets was cooling, why Renault did not cut the bodywork somewhere near the blue line, for example, exactly like on the R30 and late version of the R29, and opened a big path toward the diffuser ? they could easily place the outlets there, just in front of the suspensions, like in the cars I mentioned.
They also had the possibility to tighten the coke bottle shape a lot and use a big outlet a la RedBull...

Maybe by keeping the hot air exhaust low and above the diffuser the quality of air being directed onto the beam wing is more effective? whilst also creating a blown diffuser effect??

just food for thought, interested on your opinions

[Lindz]

Maybe by keeping the hot air exhaust low and above the diffuser the quality of air being directed onto the beam wing is more effective? whilst also creating a blown diffuser effect??

just food for thought, interested on your opinions

The ducting takes up prime real estate though. If all it was doing was venting hot air, it would be much more efficient to do that in a more neutral spot and free the space for external flow (massive amounts of air).

Besides all the other indicators, that alone should tell us they are doing something.

[marcush.]

the pressure drop across the radiator is depending a lot on air speed .so there is a law of diminishing returns.You increase airspeed increasing heat transfer ,but then you also increase drag numbers putting your idea ad absurdum .
To say the radiator core has no significant influence on drag is simply not true .
obviously this is not a free lunch.
You need to put a certain amount of air through the core to get your heat transfered .BUT you also need to maximise coolant flowspeed through the coolers without creating cavitation....I got some real world figures for a production sportscar with quite sophisticated radiators and the rad does effectively reduce air mass flow from 0,8kg/s to 0,49kg/s at only 33m/s vehicle speed .The cooling path is not setting the world on fire compared to a F1 car so the influence of the Radiator ina F1 car could be signifcantly more...

[spaman]

Couldn´t it be, that there is kind of a tunnel leading directly to the opening above of the diffusor?

Since the sidepods cause drag anyways they might have found out, that it is easier and more efficient to lead part of what "hits" the sidepod area through a tunnel within the bodywork and use this air for the diffusor.

So it might be a solution which is pretty similar to the idea of McLaren. But instead of using a channel as McLaren, they are using a tunnel.

The air which is not used for cooling (congested air) will search the easiest way to escape. At the same time the air led to the radiators has a better cooling effect, since it´s not slowed down by congested air.

Excuses for my english...