[WEC 2015]Nissan GT-R LM NISMO

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dmjunqueira
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Re: [WEC 2015]Nissan GT-R LM NISMO

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Artur Craft wrote:My take on the discussion of GT-R LM front diffuser is that it will likely either failure massively or start a trend.
I'm not able to evaluate it as an aerodynamics expert, but I don't think that they would invest so much money on a untested concept and risk a massive failure...They probably tested a scale model on a wind tunnel before (at least). Although this solution for the front diffuser may prove not to be the best, and then fade to oblivion as seems to have happened to Delta Wing.

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Artur Craft
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Re: [WEC 2015]Nissan GT-R LM NISMO

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What you're saying makes sense.

But all we can do is speculate and, on the other side, it's very likely that Audi, Porsche, Toyota, Peugeot.... have all tested the "front diffuser exit on the back rather than behind front wheels on the sides of the car" on CFD(at least) and opted to not go that route.

Teams(such as Lotus, in F1, with their front exhaust blowing in 2011) come up with inovations(or different approaches) from time to time and not always it proves to be a success.

I heard people from Nissan already admitted to some journos that the car will be a sitting duck everywhere but Le Mans and, if true, this tells us this solution could be much more about drag reduction rather than creating more downforce.

If Nissan do post their downforce values at some point, it will be interesting to compare with the 2011 Dome LMP1(a car a la Audi and etc) that I have

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Artur Craft
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Re: [WEC 2015]Nissan GT-R LM NISMO

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With air hitting the front of the GT-R LM NISMO, it envelops the car-flows beneath the car via the splitter, and heads over and around the body. By moving the engine and all of its friends to the front, Bowlby was able to create a pair of rectangular tunnels that take their feed from the trailing edge of the splitter’s upswept wing profile and carries large volumes of air around the cockpit and out the highly tapered tail section.

It’s similar to a catamaran design where the center portion of the car-the one that punches a big, disturbing whole through the air has been taken away to allow the air to pass through the area with ease. By using the empty sidepods as a bypass, Bowlby has significantly reduced aerodynamic drag, and in Nissan’s quest to win through innovation, this core design element should produce improved fuel economy, among other benefits.

“That is the complexity of the regulations, or the interest in the regulations, and why we turned the car on its head, because we wanted to produce an aerodynamically efficient car,” said Bowlby. “It is very simple. Rather than have to take the air that comes underneath the splitter and force it to take a longer path down the outside of the car by venting it behind the front wheels, then blending it into the air flow down the side of the car and basically pushing it out that way, which makes the car seem wider and less efficient.

“We gave it an easier path so the air comes underneath the splitter and comes out above the diffuser. It is a more optimized path. And before everybody jumps on the great idea of how cool that would be to do, just try doing it!”

At approximately 15 feet in length, you can stand at the back of the Nissan, and when the lighting is just right, see all the way through the tunnels and spot the front suspension. Crouch down and take a closer look, and you’ll notice the tub tapers inward starting just below the cockpit openings. Referring back to marine concepts, it does bear a resemblance to a high-performance hull, and in this case, Bowlby has done all he can to make the bottom half of the tub less of a slab-sided creation and more like a “V” to increase the volume of air passing through the built-in tunnels.

As I mentioned in my behind-the-scenes story, seeing the GT-R LM NISMO run in the wet at Circuit of The Americas [LINK], and the interaction between the spray and the Nissan’s through-flow aerodynamics, was unlike anything I’d witnessed with other LMP1-H creations.
The car underwent just two days of windtunnel testing prior to the beginning of its testing program. Thousands of hours of virtual aerodynamic testing through CFD, however, continues to be logged.
http://www.dailysportscar.com/2015/02/0 ... by-qa.html

If you want to understand this car, worth reading all of it!

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PlatinumZealot
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Re: [WEC 2015]Nissan GT-R LM NISMO

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Artur Craft wrote:What you're saying makes sense.

But all we can do is speculate and, on the other side, it's very likely that Audi, Porsche, Toyota, Peugeot.... have all tested the "front diffuser exit on the back rather than behind front wheels on the sides of the car" on CFD(at least) and opted to not go that route.

Teams(such as Lotus, in F1, with their front exhaust blowing in 2011) come up with inovations(or different approaches) from time to time and not always it proves to be a success.

I heard people from Nissan already admitted to some journos that the car will be a sitting duck everywhere but Le Mans and, if true, this tells us this solution could be much more about drag reduction rather than creating more downforce.

If Nissan do post their downforce values at some point, it will be interesting to compare with the 2011 Dome LMP1(a car a la Audi and etc) that I have
The front diffuer the nismo gtr has is better than having none at all. Regular gt cars dont have the benefit of a front diffuser and they still make very good downforce so just because the one on the nismo gtr has a slighty longer throat doe not mean it wont enhance the front splitter effectively.

My take on the tunnels is that they are essentially there to keep turbulence outside amd to give a better exit condition for the dront diffuser. Imagine if there were no tunnels but just the flanks of the fuselage alone; all sorts of unwated turbulence front the front wheels would disrupt the wake coming fron the front diffuser.
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PlatinumZealot
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Re: [WEC 2015]Nissan GT-R LM NISMO

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dmjunqueira wrote:They say that the rear wheels will be driven by the energy recovery system.
Of course much less power on rear wheels, but this "little" power may help on acceleration after slow corners.

You can see that there are half shafts on rear wheels...
http://www.racer.com/images/igallery/re ... 6-80-c.jpg
The flat disk that the half shaft is coming out of.... Could it be some sort of motor? There has been talk of a dropshaft arangemet but the photo clearly shows no such thing; the top pannels of the tunnel is just not thick enough to hous a drive shaft. It seems to me that the disks there is a motor or maybe a chain sprocket.
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Youhavebeendunn
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Re: [WEC 2015]Nissan GT-R LM NISMO

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PlatinumZealot wrote:
dmjunqueira wrote:They say that the rear wheels will be driven by the energy recovery system.
Of course much less power on rear wheels, but this "little" power may help on acceleration after slow corners.

You can see that there are half shafts on rear wheels...
http://www.racer.com/images/igallery/re ... 6-80-c.jpg
The flat disk that the half shaft is coming out of.... Could it be some sort of motor? There has been talk of a dropshaft arangemet but the photo clearly shows no such thing; the top pannels of the tunnel is just not thick enough to hous a drive shaft. It seems to me that the disks there is a motor or maybe a chain sprocket.
In the picture of the naked car, if you look closely you can assume that they are using drop gears and that they enclosed the driveshaft into the lower arm like they do in formula 1.

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dmjunqueira
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Re: [WEC 2015]Nissan GT-R LM NISMO

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PlatinumZealot wrote:
dmjunqueira wrote:They say that the rear wheels will be driven by the energy recovery system.
Of course much less power on rear wheels, but this "little" power may help on acceleration after slow corners.

You can see that there are half shafts on rear wheels...
http://www.racer.com/images/igallery/re ... 6-80-c.jpg
The flat disk that the half shaft is coming out of.... Could it be some sort of motor? There has been talk of a dropshaft arangemet but the photo clearly shows no such thing; the top pannels of the tunnel is just not thick enough to hous a drive shaft. It seems to me that the disks there is a motor or maybe a chain sprocket.
I considered it too...but I don't think so, because the wall that supports it is not thick enough. Even if they are using a thin motor, like Lynch motor (the one on top of the picture below), that would be thicker than that wall and would protrude inside the internal tunnels.
Image

On the picture below, you can see that there are two horizontal structures that stick out of the chassis to support the rear suspension...My guess is that the shaft that powers the rear wheel is enclosed inside the bottom structure (the thicker one) and they use some kind of transmission (drop gear, chain sprocket, really don't know) to connect it to the half shaft that is placed a little higher.
Image

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PlatinumZealot
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Re: [WEC 2015]Nissan GT-R LM NISMO

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I dont see anything beneath the the cricular cover (i guess i wont call it a disk anymore) and the horizontal structure is very thin for a shaft to fit into. I have some doubt that a shaft can fit in the Lower horizontal wall of the tunnel. A shaft has to have some sort of mating and that mating whether a coupling, some splines and a circlip, a tripod, whatever you want to use, will be larger in diameter than the shaft itself. So you would be seeing another small circular bump or such at the bottom corner of the tunnel below the "circular cover"

The vertical wall where the circular cover is mounted to, seems about 3 to four inches thick. I still think a flat motor could fit in there. It could be electric, hydraulic or pnuematic.

Image
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Pierce89
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Re: [WEC 2015]Nissan GT-R LM NISMO

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PlatinumZealot wrote:
Artur Craft wrote:What you're saying makes sense.

But all we can do is speculate and, on the other side, it's very likely that Audi, Porsche, Toyota, Peugeot.... have all tested the "front diffuser exit on the back rather than behind front wheels on the sides of the car" on CFD(at least) and opted to not go that route.

Teams(such as Lotus, in F1, with their front exhaust blowing in 2011) come up with inovations(or different approaches) from time to time and not always it proves to be a success.

I heard people from Nissan already admitted to some journos that the car will be a sitting duck everywhere but Le Mans and, if true, this tells us this solution could be much more about drag reduction rather than creating more downforce.

If Nissan do post their downforce values at some point, it will be interesting to compare with the 2011 Dome LMP1(a car a la Audi and etc) that I have
The front diffuer the nismo gtr has is better than having none at all. Regular gt cars dont have the benefit of a front diffuser and they still make very good downforce so just because the one on the nismo gtr has a slighty longer throat doe not mean it wont enhance the front splitter effectively.

My take on the tunnels is that they are essentially there to keep turbulence outside amd to give a better exit condition for the dront diffuser. Imagine if there were no tunnels but just the flanks of the fuselage alone; all sorts of unwated turbulence front the front wheels would disrupt the wake coming fron the front diffuser.[/quote?
Where did you get the idea that "regular gt cars" don't have front diffusers? All of the current GTE cars use front diffusers. Even Nascar uses a front diffuser, but in Nascar talk it's a "radiator pan". I guess that came from the culture of trying to trick the Nascar officials about DF enhancing ducting etc.
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NoDivergence
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Re: [WEC 2015]Nissan GT-R LM NISMO

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Their admission that the car was primarily built for Lemans is because of their powertrain choice. The car is primarily a FWD car.

Other manufacturers (Audi, Toyota, etc) have not even thought to do this front diffuser layout because they simply can't. They have radiators, intercoolers, electric motors, and a honking engine in the back taking up all the room.

Scania
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Re: [WEC 2015]Nissan GT-R LM NISMO

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machin wrote:I think this is an interesting comparison of the space available at the front ends of the Nissan and Audi... Remember the Nissan, with its front weight bias, needs to generate more front downforce than the Audi to have equal performance...

http://www.competition-car-engineering. ... arison.jpg

The question is; do those nice clear tunnels running to the back of the car make up for what appears (to me at least) to be a smaller front diffuser volume....? I certainly don't know but am fascinated to find out!

Also, I'm loving the fact that Nissan have released all these photos for the fans... I like the ones of the car without the bodywork... you can see that it is rather like a Deltawing in reverse (without the narrow track at the non-engine end of course!)...

Interestingly I saw Ben Bowlby give a talk on the Deltawing a few years back (when it was first released to the public) and he said that he had originally thought about putting the heavy/wide end at the front, and the reason he didn't was because of the acceleration effect losing traction on the driven wheels... of course, the fact that this thing has AWD means that problem effectively goes away...
we will need the help of 458 to take a photo of the down side of GTR LM :twisted:

& i think the real main point of stable is make a strong axle & weak axle, so the movement of the car will be one way & linear. if a car have equal loading axle, it will go under or over steer under different loading distribution.

GTR & DW/ZEOD are also have strong axle & weak axle, so the driver will very easy to feel how will the car turn, even it losing control, it still very easy to turn it back.

Blankow
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Joined: 25 Jan 2015, 13:02

Re: [WEC 2015]Nissan GT-R LM NISMO

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Can anyone tell me where the intercoolers get their air from and where it will exit? It looks like they are not included in the "normal" watercooler package at the front. They should be right next to the engine as the pipes show and maybe the front diffusor geometrie will rise behind them.

Anyone knows more here?

RacingManiac
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Re: [WEC 2015]Nissan GT-R LM NISMO

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Someone found some pictures with the previous NISMO Flickr pics that a someone is working on a part looks like an air-to-water intercooler...

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SectorOne
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Re: [WEC 2015]Nissan GT-R LM NISMO

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At first glance i just thought what a total disaster this is gonna be.
Then as i read more and more i came to the realization that it´s actually one of the coolest racing machines ever built.

I´m hoping it will do really well but it remains to be seen. If this thing blitzes everyone i assume there will be a bit of a paradigm shift in Le Mans prototype class.
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bit1817
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Re: [WEC 2015]Nissan GT-R LM NISMO

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SectorOne wrote:At first glance i just thought what a total disaster this is gonna be.
Then as i read more and more i came to the realization that it´s actually one of the coolest racing machines ever built.

I´m hoping it will do really well but it remains to be seen. If this thing blitzes everyone i assume there will be a bit of a paradigm shift in Le Mans prototype class.
if this car will be running shortly behind AudiPorscheToyota all of the three will rethink their approach to build Prototype racing cars.
Because what we know till now...Nissan is following a pretty clever approach...the only thing is...will it be as fast as they think it should be?
And what we also know...Nissan is not having the money and possibilities of development which Audi Toyota and Porsche have.

When will the first tests take place?

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