Nissan LMP1 Discussion

[Mt. Lynx]

Originally Posted by cdsvg

The diffuser/floor produces downforce on it's own, independent of the rear wing. The rear wing can interact favourably with the diffuser if positioned near the trailing edge.

The underfloor (unless its flat), yes, but not the diffuser. It has to have a device that produces downforce over it, to do anything but directing airflow.

[miatanut]

Originally Posted by Mt. Lynx

The underfloor (unless its flat), yes, but not the diffuser. It has to have a device that produces downforce over it, to do anything but directing airflow.

Are we all talking about the same thing?

My understanding is the diffuser is the place at the rear of the car where the bottom of the car tapers upward.



There is negative pressure behind the car and the diffuser tapering upward increases the volume for the air and that induces negative pressure (for downforce) under the car.

You could have a diffuser helping create downforce under the car with no rear wing. The DeltaWing did that. If you have a rear wing, among other things, it increases the "hole" in the air behind the car, making a larger negative pressure area which draws even more air through the diffuser, creating even more downforce under the car.

[Mike E]

Originally Posted by MyNameIsNigel

Just giving further thoughts about the minimum area that the rear fin must have pursuant to Article 3.6.3 of the Technical Regulations. I note that the relevant provision actually refers to the visible area (in lateral view) and not the effective area of the fin:


This is even clearer in the French version of the provision:


If my understanding is correct, that would imply that the area of the fin that is masked by the rear fenders (in lateral view) will not be accounted for, but only the area of the portion of the fin that is visible from the sides.

Wheels having a smaller diameter at the rear (and therefore smaller rear fenders) may help increasing the visible area of the fin, but it remains to be seen if that 3000cm2 limit can be satisfied with a cockpit being pushed so far back as speculated.

Any thoughts ?

Maybe the fin will be very, very tall.

[jee]

Must the fin be behind the cockpit? Maybe they can put it infront of it without disturbing the view of the driver.
There is an upper limit for the fin that is not much higher (if at all) than the cockpit.

[Deleted]

Originally Posted by MoMedic9019

The 2000hp figure is intentionally misleading....it's designed to make people talk, and panic.

Electric motors develop peak power instantaneously, but don't maintain it..they maintain peak torque.

So, even if the system can develop 2000hp for just a few seconds, it's still 2000hp.

Isn't it the same case with Toyota's 1000hp...

[TF110]

Originally Posted by jee

Must the fin be behind the cockpit? Maybe they can put it infront of it without disturbing the view of the driver.
There is an upper limit for the fin that is not much higher (if at all) than the cockpit.

It can be on the "engine cover", but it cant be attached to the windscreen.

[flyingshoppingcart]

Originally Posted by TF110

It wasnt really Toyotas fault for a tire failure. Unforseen circumstances. Nissan and everyone else face the same thing.

The design of the TS020 made it more prone to serious tire failures. Toyota engineers themselves have admitted this over the years. The radical fender design contributed to tire failures. Toyota engineers admit that had the car been given more conventional fenders, the tire failures would not have been as catastrophic.

Originally Posted by MoMedic9019

The 2000hp figure is intentionally misleading....it's designed to make people talk, and panic.

Electric motors develop peak power instantaneously, but don't maintain it..they maintain peak torque.

So, even if the system can develop 2000hp for just a few seconds, it's still 2000hp.

No doubt. However be careful about drawing conclusions in general. The same logic cannot be used for all of the LMP1 machines.

If the peak power of both the electric motors and engine can be used at the same time, then yes a stated power figure is accurate.

If the total system power rating is calculated by some other convoluted method, which is very possible in the case of the Nissan, then yes it is misleading.

For example Toyota engineers have stated their electric motors in fact can make more power than the officially stated total of 480 or so HP. However their supercapacitor cannot store and release more energy than that. So instead trying to go for a gimmick marketing move, Toyota decided to be more honest. Their electric motors are therefore detuned from their maximum capability due the supercapacitor's limitation.

Maybe Nissan's electric motors make that much power, but maybe that much power cannot be released simultaneously. Who knows. We shall see soon enough. Overall I simply find it very hard to believe that the Nissan machine will be releasing or utilizing 2000 HP at the same time at any given point. I can certainly see it releasing or using 2000 HP in parts or over one lap.

[miatanut]

A couple different sources have stated they are using a flywheel storage system, not electric motors.

How much HP could you get out of the flywheel if you took it all in a tenth of a second? Of course it depends on the flywheel's geometry, mass, and how fast it's spinning, but you could take the energy out of it in a fraction of a second and snap the half shafts like twigs (or do the mother of all burn-outs). It all comes down to how much time you spend getting the energy out of it. In that sense, it doesn't have the limitations of electric motors.

[MoMedic9019]

Originally Posted by flyingshoppingcart

No doubt. However be careful about drawing conclusions in general. The same logic cannot be used for all of the LMP1 machines.

I wasn't assuming about all LMP1 cars...just Nissan.

I see them using their peak power in very short duration. 2-3 seconds, as a burst off the corner as a defensive move, or as a push to pass scenario.

I think Nissan will be in a "slow release" mode if you will. I think the goal will be to reduce fuel consumption over the duration of a stint using a true hybrid mode, versus adding power and or top end. If they can keep the fuel consumption lower than their competitors, they have a distinct advantage. This, to me, is the number one reason they are focusing on reducing drag as we've been told, and or assumed.

If they could pull a 16 lap stint at LeMans, they will have a massive advantage.

Hypothetically speaking, if a car has to stop 24 times over 24 hours, and a competitor has to stop 20 times..that's a huge lead by the end of the race.

[flyingshoppingcart]

Originally Posted by miatanut

A couple different sources have stated they are using a flywheel storage system, not electric motors.

How much HP could you get out of the flywheel if you took it all in a tenth of a second? Of course it depends on the flywheel's geometry, mass, and how fast it's spinning, but you could take the energy out of it in a fraction of a second and snap the half shafts like twigs (or do the mother of all burn-outs). It all comes down to how much time you spend getting the energy out of it. In that sense, it doesn't have the limitations of electric motors.

Correct. Electric motors or flywheel, either way it makes the rumored power figure suspect.

Or what if the flywheel can actually handle that much HP, but it cannot release all at once?

All very pertinent questions which make it probable the Nissan's total power rating can only be utilized "in parts".

[flyingshoppingcart]

Originally Posted by MoMedic9019

I wasn't assuming about all LMP1 cars...just Nissan.

I see them using their peak power in very short duration. 2-3 seconds, as a burst off the corner as a defensive move, or as a push to pass scenario.

I think Nissan will be in a "slow release" mode if you will. I think the goal will be to reduce fuel consumption over the duration of a stint using a true hybrid mode, versus adding power and or top end. If they can keep the fuel consumption lower than their competitors, they have a distinct advantage. This, to me, is the number one reason they are focusing on reducing drag as we've been told, and or assumed.

If they could pull a 16 lap stint at LeMans, they will have a massive advantage.

Hypothetically speaking, if a car has to stop 24 times over 24 hours, and a competitor has to stop 20 times..that's a huge lead by the end of the race.

Perhaps. Whether the tires will hold up will be a different and equally important matter entirely.

You cannot escape physics. Having that much weight and much of the downforce up front, combined with the inertial mass and forces on the front tires during braking and cornering will make for an interesting show.

[MoMedic9019]

Originally Posted by flyingshoppingcart

Perhaps. Whether the tires will hold up will be a different and equally important matter entirely.

You cannot escape physics. Having that much weight and much of the downforce up front, combined with the inertial mass and forces on the front tires during braking and cornering will make for an interesting show.

And therein lies the fun....we assume the car to be quite heavy. I actually think the reverse. I think it's going to be quite light without the KERS and ancillaries...i see those bits working like the ballast to make up the difference. When the builder can locate the weight where they want it, it makes for perfect weight distribution to the design.

As far as tires go...well...if Bentley could quad-stint in 2003, there is little reason to think that isn't plausible now with the right conditions.

[miatanut]

Originally Posted by flyingshoppingcart

Correct. Electric motors or flywheel, either way it makes the rumored power figure suspect.

Or what if the flywheel can actually handle that much HP, but it cannot release all at once?

All very pertinent questions which make it probable the Nissan's total power rating can only be utilized "in parts".

Electric motors have genuine limits of how much torque they can produce. A flywheel, in theory, does not. The torque it can produce approaches infinity as the time approaches zero. It's kind of like crash energy absorption. G forces go up as time dissipating the energy goes down.

A Flybrid could produce 1,400 HP. Just not for very long.

But maybe not very long is long enough to launch you out of a corner.

[MoMedic9019]

Originally Posted by miatanut

Electric motors have genuine limits of how much torque they can produce. A flywheel, in theory, does not. The torque it can produce approaches infinity as the time approaches zero. It's kind of like crash energy absorption. G forces go up as time dissipating the energy goes down.

A Flybrid could produce 1,400 HP. Just not for very long.

But maybe not very long is long enough to launch you out of a corner.

In all honesty, its a matter of the physical limits of the flywheel....

[miatanut]

Originally Posted by MoMedic9019

In all honesty, its a matter of the physical limits of the flywheel....

Right.

The one on the Hope LMP was "only" 100 KW
http://www.flybridsystems.com/CFTKERS.html

This would be ten times that size. They say that system was 37.9 KG with controllers and everything. A system ten times that size might have two or three flywheels in it, maybe more, and would gain some efficiencies by one controller and other components serving a lot more energy storage.

Certainly it would be no small task, but Flybrid will have made some advancements in four years.

[TME45]

Originally Posted by miatanut

Right.

The one on the Hope LMP was "only" 100 KW
http://www.flybridsystems.com/CFTKERS.html

This would be ten times that size. They say that system was 37.9 KG with controllers and everything. A system ten times that size might have two or three flywheels in it, maybe more, and would gain some efficiencies by one controller and other components serving a lot more energy storage.

Certainly it would be no small task, but Flybrid will have made some advancements in four years.

maybe no chance for hybrid
as I remember, WEC & F1 are not allowed changeable transmission ratio of hybrid, but flybrid need a cvt to match the speed of car & flywheel.

however, I remember that flybrid have their own flywheel battery


& if they won't go electric, then the ZEOD RC which a car have only have one race they spend hole year on it is mean nothing.

[MoMedic9019]

Originally Posted by miatanut

Right.

The one on the Hope LMP was "only" 100 KW
http://www.flybridsystems.com/CFTKERS.html

This would be ten times that size. They say that system was 37.9 KG with controllers and everything. A system ten times that size might have two or three flywheels in it, maybe more, and would gain some efficiencies by one controller and other components serving a lot more energy storage.

Certainly it would be no small task, but Flybrid will have made some advancements in four years.

Worth about 140hp. If Nissan is going to develop 1400hp, the Flybrid has to make 1050-ish Kw, 1043.9 Kw to be exact. That's a tall order, but, depending on mass, rotational speed, and harvesting, I'm guessing it's completely plausible.

Having said that...I floated the idea that Nissan is using the petrol engine as a generator, versus harvesting fully off the transmission. If they would do this, and essentially have a PTO for the KERS...that changes things. They could be in a near constant charge/discharge mode.

[cokata]

Is "flybrid" allowed by the rules though? I was under the impression that only hybrid systems that use electric motors are allowed.

[MoMedic9019]

Originally Posted by cokata

Is "flybrid" allowed by the rules though? I was under the impression that only hybrid systems that use electric motors are allowed.

It's completely legal.

[TF110]

I dont think any electrical powertrain is allowed.

[TF110]

Sorry, that should read I dont think any electrical power train is excluded.

[CyberMotor]

Originally Posted by miatanut

Electric motors have genuine limits of how much torque they can produce. A flywheel, in theory, does not. The torque it can produce approaches infinity as the time approaches zero. It's kind of like crash energy absorption. G forces go up as time dissipating the energy goes down.

A Flybrid could produce 1,400 HP. Just not for very long.

But maybe not very long is long enough to launch you out of a corner.

Great stuff!

[MyNameIsNigel]

Originally Posted by MoMedic9019

It's completely legal.

Indeed, but they need to homologate a proper means to measure the amount of energy released from the unit.

[Mt. Lynx]

Originally Posted by miatanut

Are we all talking about the same thing?

My understanding is the diffuser is the place at the rear of the car where the bottom of the car tapers upward.



There is negative pressure behind the car and the diffuser tapering upward increases the volume for the air and that induces negative pressure (for downforce) under the car.

You could have a diffuser helping create downforce under the car with no rear wing. The DeltaWing did that. If you have a rear wing, among other things, it increases the "hole" in the air behind the car, making a larger negative pressure area which draws even more air through the diffuser, creating even more downforce under the car.

Absolutely correct. And it produces no DF on its own. It needs something over it that produces drag, be it the bodyshape of the car, or a wing. A flat bottom and a diffuser will most likely generate DF on just about any car, since they most likely produce drag.

[cokata]

Originally Posted by Mt. Lynx

Absolutely correct. And it produces no DF on its own. It needs something over it that produces drag, be it the bodyshape of the car, or a wing. A flat bottom and a diffuser will most likely generate DF on just about any car, since they most likely produce drag.

Wrong. It produces downforce the same way a wing does only much more efficiently. You create a pressure difference. The air is accelerated and therefore looses pressure beneath the car, and the diffuser acts as a expansion chamber, giving the air room to expand reducing it's speed and increasing it's pressure. And that pressure differential is what creates the downforce.