Nissan takes a brave leap in Le Mans
 

A revolutionary shape and approach, Nissan will support the 'Batman' DeltaWing, to be tested @ Le Mans- June 16 - 17!!
The radical aero/chassis configuration and turbocharged 4-cylinder will showcase pioneering technologies. Extreme solutions on aerodynamics & weight reduction created an unusual racing package. The Nissan team has well-seasoned partners - designer Ben Bowlby, motorsport icon/businessman Don Panoz, F1 legend Dan Gurney, championship team Highcroft Racing and Michelin Tires. Confirming drivers, Marino Franchitti & Micharl Krumm. Rulebook be damned AND burned! This should be a very interesting & historic attempt.

http://www.youtube.com/watch?v=DlLZ3d-X8aY

Not too long ago, 1-2 years a very similar design was being promoted for F-1. I think it had the same name, Delta-Wing.

I like the idea of a low frontal area, but isn't this going to handle like a 3-Wheeler?

The 'Made in the USA' DeltaWing team has been in development since 2009 for the IndyCar Series. Chip Ganassi supported the initial development but chose a Dallara design instead. It has been picked up by Nissan for the 2012 24 Heures du Mans. The delta wing shape is so unique & so narrow it is looks like it would not work in the wildly changing dynamics of road racing. The engineering/design criteria targets are utmost aerodynamic efficiencies & lightest structural weight (Colin Chapman is fluttering his wings). Ben Bowlby wins Aerodynamicist of the Year award. Michelin designed & developed specialized performance tires. Only 4" wide x 15" front wheels! ALMS champion Highcroft Racing will manage the endurance race preparations.

But still, how will it turn?!!!

It's a shame the design wasn't chosen for IndyCar... but such a revolutionary design would have to prove itself before being let loose on the track.

From what I can tell from the literature (just finished writing a feature on this for another website), the center of gravity is far back between the rear tires. This means there's almost no load on the front tires.

While this ought to mean that turning will be difficult, 911s seem to turn all right with the engine and most of the weight slung out behind the back axle. Furthermore, the DeltaWing will be

The layout is incredible. The front tires are tiny, the front brakes are tiny, the front suspension looks like what you'd see on a bicycle. Dry weight is under 500 kgs, around 200 kgs less than what an unrestricted gasoline LMP2 would weigh and some 300-400 kgs less than the diesel LMP1s.

The big question is whether the low weight and low overall drag will balance out the lack of power down those looooong straights at LeMans.

On a 911, braking torque cause by the front wheels shifts the center of inertia to a 50/50 weight balance during hard braking (entering a turn).

They also have the weight in the back for traction for powering out of a turn.

I'll post the simple diagram illustrating this, which I recall - once I find it.

Here is a thread on the topic:
Weight transfer vs brake bias - Page 2 - Pelican Parts Technical BBS

I wouldn't drive that at high speeds.

It's backwards, in terms of aerodynamic efficiency and stability.

Cool! We'll see how it works. I like this class of Le Mans cars, and I hope they are the beginning of a new trend. They did this back in the 1960's with the Panhard LM64 -- that car only had a 1L 2 cylinder motor and could go ~155MPH. This car with a 1.6L should go at least that fast.

[youtube]zs_wnHNbVCA[/youtube]

Some better pictures of the Nissan DeltaWing:

http://blog.caranddriver.com/wp-cont...-race-car3.jpghttp://www.benzboost.com/images/impo...racer_01-1.jpghttp://www.automotorblog.com/wp-cont...eltaWing-1.jpghttp://www.inautonews.com/wp-content...-le-mans-2.jpghttp://2.bp.blogspot.com/-Vc_Lf1EUb6...ltaWing_03.jpg

If nothing else, it could be the next Batmobile! :-)

Is that the blue car which you post once in a while?

I cannot seem to find information on it.

Edited version............for debate
Automobile 2 - Odds and Ends pictures by kach22i - Photobucket
http://i184.photobucket.com/albums/x...-race-car3.jpg
http://i184.photobucket.com/albums/x...racer_01-1.jpg

I would have assumed that a shorter, or more conventional wheelbase would be more stable, but still unstable.

The extra length makes it look like a dragster.

The reason for a dragster's length is the torque and counter moment arm of the length to balance it, right?

Do these two designs (Delta Wing and Dragster) have anything in common?

I just had to share this little find.

Random TRANSPORTATION pictures - Page 706 - Pelican Parts Technical BBS
http://forums.pelicanparts.com/uploa...1331754278.jpg

No new ideas under the sun?

Welcome to the home of the VIGILLANTE

If trikes can kick handling arse, near trikes should be able to.

I'll wager that if this batmobile is a success the racing bodies will ban it from competition, just like the fan car and rotary engine.

Google search Panhard LM64. 64LM indeed does not find much!

http://www.carpictures1.com/var/resi...c_1275x777.jpg

On the DeltaWing, the COG is so far back that even under braking, the rear tires do most of the work.

Apparently the long nose acts like a lever arm, with such a long arm pivoting around the rear tires, very little force needs to be applied to turn the front end. Similar to a 911 in steady-state cornering (that pendulum thing)... only even more extreme.

This one is new to me, thanks for posting it.

I'm a big fan of 3-wheelers.

Thanks, I thought it was that one.

You mean like this?
http://www.ivy50.com/story.aspx?sid=10/26/2006
http://www.ivy50.com/images/sidebars/029-morrell2.jpg

The Cg on a trike projected as a 45 degree cone to the ground forms a circle, and that circle *must* be within the triangle formed by the tire contact patches. This DeltaWing is technically not a trike, but it might as well be. Under hard braking and hard cornering at the same time would really threaten the stability of this layout.

It is odd that *both* the stability and the aerodynamics would be better if the two (widely spaced) wheels were in the front. Then the wheelbase could be shorter because the weight shift under hard braking and hard cornering would move the Cg closer to the wide track wheels and this would be far more stable.

I'm having a difficult time visualizing this, do you have a diagram?

I found some related information here:
http://www.deferredprocrastination.c...cle-stability/

As your plan view triangles show, the lengthened wheelbase puts more lateral distance between the center of gravity and the line between the two wheels on one side, thus giving the same benefit in reducing weight transfer to the outside wheels in cornering that you would get from a wider track.

I can't imagine why you would think a shorter wheelbase would be more stable. Dragsters and land speed record cars, which only want to go straight, run long wheelbases
The longer the ratio of wheelbase to CG height, the less weight transferred from the front to rear wheels at a given acceleration rate. Thus a longer wheelbased dragster can run a higher percentage of static weight on the rear wheels without wheelying.

This assumes a 1 G maximum cornering speed, and neglects aero downforce. The principle is correct, though.
True, but you don't need to do that.
If the widely spaced wheels were at the front, and the CG were near the rear, your 45 degree cone would fall outside the triangle. If the CG were near the front, you'd need FWD or AWD for any sort of decent acceleration.

As to the aerodaynamics of widely spaced rear wheels, if you assume a single, eenveloping body, you're right. If you think of the main body and each rear wheel as separate teardrops, then the wide space rear wheel setup looks pretty good.

This is incorrect.

Three-Wheel Vehicle Handling Characteristics

http://www.rqriley.com/images/fig-3whl.gif

The reverse trike is much better for aerodynamics and for high speed stability than the trike; all else being equal. Just look at the ideal template and see how to best put it on 3 wheels.

Nope, sorry. A shorter wheel base would have required much wider front tires and as a result wider front end. If they reversed the configuration there wouldnt be enough traction in the back and they would be giving up all the aerodynamic benefits. Don't forget that this is a racecar which is either accelerating or braking at all times. The engineers got it right. Also this isnt a trike.

http://www.gordonkirby.com/images/co...10/GK235-2.gif

They want fast steering response so they did it correctly.

Remember also that that COG isn't precisely centered in the vehicle, but very far back... supposedly on the rear axle itself... so the balance is not quite the way we expect it to be.

I'd gather that's the reasoning for the really long wheelbase. Those two front wheels being way out in front gives back the stability lost with the format. But the issues with getting power down in a reverse trike are harder to mitigate.

Now, this is a high power to weight ratio racer, I can imagine a reversed layout was considered, but a single (or narrow pair) driven rear wheel probably didn't meet the traction requirements for acceleration. Bare in mind this thing has one insane power to weight ratio. 631hp per ton. :eek:

I also imagine a clever differential will help this thing keep pointing in the right direction, something you lose the ability to have on a reverse delta.

Add to that your race driver doesn't need to re-learn car control skills, he still has two powered rear wheels to manage with his right foot that should work just the same.

So there's some reasoning why it is what it is, this is probably the only way to do a delta layout for racing at this level.

A couple more shots for comparison.
http://www.roadandtrack.com/var/ezfl...g-11_large.jpg

Front and rear tires
http://www.highcroftracing.com/stora...=1327994971416

If you read the Riley article I linked to, the quick steering response is a characteristic of all trikes and reverse trikes. I think though that since this a rear engined race car, and that the rear wing is need to add down force on the rear wheels, are the reasons they went this way.

I realize there are two front wheels, but it is effectively a trike.

Yeah, i dont think you can compare this to a 3 wheeler for many reasons.

I'm pretty sure the car is meant to steer primarily with torque vectoring at the back rather than using the front wheels (which have barely any weight over them). Should turn out to be interesting.

Not exactly as a joke but a pointed analogy. The DeltaWing's two rear wheels will have the bulk & double responsibilities of forward traction as well as torque steering capabilities, relegating the tiny & vestigial two front wheels essentially as forward casters or bogies. http://www.youtube.com/watch?v=rBKB1eQxEVQ

Torque vectoring is a huge factor in making this configuration work.

If it works for an "A" John Deere, it should work for this. :thumbup:

So, why spend the big bucks to develop something like this?

Apparently, motor racing is suffering bigtime from a lack of innovation and
being disconnected from current real world realities like fuel efficiency and
sustainability.

The best write up I've found on this car, and IMHO a must-read to
understand what this ecomodders dream car is all about:

The single-seater aero era has held sway since flimsy wings first
scraped the sky in late-60s Formula One. However, the unseen hand
of downforce, allowing drivers to corner with their right foot hard in,
is the enemy of all other efficiencies. Big, thirsty engines towing draggy
barn-door advertising hoardings – 'wings' if you prefer – down straights
have long been red rags to the Greens, and of no long-term interest to
mainstream car manufacturers...

Siamesed front wheels, no wings, a stabilising shark fin… Bowlby's
DeltaWing didn't break with the norm – it nuked it. Yet it would have
been more extreme still had the FIA not deemed a three-wheeler a
motorcycle and thus beyond its jurisdiction...

"When it all started to fall into place, I was completely surprised and
somewhat frightened," he admits. "It's not like I've been thinking about it
for ever; there was an element of 'What have we done?' Not everyone
believes me when I say that form followed function, but DeltaWing is
absolutely not just a styling exercise. It met all its targets – we had a long
fit-for-purpose hit list – and I saw no reason to hide it away just because it's
a little wild..."

"Our goal was to create a car that was twice as efficient for the same speed,"
says Bowlby. "No engine is twice as efficient, so first you must downsize to
reduce the fuel burn. Then you reduce weight. But most of all, you must
reduce aerodynamic drag; we aimed for 60 per cent less. Fair in the wheels,
fit enveloping bodywork, easy. Ah, but that's a sports car, not a single-
seater. Nor would you stand to make the gain we did when we brought the
front wheels into the centre-line and made it, in effect, a three-point plane."

Purnell: "As an aerodynamicist, I know the shape is going to work. It's a little
more challenging in terms of vehicle dynamics. Experts had concerns about
the car's stability in an accident, so the jury is out. When you haven't done
something before, there is risk, and you don't always get it right first time.
Of course, I may just be worrying unnecessarily."

Bowlby: "There were follow-on discoveries. The vehicle dynamics of a 'single'
front wheel with appropriate weight distribution and tyre capacity means it
uses its rubber more efficiently. Throwing away a quarter of a car causes a
cascade of lightness too. You no longer need a chassis with torsional stiffness
because you don't have to redistribute an unbalanced tyre loading around the
car. This allows a huge weight saving, and the majority of what remains –
plus all the roll stiffness – you put across the rear wheels to maximise
acceleration..."

Yeah, yeah, but how will it handle? Understeer springs to the Luddite's mind.

"It's counterintuitive," says Bowlby, "but this isn't an understeer-limited
layout. It has a very rearward weight distribution, so the appropriately small
front tyres won't have to accelerate more mass than their corresponding ratio
to initiate a turn. It will respond to steering inputs incredibly quickly and
completely. And because the roll stiffness is entirely generated between the
rear wheels, the characteristic is responsive turn-in with an oversteering
tendency towards the limit."

Lots, lots more good stuff: Institute Quarterly

Link to the Deltawing site: Technical Features | DeltaWing Racing Cars

The guys at Bonneville would like to talk to you about that.

From the excellent link Rokeby provided:

I notice that the earlier versions of the DeltaWing had the tops of both the front and the rear tires exposed, so I wonder if the Cd has improved at all. The Cd mentioned 0.24 is decent, but far short of the Panhard LM64. So I wonder if the DeltaWing will be even as fast as the Panhard LM64.

Thats because the original design was meant for INDYCAR whch requires open wheel cars.
http://harryallen.info/wp-content/up...00306147_l.jpg

60% drag reduction
 

Another thread on this car gave 50% drag reduction,which would be Cd 0.55 territory.
At a 60% drag reduction(assuming a constant frontal area) we're looking at around Cd 0.44.Yes?
With less wing the frontal area would be cut,Cd a bit higher,CdA still 60% less.
*less mass
*remarkably less drag
*R-R is impacted favorably
*aero power requirement varies as the cube of velocity
*position pilot for constant polar moment of inertia
*less tire wear
*higher fuel economy
*fewer scheduled pit stops
*position #53 waiver for 'weirdness'
I don't think the competition has a prayer.Delicious!:D

They are claiming a Cd of 0.24.

0.24
 

From looking at an older SAE paper on Indycar aero,if the car is Cd 0.24,then its drag would be about 79.5% lower than a typical racer.
At" 60% less," its Cd would have to be based on an Indycar without any wings or pods,just body and exposed wheels.

Yes the roll center of the single wheel on a trike is necessarily at ground level. With two wheels you can design it in to the the suspension geometry. Not sure what effect that has, comparing the two. Don't know too much about suspension.