Delta wing car concept

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Jersey Tom
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Re: Indy Car 2012 Concepts Break Cover

Postby Jersey Tom » Fri Jun 10, 2011 3:20 pm

Depends what type of differential.

Detroit Locker (if you want to consider that a LSD.. or a differential in general and not an abomination) biases 100% of torque to slower moving wheel, which for equal size tires is the inside wheel until it is slipped up to speed with the outside rear.

Anything with some sort of progressive locking, like a viscous diff or Salisbury-type (ramp & clutch) differential SHOULD effectively be biasing torque to the outside.. even if it's only "reactive" or passive. If it didn't, would be no better than an open diff, no?
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Tim.Wright
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Re: Indy Car 2012 Concepts Break Cover

Postby Tim.Wright » Fri Jun 10, 2011 3:41 pm

Thats what I though up until recently, but Im pretty positive its the opposite. All these diffs are capable of doing is passing more torque to the slower wheel which is what you want in a situation where one tyre starts to spin up.

For normal cornering below the limit however, the torque bias is in the opposite direction to what you want.

tim
Not the engineer at Force India

DaveW
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Re: Indy Car 2012 Concepts Break Cover

Postby DaveW » Fri Jun 10, 2011 5:12 pm

Jersey Tom wrote:You can do some interesting things with active differentials, Ciro - but there is a limit. Not quite what you are describing, which IMO is better left to 4-wheel steer.


You can indeed JT. Rear steer or an active diff. can by used a) to make a vehicle neutrally stable (laterally) & b) to convert a steering input into a trajectory demand. In the latter role rear steer angle or differential torque (depending on the system) are used to control yaw acceleration when a turn is initiated or terminated. Neither is required to sustain yaw velocity directly. Warp (weight jacking on your side of the pond) can be used in the same way, though with less authority (it's what bars do in a conventional suspension).

Of course there are envelope limits to both systems, but both are very powerful (one rear steer vehicle I was involved with had a steering bandwidth of around 6 Hz in dry conditions). I would think the biggest issue for the DW development would be setting the relative authorities of steered wheels & differential torque. It is likely this will have to vary with road/tyre conditions.

countersteer
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Re: Indy Car 2012 Concepts Break Cover

Postby countersteer » Fri Jun 10, 2011 10:28 pm

machin wrote:
Formula None wrote:Porsche? Corvair? Not quite as drastic, but close.


The 911 GT3 road car reportedly has a weight bias of 38:62 (


What were the weight bias specs on the Tucker? Rear engine, rear drive, "rectangular" car.

I'm thrilled to see it run. I hope it does well. Only time will tell.

Scania
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Re: Indy Car 2012 Concepts Break Cover

Postby Scania » Sat Jun 11, 2011 1:10 am

richard_leeds wrote:I'd have thought that configuration only suitable for drag strips.

Here's an early prototype demonstrating the inherent stability issues ...


This car is FR...........
DW's 72.5% weight on rear wheel

Scania
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Re: Delta wing car concept

Postby Scania » Sat Jun 11, 2011 2:04 am

for the 911 case, I think that the friction is the key point
for normal car, front & rear tire friction are very close, when you brake hardly, rear wheel will lock, it lose friction, and the front friction are still huge, so the car will lose control.

on DW, the front tire is very small, even the rear wheel lock, the friction are still higher then front wheel, so it will keep stable

wesley123
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Re: Indy Car 2012 Concepts Break Cover

Postby wesley123 » Sat Jun 11, 2011 2:08 am

Ciro Pabón wrote:Actually, as the nose is light and long, I think it would fulfill the crash adsorbing function in a lateral impact.


Sure but then you get the front wheels who are colliding with a really lightweight car. How much did it weight? 450kg? An F1 car weighs 640 kg, Imo the tub is lacking strength compared to other tubs, just because of this low weight.
"Bite my shiny metal ass" - Bender

Jersey Tom
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Re: Delta wing car concept

Postby Jersey Tom » Sat Jun 11, 2011 4:19 am

Scania wrote:for the 911 case, I think that the friction is the key point
for normal car, front & rear tire friction are very close, when you brake hardly, rear wheel will lock, it lose friction, and the front friction are still huge, so the car will lose control.

on DW, the front tire is very small, even the rear wheel lock, the friction are still higher then front wheel, so it will keep stable


On ANY car braking at limit, brake bias will be far enough forward to keep a rear wheel from locking before a front, and keeping the car from spinning on the brakes. Even in F1, you'll notice drivers lock the inside front tire. Hence my call of BS on the DW being any different.. doesn't matter what the configuration, have brake bias too far to the rear and you spin out on trailbraking.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

Formula None
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Re: Delta wing car concept

Postby Formula None » Thu Jul 07, 2011 6:24 am






flyboy2160
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Re: Delta wing car concept

Postby flyboy2160 » Thu Jul 07, 2011 10:03 pm

:? I just saw this. Is this an April's Fool's joke that has kept going? I'm with Jersey Tom: hype and BS.

Looks to me like they're trying to get Greenie money from filthy rich know-nothing tree huggers. " Oooo, racing is just so filthy, we can save the entire ecosystem with our toy, just give us money."

Did anybody besides me notice in the CFD video the huge separation bubble behind that huge flat aft facing rear body? Huh? "Low drag?" This thing looks like it has a lot of surface area for what it contains. Low drag?

What BS in that hey design without any restrictions and then dare to compare to highly regulated designs. If their parameters were kept the same - weight, planform area, HP, tires, cost, no crash protection - I suspect a "regular" rectangular car with the old F1 style inverted full length inverted airfoil sealed sidepods and the old F1 style folded aluminum sandwich tub would beat this thing in every single performance criteria.

Looks like a joke to me. :?

Jersey Tom
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Re: Delta wing car concept

Postby Jersey Tom » Fri Jul 08, 2011 12:28 am

Their "simulations" in rFactor or whatever nonsense are so contrived it borders on comical.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

wesley123
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Re: Delta wing car concept

Postby wesley123 » Fri Jul 08, 2011 12:39 am

I dont understans how they can even simulate something that has never been built? That 'simulation' shows how they want it to be, not how it really drives. Probably even less of a 'simulation' then codies F1 game
"Bite my shiny metal ass" - Bender

countersteer
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Re: Delta wing car concept

Postby countersteer » Fri Jul 08, 2011 2:31 am

http://www.f1technical.net/forum/viewtopic.php?f=1&t=1245&hilit=williams+6+wheel

I was interested to read the similarities between the Williams 6 wheel and the Deltawing.

I've chosen to temper my pessimism out of respect for Ben Bowlby's prior accomplishments. I'll be glad to see it run...

Scania
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Re: Delta wing car concept

Postby Scania » Fri Jul 08, 2011 2:55 am

flyboy2160 wrote::?

Did anybody besides me notice in the CFD video the huge separation bubble behind that huge flat aft facing rear body? Huh? "Low drag?" This thing looks like it has a lot of surface area for what it contains. Low drag?

What BS in :?

because indy car said they want the car easy to over take, bubble behind the car let the car behind easier to catch slip stream

Scania
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Re: Delta wing car concept

Postby Scania » Fri Jul 08, 2011 2:59 am

Ben Bowlby-- talent race enginner, build race car to race when he is 19, worked in Lola
highcroft racing--ALMS P2 2 times champion
Chip Ganassis--long term top class team in Gran-Am, NASCAR & Indy Car
ACO--Deltawing beat 918 RSR & GreenGT to get the seat of Project 56 (although GreenGT might race in LMPH2)

you are.................

who should I trust?




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