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Spats and wheel covers on concept cars


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#1 Charlieman

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Posted 16 October 2016 - 12:01

Looking at a few images of BMW concept cars, I was surprised to see wheel covers -- bodywork that enclosed the wheel arch. I've seen similar examples (Rolls-Royce for example) but they were more artistic concept than engineering design.

 

Is there a fix for lift generated in wheel arches? Are any manufacturers developing road cars with more enclosed wheel arches?



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#2 gruntguru

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Posted 17 October 2016 - 03:58

I'd have though the main advantage was drag reduction.



#3 Greg Locock

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Posted 17 October 2016 - 09:01

Concept, or show, cars, are the original form of clickbait. They mean nothing. Take for example the Volt showcar, and what got into production. I think some black paint made it from one onto the other.



#4 Allan Lupton

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Posted 17 October 2016 - 13:39

There's not much new in that as this 1938 Delahaye shows:

1938_Delahaye_135_MS_Torpedo_roadster_00

 

as the top of the front wing is a nice lifting section I'm with gruntguru that drag reduction is the real point - that and keeping the road dirt off the sides of the bodywork. Haven't seen modern concept cars so won't comment about 'em.



#5 Canuck

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Posted 17 October 2016 - 18:52

That right there is a beautiful piece of design.

#6 Wuzak

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Posted 18 October 2016 - 00:56

Is there a fix for lift generated in wheel arches?

 

Isn't that why they have the big holes atop the guards of Le Mans racers?

 

porsche-919-4.jpg



#7 desmo

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Posted 18 October 2016 - 18:02

Does the amount of lift generated even matter on a road car with no boy racer pretensions?  A little lift should incrementally reduce tire wear although it would also increase drag as well I suppose.



#8 Kelpiecross

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Posted 19 October 2016 - 04:07


Does a wheel in a wheel arch actually generate lift? Why would it?

I have read that the louvres above the front wheels of a Can-Am McLaren were so that the driver could see the smoke from locking the front wheels under braking - maybe the current Le Mans cars have the holes for the same reason?

#9 Allan Lupton

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Posted 19 October 2016 - 08:18

Does the amount of lift generated even matter on a road car with no boy racer pretensions?  A little lift should incrementally reduce tire wear although it would also increase drag as well I suppose.

The attractive swept front wings of the MG TB/TC generated enough lift to make directional control uncertain at the speeds they were capable of on the normal roads of the day. Those who used them for racing went to cycle wings which also saved a lot of weight.


Edited by Allan Lupton, 19 October 2016 - 08:45.


#10 Charlieman

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Posted 19 October 2016 - 11:19

Isn't that why they have the big holes atop the guards of Le Mans racers?

 

Rules change over the years... You wouldn't have got away with holes that size when the first wheel arch vents appeared (about 50 years ago?).

 

Think of the tyre as a big air (sometimes water) pump pushing fluid against the direction of travel. It isn't a pretty problem for the aerodynamics team -- or the person designing the windscreen wiper.

 

The second generation Can Am cars were initially F5000 single seaters fitted with a full body kit. Huge front wings, lots of wheel vents but still too much front end lift. Thankfully most teams recognised the problem but a lot of drivers were injured.



#11 Wuzak

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Posted 21 October 2016 - 01:26

Rules change over the years... You wouldn't have got away with holes that size when the first wheel arch vents appeared (about 50 years ago?).

 

Right.

 

But my understanding is that those holes are required under the regulations to prevent front end lift.One of the measures introduced to stop cars flipping at high speed.



#12 Charlieman

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Posted 22 October 2016 - 11:02

Thanks, Muzak. I thought that the hole was optional but from 2012 it became mandatory to have a 200mm x 250mm aperture on LMP cars. But you probably wouldn't legally get away with it on a road car.