rear wheel arch spats (or Pig's ears) - function?

[sallen]

morning most knowlegable aero folk

I've been wondering for ages what the spats are for which are found to the upper rear of the rear wheel well of modern vehicles.

I first noticed these on Mercedes SLK's ages ago, and other coupes (e.g. Audi TT), but they are cropping up on all sorts of cars.

I've searched a few times for info on them and finally got a lead:

SLK owners call them "Pig Ears" - you can see an example painted body colour (usually I see black ones) in this thread:
Mercedes Benz SLK Forum

what are they for?

- separating airflow before the curve at the rear of the car?
- disrupting vortices that come from the wheel well?

[kach22i]

Mercedes Benz SLK Forum


I have no idea, looks like some afterthought to protect the paint job.

[sallen]

someone mentioned paint protection, but there were full mud flaps available for that model.

Another theory I've seen online is that they are for the Euro market where bodywork has to extend further than the wheel - but I'm not convinced by that, especially on a German car.

[bikeprof]

Pig ears..., funny !
Were they original equipment on:
Mercedes 350-500's, etc...
Most Jaguars pre Ford buyout ?
Lot other English USA imported kra-p
USA sent Citroen's

'Cause majority of these vehicles died in their STY, like a PIG's STY ��

[freebeard]

My guess would be it's a wickerbill, AKA Gurney Flap.

The purpose, if true, would be to pull the turbulence roiling out of the wheelwell to lay flatter against the aft body.

[bikeprof]

Originally Posted by freebeard

My guess would be it's a wickerbill, AKA Gurney Flap.

The purpose, if true, would be to pull the turbulence roiling out of the wheelwell to lay flatter against the aft body.

Very appropriate response...

I still like my belief of the death to lesser made vehicles, but like your answer, the "bomb-awaiting" Pinto did the implosion at times very well.
Sometimes almost on its own like these flaps... 👍

[aerohead]

Originally Posted by kach22i

Mercedes Benz SLK Forum


I have no idea, looks like some afterthought to protect the paint job.

I don't know.But my guess is that there's an inherent defect in the car's original design,and the flap is a cheap,add-on palliative to make up for the deficiency.
The rear bumper fascia has a profile which might produce bi-stable flow and 'booming.' If so,the flap would trigger separation,not allowing for any reattachment in this region,'fixing' the acoustic and inclement weather 'spray' annoyance.

[freebeard]

So, since aerohead says the exact opposite, I might be wrong.

Somebody should snag an SLK and do some tuft testing.

[ChopStix]

Originally Posted by freebeard

So, since aerohead says the exact opposite, I might be wrong.
Somebody should snag an SLK and do some tuft testing.

Naw I won't buy a car with Pig Ears. But Cow Horns is a different thing! -lol

[MobilOne]

That's probably not a cow, most likely the male sex.