Do rear spoilers actually work on road cars?
Discussion
It depends on the shape of the bodywork over which they're fitted. If the car doesn't have a sharp edge to shear the air, then a spoiler will provide one, to reduce both lift and drag.
They don't need to be very big though, and properly designed bodywork will do the job just as well.
They don't need to be very big though, and properly designed bodywork will do the job just as well.
Edited by kambites on Wednesday 28th July 13:59
sootyrumble said:
BMW E30 M3 Evo's had an active spoiler,
Mercedes 190e Cosworths
Subaru's and Evo's
Corrado's
Any supercar seems to have an active rear wing which come out at high speed
But no on 1.2 Nova's, Corsa's, 2.0 8v Calibras and any other chav wagon really
See the lip above the rear window. That's a spoiler. And it's not there for the fun of it. It's not a wing. It doesn't create downforce and drag. It reduces lift and drag.Mercedes 190e Cosworths
Subaru's and Evo's
Corrado's
Any supercar seems to have an active rear wing which come out at high speed
But no on 1.2 Nova's, Corsa's, 2.0 8v Calibras and any other chav wagon really
The first thing you have to bear in mind is that most small spoilers - the type you get on the back of Givic Type Rs and the like - are actually intended as wake filling devices to reduce drag, rather than increase downforce.
Beyond that, yes, if they're designed as a genuine aero aid rather than simply a styling feature then above body devices will work as well on a road car as they would on a racer at a similar speed.
I used to have a MG ZS saloon (for my sins) and that was rock steady at three figure speeds so the enormous chavvy spoiler certainly wasn't doing it any harm.
It's true to say that virtually all road cars produce lift though, all the wings do is reduce that lift. A few high end supercars proport to produce meaningful downforce, but not many.
Beyond that, yes, if they're designed as a genuine aero aid rather than simply a styling feature then above body devices will work as well on a road car as they would on a racer at a similar speed.
I used to have a MG ZS saloon (for my sins) and that was rock steady at three figure speeds so the enormous chavvy spoiler certainly wasn't doing it any harm.
It's true to say that virtually all road cars produce lift though, all the wings do is reduce that lift. A few high end supercars proport to produce meaningful downforce, but not many.
RobCrezz said:
kambites said:
Strawman said:
The big ones, Subaru WRX or Porsche GT3 etc. do work, the smaller ones are just cosmetic really.
They aren't spoilers. They're wings. If I remember correctly, the problem with the TT was that the shape generated a laminar airflow all the way down the back of the car, producing a very low pressure area above the rear deck which generated a lot of rear-end lift. The horrible spoiler that they bolted on sheared that airflow off half way down the back to stop that from happening.
Edited by kambites on Wednesday 28th July 14:20
kambites said:
Strawman said:
The big ones, Subaru WRX or Porsche GT3 etc. do work, the smaller ones are just cosmetic really.
They aren't spoilers. They're wings. 
IIRC it's a 'spoiler' if it 'spoils' the rear edge of the car, creating a 'kamm-tail' effect, tidying up the turbulence at the rear.
It's a 'wing' if it's raised, with clear air underneath it, to increase downforce, literally like an upside-down aeroplane wing.
It's an 'aerofoil' if it channels the air in a particular direction, usually towards a spoiler, to direct the airflow over the rear window.
The BMW 3.0 CSL is a perfect example as it has all three:
There's an aerofoil at the top of the rear screen, directing the airflow down towards the spoiler on the bonnet lip, which minimises drag, whilst the wing, which sits on top of the spoiler, keeps the car tracking straight and keeps the tail from going light.
kambites said:
RobCrezz said:
kambites said:
Strawman said:
The big ones, Subaru WRX or Porsche GT3 etc. do work, the smaller ones are just cosmetic really.
They aren't spoilers. They're wings. If I remember correctly, the problem with the TT was that the shape generated a laminar airflow all the way down the back of the car, producing a very low pressure area above the rear deck which generated a lot of rear-end lift. The horrible spoiler that they bolted on sheared that airflow off half way down the back to stop that from happening.
Edited by kambites on Wednesday 28th July 14:20
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