Spoiler stops working below freezing!?

[dexter 0]

Give it some vasaline round the bottom of the plastic storks thing a me jigs. Should make for less friction.

 

No comments please :)

[Henny 0]

It's a myth that the spoiler produces downforce. It doesn't. What it does do is to alter the aerodynamic shape of the back of the car sufficiently to PREVENT uplift caused by the air passage over the car.

 

LOL, take yourself down to the Formula one pits and tell the engineers that, FBLOL!

 

Look at the shape of the spoiler on the Corrado... It's just that, a SPOILER. :roll: The wings on the back (and front!) of an F1 car are just that, inverted wings which create a pressure difference around them to push the car onto the track.

 

Look at the basic shape of a Corrado (or better yet, a TT or Beetle) and it's basically the same as an aircraft's wing: flat underside with a curved, longer topside. This shape causes the air over the top to move at a different speed to the air underneath causing lift due to the difference in air pressure. The spoiler slows the air over the top causing drag which stops the difference in pressure and hence the lift effect.

 

Oh, and the prats with the HUGE spoilers on Novas and the like just do it 'cos they're sad, misguided people who think it looks good... :roll: :lol:

[dr_mat 0]

Henny is right..

 

kev, fact of the matter is that without the spoiler, a Corrado would have net lift at high speed, because of the shape of it (and all other cars). The spoiler is there to reduce lift, it's nowhere near large enough to actually generate downforce a-la F1 cars.

 

It's called a spoiler cos it spoils the nice geometric air pattern at the rear of the car, which would otherwise form a nice wing-shaped profile, creating lift. F1 cars have wings that actually act on their own to generate force in a particular direction because of the air flow over them. Different game.

 

Oh, and he's spot on about the whale tails on the Novas too...

[Kevin Bacon 5]

So it's just a gimmic and VW's claim of XX pressure at xxx mph is a complete fabrication then?

 

It's basic physics, put anything in the path of airflow and it creates an opposing force, in our case, down....

 

I know the difference between cosmetic spoilers and functional ones.

 

We'll have to agree to disagree.

 

K

[Henny 0]

dr_mat :D 8)

 

If you've ever been in a modded original beetle at over 100MPH then you'll know where I'm coming from about needing a spoiler... :?

 

My ex-boss had a scarey trick of gently turning the steering wheel at about 80 to move into the outside lane of the motorway and then flooring it past 100 then violently swinging the steering wheel from one side to the other.... :shock: The net result was nothing, 'cos over 100MPH the front wheels were about an inch off the floor! :shock: :? 8)

 

He reckoned that over about 110MPH in a beetle without a rear spoiler was impossible 'cos the car would lift off the floor so the wheels wouldn't be able to give it any more push! :shock:

 

I'm just glad he never tried to prove that one! :? :lol:

[dr_mat 0]

kev, I'm not saying that VW are lying, just that it's not just about "creating downforce". The majority of it's action is related to "preventing lift".. The two can easily be thought of as opposite sides of the same coin, in practice, as the net effect is still the same. ;)

 

And Henny, yeah, I've heard about the beetles and their stupid lift problems.. A mate had one, used to thrash the life out of it...

[Henny 0]

Kev,

 

Taken from the original VW blurb about the Corrado:

 

An "active" rear spoiler extended automatically when the car reached 45 mph to reduce aerodynamic lift. As speed dropped below 12 mph, the spoiler retracted again.

Source Document

 

I've never heard or read any figures by VW of downforce at speed measurements... :? I also never said it was cosmetic... It DOES make a hell of a difference to the handling at speed... Try it next time you're on a track like I suggested earlier and you'll see what I mean! 8)

[dr_mat 0]

Fortunately VW were clever enough to make sure that you can't manually lower the spoiler when you're above the "raising" trigger speed. On the basis that suddenly swapping ends is not a good thing, on the whole... :)

[Henny 0]

Fortunately VW were clever enough to make sure that you can't manually lower the spoiler when you're above the "raising" trigger speed. On the basis that suddenly swapping ends is not a good thing, on the whole... :)

 

Sorry, I should have pointed out that you'd need to pull the fuse out before you do your run with the spoiler down... :oops: :lol:

[chrishill 0]

oops, what have i started? :oops:

[CorradoVR6-Turbo 0]

oops, what have i started? :oops:

 

Hmmm :? and to think i just said my spolier wont work when freezing :lol:

[Henny 0]

Sorry James... :oops: I'll have a quick look at the wiring diagrams and see if I can tell if there's any link between the spoiler and the temp sensor, or if it was just frozen up and was a co-incidence that it started working when you got the hairdryer out...

 

I'd hedge my bets on the side of VW being clever, but you never know until you check! :lol:

[CORRADO4LIFE 0]

Hahaha yep do it all the time especially when you have got some little boy racer behind you in a nova or a scooby and your about to burn him off at the lights!

[CORRADO4LIFE 0]

play with the old spolier that is!!!!

[Kevin Bacon 5]

Alright you two have backed me into a corner now, so I give up, almost :lol:

 

Last attempt, promise You two sound like you know what you're talking about but I just have this theory nagging in the back of my head.....surely the opposite of lift is push? i.e. downforce?

 

Quoted from a book called "VW Golf"....It was not just a gimmick because VW reckoned that the extra downforce created by the extended airfoil amounted to 64 percent"

 

I'm just thinking that if it's affect is minimial, why have it raise up into the airstream at all, and just leave it fixed? In the same way aeroplane airfoils and alerons (sp?) slow down or alter direction, surely the spoiler on the back creates downforce?

 

Anyway, that's just my theory anyway and I'm probably wrong :?

 

Interesting stuff though.

 

On the subject of the spoiler motor, I drove 600 miles with it strapped down by a bike rack (I forgot to disable it) so it must have thermal cutout fuse or something, so if frozen, it shouldn't damage it.

 

K

[G60Jet 1]

on a side note, does anyone else sit in traffic and play with the spoiler to see the reaction of the people behind?

 

Yep, cant be helped sometimes.

 

I normal sit in the que at the drive through (MCAUTO) playing with the spoiler to the amazment of the boy racers behind

[Henny 0]

Hi Kev,

 

The opposite of lift is, indeed, downforce, however in this case,(and this is my last one on this too! 8) ) the spoiler doesn't actually CREATE any downforce, rather it PREVENTS the car's aerodynamics from producing lift by messing around with the air flow over the back of the car. It's effect is definately not minimal and a decrease of 64% in the overall LIFT of the car wouldn't suprise me at all (in fact I think that's a figure I've heard before).

 

It's a common mis-conception that spoilers on road cars produce downforce, and the reason I've been (possibly a bit overly) passionate about this one is that I got into a huge debate at Uni with a lecturer when he decided to pick on my 16V 'rado's spoiler during an engineering lecture... I lost, badly! :roll: :lol:

I too thought that the spoiler pushed down the back of the car and he proved me wrong (in front of about 100 students... :oops: ) by showing the shape of a wing designed to give downforce (F1 styleee) and a normal car spoiler and showing the high and low pressures around them... The F1 wing actually created downforce but the spoiler did sod all but create drag... HOWEVER, when the spoiler is in the correct place on a car, that drag slows the air around it sufficiently to change the airflow around the whole back end of the car and negate some of the lift that a normal car's shape will create. 8) Thus, it doesn't create downforce per se, but it DOES stop some of the lift being produced... 8)

 

The reason that the spoiler on the C is active and not fixed is so that in normal day to day pottering to the shops at 30 to 40 mph you've got less drag from the spoiler, so your fuel economy will be better... 8)

 

It's an interesting note about the spoiler cutout... It wouldn't suprise me if there is one knowing VW's engineers... 8) They're clever sods really, aren't they?!? 8)

[Blown 0]

At least all you'se have spoilers that bl@@dy work! :mad:

Mine had a small episode of only working when it wanted to and then just flat refused to do anything.

I've changed the motor and the control unit(twice)and it didn't do anything,as well as checking the voltage through the manual switch(getting a reading of 12v)and at the motor(again 12v)I'm more stumped than a chopped down rain forest! :oops:

[G60Jet 1]

Hi Kev,

 

The opposite of lift is, indeed, downforce, however in this case,(and this is my last one on this too! 8) ) the spoiler doesn't actually CREATE any downforce, rather it PREVENTS the car's aerodynamics from producing lift by messing around with the air flow over the back of the car. It's effect is definately not minimal and a decrease of 64% in the overall LIFT of the car wouldn't suprise me at all (in fact I think that's a figure I've heard before).

 

It's a common mis-conception that spoilers on road cars produce downforce, and the reason I've been (possibly a bit overly) passionate about this one is that I got into a huge debate at Uni with a lecturer when he decided to pick on my 16V 'rado's spoiler during an engineering lecture... I lost, badly! :roll: :lol:

I too thought that the spoiler pushed down the back of the car and he proved me wrong (in front of about 100 students... :oops: ) by showing the shape of a wing designed to give downforce (F1 styleee) and a normal car spoiler and showing the high and low pressures around them... The F1 wing actually created downforce but the spoiler did sod all but create drag... HOWEVER, when the spoiler is in the correct place on a car, that drag slows the air around it sufficiently to change the airflow around the whole back end of the car and negate some of the lift that a normal car's shape will create. 8) Thus, it doesn't create downforce, but it DOES stop some of the lift being produced... 8)

 

The reason that the spoiler on the C is active and not fixed is so that in normal day to day pottering to the shops at 30 to 40 mph you've got less drag from the spoiler, so your fuel economy will be better... 8)

 

It's an interesting note about the spoiler cutout... It wouldn't suprise me if there is one knowing VW's engineers... 8) They're clever sods really, aren't they?!? 8)

 

correct but you need to add the the third dimension which i will like all good lectures demonstrate with the aid of a diagram

 

 

basically the spoiler redirects the air up very slightly. reducing drag and increasing downforce by forcing the air travelling under the car to fill the void that the spoiler has created, this has the effect of sucking the air out from under the car creating low pressure (high speed air) and increasing downforce or reducing the lift created by the shape of the top of the car.

 

Air traveling over the car will take longer to reach the back than air traveling under the car producing lift, but if you make the air coming from under the car come out faster than if can come in you creat a vaccum effect. This is why formula 1 cars have very little ground clearance but a massive deffusser on the rear, sucking out any air under the car.

 

And to add one other point, IF the spoiler Created downforce it would be at the rear, and for a front wheel drive car you are effectivly making the front of the car lighter and MAY introduce understeer.!! NOT NICE, the faster you got the heavier the back gets and the lighter the front gets

[dr_mat 0]

And to follow up the other point made - the spoiler is active simply because rearward visibility is flippin' AWFUL with the spoiler extended. VW management already didn't like the fact that the spoiler got in the way, but accepted that it was necessary for high speed driving, so insisted that it get itself OUT of the way when you're trying to reverse parallel park...

Drag from the spoiler is pretty much negligible compared to transmission losses, dragging brake pads etc etc at low speeds, so it's purely for convenience, iirc.

 

Give in, kev! Do it now! Before you get so far in you run out of escape routes! ;) ;)

[G60Jet 1]

and to add more to the point

 

American Audi TT where ALL recalled to fit the tiny rear spoiler called a conversion kit or something, as there were cases of TT leaving the roads at high speeds.

[Kevin Bacon 5]

OK, cheers Henny, Dr-Mat and G60Jet.....I now understand how it works!

 

So if you want downforce, you'd use an upside down aeroplane wing shape? And if you just want to interupt the airflow and create a vortex to alter drag characteristics, you just use a Spoiler?

 

Speaking of Vortex's, remember how MK2 Golf rear screens always get covered in crud due to said vortexes back spraying road dirt up? How come that doesn't happen in the Corrado? I rarely need to use the rear wiper! Is it just that the rear screen has a much shallower rake and therefore just doesn't collect dirt?

 

Ta

 

Kev

[biggrim 0]

I no longer have a rear wiper cause it never gets used. Looks much neater at the back now.

[Henny 0]

OK, cheers Henny, Dr-Mat and G60Jet.....I now understand how it works!

 

So if you want downforce, you'd use an upside down aeroplane wing shape? And if you just want to interupt the airflow and create a vortex to alter drag characteristics, you just use a Spoiler?

 

Speaking of Vortex's, remember how MK2 Golf rear screens always get covered in crud due to said vortexes back spraying road dirt up? How come that doesn't happen in the Corrado? I rarely need to use the rear wiper! Is it just that the rear screen has a much shallower rake and therefore just doesn't collect dirt?

 

YAY! 8) You've got it spot on... 8)

 

A nice side effect of the spoiler on the 'rado is a clear rear screen... The spoilt air stops the crud flicking back up onto the rear screen keeping it clearer than it otherwise would be... Stevemac pointed that out to me the other day. 8)

[G60Jet 1]

 

Speaking of Vortex's, remember how MK2 Golf rear screens always get covered in crud due to said vortexes back spraying road dirt up? How come that doesn't happen in the Corrado? I rarely need to use the rear wiper! Is it just that the rear screen has a much shallower rake and therefore just doesn't collect dirt?

 

Ta

 

Kev

 

the golf has a much deeper rear screen angle thus the air is pull down much harder, creating more drag. the Corrado has this but across the bumpe and reg plate area.