Astonishingly strange features on a car

[sjg]

RicksAlfas said:

For as long as I can remember Alfa headlights go on and off with the ignition which is a great feature until you actually want them on. Then you have to press in a tiny button on the ignition barrel with one hand and turn the key (with the other hand!) past it's usual OFF position before pulling it out. I never mastered it. Since going onto key fobs that push into the dash they have come up with a more seperate button called "P" - for parking lights. It's next to the odo reset which is clearly mounted down by your right kneecap.

Most italian cars do. I much prefer it that way - at this time of year your headlights are permanantly on, and you don't want to have a buzzer blaring to remind you to switch them off when you'll just turn them back on next time.

[youngsyr]

carl_w said:

youngsyr said:

I'd have thought that if the lip on the M5 reduces lift by 50kgs (even at 150 mph), these canards would rip themselves off by the time the car reaches that speed?

If you're referring to the stuff in front of the wheels, that'll be to direct the air up to the top of the wing where it can remain laminar and attached to the bodywork, rather than getting involved in the turbulent crap around the wheels. If you're referring to the vertical components of the splitter, they're there to stop the air 'falling off' the end of the splitter and creating vortices. The splitter's job is to direct as much air over the top of the car as possible, and as little (but non-zero) under the bottom to maximize the speed of the airflow under the car and hence the downforce.

I was referring to the parts in front of the wheels. So they're not to aid downforce at the front? I didn't realise that.

I still can't see how these don't generate enough downforce (reduce lift) to tear themselves off if that M5 lip can generate 50 kgs of downforce (/reduced lift)?

Edited by youngsyr on Tuesday 9th December 23:35

[djoli101]

passat has a few

Escape handle inside the boot.
Umbrella in door.
hold lock/unlock all the windows lower/raise.

[Mark-C]

youngsyr said:

Mark-C said:

youngsyr said:

<snip>
Maybe I just don't understand the principles involved and I'm just simplifying things then.

I'd have thought that if the lip on the M5 reduces lift by 50kgs (even at 150 mph), these canards would rip themselves off by the time the car reaches that speed?

[pedant]A canard is a duck or an aircraft wing .... on cars these tend to get called "dive planes" although strictly speaking the vertical element is a "gurney" which is normally used to describe any element perpendicular to the road that acts as a boundary to horizontal airflow.[/pedant]

Sorry and the answer is .... modern bonding techniques are very very good

Modern bonding techniques??? They're bolted on, aren't they?!

... and if we're being pedantic, the people that make them call them canards.

http://www.aprperformance.com/index.php?option=com...

My info comes from an interest in endurance racing. Thinking about it bonding them on is crap if you want to change them so I'll let that one go (ie ... admit I'm wrong!) but will stick to "dive plane" because I've never seen them called anything else.

http://www.radicalsportscars.com/range/sr9/index.p...
http://mazda-lola.com/lemans2006/lemans2006_wednes...
http://www.mulsannescorner.com/peugeot908-4.html
http://www.americanlemans.com/drivers_and_teams/Dr...

Which probably makes me a defensive pedant

How about "winglet" ?

[mat205125]

youngsyr said:

Doesn't add anything to the discussion, but I think it's a cool picture and it's slightly on topicish...

Love those wheels

[youngsyr]

Mark-C said:

youngsyr said:

Mark-C said:

youngsyr said:

<snip>
Maybe I just don't understand the principles involved and I'm just simplifying things then.

I'd have thought that if the lip on the M5 reduces lift by 50kgs (even at 150 mph), these canards would rip themselves off by the time the car reaches that speed?

[pedant]A canard is a duck or an aircraft wing .... on cars these tend to get called "dive planes" although strictly speaking the vertical element is a "gurney" which is normally used to describe any element perpendicular to the road that acts as a boundary to horizontal airflow.[/pedant]

Sorry and the answer is .... modern bonding techniques are very very good

Modern bonding techniques??? They're bolted on, aren't they?!

... and if we're being pedantic, the people that make them call them canards.

http://www.aprperformance.com/index.php?option=com...

My info comes from an interest in endurance racing. Thinking about it bonding them on is crap if you want to change them so I'll let that one go (ie ... admit I'm wrong!) but will stick to "dive plane" because I've never seen them called anything else.

http://www.radicalsportscars.com/range/sr9/index.p...
http://mazda-lola.com/lemans2006/lemans2006_wednes...
http://www.mulsannescorner.com/peugeot908-4.html
http://www.americanlemans.com/drivers_and_teams/Dr...

Which probably makes me a defensive pedant

How about "winglet" ?

Looking at those links, I think there's a difference between a dive plane and a canard.

The dive plane seems to work like you say, by diverting air around the wheel:



Whereas:

"APR Front Bumper Canards are the perfect answer to aerodynamically tune the handling for the front of a car. Made of lightweight and durable carbon graphite composites, APR Front Bumper Canards help increase front downforce at high speeds. The added downforce stabilizes the cars chassis during hard cornering and increases traction for faster lap times."

You can see the air isn't diverted around the wheels by the lower canard:

Edited by youngsyr on Tuesday 9th December 23:58

[tuscan_al]

garycat said:

mrmr96 said:

Another Evo one - the 7, 8 and 9 (and probably earlier ones too) have a Flare Holder built into the near side kick panel of the front passenger footwell. Yup, Flare Holder.

My import CRX had ne of those, complete with flare. I thought it was a fire extinguisher!!!

perfect anti car jacking device i would think!

[Crusoe]

Always thought the vag key in the lock lowering and opening windows was firstly so you could close a window a passenger forgot and left open but more often for lowering all the windows an inch he you were leaving pets for example in the car.

For the 50kg at 150mph consider the force on your hand area sticking it out the window at 150, the square of the force at 75mph which is already quite high. Area of the spoiler is maybe twice the surface area of your hand.

[youngsyr]

mat205125 said:

youngsyr said:

Doesn't add anything to the discussion, but I think it's a cool picture and it's slightly on topicish...

Love those wheels

My car had those wheels on before I bought it. Unfortunately they were sold separately before I could get my hands on them.

They only cost around £2,000 a set.

Edited by youngsyr on Wednesday 10th December 00:10

[youngsyr]

Crusoe said:

...
For the 50kg at 150mph consider the force on your hand area sticking it out the window at 150, the square of the force at 75mph which is already quite high. Area of the spoiler is maybe twice the surface area of your hand.

It's a good analogy, but surely it's the same as saying stack 50 kgs distributed evenly across the surface area of the lip?

If the lip can generate that much, how much are those canards/winglets ( ) having to deal with at the speeds the race cars travel?

Maybe it's my simple mind, but I just cannot comprehend how the two equate.

[GravelBen]

Aerodynamics isn't that simple though, and you still seem to be thinking of 50kg less lift as being the same thing as 50kg of positive downforce.

For example some of the reduction in lift may be (just speculation in this case) because the gurney is disrupting an airflow that would otherwise cause lift - ie not creating a downward force but stopping an upward force being created.

It certainly isn't as simple as just saying the gurney is pushing down 50kg which balances out 50kg of the upward force.

[Fiddlemesticks]

My wifes Sorento has a Barometer. Not a friggin clue why.

[Howitzer]

On a bit of a fun drive when in europe I noticed that as speeds went above 220kmh my rear interior light came on.

This was due to the bootid striker plate not being fully tight. The force of the air coming off the roof literally started to suck the boot open.

So I can understand how even a small gurney flat at speed on the E39M5 can make such a big difference.

Dave!

[LuS1fer]

The use of the remote to drop the windows is actually very useful when you park the car in the sun and want to open all the windows to let the car cool before you reach it, open the door and get greeted by a furnace.

[fathomfive]

Frederick said:

fathomfive said:

touching cloth said:

fathomfive said:

jmorgan said:

touching cloth said:

Saab's "night panel" feature has to rank highly - I used it once when I had my Saab, thought it was silly and never pressed it again - oddly I have never found the other instruments have distracted me from driving a car and am happy to have them illuminated.

I like it.

+1 I drive to work in the pitch black of 5am at the moment and I find it very useful. Especially when you dim the panel aswell.

Clearly you are both insane and/or have Top Gun delusions ... I bet you call your passengers Ice and Goose

Yes, but in a Swedish accent.

Icesh and Goosch?

You're drunk shirley?

[RicksAlfas]

LuS1fer said:

The use of the remote to drop the windows is actually very useful when you park the car in the sun and want to open all the windows to let the car cool before you reach it, open the door and get greeted by a furnace.

It's also useful in the winter for wiping them clear of condensation!
(And as mentioned previously it's useful on coupes with big doors and frameless windows if you are in a tight space).

[ian2144]

Fiddlemesticks said:

My wifes Sorento has a Barometer. Not a friggin clue why.

My Hilux Surf has Barometer as well, along with Altimeter, and compass. Just in case you get lost at the top of a mountain.

[kambites]

youngsyr said:

kambites said:

Strictly speaking the purpose of a spoiler is to reduce lift rather than add downforce. I'll admit that it's a rather arbitrary definition in practice though.

I suspect the airflow over the back of a 3-series probably hugs the rear window fairly well actually, putting that spoiler squarely in the airflow.

Rear spoilers on modern FWD hatchbacks rather amuse me - of course they're commonly known for lacking rear end grip.

I'm not an expert, but from what I've read, even with a fastback shaped car, the spoiler needs to be close to the roofline to have a significant effect:



This theory seems to be confirmed in reality. If you look at the BTCC cars, you can see that they don't have small lips on the boot, or low spoilers, they have funking great shelf panels very high up and close to the roof line.

Wings and spoilers are completely different things. Wings need to be in undisturbed air (so above the roof line is good), spoilers are simply there to break the airflow away from the body of the car (to spoil the air flow) and so need to split the air near to the body work. Hence the statement that spoilers reduce lift (by carefully managing the airflow over the rear of the car) and wings add downforce (using and aerofoil in clean air).

A spoiler will never reduce lift beyond neutral but can actually reduce drag. A wing will add drag but can apply significant actual downforce to the car.

Edited by kambites on Wednesday 10th December 08:17

[RDM]

tuscan_thunder said:

911s, until the 1990s, had a rear wiper.......but no wash function.

My 2005 has this, don't know if they still do.

[youngsyr]

kambites said:

Wings and spoilers are completely different things. Wings need to be in undisturbed air (so above the roof line is good), spoilers are simply there to break the airflow away from the body of the car (to spoil the air flow) and so need to split the air near to the body work. Hence the statement that spoilers reduce lift (by carefully managing the airflow over the rear of the car) and wings add downforce (using and aerofoil in clean air).

A spoiler will never reduce lift beyond neutral but can actually reduce drag. A wing will add drag but can apply significant actual downforce to the car.

Hmmm, I think I need a crash course in aerodynamics (who'd have thought it with a car shaped like a brick!). Do you have any links to good sites that discuss it?