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View Full Version : Does the diffusers make overtaking notably harder?



Lennat
17th April 2009, 00:26
Some people seems to think that the diffusers goes against the intention of the new rules to make it easier to follow/overtake other cars. I haven't thought about to much much myself, so I wonder if anyone here actually has noticed any difference in the first two races this season when cars have followed other cars with the diffuser compared to the ones without it?

I suppose we will know in a few months time anyway, but i would appreciate if some more knowledgeable people here on this board would share the thoughts they have so far regarding this. :)

ioan
17th April 2009, 00:48
maybe you can get an answer if you can give a definition of "notably harder".

Anyway cars without the DD diffuser are not as fast as the DD diffuser ones so they can not attempt to get cose to them and try to overtake, at least it didn't happen in the first 2 races.

However DD diffuser cars seem to be able to follow the other cars closely and even overtake them.

Another point is that from what I saw DD diffuser cars aren't really able to closely follow each other or overtake each other.

There were also cases where cars without the DD diffuser could follow each other closely and make a pass.

This being said the conclusion, based on the above, is that DD diffuser cars seem to be more difficult to pass than the ones that do not feature a DD diffuser.

big_sw2000
17th April 2009, 01:02
Am i right in thinking that a deffusa, single or double is more a ground effect tool, like venturi tunnels. On a smaller scale.
If so i should not disturbe the air flow to much. I thought last years problem, was mainly caused by the low wide rear wings. And the high front wings.

Why not go back down the ground effects route. Close racing

gloomyDAY
17th April 2009, 04:15
Am i right in thinking that a deffusa, single or double is more a ground effect tool, like venturi tunnels. On a smaller scale.
If so i should not disturbe the air flow to much. I thought last years problem, was mainly caused by the low wide rear wings. And the high front wings.

Why not go back down the ground effects route. Close racingBingo!

F1boat
17th April 2009, 06:05
Nico says no :)

Valve Bounce
17th April 2009, 07:20
YES!

ioan
17th April 2009, 07:55
Nico says no :)

But he's no engineer, and he didn't even got close to trying to overtake any of the DD diffuser cars, which make his point nil and questions the logic behind his answer.

F1boat
17th April 2009, 09:02
nil? He is an F1 driver :s hock:

ShiftingGears
17th April 2009, 09:37
If it means that the cars produce more dirty wake, or the performance of the cars are affected more by the dirty wake of other cars, then the DDDs make overtaking harder.

ioan
17th April 2009, 09:57
nil? He is an F1 driver :s hock:

So what?
Maybe you should ask him to quantify the wake and turbulence produced by a diffuser!
He barely knows how it works and that it's used to produce downforce.

F1 drivers are not aerodynamicists or engineers, they are drivers.

PS: Why don't you tell me how exactly does Rosberg now if it's harder or not to pass a DD diffuser car given that he never passed one?
You keep calling teams desperate and whiners and so on, but when I confront you with any question that would make sense but wouldn't suit your biased POV you just ignore it. It does look like discussing isn't your interest, you only call others desperate without a basis.

Norwegian Blue
17th April 2009, 10:05
Actually didn't Rosberg train as an aerodynamicist before choosing racing?

ioan
17th April 2009, 10:09
Actually didn't Rosberg train as an aerodynamicist before choosing racing?

According to Wikipedia he was offered a place for an aerodynamics course but he declined.

F1boat
17th April 2009, 10:11
I am sorry ioan. Silly me, to think that F1 drivers know more than forumers!
About BMW, I answered you in the another topic ;)

ioan
17th April 2009, 10:14
I am sorry ioan. Silly me, to think that F1 drivers know more than forumers!

Maybe we should have a 'myth busters' thread, to dismantle such beliefs like F1 drivers designing the cars and being aerodynamics specialists among other things.

F1boat
17th April 2009, 10:18
Still, I think that they have some knowledge about the cars. Maybe I am naive...

Sonic
17th April 2009, 10:20
Overtking is difficult in any catorgory when all the cars have similar power, grip, and putting cars in grid order tends to make passing difficult. We have had more passing this year thanks to variables in all those factors thanks to kers, tyre compounds etc. The only rteason a ddd car is harder to pass is its harder to make an error with more grip, so no one can get a run on the car ahead.

ioan
17th April 2009, 10:35
Still, I think that they have some knowledge about the cars. Maybe I am naive...

Sure they have some knowledge but not to the point of making estimation about the wake and turbulence produced by different diffuser types.

The only way Rosberg would know if it's easier or more difficult to pass DD diffuser or simple diffuser cars would be if he tried to pass the same car once fitted with the DD diffuser and once with a simple diffuser, or that is impossible. Not to mention he never did come close to trying to pass another DD diffuser car.

Otherwise his opinion is just a guess or a way to protect his chances, which is in no way making it an objective opinion.

F1boat
17th April 2009, 10:59
Overtking is difficult in any catorgory when all the cars have similar power, grip, and putting cars in grid order tends to make passing difficult. We have had more passing this year thanks to variables in all those factors thanks to kers, tyre compounds etc. The only rteason a ddd car is harder to pass is its harder to make an error with more grip, so no one can get a run on the car ahead.

Yes, but maybe when all cars are DD, it will be the same as before.

PolePosition_1
17th April 2009, 11:39
I've thought about this topic a lot. And orignally I assumed it would make it more difficult. But reading up about it, as I'm no expert, I haven't been able to find any reliable sources which state it will make overtaking harder.

We have the opinion of people with vested interests, saying it will and it won't, but from all the technical articles I've come across, all seem to conclude that whilst the DDD weren't in mind when the rules were written, they don't actually go against the principle of the rule changes ..... i.e. increase overtaking.

If anyone can find a technical source showing it does halt overtaking, I'd be very interested to read it, as I haven't been able to find any.

big_sw2000
17th April 2009, 12:31
Maybe this has nothing to do with it, but im going back to the good group C days.
Them cars ran with the biggest Venturi tunnels ive seen, ok not quite a deffusa, but from my limited knoladge, similar sort of thing.
Quite often, they could follow each other with there noses stuck up the arse of the car in front.
I belive that a DDDefusa car is only harder to overtake, because its slightly faster, with better downforce.

You look at the LMS now. Them cars are designed with aerodymaics, spoilers the shape of the car to produce the downforce, not ground effects like the group C days. And they struggle with the same thing as modem F1 cars, running close to each other.

I would love to go down the ground effects route again in F1, but can never see it happing, as it will produce a too high cornering speed, and if something goes wrong a big accident.

ioan
17th April 2009, 12:40
Maybe this has nothing to do with it, but im going back to the good group C days.
Them cars ran with the biggest Venturi tunnels ive seen, ok not quite a deffusa, but from my limited knoladge, similar sort of thing.
Quite often, they could follow each other with there noses stuck up the arse of the car in front.
I belive that a DDDefusa car is only harder to overtake, because its slightly faster, with better downforce.

There is a difference between how a F1 car's and a Group C prototype's aerodynamic packages work.

F1 cars get front downforce from their front wing alone, and the front wing is very sensible to turbulence.
Group C cars had (and Le mans race cars still do) flat bottoms from the front of the car to rear of it, which creates downforce all along the undertray of the cars and it is not sensible to turbulences like a F1 front wing.

So, let's not mix bananas and strawberry.

big_sw2000
17th April 2009, 13:12
There is a difference between how a F1 car's and a Group C prototype's aerodynamic packages work.

F1 cars get front downforce from their front wing alone, and the front wing is very sensible to turbulence.
Group C cars had (and Le mans race cars still do) flat bottoms from the front of the car to rear of it, which creates downforce all along the undertray of the cars and it is not sensible to turbulences like a F1 front wing.

So, let's not mix bananas and strawberry.
Ok fair enough then.
But Bananas and Strawberries, go well in a fruit smoothie :p

ioan
17th April 2009, 13:23
Ok fair enough then.
But Bananas and Strawberries, go well in a fruit smoothie :p

:)

Sleeper
17th April 2009, 13:48
We'll have to wait and see for a definitive answer but frankly I dont think so. A venturi tunnel isnt particularly susceptable to turbulance nor does it create large amounts of turbulance, unlike wings which are both.

There's a reluctance to go down the ground effect rout as the old cars were extremely fast through corners and the requirments of the skirts forced them to run rock solid suspension, making the cars difficult to drive. A modern F1 car with full ground effects would be too fast to be safely raced on any of the modern circuits IMO.

Robinho
17th April 2009, 14:17
it probably is harder to overtake, but the issue of the DD cars seeming to be difficult to overtake compared with others is moot IMO. seeing as the DD cars are the fastest out there at the moment then thay will be more difficult to overtake as you need to be quicker than the car in front to overtake.

the DD (or other) cars overtaking non-DD cars in the midfield is expected as the faster cars should be able to overtake, the fastest cars are by definition difficult to overtake, not just beacause of their trick aero, but because they are the fastest?!

ioan
17th April 2009, 15:36
There's a reluctance to go down the ground effect rout as the old cars were extremely fast through corners and the requirments of the skirts forced them to run rock solid suspension, making the cars difficult to drive. A modern F1 car with full ground effects would be too fast to be safely raced on any of the modern circuits IMO.

That's pretty much how I see it too.

ShiftingGears
17th April 2009, 17:33
We'll have to wait and see for a definitive answer but frankly I dont think so. A venturi tunnel isnt particularly susceptable to turbulance nor does it create large amounts of turbulance, unlike wings which are both.

There's a reluctance to go down the ground effect rout as the old cars were extremely fast through corners and the requirments of the skirts forced them to run rock solid suspension, making the cars difficult to drive. A modern F1 car with full ground effects would be too fast to be safely raced on any of the modern circuits IMO.

Another thing is that if you increase cornering speeds without increasing straightline speed you reduce overtaking anyway.

tintop
17th April 2009, 17:55
it probably is harder to overtake, but the issue of the DD cars seeming to be difficult to overtake compared with others is moot IMO. seeing as the DD cars are the fastest out there at the moment then thay will be more difficult to overtake as you need to be quicker than the car in front to overtake.

the DD (or other) cars overtaking non-DD cars in the midfield is expected as the faster cars should be able to overtake, the fastest cars are by definition difficult to overtake, not just beacause of their trick aero, but because they are the fastest?!

Bingo

71minus2
17th April 2009, 18:07
But he's no engineer, and he didn't even got close to trying to overtake any of the DD diffuser cars, which make his point nil and questions the logic behind his answer.

I'm sure if it had been Massa or Raikkonen passing such a comment they would be adequately qualified to make such sweeping comments about the effects the different diffusers have. In fact i'm sure you would practically big them up as being world leaders in the field.

Andrewmcm
17th April 2009, 18:16
We'll have to wait and see for a definitive answer but frankly I dont think so. A venturi tunnel isnt particularly susceptable to turbulance nor does it create large amounts of turbulance, unlike wings which are both.

There's a reluctance to go down the ground effect rout as the old cars were extremely fast through corners and the requirments of the skirts forced them to run rock solid suspension, making the cars difficult to drive. A modern F1 car with full ground effects would be too fast to be safely raced on any of the modern circuits IMO.

I was having this discussion yesterday with some PhD students yesterday - I would argue for the inclusion of limited venturis under the cars and no side-skirts à la the CART cars of the mid-1990s - they could run fairly close together and didn't go flying off the road at the first opportunity. The reason that the late 70's - early 80's cars were so dangerous is that the pitch sensitivity of cars running in full-ground effect wasn't properly understood.

As for double diffuser cars being more difficult to overtake - time will tell as no team a) will release any figures about what kind of flow pattern comes off of the back of their car and b) they wouldn't waste their time measuring turbulence intensities in the wake during valuable wind tunnel time.

ioan
17th April 2009, 18:27
I'm sure ...

You're wrong.