Air dams?

[mcrews]

Originally Posted by woodstock74

Actually what I was after is discussion on the topic, it is a discussion forum after all...I've worked in motosports for a bit over a dozen years, gotten to know more than a couple of aerodynamicists, and when I posed the question I got multiple answers. The research says they work, but the available research is more than 20 years old. How relevant is it to today's cars with their much more thought about underfloors?

Excellent work Aveomiller...seems bigger is better...

I'm contemplating a small air dam tucked in a bit from the leading edge and angled slightly. I'll mount it to the small CF underfloor infill I put in last night.

then why didint you post this as your first post?
Come to the table lo0oking like you have done some research and we can save "rolling our eyes".

[woodstock74]

Originally Posted by mcrews

then why didint you post this as your first post?
Come to the table lo0oking like you have done some research and we can save "rolling our eyes".

Heaven forbid your eyes roll out of joint...Sheesh already. The point is to ask a leading inquiry to promote discussion. To move from lurker to participant, stir the sediment so to speak. Done and done. On wards and upwards...

[mcrews]

wow, a noobie trying to create discussion.....
How about a noobie using the search function. This is a pretty active forum. we dont need to 'fake' activity.

[cfg83]

woodstock74 -

Very clean :



CarloSW2

[baldlobo]

Originally Posted by mcrews

wow, a noobie trying to create discussion.....
How about a noobie using the search function. This is a pretty active forum. we dont need to 'fake' activity.

why don't you and sven pull the sticks out of your ***'s and be nice. especially since sven doesn't like physics, or discussions; just pretty renderings.

And to keep this on topic; i think they help out cars more then trucks(but that's based more on a car having a low point of 5" off the ground versus 8" or more)

[euromodder]

Originally Posted by mcrews

wow, a noobie trying to create discussion.....

Heck, it's what a discussion / information forum is about.

The search function returns almost the entire site unless you have a very specific search term.
And "air dam" , "belly pan" or even "Kammback" isn't very specific on here ...

[euromodder]

Originally Posted by woodstock74

Though wondering if today's underbodies are better considered than they were in the 80s, and thus an air dam might simply not have the desired affect.

It's not fancy, as almost no-one gets to see it, but some manufacturers are applying varying degrees of panelling on the undersides.
Few cars have really smooth undersides, but there's a growing interest to lower drag underneath the car, so we'll see ever more of it.

The usefulness of an air dam decreases as the underside becomes smoother, but it's OK to combine both - one way is an air dam dropping down to the level of a belly pan

[kach22i]

Originally Posted by euromodder

Heck, it's what a discussion / information forum is about.

The search function returns almost the entire site unless you have a very specific search term.
And "air dam" , "belly pan" or even "Kammback" isn't very specific on here ...

We don't get a lot of "general" discussions because each case is different and I think we have a bunch of problem solvers here which excel at tackling specific problems or issues.

There have been several people in the forum claiming large chin spoilers hurt their performance. One of them is in the UK, but I forget the vehicle.

[aerohead]

Some of the 1st-gen water-cooled VWs were of Hucho's design recommendations,per wind tunnel investigations at VWs climatic wind tunnel.
This was the time of the 1st Arab Oil Embargo and many 'economy cars' had underbodies more akin to today's body-on-frame pickups and SUVs.
Hucho published in 1976 with an SAE paper which included front airdam research.
At that time,for all the cars tested,a drag decrease of up to 15% was possible by utilizing only a front airdam.
From R.G.S.White's research at MIRA in the UK,it was understood that the 'better' a cars underside,the less effective an airdam would be.
FIAT has demonstrated that airdams can increase drag on 'low-drag' cars.
'Airdams' had entered the market in 1966 with GM's 'modesty panel' on their Corvair,after development at the GALCIT wind tunnel at CAL Tech under the direction of Dr.Peter Kyropolous.
In Hucho's 1976 paper they show results from 12-airdam combinations of 4-different configurations on the sloping valance panel of a VW do Brasil 1600X.
The highest drag occured on the vertical dam closest to the front wheels at a depth of 60mm.
A 180mm,45-degree dam (ala Dodge Daytona ) showed no drag reduction at all.
The lowest drag came from a 40mm vertical dam halfway upstream towards the base of the angled dam.
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Attaching the 'optimum' nose netted a 0.05 drop in Cd.By softening the hard edges slightly they were able to come within 5-points of the 'optimum'.
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The nose of a 1976 Golf/Rabbit is within 5-points of 'ideal,'as far as zero-yaw is concerned.
This is the reason he basically recommends we blow off the front of the car as far as mods go,and just concentrate on the back.
The lowest cost entry level economy car sold today is a quantum leap,aerodynamically,from similar class vehicles of the first 'oil crisis.'
And there is a very good likelihood that whatever airdam comes from the factory on a new car,has already spent a number of hours of refinement in the tunnel or inside a $billion,neural-net, 3-D, Navier-Stokes CFD program.

[Sporty Modder]

As I posted earlier I have had great results, best percentage wise was the Towncar. That car is a body on frame design with a straight axel rear end. The other benifit I have descovered is the cars are more planted at highway speeds and less affected by crosswinds.