Increasing downforce while reducing drag?

[MadisonMPG]

Originally Posted by MechEngVT

Is the Audi TT? The Volkswagen New Beetle? Both are FWD, but both have suffered from high speed instability due to aerodynamic lift at the rear.

I know this thread is old, but I was merely asking a question when I asked was his car RWD.

And like you said, high speed in America is a little different than it is in other countries. I think the TT had a problem at 110 or so, not something you are likely to see if you're hypermiling.

[aerohead]

Originally Posted by Hermie

Obviously, I'd balance out the front. I've already got hood vents, which reduces front end lift, and I'll also be adding a front air dam, angled forward, to further reduce front end lift, as well as side skirts to create a low-pressure zone under the car.

VGs have been shown to increase downforce when paired with spoilers, because it increases the pressure of the air flowing over them. Without a spoiler, I do believe it will add to lift. I got some info on that from a Porsche 914 racing forum. The 914 has a flatter rear end than mine, so if it plants the back end on those, it should definitely help for me!

Also, the rear bumper isn't exactly smooth. I'll take a picture soon.

Dr.Alberto Morelli,working at the wind tunnel of Pininfarina,Turin,Italy,had developed a zero-lift car by 1978.
Dubbed the "banana" car,the car exhibited no lift,and without the use of any add-on devices.
The news was carried in all the US Pop Sci types of Magazines.Everybody new about it.I presume that Morelli attended the annual SAE Congress and presented his results.
Since lift would incur risk,and risk incurs liability,it would be difficult to imagine that this resource info passed without note.
Many carmakers would soon have wind tunnels of their own with which to refine their designs.
I would suspect that Ford Motor spent millions in the wind tunnel on your car's development.
I believe that Jack Telnack was head of design at the time of your car's genesis and he's no slacker,and certainly would have been attuned to aspects of vehicle stability.
My opinion is that you have nothing to fear from your Tempo.It would have received the same consideration as a racing Cosworth rally car.
Product liability suits and expensive recalls aren't the sort of thing an automaker would bring upon themselves in a time when technology could easily prevent problems before the fact.

[Domman56]

i'd think the tire spats and and air dam would do this

[Christ]

Gonna have to google that banana car, eh?

[Christ]

A Quick Google Shows This:

The second page shows ~10HP necessary at 110Km/H (About 65 MPH) for the Cd of .2-ish.

That's very impressive.

[aerohead]

Originally Posted by Christ

A Quick Google Shows This:

The second page shows ~10HP necessary at 110Km/H (About 65 MPH) for the Cd of .2-ish.

That's very impressive.

Just think of the GM Sunraycer with the wheel fairings,at Cd 0.089! Paul MacCready calculated that she'd do 400-mpg.
Low drag.Wouldn't want it!

[Christ]

I actually kinda like the banana car's look... It looks... sexy.

[tanjulio]

Originally Posted by Hermie

Did the tuft testing, and tomorrow I'll have the pleasure of removing tape residue...

I also found out, much to my relief, the hood vents do in fact vent, and don't take any air in. ^^ Front lift reduction FTW!

I had a question?
Do you have pics of your Hood Vents?
I wanted to do the same thing with my 1990 Honda Civic hatchback because
a mechanical engineering student mentioned "NACA Ducts" for more downforce but will a vented hood do the same?

NOTE: other websites stated that a "vented hood" would add downforce to the front wheels IF placed before the wheels, BUT is this wise?

A: Will a vented hood add downforce to the front wheels?
AA: How do you "test for downforce" without windtunnel to place the vent in the best location for Both reduction of lift and reduction of draft?

B: and is there an efficiency cost? MPG goes down??
BB: NACA Ducts are useful for what????

thanks.
PLEASE Help..
tanjulio@hotmail.com

[Frank Lee]

Sweet Jesus, you don't want advice from Hermie.

[Christ]

He'll explain how his Tempo can fly at 65 MPH... that's about it.