A question on historical approaches to ground effect cars

[SimpleMind]

Forgive me if this seems like a stupid question, but did ground effect cars use the top, front or bottom of the sidepods as main inlets for their venturi tunnels, or did the air come from the bottom of the front of the cars?

Also has there ever been an official F1 car that used other intakes for this purpose? Something like venturi tunnels with inlets at the front of the car or on the sides of the driver? Or would that defeat the purpose?

I'm asking not for a technical explanation of Ground effects which I would not understand anyway, but I ask out of interest in historical F1 cars with their more or less appealing appearance.

I know of the Brabham fan cars for instance, but what other less or more successfull ideas were tried that didn't use the Lotus 78 approach?

[DaveKillens]

Welcome to the forum, simplemind. No question is stupid, if we didn't ask, we wouldn't learn.

Until 1967 Formula One cars paid little attention to aerodynamics. But that was the year some inventive people started to realize that wings and such stuff could easily increase performance. As a side note, Jim Hall started work on such stuff in 1961. He was one designer ahead of his time.

As a start, I suggest you read this article.
http://en.wikipedia.org/wiki/Ground_effect_in_cars

Lotus 79

[WhiteBlue]

Basically all F1 aero is inverted aircraft aero. An aircraft is designed to produce lift in order to fly. An F1 car is designed to produce downforce in oder to accelerate, brake and corner faster.

http://www.allstar.fiu.edu/aero/fltmidfly.htm



Here we see how the undersidee and the upper side of a wing produces different air speeds v1 and v2. V1 is greater than v2.



Here we see how the air pressure relates to the different speeds. Lift or downforce is simply produced by the different pressure from the upside and the downside. P1 is smaller than P2 which makes us fly.



In this picture we could the see that the venturi channel in the Lotus really is an inverted wing profile.

In reality it is all a bit more difficult because we have not considered an angle of attack for now, but the basics are shown.

[SimpleMind]

What are the inlets at the top of the sidepods in this picture for? If the sidepods are designed to manipulate the air under the vehicle?



There may be more to a sidepod than that of course but these are why I wondered if Venturi tunnels could be fed from above.

I've also read that by using wingtips to create vortices the gap between then sidepod and the ground can be sealed (because of the turbulence?) alowwing better effect from a shaped underside.

Then there something called diffusers the idea of which I have yet to understand.

But was wondering now mostly if there were any other early designs in formula one that created ground effectt or at least downforce by using tunnels not located in the sidepods.

If one look att cars from the late 70:s some of them seem to have inlets even in or above the nose. Perhaps for cooling?

Anyway I just love how different an F1 car form the 60;s look from one from the 70:s look from one from the 80:s and so on.

[manchild]

What are the inlets at the top of the sidepods in this picture for? If the sidepods are designed to manipulate the air under the vehicle?...

Those are not inlets, but outlets for hot air from radiators (line shows direction of air flow trough radiators). Radiator is on top on wing. Inlet for radiator is on top of front edge of the wing.



High res cutaways↓

http://img216.imageshack.us/img216/7576 ... 9betti.jpg

http://img196.imageshack.us/img196/6103 ... t79wdb.jpg

http://img8.imageshack.us/img8/2110/tmlotus79.jpg

[DaveKillens]

I've also read that by using wingtips to create vortices the gap between then sidepod and the ground can be sealed (because of the turbulence?) alowwing better effect from a shaped underside.

When ground effects were still being developed, it became obvious that air could "leak" in from the sides, and ruin all that effort. So "skirts" were used, until the rules outlawed them. So that problem of air leaking from the sides degrades downforce, but those wonderful and creative engineers have found partial solutions. Please examine the following picture.



Now, I would like to define the sidepod as being two parts, upper (where the "Petronas"is, and lower (below "Malaysia"). If you look at the entire lower sidepode shape, it starts narrow, widens, then narrows again. The air accelerates along this area, producing a low pressure area. Now, just below that is the flat floor, and note the sharp lip. That's important, because air does not like flowing past sharp corners. Air likes rounded corners.

Below the flat floor is the area that is important, where as much as 50% of the car's entire downforce is generated. It too is low pressure.

Now, if that narrowed sidepod section wasn't there, then the air pressure would be higher, and want to migrate from the sides of the sidepods into the bottom of the car. But it doesn't want to, because the air pressure along the lower side of the sidepod is low, and as well, that sharp lip on the floor really seals the deal by making it very difficult for air to migrate from top to bottom.

[Roland Ehnström]

If one look att cars from the late 70:s some of them seem to have inlets even in or above the nose. Perhaps for cooling?

Those on top of the nose are also OUTlets for hot air from the radiators. The inlet would be at the front or bottom of the nose. Some cars during the early 70's still had the radiators placed in the nose. Others, like that Lotus 79 in your picture, had the main radiators in the sidepods, but also a small radiator for the oil cooler placed in the nose.

[DaveKillens]

Please remember that almost all the ground effect hardware is hidden inside the sidepods or on the bottom of the car. Most of it is hidden out of sight, and in the beginning, the only way to discover what was going on was to grab a glimpse and hopefully a camera shot of a car being winched off the ground.

[manchild]

First ever ground effect sidepods in F1 (1970) No end-plates and no skirts.

March 701 high res > http://img202.imageshack.us/img202/8227 ... rch701.jpg

[WhiteBlue]

First ever ground effect sidepods in F1 (1970) No end-plates and no skirts.

march 701

You can see the negative angle of attack and the inverted wing profile very well in this design.

[SimpleMind]

Thank you for all the answers.

I thought the late 70:s had so many different ideas tried out, and there were teams trying side mounted engines, venturi tunnels, two front wheels, turbo chargers and even sucktion fans. All this produced a variety of appearance in the cars that I think have not been equalled since, although changing rules may have affected too. (The huge airboxes behind the drivers for instance seem to have universally dissapeared from 75 to 76.)

Anyway all the different designs ahad a number of inlets and outlets that I have never been quite sure what they were for, and your answers has helped clear up some of that.

I still find it fascinating that a car like this one, really seems to have existeed, even though perhaps not successful. (And perhaps not a ground effect car.)

Edit: Sorry couldn't get the image link to work but it was the Ensign 179 with the boxy looking inlets/outlets/radiators? in the nose.

[WhiteBlue]

The really breathtaking thing is the application of performance enhancing aero downforce at a time when an F1 chassis was nothing but a heap of tubes and aluminum skin. It offered virtually no protection to the driver. It took another 11 years until Banard's MP4-1 carbon fibre chassis hit the racing world.

[manchild]

Edit: Sorry couldn't get the image link to work but it was the Ensign 179 with the boxy looking inlets/outlets/radiators? in the nose.

yes Ensign N179

[xpensive]

I don't think Robin Herd's wing-tanks on the March 701 would qualify as "gound-effects", though he had worked on the Concorde and clearly had an aerodynamic mind, which was obvious from the 711 when he dropped the wing-tank idea.

There are legends of a BRM "ground-effects" car designed by Tony Rudd in 1969, which was never built, but I would regard the 1977 Lotus 78, indeed largely designed by Rudd and Peter Wright, to be the first ground-effects car.

For the first time, air was invited to the underside of the car in order to create higher air-speed and lower pressure through the "Bernoulli-principle", where higher dynamic pressure (Rho*v^2/2) leads to a lower static such.

Before the Lotus 77, racing car designers were largely pre-occupied with preventing air from getting under the car.

[WhiteBlue]

Edit: Sorry couldn't get the image link to work but it was the Ensign 179 with the boxy looking inlets/outlets/radiators? in the nose.

yes Ensign N179

http://www.oldracingcars.com/f1/car.php?CarID=N179/MN09

Three drivers managed one 13th place out of 11 races. The rest was DNQ and retired. What an unlucky car.