Aerodynamics discussion

[djliquidsteele]

Originally Posted by plucas

Well it is a little more complicated than just changing something. Really thorough analysis and testing is needed. Basical engine cooling like radiators, oil coolers, and radiant heat need to be able to exit out of the top, like the hood or out the bottom. Both can be done but out the top is more common for simplicity. Transmissions and rear ends are cooled with the air under the car. If that gets covered, cooling in these areas are needed also. You could add things like NACA ducts for inlets and exit it out the bottom by creating an area with even lower pressure. Another option would be external heat exchangers to cool the oil in these areas. There are a ton of possibilities.

If you are really interested in doing this, I can give you a good direction. I would pm me though to keep the thread clean.

In my opinion, lets keep the discussion here as anyone that is truly interested in improving the aerodynamics of the car for race purposes is probably going to be interested in cooling possibilities.

[7thgear]

random question, the answer to which i almost know but want to confirm

at very low speeds (20kmh, for instance) is the downforce generated by almost any device essentially entirely negligible?

[FreshFRS]

Originally Posted by 7thgear

random question, the answer to which i almost know but want to confirm

at very low speeds (20kmh, for instance) is the downforce generated by almost any device essentially entirely negligible?

i would say yes, but some circumstances (F1) design around what little downforce is produced at lower speeds IIRC. i could be wrong though.

[7thgear]

Originally Posted by FreshFRS

i would say yes, but some circumstances (F1) design around what little downforce is produced at lower speeds IIRC. i could be wrong though.

Hehehe

I dunno, I doubt it, the slowest speed an F1 car goes is in the pits, and it's way faster than 20kph :P

[FreshFRS]

Originally Posted by 7thgear

Hehehe

I dunno, I doubt it, the slowest speed an F1 car goes is in the pits, and it's way faster than 20kph :P

lower speed relatively i should have clarified. 40mph in some corners is the slowest ive seen. for an average car is not affected at all i would say.

[EarlQHan]

Originally Posted by 7thgear

random question, the answer to which i almost know but want to confirm

at very low speeds (20kmh, for instance) is the downforce generated by almost any device essentially entirely negligible?

It depends on the situation, but in the situation of road cars, I'd say it is negligible. It would be like using relativistic equations when Newton's will suffice.

[Xanatos]

Originally Posted by 7thgear

random question, the answer to which i almost know but want to confirm

at very low speeds (20kmh, for instance) is the downforce generated by almost any device essentially entirely negligible?

The formula for downforce by definition uses the square of the velocity. That being said theres always a minimum speed for lift/downforce to work. Think of paper planes. The formula also includes the area relative to the angle of attack which means if you have a sufficiently big wing with a big angle you can still get some downforce at low speed (Pikes Peak Unlimited class cars) but at the cost of high drag.

[7thgear]

my inteded application is ice racing, where the cornering speeds at apex are about 15-20km/h

and if i should bother designing any aero at all

[Dimman]

Originally Posted by 7thgear

my inteded application is ice racing, where the cornering speeds at apex are about 15-20km/h

and if i should bother designing any aero at all

You'd need a World of Outlaws level of wing.

Edit:

[ZDan]

Originally Posted by 7thgear

my inteded application is ice racing, where the cornering speeds at apex are about 15-20km/h
and if i should bother designing any aero at all

You should be designing in aero a la the Chapparal 2J and Brabham BT46B "sucker cars"

[Xanatos]

Originally Posted by 7thgear

my inteded application is ice racing, where the cornering speeds at apex are about 15-20km/h

and if i should bother designing any aero at all

Nah, I wouldn't worry about aero. I suspect you will be drifting some of those turns as well which means the area of the wings is essentially zero.

The right suspension would have much more of an effect on your grip than aero.

[robispec]

Originally Posted by 7thgear

my inteded application is ice racing, where the cornering speeds at apex are about 15-20km/h

and if i should bother designing any aero at all

weight reduction CG location (if you have minimum weights) would be the big ticket items vs aero (and I'm a big fan of aero). if you look at the basic wind resistance curve it starts bending upwards pretty fast in the high teens (just ask any bicycle racer) and you start doubling HP requirements for a minimal increase in speed in the mid to high twenty mph

But we are talking about a very low HP engine here...lol

[jamal]

Basically until you are going 60-70mph you don't really gain anything. Here's a chart from a neat book I'm reading:

[plucas]

Originally Posted by djliquidsteele

In my opinion, lets keep the discussion here as anyone that is truly interested in improving the aerodynamics of the car for race purposes is probably going to be interested in cooling possibilities.

I do not get what you are saying