Aero downforce?

[ZERO25]

A racing buddy and I were chatting recently and he said, "Aero is more important now than ever." To which I replied, "Yeah, so is gravity."

My point being that before humans understood what gravity was, things were falling to the ground at the exact same rate. Our understanding of things doesn't make them more important. It just means we know how to better manage the inputs to the outcomes we want.

My college physics professor said it is absolutely necessary that every person should know how to measure the rate of gravity.....if not, they should not be allowed to live!

I believe most racers know how, but don't really understand it!

[billetbirdcage]

I guess I see frontal area as anything that can be seen from the plane opposing the direction of travel. (anything the wind directly sees. Spoiler on a dirt lm would definetely be that.)
Spoiler hid behind the "greenhouse", not so much. The side of a lm if the car if skewed from rear steer would fall into frontal area.
Maybe I'm looking at it wrong.

I guess my response wasn't as understandable as I meant it to be.

I would agree frontal area is the area the air would see, but I was referring to the spoiler on a car with windshields to explain my point. At a front view the rear spoiler may not add any frontal area, but would increase drag. Which is what I was referring to as to answer what I think your question was on if drag can be changed without altering the frontal area.

Maybe a simpler way to describe this is:

Take a LM and chop the nose off right in front of the front tires and instead of a sloped nose you have a blunt flat plate. You could have the exact same frontal area, yet the drag would be higher on the blunt front end.

Or another way is take a LM with say 900 square inches of frontal area and compare to another car or even a flat piece of plywood with the same 900 sq inches and the drags would be considerably different.

I think that would answer your question unless I didn't understand your question right. I think the main reason they figure frontal area is to get the drag coefficient into a number. Most of the data I've seen doesn't use the drag coefficient number but the drag in pounds instead. I think the drag coefficient is more drag vs surface area when comparing vehicles and for racing isn't overly cared about or all that useful.

Again NOT an aero engineer so. . . .

[billetbirdcage]

If you research some F1 aero stuff, part of the reason the front wings are so wild looking is they are directing air around the front tires to reduce drag and increase down force from the open wheels. The front lower part of the front tires (rear was well) actually increases lift so they are reducing that by moving air around the tires and they run in sort of a wake or void of air there instead of the air hitting the tires directly. It's pretty crazy when you see some in depth air flow on them, a lot of it is over my pay grade, lol.

[RaceEngineer]

Even on a SLM, a lot of the spoiler is not frontal area.

[95shaw]

I see your point, billet.
If increasing the angle on the nose, the gain is front downforce, at the expense of more drag.
No free lunch, lol.
Lose the spoiler, less drag at the expense of rear downforce.
Less body skew , less drag down straights, at expense of side force helping in the corner.


Wouldn't the spoiler being obscured by some other part, be a wash in terms of frontal area?

Obscuring the proper portion of spoiler could be benificial, yes?

[RaceEngineer]

I see your point, billet. If increasing the angle on the nose, the gain is front downforce, at the expense of more drag.No free lunch, lol.Lose the spoiler, less drag at the expense of rear downforce.Less body skew , less drag down straights, at expense of side force helping in the corner.Wouldn't the spoiler being obscured by some other part, be a wash in terms of frontal area?Obscuring the proper portion of spoiler could be benificial, yes?

It's a wash, yes. But it is a different surface.