Benton

The wing angle is measured by putting a flat plane from the leading edge to the trailing edge, right? So a zero degree wing actually appears to be angled upward? I'm just making sure I set my mounts default at zero and adjustable from there to 10 degrees or so.

Bryan Watts

Depends on the wing profile, depends on whether you are running a gurney or not, etc, etc. It's easiest to establish your own baseline and then adjust off of that. I never actually know exactly what angle my wing is set at...instead, I simply measure it as the car is setting and add or subtract from there and log the number of degrees change rather than the actual degrees relative to 0.

The only time that absolute angle is important is with relation to stall angle. Though, the air is never passing over the wing perfectly parallel to the ground, so a wing that stalls at 15 degrees relative to the air flow may stall at less with relation to the flat surface the car is driving on.

Look at the back of some of the World Challenge touring cars. They can only mount their wings fairly low to the deck. As a result, the air is coming down at a pretty significant angle when it hits the wing. A "trimmed out" wing for minimizing drag will actually point up in the front on some of the cars (I've seen the hatch-back Acuras run it this way in particular).

GUMBALL

When determining wing angle, measure a flat place on the body or chassis (frame rail, door jamb, etc) then measure the wing as Bryan suggested - the difference between the two is your wing angle.
Increasing or decreasing gurney size can be more effective than changing angle.

JackOlsen

Keep in mind that the airflow above the rear of the car on a 911 is in the 10-11 degree range, even when the wing is as high as the roofline. So the wing angle is not meaningfully measured relative to the surface of the road. When my wing is set at one degree, it's actually just about optimized (meaning: 12 degrees relative to airflow).

Benton

Thanks for the tips, guys. I'll mount it up and go from there.

mark kibort

Ive done some extensive testing on my cup car wing on my 928. the deflection off the roofline is near 9 degress, but even that doesnt mean too much. what are you trying to find? 0 lift? if that is your search, then you have to find the angle where the wing doesnt produce lift (this is variable too as the angle off the roof changes slightly with speed) also, each wing will have a differnt angle of 0 lift, depending on its NACA number. a high lift air foil like a cup car wing can produce 220lbs of downforce at 100mph even set at "0". some day ill find "0", but im sure its going to be in the positive 5-10degree range.

But you are finding the angle of attack based on being relative to the horizontal by using a level from the trailing edge to the leading edge. even with a gurney flap. the real angle of attack will only be found when you find out the angle the air moves off the roof line. then, the next or alternate step is finding 0 lift.

or do what you are doing. start out at some neutral point and start making changes until it starts to push real bad and then back off 5 degrees.

there are a lot of graphs for most wings on line. i think we use pretty close to a 64XX series air foil.

mk

95m3racer

OP: What wing are you using?