Hey guys, haven't been keeping up with this thread but Skip and I were comparing the "depth" (I believe this is called chord?) of my Ings wing (manuf. by Voltex) to the APR on his car. The Voltex wings seem to be much deeper and present more surface area.

Can anyone elaborate on the potential positive or negative effects (I'm with Skip on having the dumb on this stuff) that having more surface area like this might have?

 

1. Not sure how clean the air is in that location (I'd suspect it to actually be pretty good that high up and far back), but I do get attached flow on the side elements according to oil traces.

2. I don't have enough data to give a sweet spot for height. I have adjusted height to a few locations that were determined by other competing factors (visibility, practicality, rigidity, etc). I now have the bottom wing surface about 10"-12" off the rear deck. I'm getting better results with the wing in this position than in lower positions which I suspect is due to clean air.

 

The aspect ratio of a wing is simplistically defined as the ratio of the span to the chord. For non-rectangular wing planforms, it is more precisely defined as the span^2/planform_area. (Planform is the shape of the wing when looking from above.)

The bigger the aspect ratio, the more efficient the wing is at avoiding induced drag. Well-designed endplates/winglets effectively increase the span (and thus the aspect ratio).

Wing loading (lift divided by planform area) is important for structural reasons. It also is related to the maneuvering ability of an airplane. The lower the wing loading, the more maneuverable it is. But lower wing loading tends to mean bigger chords which tends to mean lower aspect ratios which tends to mean more drag. Everything is a tradeoff.

 

Thanks for the info, but I'm going to have to re-read that a few more times

 

What he said was, long and skinny > short and fat

<--- Enjoying this thread

 

Gearhead,

Well that makes sense. Realistically a decent wing design on a street car has to be pretty far up at ordinary speeds to have an effect. Typically to tall for street aesthetics.

I figure the load on the trunk is going to be an issue at max downforce.

You don't have to stabilize the front, but the more effective the wing is getting, the more unbalanced the car will be, any thoughts there? (Other than when the trunk lid collapses in a 120 mph turn.)

 

And long and fat? (I'm always stuch in that boat )

 

Of course not. The S2000 is tail happy to begin with and the wing was part of fixing that (I did lessen the tire stagger to get more overall grip though). I found that using the rear wing was a good way to keep the back end planted at high speeds (where a stock S2000 actually makes lift in the rear) while still allowing rotation in the slow corners.


The voltex wing, being "fat", will make more downforce, but do so less efficiently as far as drag. In other words, the Lift to Drag ratio actually decreases as you increase the cord length while keeping the span constant. Obviously though, there are structural and space limitations (i.e. width of the car) that will limit your span length and require sub optimal aspect ratios to achieve the lift goals. As Mike said, everything is trade-offs.

 

I will assume then that our two cars are setup differently.

 

A friend of mine was just saying that when she put a wing extension on her car, the handling "went to shit" (direct quote) because it dramatically increased the understeer. It took her a lot of tweaking (and a splitter extension) to tune the car to make use of the extra rear downforce.