Custom rear spoiler for the Missile
The effects a wing has on a car can only be determined by actual testing. All cars have different aerodynamic properties. More modern cars all tend to have the general "semi-teardrop" shape, so their aerodynamic properties are very similar.
When Chrysler wind tunnel tested the Superbird and Daytona Charger, they went through many wing, nose, and air dam configurations. The wing they ended up using began to provide downforce only at about 60 m.p.h. and the AOA was adjustable. However, the greatest secret of the wing assembly was the lateral directional stability it provided at speed. Everybody else concentrated on the wing itself and not on the vertical stabilizers.
I can't wait to see your results, Andrew.
Yeah don't tell all the ricers with their Civics, but most of the wings/spoilers on cars these days are too small to do much of anything. Even the larger ones don't usually have any effects below 60 mph.
Evidence of that can be seen by looking at that Superbird wing. Its huge! The problem with the design of the Dart (similar issue with the Charger) is that the profile of the greenhouse drops off so quickly. By having a tall, square greenhouse, you block a lot of air. And in the wind tunnel, you'll see separation of the air flow at the back of the roof. I'd bet the Dart is actually worse, especially the '70 up version, since the decklid is shorter than on a Charger. The wing would likely have to be taller. Modern cars have more of a "tear drop" shape so that the air flow remains laminar, and attached to the car, so you actually have a significant amount of air flow across the trunk. Which is why the wing on the Superbird had to be so tall, it had to be that way to get it back into the air stream. On a modern car, you can have a shorter wing or spoiler, since its still in the air stream.
Take a look at an 2003-2005 SRT4 (the neon based version). They had a pretty large wing from the factory, and one that was claimed by Dodge to be functional. On one of the forums I used to be on a guy bought an SRT4 wing and put it on his Neon, which originally just had a small spoiler. He immediately noticed a rattling noise at speeds starting around 60 mph. It turned out that at 60 mph, the wing created enough downforce to cause his trunk latch to rattle. That was it.
So, as far as making this modification "functional", I'd have to be a little skeptical. It has a pretty decent surface area, so it might actually work a little. But the effects would be minimal at best. And, as fishbreath pointed out, you'd actually have to put it in a wind tunnel to know if it was even a positive effect. It would be pretty easy for it to produce a significant amount of drag, without producing any downforce, and all that would do is lower your MPG's. Even downforce really isn't helpful unless you're taking corners in excess of 60 or 70 mph, since the wing likely wont be effective below those speeds. On the freeway you don't need downforce, and the added drag will just slow you down.
So, long story short, I think its a really cool idea. But like the other mopar wings and spoilers (go-wing,t/a, ductail etc) I don't think its going to be much of an aerodynamic improvement. It's different, and I think it'll look good, and will probably do about as much as any of the stock wing options (not much). But everyone puts the stock wings and spoilers on, so why not? Looking forward to seeing it finished.
