Cougar shape?

[Christ]

I was going to mention that the spoiler's line ends up shallower than the side spats, but I wasn't sure in that case it would have been true or not, as there have been cases where the spoiler's surface is actually just folded down to make the side spats on certain vehicles and for certain effects.

[cfg83]

Christ and Frank -

I had the same suspicion, but I was too lazy to go looking for the proof.

From Frank's top view picture, do you think the side spats "taper in"? That would also follow the teardrop analogy, at least from my POV.

CarloSW2

[Frank Lee]

It is definitely boat-tailed.

I was thinking of starting a new thread on this and probably should have. Split it off?

I've always seen this style of spoiler NOT boat-tailed. The Fusion is the first one I've noticed with that feature.

Also I've noticed sometimes the "end plates" are flush with the sides of the car and sometimes they are set in.


Set in from sides and boat-tailed


Flush with sides and no boat-tailing.


Set in from sides and no boat-tailing

[Christ]

Carlos -

It would appear that they follow the relative taper of the rear body work, but nothing more. To that extent, yes, they taper. I doubt, however, that it's anything close to an "ideal" angle for flow.

Frank -

A good many of those designs, the intent of the sides seems mostly to be solely to support/add rigidity to the top. It's as if they're not even concerned with side flow, but only believe that flow occurs top and bottom?!

[Frank Lee]

Of all the examples I put up, I'd trust the aero development on the Fusion the most. It's been in the wind tunnel; who knows about the other guys.

[Christ]

Originally Posted by Frank Lee

Of all the examples I put up, I'd trust the aero development on the Fusion the most. It's been in the wind tunnel; who knows about the other guys.

The "other guys" appear to be using a pretty standard design that is widely used to reduce lift, and nothing more, really. See NHRA racing. That's why I mentioned the structural capacity of the side panels, because I believe that's the only reason they're really there.

[Frank Lee]

Structure is likely most of it and the inset from the sides ones would be in the wake zone anyway- under the "shelf" anyway.

The end plates on some designs protude above the upper surface too. I wonder about the aero behavior of that, straight back vs. boat-tailed... and of course, the behavior of each in YAW!!!

[Christ]

I wouldn't venture to postulate on the effects of shape induced aerodynamics in either of those profiles... that would require extensive testing, afaic.

[winkosmosis]

Originally Posted by Christ

The "other guys" appear to be using a pretty standard design that is widely used to reduce lift, and nothing more, really. See NHRA racing. That's why I mentioned the structural capacity of the side panels, because I believe that's the only reason they're really there.

If that were the case, they'd be reducing front end traction, creating instablity

[cfg83]

Christ and Frank -

Originally Posted by Christ

Carlos -

It would appear that they follow the relative taper of the rear body work, but nothing more. To that extent, yes, they taper. I doubt, however, that it's anything close to an "ideal" angle for flow.

Frank -

A good many of those designs, the intent of the sides seems mostly to be solely to support/add rigidity to the top. It's as if they're not even concerned with side flow, but only believe that flow occurs top and bottom?!

I agree that the Fusion might be extending the rear of the trunk, hence the side spats being "interior" to the tail-lights. I keep thinking the dual-purpose of the spoiler is to "hide" the parachute from the airstream.

Time to DIY :

1975 Chevy Laguna Gets A Racing Spoiler- Popular Hot Rodding Magazine
(and the angle is ADJUSTABLE, too!)

CarloSW2