Spoiler over rear window

[Ladogaboy]

I'm only referring to it as a vortex generator because that is what Subaru (the originator of that design, as far as I know) referred to it as.

[300zxrb26dett]

The EVO shark fins are VG's, the Subaru STi version is not a VG. I have always seen it referred to as a roof vane spoiler

[Ladogaboy]

Maybe so, but I owned a Subaru for years and was fairly active within the community, and I never recall hearing it referred to as a roof vane spoiler. It's purpose is to reconnect boundary-layer air and create vortices that flow more, cleaner air over the rear airfoil (i.e., the exact same purpose as Mitsubishi's tabs). If it walks like a duck and talks like a duck...

And especially in the context of the OP's question, I think he should be made aware that it is not going to serve the purpose that he is wanting it to.

[some_other_dave]

Originally Posted by Ladogaboy

...there's no telling whether they used ballast for those jumping shots.

Actually, there is. They didn't.

(This is from insider information.)

And weight (just weight) should not have any effect on the attitude that a falling object assumes; after all light and heavy things fall at the same rate until they hit terminal velocity.

-soD

[300zxrb26dett]

Originally Posted by Ladogaboy

Maybe so, but I owned a Subaru for years and was fairly active within the community, and I never recall hearing it referred to as a roof vane spoiler. It's purpose is to reconnect boundary-layer air and create vortices that flow more, cleaner air over the rear airfoil (i.e., the exact same purpose as Mitsubishi's tabs). If it walks like a duck and talks like a duck...

And especially in the context of the OP's question, I think he should be made aware that it is not going to serve the purpose that he is wanting it to.

Considering it serves the same purpose as the EVO VG's then it has the potential to reduce the wake behind a car that does not have a spoiler intended for downforce, or no?

I am aware there will be a drag penalty for anything like this but perhaps its an alternative for people not wanting to add a boat tail or kammback.

[Ladogaboy]

@ some_other_dave: I seem to recall a MythBusters episode where they couldn't perform an experiment requiring them to drop a car because they had been using FWD cars with unequal weight distribution. They then grabbed a BMW with a 50/50 weight distribution, and it was able to free fall without taking a nosedive. Maybe there is some other factor involved?

@ 300: Maybe, but yes, I'm sure the drag penalty for that design would be greater than either the Mitsubishi VGs or the other roof spoiler that he had pictured.

[ERTW]

Originally Posted by kach22i

The first one on the white car redirects the boundary air current down so it stays attached to the rear window.

The second one on the gray car provides a clean edge for the departing air, and launches it slightly down and out. I should note that there is no hope of the trunk wing on the gray doing much of anything.

I think they both create uplift, but in my opinion most drag saving devices and forms do, just as most down-force created devices and forms cause more drag. If someone can prove me wrong with those statements, I welcome the learning experience.

I just posted my research on the current malibu. Imo Anything on the roof of a sedan or coupe is bad or useless at best. Vortex generators help very slightly for the malibu.

I found that a nascar type spoiler significantly reduced drag AND lift. Im currently optimizing size and shape for my car. Hth

[radioranger]

what about the Merkur rear window wing , anybody ever try one of those types,

[kach22i]

Originally Posted by radioranger

what about the Merkur rear window wing , anybody ever try one of those types,

Use the search function in the forum, it's been discussed several times but may be hard to find.

[aerohead]

Originally Posted by kach22i

I would not call the top foil on the white car a "vortex generator".

I would call the tiny shark fins "vortex generators", and you did not post a photo of those.

I agree that if a garnish/device redirects air somehow to a second device intended to increase drag and down-force, that this second garnish/device will operate more effectively. I have this same exact situation with my roof wing and rear spoiler, see roof wing in my signature below.

That thing on the Mitsubishi is a section of what NASA experimented with on a commercial airline fuselage,called a LEBU,for,Large Eddy BreakUp device.
It was to act as a VG.We don't see any used,20-years or so later,so one might presume they had little value.
It probably does help with rear lift on a Lancer,so during rain,etc. probably a nice foil to hydroplaning.