Lip spoiler?
 

So, I've been pondering the aerodynamics of my Malibu again(always seeking gains), and I'm working presently on a lip spoiler... Right now, I've got my old vortex generator array repurposed into the inner reinforcement for a lip spoiler... The thing is, I'm not sure how to optimize the design for aero benefit... Right now, the reinforcement is made up of triangles, roughly 1"x2", right triangles, meaning the spoiler rises at roughly a 30* angle, and has a hypotenuse of roughly 3"... The thing is, the trailing edge of the trunk is curved, and I would like to match it... Either I can curve the entire spoiler and complicate the build with a complex curved hypotenuse, or curve just the trailing edge of the spoiler, making it taller(and longer) in the center, and shorter near the edges...

Is a 30* angle suitable for aero, or should I change it now, before gluing the entire thing together? What would be the optimum height for it?

I thought those were for rear down force not slipperiness. My L200 has the flat type spoiler on the trunk lid, I don't know if it is just for looks or if it helps.

I think that the spoiler changes the effective rear glass angle, making the profile closer to the Kamm-back shape... If it also extends past the end of the trunk lid, it can also help with the fineness ratio... The one on my wife's Impreza isn't too tall, but it does extend past the trunk lid for nearly an inch, and Subaru chose to put them on all the 15-up models(even my wife's 2.0i base) for an improvement of (supposedly) up to 1mpg highway...

Which kinda straightens my perspective; I think my spoiler may end up too tall, so I might reshape the triangle reinforcements for a lower height and try to elongate the hypotenuse surface past the end of the trunk lid...

Can you put numbers on, or show a picture of, that curve? And what's the goal? Keeping the rear wheels planted or squeezing out more mileage?

Gurney flap (or wickerbill): small in scale, at right angles to to 'trip' the airflow locally.

'spoiler' spoiler: same scale as the rest of the car. I like to think of it as a fence that prevents the wake migrating up onto the decklid where it can suck on the back window.

Bonneville spoiler: flat and long. Benefits as you describe. It can also be the top of a box cavity:

http://ecomodder.com/forum/member-fr...bonnevette.jpg

I'll grab some pics tomorrow of the curve, but the idea is to get better mileage from its addition, not so much for downforce... A bonneville type spoiler would help fineness ratio, and promote detachment, but for some reason, I'm hung up on something like the Malibu SS had... It looked pretty cool...

30-degrees
 

Back in 1974,CAR and DRIVER experimented with some home-built spoilers for their CRISIS FIGHTER PINTO project.They found a drag minimum when the rear spoiler had a 30-degree up-sweep.
Some have done like you're thinking about,using the spoiler to reach up to the template profile
http://i1271.photobucket.com/albums/...ntitled3-2.jpg

Well, I'm probably not gonna reach that high with the spoiler, as I plan on a hypotenuse surface length of 3-4", but it should help at least a little

The first-gen Civic Hybrid had a small spoiler on the rear of the trunk that was supposed to be good for a reduction of ~0.02, if I recall correctly.

http://www.hiclasscar.com/wp-content...c-hybrid-3.jpg

What car is that?

Aerodynamics by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...psqzzcpnpl.jpg

I think my spoiler will end up being taller than the HCH1 spoiler, if I extend it past the end of the trunk lid, and keep my approx 30* upsweep... Ideally, I woulda just bought the factory spoiler from a Malibu SS, but I've yet to find one, and really don't wanna spend $40-60 on one...

http://ecomodder.com/forum/attachmen...1&d=1475999118

Two counts?

Yeah...

Citroen CX:

http://car-from-uk.com/ebay/carphoto...ebay650243.jpg

The neighbors have one of these parked in back. Example:

http://i.ebayimg.com/00/s/NTc2WDEwMj..._id=880000500F
http://www.usedracingcar.com/detail/spoilers-wings/01-02-SATURN-S-SERIES-COUPE-REAR-SPOILER-CPE-SC2_281836103357.html

It strikes me as somewhat strange; The part on the deck lid is weathered like a bumper, not a fender. The shape of the fender requires the bolt-on part for continuity.

It appears that it was designed to protect pedestrians if you back into them, but only in the middle. :confused:

OTOH the top is a perfect teardrop shape with a dead-flat beltline. I'd love to graft one into the top of a school bus.

I quite like the shape of the SC2... Wouldn't mind finding one in decent shape to use as a commuter car...

what car
 

I think it's the Ital Design Orca,Cd 0.263 concept car by Giorgetto Giugiaro.
PS The hash marks above and below are where I thought the roof peak occurred

Sc2
 

If you can keep the transmission alive I think you'd like the car.
CAR and DRIVER measured a ROAD LOAD horsepower of only 26,at 70-mph,which means that without their 5th-wheel hanging off the door,you could reduce that number by maybe 24%!:)

A Tesla EV conversion would fix that right up. :thumbup:

I hear the manual transmissions on the s series cars are fine, unless you spin the wheels a lot... The engines are worrisome, however, with their fuel consumption... I had an SL1 a while ago, but it sucked, being automatic and all...

I talked to the neighbors. The one outside my window* has a blown engine. They've just gotten a 4-door with a blown transmission. The coupe's transmission is going in the ($150) 4-door. So it will soon be in some other location with no drive-train.

Now, the rule-of-thumb with electrics is with a single-speed transmission you need twice the horsepower, and beefy wires, to get good low-end performance. I have, on the bench, a 68hp, 10,000rpm Lexus unit. I've been intending to put it in a Baja Bug that needs everything.

aerohead, what do you think I'd gain with the Saturn coupe over a Beetle? When I search Google for "Cd" (includes quotes) I get hits on how to steal the radio. :confused: 0.30-0.28 'ish?

I'm thinking an oval 18-24" bustle with eight '39 Chevy tail-light housings with '59 Caddy backup lenses over red LEDs. Four to a side. Maybe '56 Corvette housings? It's got the driver side half-door!

*Sometimes reality has to slap me in the face repeatedly before I take the hint. :)

The Saturn SC2 is listed at 0.33 on the EM list of drag coefficients. The 1996-2000 SC is list 0.31: Vehicle Coefficient of Drag List - EcoModder

james