Rear downforce options

[Mad Hatter]

Was thinking of adding some down force next year but a full race wing is a over the budget and the car is still doing street duty. Would going to a Gt500 rear spoiler or this MMD ducktail do any good??




In one of our longer faster curves, we get to 90mph, and I can feel that any more power to the rear just starts rotating the tail out. At these speeds is it worth getting more downforce??

 

[ford20]

Moar downforce!!!!

More downforce always helps, but why not go with something like a larger wing?

 

[Mad Hatter]

Would like too, but hard to find one for less then $1500.... thats a lot of tires

 

[Mad Hatter]

Ooops. I see this has been gone over in depth in https://trackmustangsonline.com/index.php?topic=10081.0

 

[dmichaels]

Could always make a wing... like I did... not pro quality but highly functional!!

 

[Mad Hatter]

Yes, I am looking at that right now! How did you do yours???

 

[dmichaels]

Yes, I am looking at that right now! How did you do yours???

I can't remember if I posted up details on this forum or not, but at a high level:

Bought carbon fiber supplies (several yards of 1x1 twill for layup and then 2x2 twill for the cosmetic top layer), resin, vacuum pump, vacuum bag supplies, and a few other items
Made a wire foam cutter with nichrome wire and a power inverter, set up to cut up to about 8 feet of foam
Bought 2" thick high density foam insulation board from Lowes or Home Depot (forget which one)
Researched high lift at low airspeed airfoil designs, found one I liked and printed the cross section
Traced the cross section to each end of the foam board and cut the foam to the approximate airfoil shape
Did a bunch of sanding and a bit of putty work to smooth the airfoil shape
Slotted the suction side (underside as mounted) and put in a length of angled Aluminum for structural support
Glued stainless steel plates at the attachment points on the wing
Laid up the CF (wet layup), vacuum bagged, and let it cure
Fabricated pedestals and trunk reinforcement features (quite a bit of work there!)
Trimmed the wing once out of the bagging and attached the bracketry for the pedestals, then installed

My wing is 72" wide and has a 13" chord length. I haven't calibrated downforce vs AOA (angle of attack) on this one yet (it's the version 2, I made one back in the summer as well as a trial, but decided to do another, bigger, better one), but it should be very similar or slightly more downforce-creating than the APR GT250 which has similar dimensions

I also made my splitter and canards, sort of similar process...

Lots more details in my head, but it would take quite some time to write it all up!

Oh I made the wing end plates too - they came out great, but the attachment needs some work. There is a lot more airflow angled in towards the car centerline in the back and the end plates were deflecting quite a bit at VIR!

 

[dmichaels]

And the end result? Holy grip... I ran at 10 degree AOA or so at VIR and the uphill esses were effortless. Entered at like 133-134 indicated mph by the end of the event and carried 128-129 up through them. It was just silly. The car was planted unlike anything I've felt before. In comparison, at the Glen last time I ran there with slicks, the rear felt like it was right on the hairy edge of coming around exiting those esses at similar speeds. I need more power now...

 

[Mad Hatter]

WOw!! Nice to hear it made a such a difference...... Maybe I can try the same but all aluminium......

 

[dmichaels]

WOw!! Nice to hear it made a such a difference...... Maybe I can try the same but all aluminium......

If you have a good way to form the Aluminum, then yeah absolutely. I thought about that, but I wasn't comfortable trying to fabricate out of Al. The CF cloth is very easy to work with. Surface quality is tough to get right though. It's my biggest challenge right now - structurally though, the parts are very sound. I had the car up to 144 (my redline in 5th) on both straights at VIR over 8 sessions and it was just fine. No aero loading issues.

 

[Mad Hatter]

Its been decades since I used fiberglass!! But will look into it! 2017 is going to be tough for me with lots of stiff fast competition.

 

[Mad Hatter]

I just found this one, but its only 60"

http://www.ebay.ca/itm/191185352978

Price is appealing though

 

[dmichaels]

Pete has the GT250 I think it is which is like 70". It's very very nice. Very high quality. But in my opinion if you're gonna do awrongo all out... my first wing was 58" and 11" chord. Huge difference goingbtonthe 72" one with 13" chord. Almost 50% more area

 

[VoodooBoss]

I like this one for both street and track and it's on sale!

http://www.bmcextremecustoms.net/apr-mustang-drag-rear-spoiler-carbon-fiber-2015-2016.html

 

[Grant 302]

^Pretty sure those winglets are mounted on the wrong sides. Just sayin'.

 

[LERCH]

What about the Steeda wing?
https://www.steeda.com/steeda-s550-functional-race-wing-2015-all-476-steeda-wing-15.html

Sent from my HTC One_M8 using Tapatalk

 

[Fabman]

What about the Steeda wing?
https://www.steeda.com/steeda-s550-functional-race-wing-2015-all-476-steeda-wing-15.html

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I'd want to see actual data related to pounds of downforce. Wings close to the decklid aren't very effective.
Now the new roofs are way more swoopy so this may be less of an issue, but like I said, I'd want to see some hard data before I plunked my money down. But then...WTF do I know?

Do spoilers actually work:
https://www.youtube.com/watch?v=Izgr8nNuZqw&feature=youtu.be&list=PL6R7zR4ZbGkOny_RGsc2V3DULdd2SPwSU

 

[Grant 302]

I'd want to see actual data related to pounds of downforce. Wings close to the decklid aren't very effective.
Now the new roofs are way more swoopy so this may be less of an issue, but like I said, I'd want to see some hard data before I plunked my money down. But then...WTF do I know?

Do spoilers actually work:
https://www.youtube.com/watch?v=Izgr8nNuZqw&list=PL6R7zR4ZbGkOny_RGsc2V3DULdd2SPwSU&index=22

That guy is kinda funny and entertaining, but:

1. Labels the video about 'spoilers'
2. Proceeds to talk primarily about 'wings'
3. Eyebrows. His eyebrows definitely generate lift.
4. Can't seem to keep units consistent. While I can convert to metrics, I *hate* using them.

He *is* generally right for street cars and sedans...but that doesn't really apply to us here.

 

[Fabman]

That guy is kinda funny and entertaining, but:

1. Labels the video about 'spoilers'
2. Proceeds to talk primarily about 'wings'
3. Eyebrows. His eyebrows definitely generate lift.
4. Can't seem to keep units consistent. While I can convert to metrics, I *hate* using them.

He *is* generally right for street cars and sedans...but that doesn't really apply to us here.

He's entertaining alright. I've watched a ton of his videos. He's an accredited aerodynamic engineer as well as an F1 engineer so I take what he says fairly seriously. Also, "spoiler" and "Wing" although different, are widely used to describe the same thing even though we know they aren't. Anyway, what he's saying and I've learned from other sources is that anything that close to the deck lid isn't very effective. It needs to be in clean air and that's hard to get behind a roof.

 

[Grant 302]

He's entertaining alright. I've watched a ton of his videos. He's an accredited aerodynamic engineer as well as an F1 engineer so I take what he says fairly seriously. Also, "spoiler" and "Wing" although different, are widely used to describe the same thing even though we know they aren't. Anyway, what he's saying and I've learned from other sources is that anything that close to the deck lid isn't very effective. It needs to be in clean air and that's hard to get behind a roof.

Actually, there's a fair amount of usable flow toward the outer sides of the decklid. This is one reason why '3d' spoiler designs have a higher angle of attack on the outer section of the wing. That flow comes from the air that 'spills' over the sail panels/quarter window area.

As an engineer, I *always* question what another engineer says. And to be fair...that spoiler video looks like one of his older videos dated in May '13. His videos get better