Seriously "active" aero

[Cobrar]

Kendall,

I agree but think the "deployable" technology is so new in the automotive field, people are struggling to use common aerodynamic terms to relate to this newly applied technology. It is a matter of semantics.

Yes, flaps on an airplane wing do go "down" or more accurately are lowered into the low(er) velocity flow stream on the underside of the wing. Recall that air velocity is higher on the upper wing surface according to Bernoulli's Principal. This action does result in increased wing lift at a slower wing velocity (with higher attending drag as well). Spoilers do go "up" into the upper high(er) velocity stream but only after the pilot determines he no longer wants the wing to produce lift (ie after the plane has landed) and is being slowed. Their deployment is a lift killer so the aircraft weight can be quickly transferred to the undercarriage wheels and also develops drag which helps slow the plane on the tarmac.

Rear wing application on a car is to produce downforce (not lift) to increase car/tire grip to the road surface. Sustainable tire forces through the contact patch (tire/surface) interface are dependent on the applied normal force through this patch which a rear wing can selectively (if adjustable) increase.

The rear wing airfoil in an automotive application is turned upside down so the "lift" it generates is actually directed toward the ground to increase the patch normal force. So really the flap (or deployable wicker which is certainly an acceptable term as well) is still deployed toward and into the slower velocity airstream which, in the automotive application, is on the upper surface of the wing since it has been mounted upside down.:wink

Are you sure of this Bill??? ;-))

 

[STORMCAT]

Damn, and I was just gonna post pretty much the same thing.

:biggrin gota love that guy !

 

[nota4re]

Damn, and I was just gonna post pretty much the same thing.

I am merely the set-up guy for Bill.....

 

[Indy GT]

WOW! That was fast!!!

Thanks for the comments. Always welcome! And thanks Kendall for setting me up.:thumbsup

Just the facts mam....

 

[twobjshelbys]

A really good (but long) explanation of the Gurney Flap

https://www.youtube.com/watch?v=TK8-VuwPqq4

 

[RALPHIE]

...
The rear wing airfoil in an automotive application is turned upside down so the "lift" it generates is actually directed toward the ground to increase the patch normal force. So really the flap (or deployable wicker which is certainly an acceptable term as well) is still deployed toward and into the slower velocity airstream which, in the automotive application, is on the upper surface of the wing since it has been mounted upside down.:wink

:thumbsup - Envision a plane flying upside down - the employment of the flaps would create increased lift in the downward direction. Such is the intent of downforce created in the automobile application.

 

[STORMCAT]

:thumbsup - Envision a plane flying upside down - the employment of the flaps would create increased lift in the downward direction. Such is the intent of downforce created in the automobile application.

I'm originally from from Iowa. In the winter we wore those hats with the big side flaps over the ears. I think they created down force to keep the hat on your head.. is that the same thing you guys are talking about... ?? confused :biggrin:biggrin

 

[Bullitt2065]

The street car will have active aero. The race versions can't have active - the wing is fixed - both mounting and adjustment.

I wonder if the active wing is deployed using hydraulics or electric.

The race car wing itself is in a fixed position, but there are a number of adjustments they can make for the angle of the wing element itself.

 

[twobjshelbys]

The race car wing itself is in a fixed position, but there are a number of adjustments they can make for the angle of the wing element itself.

Yes for static adjustments. Movable parts are not allowed while the car is in motion.

 

[timcantwell]

Jim Hall is smiling. ;-))

+2

 

[Fubar]

Kendall,

I agree but think the "deployable" technology is so new in the automotive field, people are struggling to use common aerodynamic terms to relate to this newly applied technology. It is a matter of semantics.

Yes, flaps on an airplane wing do go "down" or more accurately are lowered into the low(er) velocity flow stream on the underside of the wing. Recall that air velocity is higher on the upper wing surface according to Bernoulli's Principal. This action does result in increased wing lift at a slower wing velocity (with higher attending drag as well). Spoilers do go "up" into the upper high(er) velocity stream but only after the pilot determines he no longer wants the wing to produce lift (ie after the plane has landed) and is being slowed. Their deployment is a lift killer so the aircraft weight can be quickly transferred to the undercarriage wheels and also develops drag which helps slow the plane on the tarmac.

Rear wing application on a car is to produce downforce (not lift) to increase car/tire grip to the road surface. Sustainable tire forces through the contact patch (tire/surface) interface are dependent on the applied normal force through this patch which a rear wing can selectively (if adjustable) increase.

The rear wing airfoil in an automotive application is turned upside down so the "lift" it generates is actually directed toward the ground to increase the patch normal force. So really the flap (or deployable wicker which is certainly an acceptable term as well) is still deployed toward and into the slower velocity airstream which, in the automotive application, is on the upper surface of the wing since it has been mounted upside down.:wink

Incase anyone was unclear... Indy rocks! I can see him explaining this to his 4 year old grandchildren just like that. Where I might say "traction guud, cars no suppose to fly... see?

 

[Indy GT]

Thanks for your kind comments, Mark!

Now let the owners see the fruit of all your hard development work on your car. Hope to see you and your amazing car at a rally SOON!!:thumbsup

Oh and my 3 year old grandson is a huge "Blue Oval" fan. He spots the trademark everywhere and exclaims "Blue Oval Papa"! Technical lectures to start soon....:biggrin

 

[Topnotch]

http://cdn.makeagif.com/media/1-06-2016/pRpzkb.gif

 

[Fubar]

I presume he will be applying for his own 2016 FGT. I think that's the kind of customer loyalty they are looking for.

I'll post up a few pix of my car. I think we are close (but I've thought that before).

 

[Bullitt2065]

So after having watched the CGI video Ford released a few days ago, it's clearly visible that there ARE flaps that extend up on the trailing edge of the rear wing. You can see in in real time between 0:19 and 0:21 in the link below. Granted this is all a CGI video, so it's possible it isn't on the real car, but I doubt they would go through the trouble of including something that wasn't bound for the production car at this point.

[video=youtube;oybeEvACGwA]https://www.youtube.com/watch?v=oybeEvACGwA[/video]

 

[Bullitt2065]

I created a GIF from the YouTube linke, too. Prettty clear to see what's going on, here.

 

[DoctorV8]

A really good (but long) explanation of the Gurney Flap

https://www.youtube.com/watch?v=TK8-VuwPqq4

Wow, great link.

His follow up video with a 1982 Holden Commodore is very interesting.

https://www.youtube.com/watch?v=vzMe1e9fE50

 

[Indy GT]

Actually the Gurney Flap video suggested by twobjshelbys is very good.

I understand the complaint by some that the Grey’s Garage video is a bit long, but discussing aerodynamics to people not familiar with the topic requires some time to define and discuss aerodynamic terms used in the discussion. I believe the author does a pretty good job of this and most will be able to follow his topic development. Aerodynamics is a complex topic requiring testing and measuring results to draw conclusions. As well as understanding basic aerodynamic principals. Modification intuition and what “looks good” many times turn out to be the exact opposite of what the designers actually want. This is why actual testing (or analytical modeling) is so important especially with the high speeds capable in our FGT.

In aerodynamic development of the 05-06 FGT, the Ford engineers used as a starting point aerodynamic data collected from putting an actual 1968 GT40 (chassis # 1030) in the wind tunnel and measuring /documenting the baseline shape aero characteristics. This model represented the 1968 and 1969 Le Mans winning vehicle. See SAE publication 2004-01-1254. Although the GT40’s overall coefficient of drag and Lift over Drag coefficients (L/D) were quite good and lower than the 05-06 design targets, the frontal coefficient of lift was terrible (up to 340% above the new GT design target) and rear coefficient of lift was not great either at 100% over target. See report Table 1. After measuring this data, the Ford engineers concluded, “it was clear why GT40 drivers complained of front-end lift on the Mulsanne straight!”. These shape deficiencies were corrected in our 05-06 FGT design as many of our high speed owners will attest.

As the aerodynamic analysis “state-of-the-art” has advanced in the 13 years since the 05-06 design was brought into production, I am sure aerodynamic design elegance in the 2016 FGT will be amazing. It has been reported that aerodynamics was THE design factor in arriving at the new Ford GT shape.

Likewise, the second aero video recommended by DoctorV8 by Gray’s Garage on aerodynamic modifications to enhance track stability of the 1982 Holden Commodore is also good and emphasizes the need for testing and results analysis before embarking on a modification program. Although I could do without the piano background music in this video.:biggrin

 

[Cobrar]

Prefer something more contemporary. - like Stairway to Heaven? ;-))

 

[Indy GT]

Prefer something more contemporary. - like Stairway to Heaven? ;-))

Contemporary???

Rex, you are showing your age....:biggrin
Although Stairway IS a classic!