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The History Of Active Aero & Split Twin Element Rear Wings In Motorsport

Nissan R381 with active split element rear wing - image credit Tennen-Gas - This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License

Active aero has been used in a number of forms of motorsport over the years.

The active split wing was pioneered by Nissan on the R381 (shown above) which won the 1968 Japanese Grand Prix.

As the car turns, the wing splits to provide more downforce on the inside wheel.

Nissan R381 with active split element rear wing. Image credit Tennen-Gas - This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License

Cornering speeds are generally limited by the amount of grip available to the tyres.

With a split wing, the wing splits and more downforce is applied to the inside rear wheel.

This additional downforce then provides more grip to the inside rear wheel, enable higher cornering speeds.

More info on the R381 can be found here ... http://en.wikipedia.org/wiki/Nissan_R381

Jim Hall & Chaparral

Active aero was also used with great success on the Chaparral 2E campaigned by Jim Hall in CanAm racing.

http://en.wikipedia.org/wiki/Chaparral_Cars reads ...

The 2E was based on the Chevrolet designed aluminum 2C chassis and presented Jim Hall's most advanced aerodynamic theories to the racing world in the 1966 inaugural Can Am championship.

The 2E established the paradigm for virtually all racing cars built since ...

By depressing a pedal that was in the position of the clutch pedal on a car with a manual transmission, Hall was able to feather, or flatten out, the angle of the wing when downforce was not needed, such as on a straight section of the track, to reduce drag and increase top speed.

In addition, an interconnected air dam closed off the nose ducting for streamlining as well. When the pedal was released, the front ducting and wing returned to their full downforce position.

It was a brilliant design. But the moveable-wing was banned by the FIA so Jim Hall had to make do with a fixed-wing which was not adjustable by the driver during the race.

Within two years every sports racing car as well as formula one car had wings on tall struts ...

More info on the Chaparral 2E here ...

http://www.chaparralcars.com/2e.php

You can view photos and video of the Chaparral 2E here ...

http://www.autoblog.com/2007/01/02/video-chapparal-2e-continuation-racer/

Active Aero Use In Modern Supercars & Road Cars

There are a number of supercars that run active aero, some are at the higher end of the price range and not frequently seen, so many people don't know that they run active aero ...

Bugatti Veyron

Bugatti Veyron hydraulic spoiler. Image Credit: Trevor P. Hirst

The Bugatti Veyron has an active rear wing which changes height and angle of attack.

Adding height to the wing moves it into cleaner air (making it more effective), and adding angle increases the downforce coefficient of the airfoil (blade).

Click here to view a video of the Veyron's rear wing in operation ...

http://www.youtube.com/watch?v=uXcN57tihGI

McLaren F1 Roadcar

The McLaren F1 roadcar also changes the angle of attack of it's rear wing.

http://en.wikipedia.org/wiki/McLaren_F1 reads ...

There is a small rear spoiler on the tail of the vehicle, which is dynamic, the device will adjust dynamically and automatically attempt to balance the center of gravity of the car under braking – which will be shifted forward when the brakes are applied.

Mitsubishi

Mitsubishi ran active aero on the GTO / GT3000.

You can view a video of it in action here ...

http://www.youtube.com/watch?v=RJ3RnJSOmpY

Porsche Panamera

Porsche Panamera Turbo Dynamic Rear Wing Assembly. Image Credit: Porsche AG

The Porsche Panamera also uses active aero.

http://www.autoblog.com/2009/06/25/first-drive-2010-porsche-panamera-a-4-door-sedan-78-years-in-th/ reads ...

Active aerodynamics are standard equipment on all variants of the Panamera, but they alter slightly based on trim level.

The Panarama S and 4S feature a one-piece rear spoiler that is retracted and flush with the bodywork until the sedan reaches 56 mph, at which point it moves into an angle of -3 degrees.

At 100 mph, the wing angle lifts to +5 degrees to increase downforce. At 127 mph the spoiler moves to its maximum deflection of +14 degrees.

The spoiler on the Turbo model is fitted with two additional flaps that extend to increase surface area. It too deploys to -3 degrees at 56 mph, but then locks at +10 degrees at 127 mph and up.

Ferrari 458 Italia

Ferrari 458 Italia uses active aero. Photo Credit: Ferrari

The Ferrari 458 Italia also uses active aero.

http://news.teamxbox.com/xbox/21027/Forza-Motorsport-3-Ferrari-458-Italia-Screens-Video/ reads ...

The 458 Italia is a combination of banned F1 active-aero technology and the voluptuous vision of the Pininfarina design house. The Ferrari features ‘aerolastic’ spoilers in front that shape shift as the car accelerates altering the flow of air into the radiator and decreasing drag.

Honda

Honda is also working on active aero.

http://www.autocar.co.uk/News/NewsArticle/Honda-Concepts/244309/ reads ...

Honda is working on active aerodynamics for its next generation of cars, and will introduce the technology within five years.

Nobuki Ebisawa, Honda's R and D managing director, said active aero would be introduced to get away from the high, cut off tail that characterises cars such as the Insight and forthcoming CR-Z.

So active aero is definitely not a gimmick, has a long and distinguished history, and is proven to work in lowering lap times.

Why are split wings and active aero not used in Formula One ?

Photo credit: Montreal, 1998, by Rick Dikeman. Licensed under the GFDL by the author; Released under the GNU Free Documentation License.

Shown above is the rear wing of a modern Formula One car, with three aerodynamic elements (1, 2, 3). The rows of holes for adjustment of the angle of attack (4) and installation of another element (5) are visible on the wing's endplate.

Active aero is currently banned in Formula One.

When you have a ban on active aero (particularly in categories like Formula One), teams do not spend money on developing such technology.

One of the driving forces in the more recent developments in active aero has been time attack categories, many of which do not ban active aero.

Allowing active aero in those categories has led to development, and now that Formula One is looking to lift the ban on active aero, money will be spent again in research by F1 teams on active aero.

Drive.com.au article

http://www.drive.com.au/Editorial/ArticleDetail.aspx?ArticleID=64211 reads:

Moveable aerodynamic aids are banned in formula one ...

Race car designers would love them ... instead of having to make wings and spoilers that have to combine high downforce and moderate drag, they could come up with something that doesn't hinder speed on straights but then deploys in corners to maximise grip.

F1technical.com article

Formula One is currently looking at allowing active aero again.

http://www.f1technical.net/articles/4577 reads ...

The FIA (Federation Internationale de l’Automobile) has proposed a set of new rules for the 2008 FIA Formula 1 season....

Part of the changes proposed involves major dimensional changes and the introduction of split rear wings ...

The following image shows two views of the model being used for the purpose of this analysis.

So as shown above, the concept of splitting the rear aero into two independent surfaces is something that is well know to F1 also.

FIA World Motor Sport Council Article

http://www.fia.com/mediacentre/Press_Releases/FIA_Sport/2007/June/270607-01.html reads ...

The World Motor Sport Council met in Paris on 27 June, 2007. The following decisions were taken:

FORMULA ONE WORLD CHAMPIONSHIP

The WMSC received a report on the status of current discussions on the FIA Formula One World Championship from 2011. Proposals include: ...

Drag
To allow moving aerodynamic devices, which will reduce drag by over 50% and allow a 40% reduction in the power required to maintain current speeds."

Formula One 2011 Chassis Regulations Framework Article

The Formula One 2011 Chassis Regulations Framework - Proposed Regulations for the 2011 Formula One season which you can find here

http://www.fia.com/resources/documents/1775783383__2011_Chassis_Regulations_Framework.pdf

reads ...

The variation will be primarily achieved by the use of active wings that reduce downforce generation along the straights and maximise it in slow corners ...

Front and rear wings will be constrained in shape, but may be actively controlled ...

The rear wing will be the main mechanism by which adaptive drag will be achieved, while the relatively small (compared to today) front wing is to serve as a trim to achieve balance ...

Front and rear wings maybe electronically controlled within set limits defined from time to time by the FIA. This is to allow much reduced drag along the straights to improve fuel efficiency and yet retain the downforce required around corners, under braking and acceleration so as to retain overall lap times.

Learning From Aerospace

Airbus A380 Wing Tip - Image Credit Dennis Nehrener

Above is a photo of the wing tips from an Airbus A380.

There is a diagram here of the effect on airflow ...

737 Winglets - effect on airflow and turbulence diagram. Image Credit: Hfma Elmejor. This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License.

There is an article on Wikipedia about that effect here ...

http://en.wikipedia.org/wiki/Wingtip_device

It reads ...

Wingtip devices are usually intended to improve the efficiency of fixed-wing aircraft. There are several types of wingtip devices, and though they function in different manners, the intended effect is always to reduce the aircraft's drag by altering the airflow near the wingtips. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without materially increasing the wingspan. An extension of span would lower lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan e.g. available width at airport gates.

Wingtip devices increase the lift generated at the wingtip (by smoothing the airflow across the upper wing near the tip) and reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio.

This increases fuel efficiency, in powered aircraft, and it increases cross-country speed in gliders, in both cases increasing range. U.S. Air Force studies indicate that a given improvement in fuel efficiency correlates directly with the causal increase in L/D ratio.

A number of other planes run upturned wingtips for the same reason ...

Gulfstream V model during winglet flutter investigation at the NASA Langley Transonic Dynamics Tunnel. Image Credit: NASA The Rutan VariEze, the first aircraft to use winglets in 1975. Image credit: Adrian Pingstone Beechcraft Starship business aircraft. Image Credit: NASA

Applying The Aerospace Lessons To Motorsport

In the case of rearwings on race cars, which are inverted to created downforce instead of lift, vertical fences on the wing:

• increase the effective aspect ratio of a wing without materially increasing the wingspan


• avoid increased parasitic drag


• increase the downforce generated at the wingtips (by smoothing the airflow across the wing near the tip)


• stop the airflow from "falling off" the end of the wing

There is an excellent article here titled "CFD Analysis of Endplate Effect" ...

http://www.mulsannescorner.com/techarticle2.html

created on 2009-11-02 12:03:26 by adamr