Brabham BT46 B "The Fan Car" F1

[911T1971]

Brabham BT46 B
Always loved this special F1 car.
There is a short movie documentary about the car:

http://www.youtube.com/watch?v=ScBCoOv50dA

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[Chuck Miller]

Excellent Karim....... Thanks

[RSTarga]

Copied from Jim Hall Chaparral Can Am car. Except Hall used a snowmobile engine to drive the fan.

[Richardnew]

Another one.

Brabham Fan Car 1978.jpg

Richard Newton
Car Tech Stuff

[72targa]

Copied from Jim Hall Chaparral Can Am car. Except Hall used a snowmobile engine to drive the fan.

This is the fan car I remember...

http://www.youtube.com/watch?v=rWzUsW18k3c

[911T1971]

Hall's car is commonly known as the "sucker car" and not the "fan car" (which is BT46).

Hall (for which I have great respect) had it first but Can Am is not F1, where cars needed to be much lighter.

"In 1970 the Chaparral 2J "sucker car" had proved significantly faster than its opposition in the American Can-Am sportscar series. The 2J had two fans at the rear of the car driven by a dedicated two-stroke engine to draw large amounts of air from under the chassis, reducing pressure and creating downforce. It had suffered from reliability problems with the second engine before being banned by the sporting authorities.
Murray designed a version driven by a complex series of clutches running from the engine to a large single fan at the back of the car. Therefore the faster the engine ran, the stronger the suction effect. Like the Lotus, it had sliding "skirts" that sealed the gap between the sides of the cars and the ground. These prevented excessive air from being sucked into the low pressure area under the car and dissipating the ground effect. There was a rule banning "moveable aerodynamic devices", but the fan also drew air through a horizontally mounted radiator over the engine. Using a fan to assist cooling was legal—Brabham had used a small electric fan to this effect on the BT45Cs at the South American races at the start of the year—and Brabham claimed that this was the primary effect of the new device. These claims were lent some legitimacy by the cooling system design issues that had affected the original design at the start of the year.
The cars were modified BT46s—chassis numbers BT46/4 and BT46/6. Modifications to implement the fan concept were quite extensive—involving sealing the engine bay as well as adding the clutch system and the fan. They were designed and tested in some secrecy. Brabham's lead driver, Niki Lauda, realised he had to adjust his driving style, mostly for cornering. He found that if he accelerated around corners, the car would "stick" to the road as if it were on rails. This had the side effect of exposing the driver to very high lateral acceleration, which would become a major problem in the ground effect era. In his autobiography, Lauda described the car as being unpleasant to drive due to the lateral loads and reliance on aerodynamics over driver skill. He realised early on that the rate of ground effect development meant that in the future, every driver would be exposed to such g-loading while behind the wheel of such a car, and the physical effort needed to drive the cars would leave the drivers exhausted by the end of the races."
Wikipedia

[Flieger]

Hall's design was better because the downforce was independent of the propulsion engine speed. The Brabham was probably not much better than the blown diffusers at the height of their development.