Re: Follows old adage...
The BT46, designed by Gordon Murray, was not banned. He proved that the majority of the fan use was to provide cooling. It was dropped after one race, which it won, because it wasn't suitable for all the circuits of the time which meant a completely different car would have to be designed and built.
The other race car with a fan was the Chapparal 2J which was banned after 1 unsuccessful season. It was faster than other cars but very unreliable.