Gordon Murray's Brabham BT46B used a rear-mounted fan to suck the car onto the track, officially for engine cooling. It won its only race by half a minute. Brabham withdrew it days later rather than fight the argument it clearly could have won.
The Paddock Breakdown
Barry · Gary · KatGary Finch
The result itself tells you everything: Lauda won by roughly half a minute over the next car, an enormous margin for that era of racing, in the car's only appearance. That's not a marginal technical edge. That's a car operating in a different performance category to everything else on the grid, for one afternoon.
What's statistically unusual is how short the whole episode was. One race, one entry, one overwhelming win, one voluntary withdrawal. Most technical controversies in this sport play out over months or years of protests and counter-protests. This one started and ended inside about two weeks, entirely on Brabham's own decision.
Kat Moreno
Technically this is one of the cleanest examples of the sport's long argument over what counts as a 'movable aerodynamic device,' which the regulations at the time restricted. The fan's stated purpose was cooling the engine bay, but the dominant effect was extracting air from under the car and creating ground-effect suction well beyond anything the passive venturi-tunnel cars of the same era were generating.
The other teams' argument was straightforward: if a device's primary measurable effect is aerodynamic, its stated purpose doesn't matter. Brabham's decision to withdraw rather than defend that distinction in a prolonged hearing is arguably an admission the argument had merit, even though the result on the day stood. It's a template the sport has come back to repeatedly since, whenever a genuinely clever piece of engineering skates right up to a rule's actual intent.