A pair sits in perfect symmetry on a Ferrari F40’s bonnet. A rather large one adds a muscular flash to a Countach’s flanks. Better still, some say, a single bonnet inlet, not centrally located but functionally offset to one side. The NACA duct. Pure visual speed.
Looks apart, NACA ducts do a great job of getting air to the right place because they don’t create the drag you get with a protruberant airscoop. It’s all to do with getting the air’s boundary layer to create a vortex, which directs the bulk of the air where it’s needed, and it arose from the brains of the US National Advisory Committee for Aeronautics (which became NASA), who intended it for jet engines.
Britain’s aerodynamics guru Frank Costin was the first to use one on a car, though – the 1957 Vanwall Grand Prix racer. And the first road-car use, thanks to Costin again, was on the bonnet of the Lotus Elite Super 95 in 1961. It’s a form-and-function dead heat.