This specific inlet type is called a "NACA inlet", "NACA scoop" or "NACA duct", since it had been invented by Francis Melvin Rogallo at NACA in 1941 (PDF) and refined by scientists at NACA (now NASA) Ames. Its main advantage is its simplicity: It just needs a properly shaped cutout in the skin and a rounded rear edge, whereas the airscoops it replaces need carefully shaped contours.

The working principle is quite similar to that of a delta wing, only in this case the actual wing is missing, and is surrounded by sheet metal. But like on the swept leading edge of a delta wing, the swept left and right edges create a vortex which is swallowed by the actual intake at the rear of the cutout. This helps to create a lot of flow for the given area, even though efficiency is below that of a well-shaped airship.

This specific inlet type is called a "NACA inlet", "NACA scoop" or "NACA duct", since it had been invented by Francis Melvin Rogallo at NACA in 1941 (PDF) and refined by scientists at NACA (now NASA) Ames. Its main advantage is its simplicity: It just needs a properly shaped cutout in the skin and a rounded rear edge, whereas the airscoops it replaces need carefully shaped contours.

The working principle is quite similar to that of a delta wing, only in this case the actual wing is missing, and is surrounded by sheet metal. But like on the swept leading edge of a delta wing, the swept left and right edges create a vortex which is swallowed by the actual intake at the rear of the cutout. This helps to create a lot of flow for the given area, even though efficiency is below that of a well-shaped airscoop.

This specific inlet type is called a "NACA inlet", "NACA scoop" or "NACA duct", since it had been invented by Francis Melvin Rogallo at NACA in 1941 (PDF). Its main advantage is its simplicity: It just needs a properly shaped cutout in the skin and a rounded rear edge, whereas the airscoops it replaces need carefully shaped contours.

The working principle is quite similar to that of a delta wing, only in this case the actual wing is missing, and is surrounded by sheet metal. But like on the swept leading edge of a delta wing, the swept left and right edges create a vortex which is swallowed by the actual intake at the rear of the cutout. This helps to create a lot of flow for the given area, even though efficiency is below that of a well-shaped airship.

This specific inlet type is called a "NACA inlet", "NACA scoop" or "NACA duct", since it had been invented by Francis Melvin Rogallo at NACA in 1941 (PDF) and refined by scientists at NACA (now NASA) Ames. Its main advantage is its simplicity: It just needs a properly shaped cutout in the skin and a rounded rear edge, whereas the airscoops it replaces need carefully shaped contours.

The working principle is quite similar to that of a delta wing, only in this case the actual wing is missing, and is surrounded by sheet metal. But like on the swept leading edge of a delta wing, the swept left and right edges create a vortex which is swallowed by the actual intake at the rear of the cutout. This helps to create a lot of flow for the given area, even though efficiency is below that of a well-shaped airship.