Gull-winged door

A gull-wing door, also known as a falcon-wing door, is an automotive industry term describing car doors that are hinged at the roof rather than the side, as pioneered by the 1952 Mercedes-Benz 300SL race car (W194) and its road-legal version (W198) introduced in 1954.

Opening upwards, the doors evoke the image of a seagull's wings. In French they are portes papillon (butterfly doors). The papillon door, slightly different in its architecture from a gullwing door – designed by Jean Bugatti in 1939 Type 64, 14 years before Mercedes-Benz produced its similar, famous 300SL gullwing door – is a precursor, but is often overlooked when discussing gull-wing design. Conventional car doors are typically hinged at the front-facing edge of the door, with the door swinging outward horizontally.

Apart from the Mercedes-Benz 300SL of the mid-1950s and the experimental Mercedes-Benz C111 of the early 1970s, the best-known examples of road-cars with gull-wing doors are the Bricklin SV-1 from the 1970s, the DeLorean DMC-12 from the 1980s, and the Tesla Model X of the 2010s. Gull-wing doors have also been used in aircraft designs, such as the four-seat single-engine Socata TB series built in France.

The design is a very practical one in a tight urban parking space. When properly designed and counterbalanced, they require little side-clearance to open (about 27.5 cm, or 11" in the DeLorean) and allow much better entrance/egress than conventional doors. The most obvious downside to having gull-wing doors is that, should the car roll over and come to rest on its roof, exit by the doors would be impossible, requiring a large windscreen opening to escape. The Mercedes SLS solved this problem by fitting explosive bolts in the hinges, that would blow up in the event that the car rolls over.

The Volvo YCC, a concept car that was designed by and for women, had gull-wing doors as part of a design meant to be appealing from a woman's perspective. Gull-wing doors to make it easier to lift a bag to store it behind the drivers seat, increases visibility over the driver's shoulder, and makes it easier to get in and out of the vehicle.

...
Wikipedia