If you ask those of us who grew up somewhere in the 1950s to 1970s what our car would be like in the year 2020, we might have described an Avrocar. This top secret vehicle from Canadian Avro was part hovercraft and part jet-powered vertical takeoff vehicle. There were two prototypes actually made and [Real Engineering] has a short video on how the prototypes worked, how the real design might have worked, and even has a lot of footage of the actual devices. You can see the video below.
The designer, [Jack Frost], experimented with ground effect and the Coanda effect. The Canadian branch of Avro, a British company, worked with the U.S. military and if you look at it, you wonder how many UFO sightings it caused. Nothing like a flying disk 18 feet in diameter going over your backyard to make you call the newspapers. On second thought, it probably never got enough altitude for that to happen.
The ground effect is well understood by anyone who has seen a hovercraft working. The Conada effect is a little more obscure. This is the effect where a fluid — and for this purpose, air is a fluid — will hug a convex shape. According to the video, the Conada effect inspired the shape, but might not have been very significant for the actual operation.
[Frost’s] saucer was airflow neutral, but with some carefully-placed jet engines, the craft could create a virtual airfoil. In theory, the craft could take off and land vertically, but also be made to perform well at both subsonic and supersonic speeds.
Of course, a theory is one thing and practice often another. The aerodynamic center of pressure was too far away from the center of gravity. The craft was unstable and the mechanical systems of the day couldn’t tame it.
Although the project survived in one way or another from the early 1950s, by 1961 the program ended. What had started as a futuristic combination helicopter and jet fighter had been reduced to little more than a hovercraft. Ironically, if the Avrocar had a skirt to form a plenum chamber, it would have probably been the first hovercraft, which launched in 1959.