UFO Flight and Propulsion: Can the Coandă Effect Explain Part of the Enigma?

Could a “flying saucer” fly using familiar physics?

The Coandă effect offers an intriguing engineering possibility.

An air jet discharged close to a curved surface can remain attached and follow its contour. Entrainment of surrounding air and the resulting pressure field bend the flow. In a suitably designed aircraft, directing that airflow downward produces an upward reaction, enabling powered lift.

The concept has historical precedents, including the 1964 Astro Kinetics Dynafan. Another distinct project, the Avro Canada VZ-9AV Avrocar, used three turbojet engines driving a central turborotor to generate lifting airflow.

But appearance and ambition did not guarantee performance. The Avrocar’s two prototypes encountered uncontrollable pitch-and-roll oscillations—“hubcapping”—above approximately 0.91 metres. Its maximum achieved speed was about 56 km/h, and the programme ended in December 1961.

Modern research continues.

A 2024 study investigated a Coandă-effect UAV with one lift motor and two types of flaps. Its fuzzy logic controller achieved a reported 0.417-second settling time, 35.23% shorter than the PID comparison under the study’s conditions. That improvement concerns stabilization, rather than propulsion efficiency.

Could this help us understand UFO reports?

It provides a plausible mechanism for some human-built saucer-shaped aircraft. However, explaining an unidentified observation requires evidence of its actual airflow, power source and flight behaviour.

A silhouette alone cannot reveal propulsion.

Coandă-effect flight still requires energy and an atmospheric working fluid.

It does not establish antigravity or explain extraordinary reported manoeuvres.

Disclaimer: This is my educational interpretation of publicly available research. The proposed connection to UFO/UAP observations is speculative. Corrections from aerodynamicists, researchers and aviation professionals are welcome.