What is the Coandă effect in the An-72?

Short answer

The An-72 exploits the Coandă effect by directing engine exhaust over the upper surface of the wing to increase lift and improve STOL performance. For this, the engines are mounted high above the wing and relatively close to the longitudinal axis.

Published: November 1, 2026 · Updated: November 1, 2026 · Edited by Above Ten Thousand · Editorial policy

Pioneer RQ-2A UAV

Exhaust Over the Wing's Upper Surface

The An-72 used the Coandă effect to improve its short takeoff and landing (STOL) performance, directing engine exhaust over the upper surface of the wing to increase lift. This solution shaped the engine installation: they were mounted relatively high above the wing and relatively close to the longitudinal axis, which allowed the aircraft to exploit the Coandă effect.

A STOL Transport from the 1970s

Design work on the An-72 began in the early 1970s, likely as the Soviet Union's response to the American AMST (Advanced Medium STOL Transport) program. The aircraft was developed with relative secrecy as a short takeoff and landing transport. It first flew on 31 August 1977. The An-72 was the first jet in the Antonov family.

Another Reason to Raise the Engines

On the An-32, by contrast, the engines were raised 1.5 m above the wing to avoid foreign object damage on rough, unprepared runways. There, the high nacelle placement allowed larger-diameter propellers, driven by Ivchenko AI-20 turboprops delivering almost twice the power of the An-26's AI-24s.