Mil Mi-4 on static display

The Mil Mi-4 (originally known to US intelligence as the Type-36 and later by the NATO reporting name "Hound") was a Soviet transport helicopter that served in both military and civilian roles.

The Mi-4 was designed in response to the American H-19 Chickasaw and the deployment of U.S. helicopters during the Korean War. While the Mi-4 superficially resembles the H-19 Chickasaw, it is a larger helicopter and is able to lift more weight. The first model entered service in 1952 and replaced the Mi-1. The helicopter was first displayed to the outside world in 1953 at the Soviet Aviation Day in Tushino.

One Mi-4 was built with a jettisonable rotor.