The Ivchenko AI-26 is a seven-cylinder air-cooled radial engine used in early Soviet helicopters and later used in light utility aircraft.
The AI-26 retained the bore, stroke and displacement of the ASh-21 while incorporating new features peculiar to its role.
The engine was envisioned as a helicopter engine, but the early test models lacked the necessary equipment to facilitate this role, such as an auxiliary cooling fan, reduction gears and clutch.
The GR suffix means "Gelikopter", or helicopter.
In late 1947 the decision to mass-produce the engine was made and production commenced at factory No.478 located in Zaporizhia.