 The aircraft designation "VMT Pyörremyrsky" is also sometimes used, as the factory had been formed into the State Metal Factories ("Valtion Metallitehtaat") during the construction of the aircraft.The Finnish Air Force airplane code letters PM gave the plane nickname "Puu-Mersu" (Wooden Messerschmitt), but the plane was an independent design.The use of wood in the construction of the aircraft was maximized due to the scarcity of metals.