The Kjeller PK X-1 was a two-seater helicopter developed at Kjeller Flyfabrikk under the leadership of engineer Paul Kjølseth. The PK X-1 first flew in 1955, but was considered a purely experimental helicopter and never evaluated in terms of performance.
Further development of PK X-1 was cancelled in 1956 in favour of the development of PK X-2. Aeronautical calculations were made by Erik Tandberg and the powertrain was made by Torbjørn Syverstad.
The PK X-1 was equipped with a 180 hp Franklin 60440-C4 (Some sources say a 200 hp Ranger) and the rotor diameter was 9.26 m.
All Aero 