Firth Helicopters Ltd. had obtained rights to the Landgraf patents regarding a concept which involved twin outrigger pylons carrying three-bladed rotors fitted with ailerons to change direction.

The small, streamlined Satellite monocoque fuselage consisted of panels of an extremely light magnesium-zirconium alloy.

The twin non-articulated type rotors were powered by two 145 hp de Havilland Gipsy Majors.

In 1952, Firth Helicopters began the construction of the FH-01/4 (still registered as G-ALXP) at their Thame, UK facilities.

Although the majority of the work had been completed, technical problems with excessive weight on the anterior part of the rotors seemed to be unsurmountable given the limited financial resources of the company.