Lear AirplaneLearn plane
This was a pushing arrangement in which two thrusters drive a three- or four-bladed prop at steady speeds in the tail of the plane. Two Pratt & Whitney Canada PT6B turbo-wave motors were equipped with a specially developed gear unit to deliver energy via two separate drive shafts. It was the intention of the construction to ensure the security of the dependability of several motors, in combination with the operation of a solitary motor in case of breakdown of one of the motors.
Aeroplanes were made of light composites instead of the usual aluminium alloys. The two stabilisers were pointing upwards at an angled, similar to a V-tail, and a brief stabiliser was pointing downwards. In contrast to traditional V-tail systems there was no pitch/gyaw check at the Lear fan.
Following the technically induced annulment of a test mission on 31 December 1980, the first prototypes completed their debut on 1 January 1981 (a date formally entered by congenial UK representatives as "32 December 1980" in order to ensure the financing which was due to expire at the end of this year).
But the Lear fan didn't go into it. The US Department of Aviation declined to grant a certification of competency to the fuselage, which was made entirely of composites, because it feared that the combination gear that powers the individual propellers would not be sufficiently reliable despite two engines.
These three Lear Fan planes are on show at the Museum of Flight in Seattle, Washington, the Frontiers of Flight Museum in Dallas, Texas, and at the Civil Aerospace Medical Institute in Oklahoma City, Oklahoma.