The Shackleton is the last in a line of four-engine piston driven
aircraft designed by Avro. The line started with the twin-engine
Manchester of 1939 that became the four-engine Lancaster. The
Lancaster in turn became the Lincoln when modified for the distances
required in the Pacific theater.
When the United Kingdom needed a maritime reconnaissance aircraft in
1946, it turned to the Lincoln. Modified again, the new aircraft was
called the Shackleton. The Shackleton first flew in 1949.
The last variant of the Shackleton, the AEW.2, remained in service with
the RAF in the airborne early warning role until the early 1990s.
