Bristol
Siddeley Olympus 301 ECU (Engine Change Unit). By modifications to the
LP compressor (that included adding an extra LP stage) and the LP turbine,
it was possible to increase the thrust from the 17000 lb of the Olympus
201 (similar to the 202, right) to 20000 lb. The new engine was given
the type No B.Ol 21 which became the Olympus 301 in service use. It
was possible to modify Olympus 201s to 301s though retrofitting the
more powerful engine was not simple. Because of the increased air mass,
the Vulcan's air intakes had to be widened. And because of the extra
compressor stage, the engines were larger and would not fit into the
engine bays without extensive modifications. The B.Ol 21 first ran in
January 1959 and the first flew the next year as the port inner in Vulcan
XH557 which had been built with 201s but with the wider intakes. Though
some 201-engined Vulcans were re-engined with 301s, the cancellation
of Skybolt which would have resulted in a higher all-up weight made
the retrofit unnecessary. By the mid-1970s, the 301 was rated at 18000
lb thrust though the original full power was restored for Black Buck
aircraft in the Falklands conflict.
Paul O'Gorman collection. © Crown Copyright >>