Rolls-Royce Gem


The Rolls-Royce Gem is a turboshaft engine developed specifically for the Westland Lynx helicopter in the 1970s. The design started off at de Havilland Engine division and passed to Bristol Siddeley as the BS.360. Rolls-Royce bought out Bristol Siddeley in 1966 and after it dropped the Bristol Siddeley identity the engine became the RS.360.

Design and development

The Gem's three-shaft engine configuration is rather unusual for turboshaft/turboprop engines. Basic arrangement is a four-stage axial LP compressor, driven by a single stage LP turbine, supercharging a centrifugal HP compressor, driven by a single stage HP turbine. Power from a two-stage free turbine is delivered to the load via a third shaft. A reverse flow combustor is featured.
The Gem 42 develops at Take-off, Sea Level Static, ISA, but the Maximum Contingency Rating is.
Until recently all versions of the Lynx have been Gem powered. However, now that Rolls-Royce owns Allison, it has been marketing the more modern LHTEC T800, developed jointly with Honeywell.

Applications

Engines on display