The Napier Eland is a British
turboshaft or
turboprop gas-turbine engine built by
Napier & Son in the early 1950s. Production of the Eland ceased in 1961 when the Napier company was taken over by
Rolls-Royce.[1]
Design and development
The Eland was first tested in flight in 1953 in a
Vickers Varsity aircraft.[2] Further flight proving was carried out from 1955 using the first production
Airspeed Ambassador 2.[3] The Eland was dropped from production when Napier was acquired by
Rolls-Royce Limited in 1961.[2]
The only production applications for the engine were two variants of the
Convair CV-240 family, the Royal Canadian Air Force
Canadair CC-109 Cosmopolitan and the civil
Convair CV-540. The military and civil operators had perpetual trouble with the engines which were considered complex.[4] Due to their unreliability
The Department of Transport reduced the
time between overhauls.[5] The CC-106 had its Elands replaced with the
Allison T56 turboprop and the CV540 was re-engined with the
Pratt & Whitney R-2800 Double Wasp piston engine. Potential production applications which were subsequently cancelled were the
Westland Westminster heavy-lift helicopter and the
Fairey Rotodynegyrodyne. The Rotodyne operated as an autogyro in forward flight using the Eland turboprops. For vertical flight the rotor was driven using an auxiliary compressor clutched to each Eland. They supplied compressed air to a combustion chamber at each rotor tip.[6]
Variants
Eland N.El.1
2,690 hp (2,010 kW) + 825 lbf (3.67 kN) residual thrust, static at sea level ICAN conditions.[7]
Eland N.El.3
Powerplant for the
Fairey Rotodyne driving the propeller and an auxiliary compressor to feed the rotor
tip jets 2,805 hp (2,092 kW) + 500 lbf (2.22 kN) residual thrust, static at sea level ICAN conditions.[7]
Eland N.El.4
3,765 hp (2,808 kW) + 610 lbf (2.71 kN) residual thrust, static at sea level ICAN conditions.[7]