Napier Eland

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.

Design and development
The Eland was first tested in flight in 1953 in a Vickers Varsity aircraft. Further flight proving was carried out from 1955 using the first production Airspeed Ambassador 2. The Eland was dropped from production when Napier was acquired by Rolls-Royce Limited in 1961.

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. Due to their unreliability The Department of Transport reduced the time between overhauls. 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 Rotodyne gyrodyne. 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.

Variants

 * Eland N.El.1: 2690 hp + 825 lbf residual thrust, static at sea level ICAN conditions.
 * Eland N.El.3: Powerplant for the Fairey Rotodyne driving the propeller and an auxiliary compressor to feed the rotor tip jets 2805 hp + 500 lbf residual thrust, static at sea level ICAN conditions.
 * Eland N.El.4: 3765 hp + 610 lbf residual thrust, static at sea level ICAN conditions.
 * Eland N.El.6:
 * Eland N.El.7: The 504 adapted to helicopter / convertiplane, compressed air generator use.
 * Eland E.211: The 504 adapted for mechanically driven helicopter rotors.
 * Eland 504:(N.El.6)
 * Eland 508: 504 with increased max continuous rating.

Turboshaft

 * Westland Westminster

Turboprop

 * Airspeed Ambassador
 * Canadair CC-109 Cosmopolitan (CL-66)
 * Convair CV-540
 * Fairey Rotodyne
 * Vickers Varsity (one aircraft as an engine test bed in 1954)

Engines on display
A turboshaft Eland is on display at the Helicopter Museum, Weston-super-Mare.