Napier Eland

The military and civil operators had perpetual trouble with the engines which were considered complex.

[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 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.

Napier's Eland testbed Airspeed Ambassador at Farnborough SBAC Show 1955
The Eland has a single shaft so the silver-coloured output shaft is connected to the compressor using gears inside the red-painted gearbox. The gears reduce the compressor speed to that required for a propeller of diameter 12 to 16 feet. [ 10 ] For a helicopter application the output shaft goes into the helicopter gearbox for further speed reduction required by a large diameter rotor, 72 feet for the Westminster.