Westland_Wessex

Westland Wessex

The Westland Wessex is a British turbine-powered version of the Sikorsky S-58 "Choctaw", developed under license by Westland Aircraft, initially for the Royal Navy, but later for the Royal Air Force (RAF). The Wessex was built at Westland's factory at Yeovil in Somerset.

The name Wessex had also been used for a fixed wing light transport of 1930, a modification of the Westland IV.

Design and development

An American built Sikorsky HSS-1 was shipped to Westland's in 1956 to act as a pattern aircraft. It was re-engined with a Napier Gazelle engine and first flew in that configuration on the 17 May 1957. The first Westland-built Wessex XL727, a Wessex HAS.1 first flew on 20 June 1958, and they entered anti-submarine duties in 1961 with the Royal Navy. Royal Navy's Fleet Air Arm anti-submarine examples (HAS Mk.1, HAS Mk.3) used the Napier Gazelle engine, a turboprop engine developed into a turboshaft. This made the Wessex the first helicopter to have a free-power turbine, where the power shaft is not physically connected to the compressor shaft.

The design was adapted in the early 1960s for the RAF, and later Royal Marines, to become a general-purpose helicopter capable of troop-carrying, air ambulance and ground support roles. In contrast with the HAS.1, it used twin Bristol Siddeley Gnome engines. These marks (HC Mk.2, HCC Mk.4, HU Mk.5) had a single large exhaust on each side of the nose, the Gazelle-powered examples having a pair of smaller exhausts on either side.

Operational history

The Wessex was first used by the RAF in 1962, and did not finally retire until January 2003, being the main transport helicopter until the introduction of the Aérospatiale Puma. The bright yellow RAF machines used for air-sea or mountain rescue duties became especially famous and saved many lives.

The Navy pressed the development of the HAS.1 into the improved HAS.3, coming into service in 1967. It saw embarked service on the County Class destroyers. The HAS Mk.3 could be identified by a dorsal radome and strake extending behind the "hump".

Wessex helicopters were also used by the Queen's Flight of the RAF to transport VIPs including members of the British Royal Family, from 1969 to 1998. Those Royal helicopters were designated HCC.4 and were essentially similar to the HC.2 but with an upgraded interior, additional navigation equipment and enhanced maintenance programmes. A later version used by the Royal Marine Commandos was the HU.5.

16 former RAF Wessex HC.2 were supplied to Uruguay. The Uruguayan Navy received 5 helicopters in 1998, with the Uruguayan Air Force taking delivery of 11 helicopters in three batches from 2000 until 2003.

Variants

Wessex HAS1

RN utility, anti-submarine warfare, later air-sea rescue only, 140 built, some later comverted to HAS3.Wessex HC2

RAF Troop carrier for up to 16 troops, One prototype converted from HAS1 and 73 built.Wessex HAR2

RAF search and rescue conversions.Wessex HAS3

RN anti-submarine version with improved avionics with a radome on the rear fuselage, 3 new-build development aircraft and 43 converted from HAS.1Wessex HCC4

VVIP transport for the Queens Flight, two builtWessex HU5

RN service troop transporter, carried 16 Royal Marines, 101 builtWessex HAS31

Royal Australian Navy anti-submarine warfare model, 27 built.Wessex HAS31B

Updated anti-submarine warfare model for the Royal Australian Navy.Wessex 52

military transport version of the HC2 for the Iraqi Air Force, 12 built.Wessex 53

Military transport version of the HC2 for the Ghana Air Force, two built.Wessex 54

Military transport version of the HC2 for the Brunei Air Wing, two builtWessex 60

Civilian version of the Wessex HC2, 20 built.

In RN service the armament carried was:

Pylon mounting (selection from)

4 Aerospatiale SS-11
2 Aerospatiale AS-12 Anti-shipping missile
2 x 7.62 mm L7 GMPG machine guns.

Fixed mounts

Depth charges or lightweight torpedoes.

Accidents and Incidents

G-ATSC - Bristow Helicopters. Ditched (North Sea) March '76 - all saved
G-ASWI - Bristow Helicopters. Crashed (North Sea) August '81 - no survivors

Operators

Military Operators

Royal Australian Navy Fleet Air Arm

No. 18 Squadron RAF
No. 22 Squadron RAF
No. 28 Squadron RAF
No. 32 Squadron RAF
No. 60 Squadron RAF
No. 72 Squadron RAF
No. 78 Squadron RAF
No. 84 Squadron RAF
No. 103 Squadron RAF
No. 2 Flying Training School RAF
Queen's Flight
SAR Training Squadron RAF
Wessex Operational Conversion Flight RAF

Fleet Air Arm

Uruguayan Air Force
Uruguayan Navy

Civil Operators

Bristow Helicopters

Specifications (Wessex HC.2)

References

Michal Ovcacik & Karel Susa, Westland Wessex: Rotary Wiings Line, 1st edition 1998, 4+ Publications, Prague Czech Republic, (in English) ISBN 80-902559-0-6.
Patrick Allen, Wessex,1988, Airlife ISBN 1-85310-050-1.