Westland-Sikorsky WS55 Whirlwind Mark 10 XJ 398

History of Whirlwind XJ398

16-5-1955 : Originally planned as a mark 3 with four others it was taken from the production line incomplete to be converted to MK5 configuration. The MK5 was developed to accept the Alvis Leonoides Major 755 air cooled radial radial piston engine to overcome the serious lack of power of the American Pratt and Whitney engined earlier versions. At this time on the strength of Westland Aircraft Ltd experimental dept.

26-5-1955 : Trial installation of the Leonides Major Engine .

(Below: XJ396, Sister prototype to XJ398 originally built as MK5’s. Both looked identical.)


(Photo GKN Westland helicopters archive))

1-6-1955 : Transferred to ‘Rear Admiral Reserve Aircraft’, a paper transfer to indicate that it would not enter FAA operational service.

29-6-1956 : Taken of charge by R.N

22-12-1956 : Transferred to Westland’s charge.

4-5-1957 : First flight after being retained by Westlands for HAR5 engine development trials. In the interim the MK5 sub type was abandoned and the HAS7 became the next FAA mark. Around this time we believe ‘398was trial fitted with an Armstrong Siddley AS181 turbo shaft engine which was Westlands first use of turbine power in helicopters.

1-8-1959 : When it was decided the AS181 power plant was not to go into production, conversion to the General Electric T58 power plant commenced and ‘398 remained with Westlands for further development to De-Haviland Gnome engine configuration.

Above: XJ398 as converted to De Haviland Gnome format and painted for S.B.A.C airshow (Farnborough) (photo GKN Westland helicopter archive)

 23-12-1960 : Transfer to A&AEE Boscome Down ‘D’ Squadron (Rotary Wing) for handling/Engineeering/Performance trials (on MOD/PE charge)
13-06-1961 : Return to WHL yeovil by road to investigate partial seizure of main reduction engine gearbox.
12-9-1961 : Conversion to “Remote Computer” engine control system standard.
30-1-1962 : Transfer to De Haviland engines, Hatfield for mainenance and development of the Gnome control system.
4-9-1962 : Transfer to Bristol Siddeley engines (BSE) Filton, continuation of gnome control system development.
29-5-1963 : Engine Off landing, suffered CAT4 damage and subsequently repaired.
23-5-1966 : XJ398 appears to have been stored at this time. Moved back to Westlands at Weston Super Mare.
28-6-1968 : Returned to Yeovil from Weston Super Mare where conversion to ‘almost’ HAR10 standard undertaken. Flight tested at weston Super Mare.
30-7-1968 : Transferred to Boscome Down for Empire test pilots school.
2-11-1971 : Cat 3 damage, No details.
15-9-1972 : Transfer to RAE Bedford by air, rotary wing continuation training.
8-4-1974 : Transfer RNAS Culdrose – Trials of RFD/GQ “Aero Conical Canopy”.
10-4-1975 : Sold out of service to Autair Ltd.
23-4-1975 : Registered as G-BDBZ to Autair Ltd, Luton (registered as WS55 series 2).
19-5-1978 : Moved by road to CSE/Oats Kidlington for GI duties.

25-8-1999 : Having cared for it for over 20 years XJ398 was donated to YHPG by Oxford Aviation College, Kidlington and moved by road. It is now based at Aeroventure Doncaster.


Above :XJ398 being loaded onto transporter at Oxford Aviation College.

15-4-2000 :  XJ398’s engine started for the first time in preservation (we beleive the first MK10 to be started in a UK museum). Two further engine starts followed on 15/4 all thanks to pilot Derek Jones, Whirlwind pilot of long standing (RAF & Bristows Helicopters) who traveled to the event from Aberdeen.

Above : XJ398’s engine start at 2000 helicopter weekend (photo Alan Beattie)

3982It is highly appropriate that ‘398 is housed alongside XP345 which flew the last operational Whirlwind flight at Akrotiri in Cyprus in March 1982. The first and last of the breed will now see out their retirement under the same roof. if you have any further detail to add to the above we would be most pleased and interested to hear from you.