Bristol Sycamore

Type 171 Sycamore
Bristol 171 Sycamore in Ansett-ANA service in Australia around 1960. Note possible spraying arm attachments.
Role Rescue and Anti-Submarine Helicopter
National origin United Kingdom
Manufacturer Bristol Aeroplane Company
Designer Raoul Hafner
First flight 27 July 1947
Introduction 1953
Primary users Royal Air Force
Royal Australian Navy
German Army
Produced 1947 - 1955
Number built 180


The Bristol Type 171 Sycamore was the first British-designed helicopter to fly and serve with the Royal Air Force. Created by the Bristol Aeroplane Company, it was used for search and rescue and anti-submarine warfare.

The name refers to the seeds of the Sycamore tree, Acer pseudoplatanus, which fall with a rotating motion.

Design and development

Bristol set up its helicopter division after the Allied invasion of Europe in 1944, when engineers from the Airborne Forces Experimental Establishment at Beaulieu became available. The AFEE had been working on the development of helicopter designs under helicopter pioneer Raoul Hafner, but the success of Horsa and Hamilcar gliders during Operation Overlord led to helicopter development now being given a priority. Hafner was appointed by Bristol as head of this new helicopter division.[1]

A sectioned Sycamore main gearbox, displayed in the Deutsches Museum, Munich, Germany

The design of the Sycamore commenced in June 1944, and extended over more than two years, with especial emphasis being given to the endurance of the mechanical components. The maiden flight took place on 27 July 1947, with the prototype VL958 powered by a 450 horsepower (340 kW) Pratt & Whitney Wasp Junior (there being no suitable engine in the Bristol range). The prototype Sycamore Mk.2 was completed in the summer of 1948, fitted with a 550 horsepower (410 kW) Alvis Leonides engine; this became the standard for all subsequent Sycamore production.

Bristol's key development pilots for the Type 171 included Charles "Sox" Hosegood and Col. Robert "Bob" Smith, both test pilots with Bristol.

Versions of the Sycamore up to and including the Mk.3A kept to the standard two-seat aircraft layout of having the pilot in the left-hand seat and co-pilot in the right. The main production, the Mk.4, switched to the American standard practice of having the pilot's seat on the right. There were also a number of other developments from earlier versions, such as a four-door design, that were standardised for the Mk.4. This version entered RAF service as the HR14.

Civil versions did not use the name Sycamore, and were known simply as Bristol Type 171.

Operational history

A West German air force Sycamore Mk.14 at the 1958 Farnborough Air Show

The Sycamore HR14 entered service with 275 Squadron of the RAF in April 1953, and went on to serve with nine squadrons in total. It was used during the Malayan Emergency (1948-1960) for deploying Army foot patrols into the jungle. The type was used by the Royal Air Force Central Flying School for pilot training.

A total of 50 Sycamores were delivered to the German Federal Government, and three to the Belgian Government.

The Sycamore also has the distinction of being the second helicopter type to be used by the Australian Defence Force, when seven were delivered to the Royal Australian Navy.

The RAFs last Sycamores were officially retired in December 1971, as critical parts had reached the end of their fatigue life. However 32 Squadron continued to operate two Sycamores until August 1972.[2]

Variants

Type 171

Mk 1
Prototype; two built.
Mk 2
Second prototype; one built.
Mk 3
Production model with five seats in a widened fuselages and a shortened nose to improve visibility. Fifteen built.
Mk 3A
Civilian version with additional freight hold, two built for British European Airways.
Mk 4
This was the main production model and similar to the military version called Sycamore with a more powerful engine.

Sycamore

Sycamore HC10
(=Mk.3) one built for evaluation by the Army Air Corps as an air ambulance.
Sycamore HC11
(=Mk.3) four built for evaluation by the Army Air Corps, as communications aircraft.
Sycamore HR12
(=Mk.3A) four built for the RAF for evaluation as search and rescue aircraft.
Sycamore HR13
(=Mk.3A) two built with rescue winches for the RAF for evaluation as search and rescue aircraft.
Sycamore HR14
(=Mk.4) 85 built for the RAF, as search and rescue aircraft.
Sycamore Mk 14
three built for the Belgian Air Force, for use in the Belgian Congo.
Sycamore Mk 50
three built for the Royal Australian Navy, for search and rescue, and plane guard duties.
Sycamore HC51
seven built for the Royal Australian Navy, for search and rescue, and plane guard duties.
Sycamore Mk 52
50 built for the German Army and Navy.

Operators

Civil operators

British European Airways Bristol 171 Mk 3A at London Gatwick on the scheduled passenger service from Birmingham in 1955
 United Kingdom
 Australia
 Austria

Military operators

Bristol 171 Sycamore in Royal Australian Navy service around 1960 taking off from the flight deck of HMAS Melbourne.
 Australia
 Belgium
 Germany
 United Kingdom
Sycamore HR.14 of the Royal Air Force Central Flying School (1977)

Surviving aircraft

The RAF Museum Cosford displays Sycamore XJ918. This aircraft saw active service in the Malayan Emergency and was one of the last four Sycamores to be officially retired from RAF service in 1971. It went to the RAF Museum Cosford in 1983.[2]

Other Sycamores are at the Hubschraubermuseum Bückeburg (Bückeburg Helicopter Museum), in Bückeburg, Germany, the Fleet Air Arm Museum in the United Kingdom, the Royal Museum of the Armed Forces and Military History in Brussels, Belgium, the The Helicopter Museum in Weston-super-Mare, the Museum of Army Flying (Middle Wallop, Hampshire) and the Australian Fleet Air Arm Museum in Nowra, Australia.

Specifications (Mk.4 / HR14)

The interior of a Bristol Sycamore

Data from [5]

General characteristics

Performance

See also

Aircraft of comparable role, configuration and era
Related lists

References

Notes
  1. ↑ Myall, Eric : Sycamore Seeds Background and Development of the Bristol Type 171 Air Enthusiast#77 September/October 1998 pp14-19
  2. 1 2 Simpson, Andrew. "INDIVIDUAL HISTORY BRISTOL SYCAMORE HR. 14 XJ918/8190M MUSEUM ACCESSION NUMBER 84/A/1168" (PDF). RAF Museum. Retrieved 18 June 2015.
  3. ↑ "Bristol 171 Sycamore Mk.14, XG547 / G-HAPR". Brussels Air Museum Fund. Retrieved 11 October 2015.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 Jefford 1988, p. 139.
  5. ↑ "Bristol 171 Sycamore". Flugzeug. Retrieved 11 October 2015.
Bibliography
  • Barnes, C. H. (1964). Bristol aircraft since 1910. Putnam. ISBN 0-85177-823-2. 
  • Bowyer, Chaz. The Encyclopedia of British Military Aircraft. Bison Books Limited. ISBN 0-86124-258-0. 
  • Bridgman, Leonard, ed. Jane's All The World's Aircraft 1951–1952. London: Samson Low, Marston & Company, Ltd 1951.
  • Jefford MBE, Wg Cdr C G (1988). RAF Squadrons. A comprehensive record of the movement and equipment of all RAF squadrons and their antecedents since 1912. Shrewsbury: Airlife. ISBN 1-85310-053-6. 
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