Rose turret
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The Rose turret (sometimes known as the Rose-Rice turret) was a
gun turret A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...
fit to the rear position of some British
Avro Lancaster The Avro Lancaster is a British Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to the same specification, as well as the Short Stirlin ...
heavy bombers in 1944–45. It was armed with two American light-barrel Browning .50-calibre AN/M2 heavy machine guns — the standard American defensive weapon used in turreted and flexible mounts in the
B-17 Flying Fortress The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Relatively fast and high-flying for a bomber of its era, the B-17 was used primarily in the European Theater ...
and
B-24 Liberator The Consolidated B-24 Liberator is an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and some initial production aircraft were laid down as export models des ...
. Development of the turret began in 1943 as part of a program to improve the Lancaster's defensive armament but it did not enter production until late 1944. The
Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...
(RAF) ordered 600 Rose turrets in June 1944 and 400 were completed by the end of the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
in Europe. The turret was generally regarded as an improvement over previous designs, although its guns had a high rate of stoppage during combat.


Development

When introduced to service, all three of the Avro Lancaster's gun turrets were fitted with Browning medium machine guns firing the
.303 British The .303 British (designated as the 303 British by the C.I.P. and SAAMI) or 7.7×56mmR, is a calibre rimmed rifle cartridge. The .303 inch bore diameter is measured between rifling lands as is the common practice in Europe which follows th ...
round. The front and mid-upper turret were each fitted with two .303 guns, and the rear turret had four. A small number of early Lancasters were also equipped with a ventral turret on the bottom of the fuselage fitted with two .303s, but this turret was phased out from 1942. The .303 guns were soon regarded as being inadequate, however, and in 1942 the Air Staff identified a requirement to fit the Lancasters with a turret armed with more powerful 0.50 inch (12.7 mm) heavy machine guns "as soon as possible"; this view was supported by Air Marshal Arthur Harris, the commanding officer of
Bomber Command Bomber Command is an organisational military unit, generally subordinate to the air force of a country. The best known were in Britain and the United States. A Bomber Command is generally used for strategic bombing (although at times, e.g. during t ...
. A conference was held at the
Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...
on 11 January 1943 to discuss the optimal armament for the Lancaster. The consensus view of the participants was that the aircraft should be fitted with two 20 mm cannon in its mid-upper turret, two .303 inch guns in the forward turret and two .50 inch guns in the rear turret. At the conclusion of the conference, Air Vice Marshal
Ralph Sorley Air Marshal Sir Ralph Squire Sorley, (9 January 1898 – 17 November 1974) was a senior commander in the Royal Air Force (RAF). He began was a pilot in the Royal Naval Air Service during the First World War, and rose to senior command in the Sec ...
, who was responsible for the RAF's technical requirements, stated that "every effort should be made to introduce the mid-upper and redesigned tail turrets in a year's time" and that the Lancaster's armament would be obsolete if this deadline was not met. Despite Sorley's views, development of an upgraded rear turret for the Lancaster proceeded slowly. Harris became frustrated with the slow progress of the project, and did not believe that the Air Ministry would be able to produce the turret in time. As a result, he decided to go outside the official channels and personally asked the small
Gainsborough Gainsborough or Gainsboro may refer to: Places * Gainsborough, Ipswich, Suffolk, England ** Gainsborough Ward, Ipswich * Gainsborough, Lincolnshire, a town in England ** Gainsborough (UK Parliament constituency) * Gainsborough, New South Wales, ...
firm of Rose Brothers to develop a turret for the Lancaster; this company had previously developed an improved gun mounting for the
Handley Page Hampden The Handley Page HP.52 Hampden is a British twin-engine medium bomber that was operated by the Royal Air Force (RAF). It was part of the trio of large twin-engine bombers procured for the RAF, joining the Armstrong Whitworth Whitley and Vickers ...
bomber in 1940 upon a request from Harris. The
Ministry of Aircraft Production Ministry may refer to: Government * Ministry (collective executive), the complete body of government ministers under the leadership of a prime minister * Ministry (government department), a department of a government Religion * Christian ...
subsequently offered to provide draughtsmen to help Rose Brothers develop the turret, but the head of the company turned down this offer and relied upon Air Vice Marshal Edward Rice for technical advice. Rice was one of the senior Bomber Command station commanders, and had travelled with Harris to visit Rose Brothers at the start of the project. He subsequently led
No. 1 Group RAF No. 1 Group of the Royal Air Force is one of the two operations groups in RAF Air Command. Today, the group is referred to as the Air Combat Group, as it controls the RAF's combat fast-jet aircraft and has airfields in the UK, as well as RAF Sup ...
.McKinstry (2009), p. 431 Harris obtained Sorley's agreement to support the development of what was by then known as the Rose turret in June 1943. However,
Nash & Thompson Nash & Thompson was a British engineering firm that developed and produced hydraulically operated gun turrets for aircraft. As part of Parnall Aircraft it was also an important manufacturer of hydraulic-powered radar scanners used on radar sys ...
, which produced the Lancaster's .303 turrets, was also commissioned to develop a .50 inch armed turret as the Air Ministry and Ministry of Aircraft production did not want to rely upon Rose Brothers alone. Nash & Thompson's design was known as the FN82. Development of the two new turret designs continued throughout 1943, but neither was ready by early 1944. The Rose turret shook severely during its early firing trials; this was eventually attributed to poor workmanship of the turret's base ring. In June 1944, the RAF placed an order for 600 Rose turrets after the problems with the design had been resolved. The turrets were built by hand at Rose Brothers' factory at Gainsborough, and were eventually produced at the rate of one per day; this rate was considered to be slow by the Air Staff. Production of the Rose turret ceased at the end of the war – by this time 400 had been completed.McKinstry (2009), pp. 433–436 The FN82 took even longer to develop, and the first production model was completed in January 1945.McKinstry (2009), p. 434 None of Bomber Command's Lancasters had been fitted with an FN82 by the end of the war.


Characteristics

The Rose turret was a roomy design equipped with two
M2 Browning The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed towards the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, w ...
heavy machine guns. The turret was driven by
hydraulics Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...
, and the hydraulic system was easier to use than that in previous designs. The considerable internal space meant that the turret could be fitted with two seats: a layout in which one man operated the guns and the other fed targeting data into the gunsight computer was developed, but not used in practice.Bowyer (1979), p. 51 An unusual feature of the Rose design was that the turret was not fully enclosed. Previous designs had
perspex Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite ...
around the gun position, but in the Rose turret there was no protective shielding immediately in front of the gunner. This feature reflected operational experience: many Lancaster gunners had cut away parts of their turret perspex in order to obtain a better view, a practice that had originated at
RAF Gransden Lodge The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...
, and which was subsequently known as the "Gransden Lodge modification". Testing of the Rose turret found that the open design reduced the temperature in the turret – which was typically very low – by only four degrees
Celsius The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...
compared with a closed design.Bowyer (1979), pp. 51–52 As well as improving the gunner's view, this feature also made it easier for him to bail out of the aircraft in an emergency.McKinstry (2009), p. 435


Operational service

Rose turrets began to be used operationally from late 1944.Bowyer (1979), p. 52 The turrets were mainly fitted to aircraft in No. 1 Group, though some were allocated to No. 5 Group.Falconer (1998), p. 94 Most Lancaster rear gunners regarded the turret as an improvement because of its heavier firepower. However, the turrets proved to be less reliable than the older design, and research conducted by the Ministry of Air found that 60 percent of Rose turrets experienced gun stoppages during combat compared with 23 percent of the .303-equipped turrets. On the positive side, aircraft fitted with the Rose turret were found to be half as likely to be attacked by fighters as other Lancasters – the researchers suggested that "this may be accounted by the increased field of view from the turret which would assist evasion from attacks". By the end of the war, 180 Rose turrets had been fitted to Lancasters.Harris (1995), p. 108 In his ''Despatch on War Operations'', Harris stated that the turret was the only improvement made to the defensive armament of the RAF's
heavy bomber Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range (takeoff to landing) of their era. Archetypal heavy bombers have therefore usually been among the larges ...
s after 1942, and argued that "those responsible for turret design and production displayed an extraordinary disregard" for Bomber Command's requirements.Harris (1995), p. 111


References

;Citations ;Bibliography * * * * {{cite book, last=McKinstry, first=Leo, title=Lancaster : The Second World War's Greatest Bomber, year=2009, publisher=John Murray, location=London, isbn=9780719523533 British inventions Aircraft weapons