Blackburn Roc

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B-25 Roc
Blackburn Roc.jpg
Role Carrier-based fighter
Manufacturer Blackburn Aircraft
Boulton Paul
Designer George Edward Petty
First flight 23 December 1938
Introduction April 1939
Retired 1943
Primary user Fleet Air Arm
Number built 136
Variants Blackburn Skua

The Blackburn B-25 Roc was a British Second World War-era Fleet Air Arm fighter aircraft designed by Blackburn Aircraft Ltd. It took its name from the mythical bird of the tales of the Arabian Nights, the Roc. Derived from the Blackburn Skua and developed in parallel, the Roc differed in its adoption of a turret for its armament. Operationally, the Roc came to be viewed as inferior to existing aircraft, such as the Skua and the type only had a brief front line service.

Design and development[edit]

On 31 December 1935, the British Air Ministry issued Specification O.30/35 for a carrier-based turret-armed fighter.[1] Blackburn proposed a derivative of the Blackburn Skua dive bomber, of which two prototypes had been ordered for the Fleet Air Arm earlier that year, while Boulton Paul proposed the P.85, a redesigned version of its land-based Defiant P.82 turret fighter, with either a Hercules radial or Merlin in-line engine.[1][2][3] Although the "Sea Defiant" was expected to be 85 mph (137 km/h) faster, the Roc was chosen.[3]

Like the Skua, the B-25 Roc was a two-seat low-wing cantilever monoplane of all-metal construction. It was fitted with a retractable tailwheel undercarriage, while its wings folded for storage aboard aircraft carriers. It was powered by a Bristol Perseus radial engine driving a three-bladed propeller. It used the same Boulton Paul power operated gun turret as the Defiant, with four .303 in (7.7 mm) Browning machine guns. It retained the wing mounted dive brakes of the Skua, with bomb racks under each wing for two 250 lb (110 kg) bombs and eight practice bombs to be carried.[4][5]

On 28 April 1937, the Air Ministry placed an order for 136 Rocs. As Blackburn already had full order books for the Skua and the Botha torpedo bomber for the RAF, it was decided to sub-contract detailed design and production to Boulton Paul at Wolverhampton, which delayed deliveries of the Defiant.[6][7]

The prototype Roc in May 1939

The first flight by a Roc was on 23 December 1938; handling was acceptable and better than that of the Skua but its performance was poor, with a maximum speed of only 223 mph (194 kn; 359 km/h).[8][9] It had been already realised by some that this performance was inadequate, with the Fifth Sea Lord (the Chief of Naval Air Services) Alexander Ramsay suggesting that the Roc be abandoned in October 1938. Production was allowed to continue, as cancellation would cause too much disruption for Boulton Paul, with work beginning to adapt the aircraft for target towing.[10]

As well as its primary role as a carrier-based fighter, the Roc was also required to be capable of operating as a floatplane, with a conversion kit being designed for a set of floats from a Blackburn Shark to be fitted. The first example to be converted proved to be unstable and crashed when being tested at Helensburgh (where the Marine Aircraft Experimental Establishment had moved to at the start of the war) in December 1939. While the addition of an enlarged ventral fin solved the stability problems, the effects of the floats on the aircraft's performance was too great to be ignored, with maximum speed falling to only 193 mph (168 kn; 311 km/h) and plans to form a fighter squadron equipped with Roc floatplanes abandoned.[11]

Operational history[edit]

The Roc Seaplane prototype, L3059

Delivery of the Roc began to the Skua-equipped 800 and 803 Naval Air Squadrons late in 1939, with three or four Rocs supplementing the Skuas. When 803 Squadron moved to RAF Wick in northern Scotland, to provide fighter cover to the Royal Naval base at Scapa Flow in the Orkney Islands, the Rocs proved ineffective, being described as a "constant hindrance" by the squadron commanding officer, who requested that they be replaced by more Skuas.[12] During the Allied campaign in Norway a small contingent of Rocs travelled with 800 and 801 Naval Air Squadrons on HMS Ark Royal (803 had abandoned its Rocs to become an all-Skua squadron). They were used to carry out combat air patrols over the fleet and again were of little use, showing inadequate performance to intercept German aircraft.[13]

Skuas and Rocs operated over the English Channel in the summer of 1940 and supported Operation Dynamo and Operation Ariel, the evacuations of Allied forces from Dunkirk and other French ports.[14] Probably the Roc's sole confirmed victory occurred on 28 May 1940, when a patrolling 806 Naval Air Squadron Roc, flown by pilot Midshipman A. G. Day and two Blackburn Skuas, intercepted five Junkers Ju 88s which were attacking a convoy off Ostende in Belgium. Flying underneath the Junkers while the Skuas attacked from above, Midshipman Day's Roc destroyed one Ju 88 before returning safely to RAF Detling.[15] Rocs and Skuas of 801 Naval Air Squadron, strafed and dive-bombed German E-boats in Boulogne harbour on 12 June, damaging several E-boats and on 20 June, Skuas and Rocs were used to bomb gun emplacements at Cap Gris Nez.[16]

The Roc was relegated to air sea rescue and target-towing until 1943, when the type was withdrawn from service.[16][17] Until late 1944, four non-airworthy Rocs were stationed at HMS Daedalus in Gosport, their turrets being used for anti-aircraft defence.[18]

Operators[edit]

 United Kingdom

Specifications[edit]

Roc Mk.I L3154, 805 sqn., RNAS Donibristle, 1940

Data from British Naval Aircraft since 1912 [19]

General characteristics

Performance

Armament

See also[edit]

Related development
Aircraft of comparable role, configuration and era
Related lists

References[edit]

Notes
  1. ^ a b Brew 2002, p. 26.
  2. ^ Jackson 1968, p. 399.
  3. ^ a b Buttler, Tony British Secret Projects: Fighters and Bombers p55
  4. ^ Mason 1992, p. 271.
  5. ^ Jackson 1968, pp. 411–412.
  6. ^ Jackson 1968, p. 412.
  7. ^ Buttler, Tony British Secret Projects: Fighters and Bombers p. 54
  8. ^ Thetford 1978, p. 60.
  9. ^ Lumsden and Heffernen Aeroplane Monthly March 1990, p. 149.
  10. ^ Brew 2002, pp. 38–39.
  11. ^ Brew 2002, pp. 50–51.
  12. ^ Willis Aeroplane December 2007, p. 57.
  13. ^ Willis Aeroplane December 2007, p. 58.
  14. ^ Willis Aeroplane December 2007, pp. 58–59.
  15. ^ Thomas 2007, p. 17.
  16. ^ a b Willis Aeroplane December 2007, p. 59.
  17. ^ Jackson 1968, pp. 415–416.
  18. ^ Dell, John "Dinger". "Blackburn Roc: A short description and appreciation." Dinger's Aviation pages. Retrieved: 17 July 2010.
  19. ^ Thetford 1978, p. 61.
  20. ^ a b Lumsden and Heffernan Aeroplane Monthly March 1990, p. 150
  21. ^ Green 1961, p. 5.
Bibliography
  • Brew, Alec. The Turret Fighters: Defiant and Roc. Ramsbury, Marlborough, Wiltshire, UK: Crowood Press, 2002. ISBN 1-86126-497-6.
  • Brown, Eric, CBE, DCS, AFC, RN.; William Green and Gordon Swanborough. "Blackburn Skua and Roc." Wings of the Navy, Flying Allied Carrier Aircraft of World War Two. London: Jane's Publishing Company, 1980, pp. 29–40. ISBN 0-7106-0002-X.
  • Green, William. War Planes of the Second World War: Volume Two Fighters. London: Macdonald, 1961.
  • Jackson, A.J. Blackburn Aircraft since 1909. London: Putnam, 1968. ISBN 0-370-00053-6.
  • Lumsden, Alec and Terry Heffernan. "Probe Probare: Blackburn Skua and Roc Part Two". Aeroplane Monthly, March 1990, Vol. 18, No. 3. pp. 146–150.
  • Mason, Francis K. The British Fighter since 1912. Annapolis, Maryland, USA: Naval Institute Press, 1992. ISBN 1-55750-082-7.
  • Mondey, David. The Hamlyn Concise Guide to British Aircraft of World War II. London: Chancellor Press, 1994. ISBN 1-85152-668-4.
  • Thetford, Owen. British Naval Aircraft since 1912. London: Putnam, Fourth edition, 1978. ISBN 0-370-30021-1.
  • Thomas, Andrew. Royal Navy Aces of World War 2. Oxford, UK: Osprey Publishing, 2007. ISBN 978-1-84603-178-6.
  • Willis, Matthew. "Database: The Blackburn Skua & Roc". Aeroplane, December 2007, Vol. 35, No. 12, pp. 52–69.
  • Willis, Matthew. Blackburn Skua and Roc. Sandomierz, Poland/Redbourn, UK: Mushroom Model Publications, 2007. ISBN 83-89450-44-5.

External links[edit]