Blackburn Roc

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 had its armament in a turret. The Roc came to be viewed as inferior to existing aircraft such as the Skua and the type had only brief front-line service.

B-25 Roc
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 Royal Navy
Number built 136
Developed from Blackburn Skua

Design and development

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 P.82 turret fighter (for specification F.9/35, which would enter service as the "Defiant"), with either a Bristol Hercules radial or Rolls-Royce Merlin inline 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, 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 and used the same Boulton Paul Type A 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 already been realised by some that this performance was inadequate, with the Fifth Sea Lord (the Chief of Naval Air Services) Alexander Ramsay suggesting in October 1938 that the Roc be abandoned. However production was allowed to continue as cancellation would cause too much disruption for Boulton Paul, instead beginning plans 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 but the first such conversion proved unstable and in December 1939 it crashed when being tested at Helensburgh Marine Aircraft Experimental Establishment where it had been moved at the start of the war. While the addition of an enlarged ventral fin solved the stability problems, the effect 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 were abandoned.[11]

Operational history
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 for 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 in 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, 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 in various locations; No 2 Anti-Aircraft Co-operation Unit at Gosport received 16 Rocs to replace Blackburn Sharks in June 1940.[17] On 26 September 1940 during an air sea rescue patrol, Pilot Officer D. H. Clarke and his gunner, Sergeant Hunt, engaged a Heinkel He 59 seaplane, also on a rescue mission, which had fired on them first. The two aircraft exchanged fire until they reached the coast of France where the Heinkel escaped in a damaged condition.[18] Some Rocs were sent as far as Bermuda, until the last two examples were withdrawn from service in June 1943.[16][19] The last four Rocs stationed at HMS Daedalus in Gosport survived until late 1944, all unairworthy, with their turrets still being used for anti-aircraft defence.[17][20]

Operators
 United Kingdom

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

Data from British Naval Aircraft since 1912.[22]

General characteristics

  • Crew: 2
  • Length: 35 ft 7 in (10.85 m)
  • Wingspan: 46 ft 0 in (14.02 m)
  • Height: 12 ft 1 in (3.68 m)
  • Wing area: 310 sq ft (29 m2)
  • Empty weight: 6,121 lb (2,776 kg)
  • Gross weight: 7,950 lb (3,606 kg)
  • Powerplant: 1 × Bristol Perseus XII 9-cylinder air-cooled sleeve-valve radial piston engine, 890 hp (660 kW)
  • Propellers: 3-bladed variable-pitch propeller

Performance

  • Maximum speed: 194 kn (223 mph, 359 km/h) at 10,000 ft (3,000 m)
  • Cruise speed: 117 kn (135 mph, 217 km/h) [23]
  • Range: 700 nmi (810 mi, 1,300 km) with 70 imp gal (320 l; 84 US gal) long-range tank[23]
  • Service ceiling: 18,000 ft (5,500 m)
  • Rate of climb: 1,500 ft/min (7.6 m/s)

Armament

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

References

Notes
  1. Brew 2002, p. 26.
  2. Jackson 1968, p. 399.
  3. 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. Willis Aeroplane December 2007, p. 59.
  17. Mondey 1994, p. 37.
  18. Kinsey 1992, p. 80
  19. Jackson 1968, pp. 415–416.
  20. Dell, John "Dinger". "Blackburn Roc: A short description and appreciation." Archived 6 August 2007 at the Wayback Machine Dinger's Aviation pages. Retrieved: 17 July 2010.
  21. Sturtivant and Ballance 1994, p. 362.
  22. Thetford 1978, p. 61.
  23. Lumsden and Heffernan Aeroplane Monthly March 1990, p. 150
  24. 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.
  • Kinsey, Gordon. Boulton & Paul Aircraft : The History of the Companies at Norwich and Wolverhampton. Lavenham: Terence Dalton Ltd, 1992 ISBN 978-0861380855
  • 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.
  • Sturtivant, Ray and Theo Ballance. The Squadrons of the Fleet Air Arm. Tonbridge, Kent, UK: Air Britain (Historians) Ltd, 1994. ISBN 0-85130-223-8.
  • 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.
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