Blackburn B-25 ROC
by Jeff 'Jed' Marsh
Blackburn B-25 ROC
by Jeff 'Jed' Marsh
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Head Count 28 |
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The order for the naval turret fighter was allocated to Blackburn who had already developed a new fighter/dive bomber for the Fleet Air Arm the Skua. Blackburn simply proposed the addition of a four gun turret to their existing airframe. An order for 136 Roc's was placed on or around the 27th April 1937. The commonality with the Skua was obviously an important factor in the Fleet Air Arm which was able to plan for joint Skua/Roc squadrons. This said Boulton Paul's Naval Sea Defiant, the P85, had a predicted top speed in excess of 100mph greater than the Roc.
Blackburn's factories where at the time working to full capacity building the Shark, Skua, 190 of which had been ordered, along with 422 Botha torpedo bombers both 'off the drawing board'. Blackburn passed on the detail design and production of the Roc to Boulton Paul who was to supply the turrets for the Roc in any case. Boulton's allocated the project number P93 for the task. Boulton Paul, therefore, had to lay down two production lines for two entirely different turret fighters which would be produced along side each other. In hindsight it would have been more sensible for the Air Ministry to rationalise production by cancelling the Roc and transferring the orders to the P85 Sea Defiant.
In 1937 Boulton Paul began a factory expansion which led to an 80% increase in floor area to make room for Roc and Defiant production. As the Roc was to be very similar to the Skua which was already in production no prototypes were ordered, the first three production Rocs were to act in this role. Boulton's redesign involved a widening of the fuselage centre section to take their Type A MkIIR turret with retractable fairings fore and aft, similar to the Defiant. Also the wings were altered by removal of the Skua's winglets and by providing 2 degrees of dihedral. Aft of the cockpit was a small wireless cabin housing the radio equipment to be operated by the air gunner. It is also rumoured that the IFF (identification friend or foe) equipment was never fitted due to lack of space. Boulton Paul allocated the General Aircraft to produce tail sections complete.
The Roc was to be powered by the 890 h.p. Bristol Perseus XI nine cylinder radial driving a three bladed propeller. The Roc was slightly larger than the Defiant with an all up weight of 7,950 lbs. Pick up points for catapult launch and floats were designed in from the outset as it was a standard naval requirement at that time. In May of 1938 the Air Council Committee on supply contacted Boulton Paul re delivery dates for both the Roc and Defiant. Boulton's stated that all 136 Rocs should be completed by November 1939, although non had yet flown, and stated that the delays had been the result of waiting for modifications to the Skua to be approved before they could be implemented on the Roc.
The first Blackburn Roc, L3057, rolled of the production line ready for flight on the 23rd of December 1938 and Blackburn's test pilot Fl Lt H. J. Wilson came down from Brough to take it out. L3057 was then flown to Brough for Blackburn to carry out tests before being flown to A & AEE (at Martlesham Heath where it was joined by L3058 and L3059 for performance and armament trails. The Roc was found to be a pleasant aircraft to fly and like the Skua could be held in a steep dive due to it's generous dive brakes. However as was expected it's performance was abysmal. The top speed was only 223 mph at 10,000 ft on full boost, which could be maintained for only short bursts of 10 or so minutes. The service ceiling was 18,000ft, however it did have a useful endurance of six hours.
After the first aircraft all Rocs where test flown by Bouton Paul's Cecil Feather and George Skelton. What is thought as the first production machine L3060 was flown to Brough in March 1939 for fitting of floats and the next two L3061 & L3062 were despatched to Worthy Down for the Pilots Notes to be prepared. Production then picked up with seven more going to Worthy Down for No.800 Sqn and No.803 Sqn. A single machine was also supplied to the A & AEE at Martlesham Heath for further armament trials. July saw a further six produced all of which went to maintenance units (MU's). No.800 and No. 803 where the first fighter squadrons to be equipped with the Roc. Both had been equipped with the Blackburn Skua earlier in the year and it was envisaged that the squadrons would operate mixed flights of Rocs and Skuas form the HMS Ark Royal, the Navys newest carrier. However the Rocs never joined the Skuas aboard. The Ark Royal was operating in the North Sea as war broke out and then sailed to the South Atlantic leaving her Rocs behind at Worthy Down from where they were reassigned to other units. In fact no Roc ever made a deck landing. Two other operational Fleet Air Arm Squadrons flew the Roc, No.801 and No.806. These too had been equipped with the Skua before the war. No.801 operated from HMS Furious and No.806 from Eastleigh.
No.806 received six Rocs in early in 1940 and where move forward to Detling to give cover to the Dunkirk operations as a fighter unit of Coastal Command. Their role was primarily dive bombing of German gun inplacements. By the end of July the squadon had replaced it's Rocs and Skuas and was re-equipped with the Fairey Fulmar. No.801 operating from Hatston in the Orkneys, received its Rocs as No.806 was getting rid of theirs. Almost imediately the squadron was moved to Detling to replace No.806 and cover the Dunkirk evacuation. The Rocs continued to operate over the channel and one is reproted as being shot down during an attack on a gun battery at Cap Blanc Nez on the 21st of June; Sqn Ldr A. V. M Day and his gunner F. Berry were both killed. By the end of August No.801 Sqn had been re-equiped with Sea Hurricanes.
And so the Roc's front line career was over. The Skua was too slow and lacked fire power, the Roc was even slower.
Manufacturers: Boulton Paul Aircraft Ltd., Wolverhampton.
Purpose: Two-seater Fleet fighter. A replacement type for the Hawker" Osprey."
Origin & Development: First appeared in 1939 as a development of the Skua for fighter duties only. Most important modification was the power-driven turret for the rear gnnner in place of mannally operated installation.
Power Plant: One Bristol Perseus XII motor. Maximum power, 905 h.p. at 2,750 r.p.m. at 6,500 ft. Cruising, 715-745 h.p. at 2,400 r.p.m. at 6,500 ft. Take-off, 815 h.p.
Construction: Wings:Two Alclad box-spars with Z-section stringers and stressed-skin covering. Water-tight compartments and Zapp flaps. Folding type. Fuselage: Metal monocoque structurc in two sections, joined just forward of fin. Alclad frames and stringers carrying flush-riveted plating. Two water-tight compartments. Tail unit: Metal framework, metal covering but fabric covered control surfaces.
Dimensions: Span, 46 ft. Length, 35 ft. Height, 12 ft. 4 in. Wing area 310 sq ft. Empty weight 5,018 lbs. Max weight 8,800 lbs.
Performance: Max speed 196 mph. Max speed (with engine on emergency power) 223 mph. Cruising speed 135 mph. Endurance 6 hours, Range 810 miles
History: Specification F9/35 was approved on 20th May 1935 calling for a turret fighter of which the Boulton Paul Defiant was ultimately chosen from designs submitted by the other major manufactures of the period. Later in 1935 specification O.30/35 for an equivalent naval turret fighter was released.