Blackburn B-24 Skua

Истребитель и пикирующий бомбардировщик Blackburn B-24 Skua имел цельнометаллическую конструкцию, радикально отличавшую его от традиционных обтянутых тканью английских бипланов тех времен. В Великобритании это был первый пикирующий бомбардировщик и первый палубный самолет с закрылками, убирающимся шасси и винтом изменяемого шага.
   За получение контракта Skua конкурировал с разработками "Avro", "Boulton Paul", "Hawker" и "Vickers". В апреле 1935 года были заказаны два прототипа. Первый из них полетел 9 февраля 1937 года со звездообразным мотором Bristol Mercury IX мощностью 840 л. с. (626 кВт). Еще за шесть месяцев до этого с фирмой заключили договор на поставку 190 машин Skua. Поскольку весь выпуск двигателей Mercury шел на легкие бомбардировщики Bristol Blenheim, на серийных B-24 ставили звездообразный Bristol Perseus XII. Такие самолеты обозначили Skua Mk II. Первая серийная машина поднялась в воздух 28 августа 1938 года. Помимо двигателя, она отличалась от прототипа приподнятыми законцовками крыла, установкой масляных амортизаторов шасси и рядом других изменений. Все заказанные самолеты были поставлены с октября 1938-го по март 1940 года.
   В 1938 году Skua начали получать 800-я и 803-я эскадрильи морской авиации с авианосца "Арк Ройял" для замены устаревших Hawker Nimrod и Osprey. Затем перевооружили 801-ю эскадрилью (авианосец "Фьюриес"), а перед началом войны - 806-ю.
   Как истребитель Skua оказался морально устаревшим, но в начале войны он успешно использовался как пикирующий бомбардировщик. 10 апреля 1940 года 16 самолетов из 800-й и 803-й эскадрилий у берегов Норвегии потопили немецкий крейсер "Кенигсберг".


ТАКТИКО-ТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ

   Blackburn Skua Mk II

   Тип: двухместный истребитель и пикирующий бомбардировщик
   Силовая установка: звездообразный двигатель Bristol Perseus XII мощностью 890 л. с. (664 кВт)
   Характеристики: максимальная скорость 362 км/ч на 1980 м; крейсерская скорость 266 км/ч на 4570 м; начальная скороподъемность 482 м/мин; практический потолок 6160 м; дальность полета 1223 км
   Масса: пустого самолета 2490 кг; максимальная взлетная 3732 кг
   Размеры: размах крыла 14,07 м; длина 10,85 м; высота 3,81 м; площадь крыла 28,98 м2
   Вооружение: четыре крыльевых пулемета Browning калибра 7,7 мм, один пулемет Lewis калибра 7,7 мм на турели в задней кабине, одна 227-кг бомба под фюзеляжем и восемь 14-кг бомб на подкрыльевых подвесках

Flight, August 1939

A Formidable Ship-plane
The Blackburn Skua O Fighter Dive-bomber : “Diving-brake” Flaps and Built-in Flotation : Bristol Perseus Sleeve-valve Engine

   THE naval air arms of the world are attaching great importance to the diving method of bombing attack. Great Britain is well to the fore in this respect and large numbers of Blackburn Skua I deck-landing monoplanes, which specialise in dive-bombing and fighting, are being delivered to units of the Fleet Air Arm, now under Naval control.
   Thanks to unique flaps which, apart from facilitating take-off and landing, can be used in the dive to limit the speed to 220 knots, the Skua is able to approach close to its target in an almost vertical dive and release its bomb load with exceptional accuracy.
   As a long-range two-seater fighter the Skua has four fixed machine guns and a fifth weapon in the rear cockpit. The machine can also be employed to tow drogue targets for gunnery practice.
   Other points of special interest are the effective wing-folding arrangements and the water-tight compartments in the fuselage (features which characterised the Blackburn Shark T.S.R. machine) and the unusual tail unit with the fin and rudder placed forward of the horizontal surfaces.
   A development of the Skua, designated the Roc, is fitted with a power-driven multi-gun Boulton Paul turret. This specialised two-seater fighter is also in production for the Fleet Air Arm.
   Fundamentally the Skua is a single-engined low-wing cantilever monoplane of metal construction powered with a Bristol Perseus XII radial engine. The wing is built in three portions - the centre section and the two outer panels. The centre section, the upper surface of which forms the bottom of the front water-tight compartment, is bolted under the fuselage and is detachable.
   Official restrictions prohibit publication of wing-folding details and it is not possible to describe the methods adopted for stowing the Skua in the hangar of an aircraft carrier. The success of the Blackburn Shark in this respect augurs well for the Skua.
   Structurally, the centre section comprises two box spars composed of Alclad plate webs reinforced by vertical stiffeners and flanges of extruded section, flanged plate ribs, Z-section stringers and plating attached by flush and hollow rivets. Tapering in plan and thickness, the outer wing panels have detachable upswept tips. Structurally they are similar to the centre-section except that the main spars are of box-section for part only of their length, changing to single webs towards the tips. Between the main spars, forward of the ailerons, are watertight compartments to provide flotation, and near the roots are circular recesses for the wheels of the undercarriage together with appropriate troughs for the struts.
   Between the ailerons and the wing roots, forward of the trailing edge, are troughs which house the special flaps. These have a combined, area of 18.5 sq. ft. and are normally stowed flush with the lower surface of the wing. They are entirely of metal construction, even to the covering.
   The ailerons have inset hinges and are mounted on ball bearings. Each is built round a single girder-type spar reinforced by a metal leading edge and having ribs pressed from Alclad sheet. They are covered with fabric.
   Of metal monocoque construction, the fuselage is built in two sections with a joint just forward of the fin. Essentially the structure comprises Alclad frames, stringers and special sections riveted together, and flush-riveted plating. There are two water-tight compartments in the main fuselage, one forward under the floor of the pilot's cockpit and the other aft of the gunner’s position. The cockpit itself is water-tight up to the coaming. The bomb compartment is built integral with the fuselage.
   Of similar construction, the rear fuselage is bolted to the main structure. This carries the tail and tail wheel, the latter having light metal fairings.
   The explanation of the unusual tail layout is that for stowage in the hangars of aircraft carriers dimensions must be kept down to a minimum and the Blackburn designers accordingly decided to keep the vertical surfaces forward. The tail plane is bolted to two frames of the rear fuselage structure and is non-adjustable, though the elevators have trimming tabs with irreversible controls operated from the cockpit. It has two girder-type spars with formers and transverse stringers of Z-section, the metal plating being attached by hollow rivets. A cross-shaft connects the elevators, which have single girder spars, with Alclad formers and leading edges, the main covering being of fabric. All hinges have ball bearings. The fin is detachable from the fuselage and is a metal-covered structure having an Alclad stern post, a stern post bracing strut and flanged formers. The rudder is similar in construction to the elevators and has a horn balance, inset hinges and automatic balance flap and hand-operated trimming tab inset into the trailing edge.
   Each unit of the retractable undercarriage folds outward and upward into wells in the outer wing. The wheels have intermediate-pressure Dunlop tyres and are attached to Vickers oleo-pneumatic compression struts. Each unit comprises one of these struts with a stub axle and wheel, a rear stay tube and a telescopic side-stay strut. The shock-absorber unit and the rear stay tube are arranged to hinge about the same fore and aft axis, while the telescopic strut is hinged between, and inboard of, these members. A light metal fairing is attached to each strut and fairs the under-surface of the wing when the undercarriage is retracted. Bolted to the top of the shock absorber strut is a lever which extends above the hinge centre. This is coupled to a hydraulic jack which raises and lowers the undercarriage. Locking devices, also operated by hydraulic jacks, are fitted in the telescopic side-stay struts and in the wheel wells, their purpose being to secure the undercarriage in raised and lowered positions. Each of these locks operates an electrical indicator which shows by means of coloured lights in the pilot’s cockpit the position of the lock. In the wing is a mechanical indicator which also notifies the pilot of the position of his wheels. An audible warning device is also incorporated.
   The Palmer tail wheel unit comprises a coiled spring shock-absorbing strut with castored fork axle and wheel and electrically conductive tyre. In flight the wheel is maintained in a fore-and-aft position by a self-centring device in the strut.
   The single Bristol Perseus XII nine-cylinder radial sleeve-valve engine drives a two-position De Havilland variable-pitch airscrew 11ft. 6in. in diameter. The Perseus XII is a medium-supercharged unit rated at 745 h p. at 2,400 r.p.m. at 6,500ft. For all-out level flight at the same height 905 h.p. is available, and, the take-off output is 830 h.p. The engine is provided with a standard Bristol long-chord cowling with single-outlet leading edge exhaust collector and adjustable gilled outlet. Its mounting is a tubular two-bay structure.
   Fuel is carried in two main tanks installed in the sides of the fuselage aft of the pilot's seat, and in a third tank mounted in the front water-tight compartment. Supply is by an engine-driven pump through selector cocks which enable the feed to he taken from any tank or combination of tanks. An electrical contents gauge is fitted to each tank and there are special traps to retain the fuel at the supply pipe during dive bombing.
   The oil system is engine-operated by pressure and scavenge pumps and embodies the usual filters. In the pressure pump is an automatic device giving a high initial oil pressure, allowing cold oil, by-passed by the relief valve, to build up a pressure adequate for the lubrication of all bearings when the engine is started from cold. The oil tank holds 12 gallons and is situated in the fuselage in front of the pilot's instrument board. The oil cooler is mounted internally on the engine mounting and is fed by two forward-facing ducts. At the rear of the cowling is a manifold which has three ducts, the outer two being led to the atmosphere and the centre one, which incorporates a shutter, being taken to the pilot's cockpit. When cockpit heating is not required the shutter deflects the warm air into the outer ducts.
   Engine starting is effected by an electrically fired cartridge starter, the pistol unit of which is mounted on the port side of the cockpit and connected by a pipe line to the turbine unit oh the rear of the engine. First, the engine is primed, then a cartridge is inserted into the pistol and the starter button pressed.
   The retractable undercarriage and the wing flaps are operated hydraulically but the wheel brakes and the control of the four fixed guns is pneumatic.
   In the hydraulic system are an engine-driven pump, fluid reservoir, main and emergency selector valves, restrictor valve and the hydraulic jacks. The selector valve has separate control valves and levers for operating the undercarriage and flaps. When the levers are neutral fluid is circulated by the engine pump from the reservoir and goes through a by-pass back to the reservoir without pressure. When the undercarriage selector valve lever is moved in to the “up” or “down” position the by-pass is closed, the fluid is passed into the pipe lines, pressure is built up and the jack connected to the undercarriage strut is set in operation. Simultaneously the restrictor valves ensure that the locking devices operate before and after the movement.
   To guard against failure of the engine-driven pump and to provide for occasions when the engine is not running, a hand pump is fitted. This is driven through a normal system and an emergency system, the former operating through the main selector-valve box in the same way as the engine-driven pump system. The emergency system can be used only to lower the undercarriage.
   To operate the flaps, hydraulic jacks are mounted between the inner flap runners in the wings. These jacks are connected by pipe lines to the main selector-valve box, which has a separate control valve and lever. A flow control valve is introduced into the system to form a hydraulic lock for any position of the flaps. Thus, the flaps may be set at any angle and the main system is relieved of the high pressure set up by the flaps when the machine is diving at high speed. As in the case of the undercarriage either the engine-driven pump or hand-pump system may be used.
   The pneumatic system comprises an engine-driven compressor air reservoir, oil reservoir and trap, air filter, pressure gauge and charging union. The wheel-brake system (an important item in the machines used from aircraft carriers) is worked by a hand lever on the control column, the braking pressure varying according to the movement applied. The lever can be locked for parking. It is arranged that movement of the rudder bar has a differential effect.
   The equipment and accommodation of the Skua is as interesting as the structure. The four fixed machine guns are mounted in the leading edge of the wings, each pair firing outside the airscrew arc. The rear gun is on a special manually operated mounting.
   Wireless transmitting and receiving apparatus is fitted in the rear cockpit. There are fixed and trailing aerials and the electrical services include navigation and identification lights, and a landing light in the port wing.
   Being a naval machine the Skua carries an inflatable dinghy (stowed in the rear section of the fuselage), marine distress signals, slinging gear and an arrester hook for deck landing.
   The seats for the pilot and air gunner correspond approximately with the leading and trailing edges of the wing. The two positions are connected by a long transparent enclosure on top of the fuselage. Access to the pilot’s seat is gained by means of a sliding hood, which may be locked in open, closed or intermediate positions. The windscreen has three flat panels and was designed to give good vision in wet weather and to prevent draught in the cockpit when the sliding hood is pushed back. The gunner’s position has a hinged hood which folds forward and the cabin enclosure has sliding side panels which, when open, operate wind deflectors which prevent the slipstream entering the cockpit.
   Apart from special strengthening of the pilot’s windscreen, two fuselage frames behind the pilot’s seat are stiffened up and extend to the cabin roof to give protection for the crew in the event of the machine nosing over on the ground.
   A representative of Flight who has been dived in a Skua reports that with flaps down at about 220 knots the machine is "steady as a rock." Manoeuvrability, too, is outstandingly good, as has been demonstrated in public during the low-flying converging attacks for which the Fleet Air Arm is famed, and to which the Skua, with its heavy armament, is particularly suited.
  
BLACKBURN SKUA I
Fighter Dive-bomber
Bristol Perseus XII Engine (745 h.p. at 2,400 r.p.m. at 6,500ft.)
Span 46ft. 2in.
Length 35ft. 7in.
Height (over mast) 14ft. 2in.
Wing area 312 sq.ft.
Track 9ft. 7in.
Airscrew diameter 11ft. 6in.
Normal Service Equipment Drogue Target Aircraft
Weight empty 5,400 lb. 5,490 lb.
Military load 1,321 lb. 1,381 lb.
Oil capacity 10 gal. 6 gal.
Oil weight 90 lb. 54 lb.
Top speed at 6,500ft. 225 m.p.h. 224 m.p.h.
Max. cruising speed at 15,000ft. 187 m.p.h. 189 m.p.h.
Economical cruising speed at 15,000ft. 144 m.p.h. 145 m.p.h.
Top speed at sea level 204 m.p.h. 205 m.p.h.
Landing speed 75 m.p.h. 70 m.p.h.
Service ceiling 20,200ft. 22,800 ft.

Flight, November 1939

Britain's Military Aircraft
A Survey of Our Service Machines

BLACKBURN

   THE Skua fleet fighter dive-bomber, which has been in production in the Blackburn works for some time past, was the first monoplane to be adopted for use from British aircraft carriers.
   Operationally, as well as structurally, the Skua is of quite exceptional interest as its unique flaps not only facilitate take-off and landing, but are used in bombing dives to limit the speed to about 220 knots, enabling the machine to approach close to its target and release bomb with great accuracy.
   The low cantilever wing is built in three portions, the centre section, the upper surface of which forms the. bottom o! one of the watertight compartments provided, being bolted under tire fuselage. This centre section comprises two box spars, flanged plate ribs, Z-section stringers and plating attached by flush and hollow rivets. The outer panels are of similar construction except that the main spars are of box section only for part of their length, changing to single webs toward the tips. Watertight flotation compartments are provided between the spars forward of the ailerons. Near the roots are circular recesses which accommodate the wheels of the retractable undercarriage.
   The metal monocoque fuselage is built in two sections which are joined just forward of the fin. It contains two watertight compartments, one under the floor of the pilot’s cockpit, and the second aft of the gunner's position. The cockpit itself is watertight up to the coaming.
   A distinctive feature of the Skua is the tail, in which the vertical surfaces are set well forward in relation to the tailplane and elevator. The explanation of this arrangement is that for stowage in the hangars of aircraft carriers dimensions have to be kept down to a minimum.
   The engine of the Skua is the Bristol Perseus XII sleeve-valve radial, which gives a top speed of 225 m.p.h. and a service ceiling of 20,200ft. Dimensions are: Span, 46ft. 2in.; length, 35ft. 7n.; and wing area, 312 sq. ft.
   The Blackburn Company is also responsible for the design of the Roc two-seater fleet fighter, which will be dealt with under "Boulton Paul."
   The company has also delivered large numbers of Shark T.S.R. aircraft to the Fleet Air Arm.

Blackburn Aircraft. Ltd.. Brough. E. Yorks.