Hawker Hart

infobox Aircraft
name = Hawker Hart
type = light bomber
manufacturer = Hawker Aircraft Limited



caption = Hawker Hart
designer = Sydney Camm
first flight = June avyear|1928
introduced =avyear|1930
retired =
status =
primary user = Royal Air Force
more users =
produced =
number built =
unit cost =
variants with their own articles = Hawker Hind
Hawker HectorThe Hawker Hart was a British two-seater biplane light-bomber of the Royal Air Force (RAF), which had a prominent role during the RAF's inter-war period. The Hart was designed during the 1920s by Sydney Camm and built by Hawker Aircraft. It spawned several variants, including a naval version.

Design and development

In 1926, the Air Ministry stated a requirement for a high performance light-bomber, and which culminated in the choice of the "Hawker Hart" over other rivals (Avro Antelope and Fairey Fox) due to it being far cheaper to maintain, a vital aspect to a programme during defence budget constraints that the British armed forces faced during the 1920s.

"J9052", the prototype Hart, first flew in June 1928 and entered service with No. 33 Squadron RAF in 1930. Over 900 Harts of all types were built. It became the most widely used light-bomber of its time and the design would prove to be a successful one with a number of derivatives, including the Hawker Hind and Hector, being made. There were a number of Hart variants made, though only slight alterations were made. The Hart India was basically a tropicalised version of the aircraft; the Hart Special was another tropicalised version based on the Hawker Audax, a Hart variant, with desert equipment; a specialised Hart Trainer was also designed. Vickers built 114 of the latter model at Weybridge between 1931 and June 1936.

The Hart was armed with a single forward .303 cal. Vickers machine gun and one rear .303 inch Lewis light machine-gun; the Hart also had a capacity to carry 520 lb (235 kg) of bombs. The Hart had a single 525 hp (390 kW) Rolls-Royce Kestrel IB 12-cylinder V-type engine; a speed of 184 mph (296 km/h) and a range of over 400 miles (640 km). It was much faster than contemporary fighters, an astonishing achievement considering it was a light-bomber, and had high manoeuvrability, making the Hart one of the most effective biplane bombers ever produced for the Royal Air Force.

Demand for the bomber was such that 164 were built by Vickers at their Weybridge factory between 1931 and 1936 after that company's submission of a tender, alongside the trainers mentioned above.

Operational history

Harts were deployed to the Middle East during the Abyssinia Crisis of 1935-1936. The Hart saw extensive, and successful, service in the North-West Frontier, British India during the inter-war period. Four Hawker Harts from the Swedish Air Force saw action as dive bombers during the 1939-1940 Winter War as part of a Swedish volunteer squadron, designated F19, fighting on the Finnish side. Though obsolete compared to the United Kingdom's opposition at the start of the Second World War, the Hart continued in service, mainly performing in the communications and training roles until being declared obsolete in 1943.

The Hart proved to be a successful export, seeing service with the Royal Egyptian Air Force, Royal Indian Air Force, South African Air Force, Estonia, Southern Rhodesia, Sweden (wehere it was designated B4) and Kingdom of Yugoslavia.

Swedish air force general Bjorn Bjuggren wrote in his memoirs how his squadron in the mid 1930s developed dive-bombing techniques for their B4s. When the Hawker engineers found out, they issued a formal objection, saying that the plane had not been designed for that purpose. But the Swedish pilots proved that the aircraft was up to that task and dispelled their concern.

Variants

Hart

;Hart I:Two-seat light bomber aircraft.;Hart Two-Seat Fighter:Two-seat fighter version of the Hart. Used by No.23 Squadron RAF. Later redesignated as the Hart Fighter.;Hart Trainer:Two-seat training version.;Hart Communications:Two-seat communications version. Used by No.24 Squadron RAF.;Hart (India):Tropicalised version for service in India.;Hart (Special):Tropicalised version.

Audax

The Hawker Audax was a Hart variant, designed for the army co-operation role, seeing much service in the British Empire. The first Audax flew in late 1931, and eventually, over 700 Audaxes were produced (including export). The Audax very similar to the Hart, though had some modifications, including a hook to pick up messages. The Audax was armed with a single .303 in (7.7 mm) Lewis light machine gun and a Vickers .303 machine gun. The Audax was powered by a version of the Kestrel engine and had a maximum speed of 170 mph (270 km/h). A number of variants of the Audax were produced, including the Audax India, a tropicalised version of the Audax for service in India; the Audax Singapore for service there.

The Audax saw service with other air forces, including the Royal Canadian Air Force, Royal Indian Air Force, the South African Air Force, Egypt, Iraq, Persia, Straits Settlements and South Rhodesia. The Audax saw limited service during the Second World War, seeing service in Africa on the Kenya-Abyssinia border, the latter of which had been occupied by Italy. The Audax also saw service in Iraq, at RAF Habbaniya, west of Baghdad, after the uprising there; influenced by Axis forces, but the Audax ended its service by 1945. A derivative of the Audax, the Hawker Hartebees, a light-bomber, was built for the South African Air Force with modifications made from the Audax. Sixty-five of these aircraft were built, the majority in South Africa. The aircraft saw action in East Africa during clashes against Italy who occupied Abyssinia.

;Audax I:Two-seat army co-operation aircraft.;Audax India:Army co-operation version for the RAF, for service in India.;Audax Singapore:Army co-operation version for the RAF, for service in Singapore.;Hartebees I:Two-seat general-purpose, ground-attack aircraft for the South African Air Force.

Demon

The Hawker Demon was a fighter variant of the Hart light-bomber, and which the Air Ministry stated should be able to intercept the Hart. The intention was for the Demon to just be an interim fighter until the Hawker Fury, arguably the pinnacle of biplane fighter design, entered service. Over 200 of the Hawker Demon were built for the RAF. The Demon were powered by varying types of the Kestrel engine. It had an armament of a single rear .303 in (7.7 mm) Lewis light machine gun with two .303 (7.7 mm) Vickers machine guns in the nose. Large numbers of the Hawker Demon were fitted with an hydraulically powered turret in the rear, which had been tested on the Hawker Hart. The Hawker Demon was also sold to the Royal Australian Air Force. The Demon saw only brief second-line operations during the Second World War.

Production of the Demon was by Hawker and by Boulton Paul Aircraft, Norwich

;Hart Two-Seat Fighter:Two-seat fighter version of the Hart. Used by No. 24 Squadron RAF. Later redesignated as the Hart Fighter.;Demon I:Two-seat fighter aircraft for the RAF.;Australian Demon I:Two-seat fighter aircraft for the RAAF.;Australian Demon II:Two-seat training version For the RAAF.;Turret Demon:Two-seat fighter version, fitted with a Frazer-Nash gun turret in the rear cockpit.

Hardy

The Hawker Hardy was general-purpose variant of the "Hawker Hart" tropicalised to meet Air Ministry Specification G.23/33 as a Wapiti replacement in Iraq. The prototype was a production Hart which was modified with a modified radiator, a message pick-up hook, water containers and a dester survival kit. The prototype first flew on 7 September 1934 and the first production aircraft were delivered to 30 Squadron in January 1935. The "Hardy" saw some service during the Second World War, in Africa and the Middle East; the "Hardys" performing a number of operations against Italian-occupied Abyssinia as-well as other areas of Africa. The "Hardy" also saw service with Southern Rhodesia. The last operational sortie by a Hardy was on the 9 May 1941 and most of the survivors were scrapped, although some continued in service as communications aircraft. On 14 May 1941 the Belgian Colonial authorities obtained a Hawker Hardy from the South African Air Force. Painted in Belgian colours the machine was used for observation missions, but unfortunately overturned while landing at Gambela airfield on 26 May 1941, effectively writing off the machine.

;Hardy I:Two-seat general-purpose aircraft for the RAF, 47 built excluding one prototype modified from a Hart.

Hind

The Hawker Hind was a derivative of the "Hart" and was intended to replace it. The Hawker Hector was a variant of the "Hind" and was used in the army co-operation role. It saw only limited service during the Second World War with the Royal Air Force. Hectors were also sold to Ireland.

Osprey

The Hawker Osprey was the navalised carrier-borne version of the "Hart", performing in the fighter and reconnaissance roles. The "Osprey" had a single Rolls-Royce Kestrel II engine, and had a max speed of 168mph. Its armament consisted of a single forward .303 in (7.7 mm) Vickers machine gun and one .303 in (7.7 mm) Lewis light machine gun. The "Osprey" joined the Fleet Air Arm (FAA) in 1932, with just over 100 being built, and ended its career in 1944 after serving as a trainer for FAA pilots during her career in the Second World War. The "Osprey" was also sold to the Swedish Navy being used on the aircraft cruiser HMS "Gotland", which carried six "Ospreys". Ospreys were also sold to the air forces of Portugal and Spain.

;Osprey I:Two-seat fleet spotter and reconnaissance biplane. Power by a 630 hp (470 kW) Rolls-Royce Kestrel IIMS inline piston engine.;Osprey II:The Osprey Mk II had a different float installation.;Osprey III:The Osprey Mk III had a dinghy stowed away in the starboard upper wing.;Osprey IV:Two-seat fleet spotter and reconnaissance biplane. Powered by a Rolls-Royce Kestrel V inline piston engine.

Operators

Hawker Hart

*flag|Afghanistan|1931
*flag|Egypt|1922
*EST
*flagicon|India|British British India
*flag|South Africa|1928
*flag|Southern Rhodesia
*SWE
*UK
*flagicon|Yugoslavia|kingdom Kingdom of Yugoslavia

Hawker Audax

*flagicon|India|British British India
*flag|Canada|1921
*flag|Egypt|1922
*flag|Iraq|1924
*flagicon|Iran|1925 Persia
*flag|Southern Rhodesia
*flag|Straits Settlements
*UK

Hawker Demon

*AUS
*UK

Hawker Hardy

*UK
*flag|Southern Rhodesia
*BEL (1 aircraft, ex-RAF K4316)

Hawker Hartebees

*flag|South Africa|1928

Hawker Osprey

*POR
*flagicon|Spain|1931 Spanish Republic
*SWE
*UK

pecifications (Hart (Kestrel IB powered day bomber))

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=The British Bomber since 1914 [Mason 1994]
crew=2
capacity=
length main= 29 ft 4 in
length alt= 8.94 m
span main= 37 ft 3 in
span alt= 11.36 m
height main= 10 ft 5 in
height alt= 3.18 m
area main= 349.5 ft²
area alt= 32.5 m²
airfoil=
empty weight main= 2,530lb
empty weight alt= 1,150 kg
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main= 4,596 lb
max takeoff weight alt= 2,089 kg
more general=
engine (prop)= Rolls-Royce Kestrel IB
type of prop= water-cooled V12 engine
number of props= 1
power main= 510 hp
power alt= 380 kW
power original=
max speed main= 161 knots
max speed alt= 185 mph, 298 km/h
max speed more= at 13,000 ft
cruise speed main=
cruise speed alt=
never exceed speed main=
never exceed speed alt=
stall speed main= 39 knots
stall speed alt= 45 mph, 72 km/h
stall speed more= "Air Transport Auxiliary Ferry Pilots Notes (reproduction)". Elvington, York, UK: Yorkshire Air Museum, 1996. ISBN 0-9512379-8-5.]
range main= 374 nm
range alt= 430 mi, 692 km
ceiling main= 22,800 ft
ceiling alt= 6,950 m
climb rate main=
climb rate alt=
loading main= 13.2 lb/ft²
loading alt= 64.3 kg/m²
thrust/weight=
power/mass main= 0.11 hp/lb
power/mass alt= 0.182 kW/kg
more performance=*Climb to 10,000 ft 8 minutes, 30 seconds
guns=1 × synchronised forward firing .303 in Vickers machine gun, 1 × Lewis gun on Scarff ring in rear cockpit.
bombs=Up to 500lb (227 kg) bombs under wings.
avionics=

ee also

aircontent
related=
similar aircraft=
lists=
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References

Notes

Bibliography

* Goulding, James and Jones, Robert. "Gladiator, Gauntlet, Fury, Demon"."Camouflage & Markings: RAF Fighter Command Northern Europe, 1936 to 1945". London: Ducimus Books Ltd., 1971.
* Hannah, Donald. "Hawker FlyPast Reference Library". Stamford, Lincolnshire, UK: Key Publishing Ltd., 1982. ISBN 0-946219-01-X.
* James, Derek N. "Hawker, an Aircraft Album No. 5". New York: Arco Publishing Company, 1973. ISBN 0-668-02699-5. (First published in the UK by Ian Allan in 1972)
* Mason, Francis K. "Hawker Aircraft since 1920." London: Putnam Aeronautical Books, 1991. ISBN 0-85177-839-9
* Mason, Francis K. "The British Bomber Since 1914". London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
* Mason, Francis K. "The Hawker Audax & Hardy (Aircraft in Profile nr. 140)". Leatherhead, Surrey, UK: Profile Publications Ltd., 1966.
* Rimell, Raymond Laurence. "The Hart Family - Hawker Hart & Derivatives (Aeroguide Classics Number 5)". Chipping Ongar, Essex, UK: Linewrights Ltd., 1989. ISBN 0-946958-34-3.

External links

* [http://www.britishaircraft.co.uk/aircraftpage.php?ID=326 British Aircraft Directory]