Hawker Hart

https://en.wikipedia.org/wiki/Hawker_Hart

The Hawker Hart was a British two-seater biplane light bomber aircraft of the
Royal Air Force (RAF). It was designed during the 1920s by Sydney Camm and
manufactured by Hawker Aircraft. The Hart was a prominent British aircraft in
the inter-war period, but was obsolete and already side-lined for newer
monoplane aircraft designs by the start of the Second World War, playing only
minor roles in the conflict before being retired.

Several major variants of the Hart were developed, including a navalised version
for the Royal Navy's aircraft carriers. Beyond Britain, the Hart would be
operated by a number of foreign nations, including Sweden, Yugoslavia, Estonia,
South Africa, and Canada.

In 1926, the Air Ministry stated a requirement for a two-seat high-performance
light day-bomber, to be of all-metal construction and with a maximum speed of
160 mph (258 km/h). Designs were tendered by Hawker, Avro and de Havilland.
Fairey, who had sold a squadron's worth of its wooden Fox bomber in 1925, was
not at first invited to tender to the specification, and was sent a copy of the
specification only after protesting to the Chief of the Air Staff, Hugh
Trenchard.

Hawker's design was a single-bay biplane powered by a Rolls-Royce F.XI
water-cooled V12 engine (the engine that later became known as the Rolls-Royce
Kestrel). It had, as the specification required, a metal structure, with a
fuselage structure of steel-tube covered by aluminium panels and fabric, with
the wings having steel spars and duralumin ribs, covered in fabric. The crew of
two sat in individual tandem cockpits, with the pilot sitting under the wing
trailing edge, and operating a single .303 in (7.7 mm) Vickers machine gun
mounted on the port side of the cockpit. The observer sat behind the pilot, and
was armed with a single Lewis gun on a ring mount, while for bomb-aiming, he lay
prone under the pilot's seat. Up to 520 pounds (240 kg) of bombs could be
carried under the aircraft's wings.

J9052, the prototype Hart, first flew in June 1928, being delivered to the
Aeroplane and Armament Experimental Establishment at RAF Martlesham Heath on 8
September. It demonstrated good performance and handling, reaching 176 mph (283
km/h) in level flight and 282 miles per hour (454 km/h) in a vertical dive. The
competition culminated in the choice of the Hawker Hart in April 1929. The de
Havilland Hound was rejected due to handling problems during landing and because
of its part-wooden primary structure. While the Avro Antelope demonstrated
similar performance and good handling, the Hart was preferred as it was far
cheaper to maintain, a vital aspect to a programme during defence budget
constraints that the British armed forces faced during the 1920s. The Fairey Fox
IIM (which despite the name was a new aircraft), delayed by Fairey's late start
on the design compared to the other competitors, only flew for the first time on
25 October 1929, long after the Hart had been selected.

A total of 992 aircraft were built as Harts. 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. There were a
number of Hart variants, though only slight alterations were made to the design.
The Hart India was a tropical version, the Hart Special was a tropical Hawker
Audax, a Hart variant with desert equipment; a specialised Hart Trainer was also
built which dispensed with the gunner's ring. Vickers built 114 of the latter
model at Weybridge between 1931 and June 1936.

Demand was such that production was spread out among a wide selection of
aircraft companies. Of the 962 built in the United Kingdom, Hawker produced 234,
Armstrong Whitworth 456, Gloster 46, Vickers 226 and 42 were produced in Sweden
under licence by ASJA who built 18, Götaverken who built three and the Central
Workshops of the Air Force (CVM) who built 21. 1004 Harts were produced.


Role
Light bomber

Manufacturer
Hawker Aircraft Limited

Designer
Sydney Camm

First flight
June 1928

Introduction
1930

Primary user
Royal Air Force

Variants
Hawker Hind
Hawker Hector

The Hart entered service with No. 33 Squadron RAF in February 1930, replacing
the larger and slower Hawker Horsley. No. 12 Squadron replaced its Foxes with
Harts in January 1931, with a further two British-based Hart light bomber
squadrons forming during 1931.

Harts were deployed to the Middle East during the Abyssinia Crisis of 1935–1936.
The Hart saw extensive and successful service on 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, Estonian
Air Force, Southern Rhodesia, Sweden (where it was designated B4) and the
Kingdom of Yugoslavia. The Rhodesian Hardys saw service on the Allied side
during the opening moves of the East African theatre of World War II.

Swedish Air Force General Björn Bjuggren wrote in his memoirs how his squadron
developed dive-bombing techniques in the mid-1930s for their B4s. When the
Hawker engineers found out, they issued a formal objection, saying that the
aircraft had not been designed for that purpose. However, the Swedish pilots
proved that the aircraft was up to the task and dispelled their concerns.

Demon

The Hawker Demon was a fighter variant of the Hart light bomber. During air
defence exercises the RAF's Siskins and Bulldogs were often unable to intercept
the new Hart bombers, which were sometimes instructed to restrict their height
and speed in order to give the fighters a chance, which prompted the development
of a fighter variant of the Hart.

While the Hawker Fury offered better performance, lower production volumes made
it more expensive and therefore it remained available only in small numbers, so
when a fighter version of the Hart was suggested, the Air Ministry selected the
type as an interim fighter until higher-performance fighters could be bought in
larger numbers. The new fighter variant added a second Vickers machine gun,
while the coaming of the rear cockpit was angled to give a better field of fire,
and a supercharged Kestrel IS engine was fitted. Evaluation of an initial batch
of six aircraft, known as Hart Fighters by one flight of 23 Squadron during 1931
was successful, and larger orders followed for the fighter Hart, now known as
the Hawker Demon. The Demon's first flight was on 10 February 1933.

305 Hawker Demons were built, including 232 for the RAF. The Demon was powered
by varying versions of the Kestrel engine. It had an armament of a single rear
..303 in (7.7 mm) Lewis Gun with two fixed .303 in (7.7 mm) Vickers machine guns
in the nose. Many were fitted with a hydraulically-powered turret in the rear
gunner's position, which had been tested on the Hawker Hart. Demons were also
sold to the Royal Australian Air Force. It saw only second-line operations
during the Second World War.

Production of the Demon was undertaken by Hawker and by Boulton Paul Aircraft at
their Wolverhampton factory, where their last example of 106 to be completed was
delivered to the RAF in December 1937.

Specifications Hart (Kestrel IB powered day bomber)

General characteristics
Crew: 2
Length: 29 ft 4 in (8.94 m)
Wingspan: 37 ft 3 in (11.35 m)
Height: 10 ft 5 in (3.18 m)
Wing area: 349.5 sq ft (32.47 m2)
Airfoil: RAF 28
Empty weight: 2,530 lb (1,148 kg)
Max takeoff weight: 4,596 lb (2,085 kg)
Fuel capacity: 83 imp gal (100 US gal; 380 L)
Powerplant: 1 × Rolls-Royce Kestrel IB water-cooled V12 engine, 525 hp (391 kW)

Performance
Maximum speed: 185 mph (298 km/h; 161 kn) at 13,000 ft (4,000 m)
Stall speed: 45 mph (72 km/h; 39 kn)
Range: 430 mi (374 nmi; 692 km)
Service ceiling: 22,800 ft (6,900 m)
Time to altitude: 8 min 30 s to 10,000 ft (3,000 m)

Armament

Guns: 1 × synchronised forward firing .303 in (7.7 mm) Vickers machine gun, 1 ×
..303 in (7.7 mm) Lewis Gun on Scarff ring in rear cockpit.
Bombs: Up to 520 lb (240 kg) bombs under wings




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