Avro Shackleton

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

The Avro Shackleton was a British long-range maritime patrol aircraft (MPA) used
by the Royal Air Force (RAF) and the South African Air Force (SAAF). It was
developed by Avro from the Avro Lincoln bomber, which itself has been a
development of the famous wartime Avro Lancaster bomber.

The Shackleton was developed during the late 1940s as part of Britain's military
response to the rapid expansion of the Soviet Navy, in particular its submarine
force. Produced as the primary type equipping RAF Coastal Command, the Type 696,
as it was initially designated, incorporated major elements of the Lincoln, as
well as the Avro Tudor passenger aircraft, and was furnished with extensive
electronics suites in order to perform the anti-submarine warfare (ASW) mission
along with a much improved crew environment to accommodate the long mission
times involved in patrol work. Being known for a short time as the Lincoln
ASR.3, it was decided that the Type 696 would be named Shackleton in service,
after the polar explorer Sir Ernest Shackleton.

In April 1951, it entered operational service with the RAF. The Shackleton was
used primarily in the anti-submarine warfare (ASW) and maritime patrol aircraft
(MPA) roles; it was also frequently deployed as an aerial search and rescue
(SAR) platform and for performing several other secondary roles such as mail
delivery and as a crude troop-transport aircraft. In addition to its service
with the RAF, South Africa also elected to procure the Shackleton to equip the
SAAF. In South African service, the type was operated in the maritime patrol
capacity between 1957 and 1984. During March 1971, in one high-profile incident,
a number of SAAF Shackletons were used to effect during the SS Wafra oil spill,
having intentionally sunk the stricken oil tanker using depth charges in order
to prevent further ecological contamination.

During the 1970s, the Shackleton was replaced in the maritime patrol role by the
jet-powered Hawker Siddeley Nimrod. During its later life, a small number of the
RAF's existing Shackletons received extensive modifications in order to adapt
them to perform the airborne early warning (AEW) role. The type continued to be
used in this support capacity until 1991, at which point it has been replaced by
the newer Boeing E-3 Sentry AEW aircraft. These were the last examples of the
type remaining in active service.


Role
Maritime patrol aircraft

Manufacturer
Avro

First flight
9 March 1949

Introduction
April 1951

Retired
1991

Primary users
Royal Air Force
South African Air Force

Produced
1951–1958

Number built
185

Developed from
Avro Lincoln

Various armaments and equipment were carried by the Shackleton in order to
perform its missions. In ASW operations, the ASV Mk 13 radar was the primary
detection tool; it could detect a destroyer at a range of 40 nautical miles, a
surfaced submarine at 20 nautical miles, and a submarine's conning tower at
eight nautical miles, although rough seas considerably reduced the radar's
effectiveness. Other equipment included droppable sonobuoys, electronic warfare
support measures, an Autolycus diesel fume detection system and a magnetic
anomaly detector (MAD) system. A special camera bay housed several
reconnaissance cameras capable of medium altitude and nighttime vertical
photography, and low-altitude oblique photography. The crew would also perform
visual searches using various lookout positions that were provided for this
purpose. Weapons carried included up to nine bombs, three homing torpedoes or
depth-charges; the aircraft also had two 20 mm cannon in a Bristol dorsal
turret. An in-flight refueling receptacle could be accommodated, but was not
fitted on production aircraft.

The Merlin engines were replaced with the larger, more powerful and
slower-revving Rolls-Royce Griffons with 13 ft (4 m)-diameter contra-rotating
propellers. This engine's distinctive noise often caused pilots to develop
high-tone deafness. Use of the Griffon was necessitated by the Shackleton
weighing more than the preceding Lincoln, and suffering from greater drag. The
Griffon provided equivalent power to the Merlins but at lower engine speed,
which led to greater fuel efficiency in the dense air encountered at low
altitude; the Shackleton would often loiter for several hours at roughly 500 ft
(150 m) or lower when hunting submarines.

Numerous problems were encountered during the Shackleton's operational service.
In practice, the diesel fume detection system was prone to false alarms and thus
received little operational use. The engines, hydraulics, and elements of the
avionics were known for their unreliability, and the aircraft proved to be
fairly maintenance-intensive. The prototype MR 3 was lost due to poor stalling
characteristics; this was rectified prior to production, although a satisfactory
stall-warning device was not installed until 1969. The Shackleton is often
incorrectly attributed the unfortunate distinction of holding the record for the
highest number of aircrew killed in one type in peacetime in the RAF.

Specifications

General characteristics
Crew: ten
Length: 87 ft 4 in (26.61 m)
Wingspan: 120 ft (36.58 m)
Height: 17 ft 6 in (5.33 m)
Wing area: 1,421 ft² (132 m²)
Airfoil: modified NACA 23018 at root, NACA 23012 at wingtip
Empty weight: 51,400 lb (23,300 kg)
Max. takeoff weight: 86,000 lb (39,000 kg
Fuel capacity: 4,258 imperial gallons (19,360 L)
Powerplant: four × Rolls-Royce Griffon 57 liquid-cooled V12 engine, 1,960 hp
(1,460 kW) each
Propellers: contra-rotating propeller, two per engine Propeller diameter: 13 ft
(4 m)


Performance
Maximum speed: 260 kn (300 mph, 480 km/h)
Range: 1,950 nmi (2,250 mi, 3,620 km)
Endurance: 14.6 hours
Service ceiling: 20,200 ft (6,200 m)
Max. wing loading: 61 lb/ft² (300 kg/m²)
Minimum power/mass: 91 hp/lb (150 W/kg))

Armament

Guns: 2 × 20 mm Hispano Mark V cannon in the nose
Bombs: 10,000 lb (4,536 kg) of bombs, torpedoes, mines, or conventional or
nuclear depth charges, such as the Mk 101 Lulu




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