Short Stirling

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

The Short Stirling was a British four-engined heavy bomber of the Second World
War. It has the distinction of being the first four-engined bomber to be
introduced into service with the Royal Air Force (RAF).

The Stirling was designed during the late 1930s by Short Brothers to conform
with the requirements laid out in Air Ministry Specification B.12/36. Prior to
this, the RAF had been primarily interested in developing increasingly capable
twin-engined bombers but had been persuaded to investigate a prospective
four-engined bomber as a result of promising foreign developments in the field.
Out of the submissions made to the specification, Supermarine proposed the Type
317 which was viewed as the favourite, while Short's submission, named the S.29,
was selected as an alternative. When the preferred Type 317 had to be abandoned,
the S.29, which later received the name Stirling, proceeded to production.

During early 1941, the Stirling entered squadron service. During its use as a
bomber, pilots praised the type for its ability to out-turn enemy night fighters
and its favourable handling characteristics, while the altitude ceiling was
often a subject of criticism. The Stirling had a relatively brief operational
career as a bomber before being relegated to second line duties from late 1943.
This was due to the increasing availability of the more capable Handley Page
Halifax and Avro Lancaster, which took over the strategic bombing of Germany.
Decisions by the Air Ministry on certain performance requirements, such as to
restrict the wingspan of the aircraft to 100 feet, had played a role in limiting
the Stirling's performance; these restrictive demands had not been placed upon
the Halifax and Lancaster bombers.

During its later service, the Stirling was used for mining German ports; new and
converted aircraft also flew as glider tugs and supply aircraft during the
Allied invasion of Europe during 1944–1945. In the aftermath of the Second World
War, the type was rapidly withdrawn from RAF service, having been replaced in
the transport role by the Avro York, a derivative of the Lancaster that had
previously displaced it from the bomber role. A handful of ex-military Stirlings
were rebuilt for the civil market.


Role
Heavy bomber
Glider tug

National origin
United Kingdom

Manufacturer
Short Brothers, Rochester
Short Bros. and Harland, Belfast
Austin Motor Company

Designer
Claude Lipscomb / Sir Arthur Gouge

First flight
14 May 1939

Introduction
1940

Retired
1946 (UK); 1951 (Egypt)

Status
Retired

Primary users
Royal Air Force
Egyptian Air Force

Produced
1939–1945

Number built
2,371

Developed from
Short Sunderland

Under typical operations, most variants of the Stirling were flown with a crew
of seven, performing several different roles. It was flown by a pair of pilots,
who were supported by a navigator/bomb aimer, a front gunner/wireless operator,
two further gunners, and a flight engineer. The flight engineer and wireless
operator were housed in a cabin just forward of the leading edge of the wing,
and directly forward of them was the navigator's station. The two pilots were
contained within a fully glazed flight deck positioned level with the forward
end of the bomb cells; the provision of a separate flight engineer's station led
to the cockpit having a relatively simple appearance in comparison with the
majority of the RAF's bombers.

The cockpit containing the flying officers was provided with numerous controls
and features; to the left of the first pilot were the controls for the
auto-pilot and a P.4 compass; the pilot was also provided with a beam approach
indicator (to aid nighttime landings) and DF visual loop indicator in addition
to the standard flight controls. Switches for the flaps and position indicators
were located on a central panel set between the two pilots, while the master
fuel cocks were set above these on the roof; throttle and mixture controls were
also normally positioned between the pilots. Only limited engine instrumentation
was provisioned for, such as engine speed indicators and boost gauges.

The Stirling was armed with nose and tail turrets (the latter was notable for
the wide angles of fire) along with a single retractable ventral ("dustbin")
turret located just behind the bomb-bay. This proved almost useless due to
cramped conditions, with the added distraction that the turret tended to drop
and hit the ground when taxiing over bumps. The retractable turret was removed
almost from the start and temporarily replaced by beam hatches mounting pairs of
machine guns, until a twin-gun dorsal turret could be provided. This turret also
had problems; it had a metal back fitted with an escape hatch which turned out
to be almost impossible to use. The later Stirling Mk.III used a fully glazed
turret (the same FN.50 as in Lancaster) that had more room and an improved view.
Later Stirlings could also carry an improved, low-drag remotely-controlled FN.64
ventral turret.

Pilot accounts generally report that, once airborne, the Short Stirling was a
delight to fly, surprisingly manoeuvrable for such a large aircraft and without
any vices. According to Norris, the Stirling was "more maneuvreable and
responsive than any other aircraft in its class". The shortcomings of the
aircraft in terms of lower operational altitudes and limited range are largely
forgiven in pilot autobiographies. The Stirling did, however, exhibit some
vicious flying characteristics during takeoff and landings.

As a class, the large and heavy four-engined tail-wheeled bombers such as the
Stirling, Handley Page Halifax, Avro Lancaster and Boeing B-17 Flying Fortress
could be a handful on takeoff and landing, more so for relatively young and
inexperienced new pilots who formed the vast majority of the expanding
Commonwealth and American air forces. Later heavy bomber designs such as the
Consolidated B-24 Liberator and Boeing B-29 Superfortress used a nose-wheel
(tricycle) configuration as did most successful four engined commercial aircraft
in the post-war years. Tricycle geared aircraft are typically easier to control
on takeoff, landing and during taxing, and also make for easier cargo loading
and servicing as the cabin, engines and other systems are closer to the ground.
The long undercarriage of the Stirling was a result of a request by the RAF who
sought to increase the wing incidence.

From late 1941 onwards, the Stirling played a pioneering role in the formation
of the RAF's Pathfinder squadrons - bombers that were dedicated to indicating
targets for following bombers to more accurately deploy their payloads upon.
From the spring of 1942, the bomber started to be deployed in greater numbers.
From May 1943, raids on Germany were often conducted using over a hundred
Stirling bombers at a time. Stirlings were amongst the RAF bombers used during
the First 1,000 bomber raid against Cologne. Norris observed that, by 1942, the
type had "given plenty of punishment to the Germans, and was also proving that
it could itself take punishment to an incredible extent. There were several
incidents in which heavily damaged aircraft, such as one Stirling which suffered
a head-on collision with a Messerschmitt Bf 109 fighter over Hamburg, were able
to continue flying and safely return to base.

Despite the "disappointing performance" at maximum altitude, Stirling pilots
were delighted to discover that, due to the thick wing, they could out-turn the
Ju 88 and Bf 110 nightfighters they faced. Its handling was much better than
that of the Halifax and some preferred it to the Lancaster. Based on its flight
characteristics, Flt Lt Murray Peden (RCAF) of No. 214 Squadron RAF described
the Stirling as "one of the finest aircraft ever built". However, a consequence
of the thick wing was a low ceiling. Many missions were flown as low as 12,000
ft (4,000 m). This was a disadvantage on many raids, notably if crews were
attacking Italy and had to fly through (rather than "over") the Alps. When
Stirlings were on combined operations with other RAF bombers which could fly
higher, the Luftwaffe concentrated on the Stirlings. Within five months of being
introduced, 67 out of the 84 aircraft delivered had been lost to enemy action or
written off after crashes.

Specifications (Short Stirling I)

General characteristics
Crew: 7 (First and second pilot, navigator/bomb aimer, front gunner/WT operator,
two air gunners, and flight engineer)
Length: 87 ft 3 in (26.6 m)
Wingspan: 99 ft 1 in (30.2 m)
Height: 22 ft 9 in (6.9 m)
Wing area: 1,460 ft² (135.6 m²)
Aspect ratio: 6.5
Empty weight: 46,900 lb (21,274 kg)
Loaded weight: 59,400 lb (26,944 kg)
Max. takeoff weight: 70,000 lb (31,752 kg)
Powerplant: 4 × Bristol Hercules II radial engine, 1,375 hp (1,025 kW) each
Propellers: Three-bladed metal fully feathering propeller Propeller diameter: 13
ft 6 in (4.11 m)


Performance
Maximum speed: 282 mph (454 km/h) at 12,500 ft (3,800 m)
Cruise speed: 200 mph (320 km/h)
Range: 2,330 mi (3,750 km)
Service ceiling: 16,500 ft (5,030 m)
Rate of climb: 800 ft/min (4 m/s)
Wing loading: 40.69 lb/ft² (198.7 kg/m²)
Power/mass: 0.093 hp/lb (0.153 kW/kg)

Armament

Guns: 8 x 0.303 in (7.7 mm) Browning machine guns: 2 in powered nose turret, 4
in tail turret, 2 in dorsal turret
Bombs: Up to 14,000 lb (6,350 kg) of bombs




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