It has the distinction of being the first four-engined bomber to be introduced into service with the Royal Air Force (RAF) during the war (the earlier Handley Page V/1500 being a WWI design that served during the 1920s).
During its use as a bomber, pilots praised the type for its ability to out-turn enemy night fighters and its favourable handling characteristics, whereas 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, due to the increasing availability of the more capable Handley Page Halifax and Avro Lancaster, which took over the strategic bombing of Germany.
[4] The Air Ministry published Specification B.12/36, for a high-speed, long-range, four-engined strategic bomber aircraft that would be capable of being designed and constructed at speed.
[4] The aircraft would have to be capable of cruising at speeds of 230 mph or greater while flying at 15,000 ft (4,600 m), carrying three gun turrets (located in the nose, amidships, and rear positions) for defence.
[4] However, prior to this, Shorts had decided to undertake a successful practice, which had been performed with the earlier Empire flying boat, in producing a half-scale version of the aircraft, known as the S.31 (also known internally as the M4 – as per the title on the tailfin), to prove the aerodynamic characteristics of the design.
[4] The S.31, which was largely composed of wood, was powered by an arrangement of four Pobjoy Niagara engines and featured a retractable undercarriage, operable bomb-bay doors, and other measures to realistically represent the larger production aircraft.
Impressed with its performance, on 21 October 1938, Parker flew the S.31 to RAF Martlesham Heath, Suffolk, where it was evaluated by the Aeroplane and Armament Experimental Establishment and received mostly favourable reviews.
Thus, Shorts lengthened the undercarriage struts to tilt the nose up on take-off, leading to its spindly gear, which, in turn, contributed to many takeoff and landing accidents.
Meanwhile, before either of the prototypes had flown, the Air Ministry had decided to order the S.29 into production "off the drawing board" in response to reports of further increases in strength on the part of the German Luftwaffe.
It has also been alleged that production of the Stirling was negatively impacted by a decision by Lord Beaverbrook, the MAP, which had ordered a change in priority from four-engined bombers towards fighters and twin-engined aircraft to replace those lost during the Battle of Britain.
The new design featured longer-span wings and a revised fuselage able to carry dorsal and ventral power-operated turrets each fitted with four 20 mm Hispano cannons; despite the obvious gains in performance and capability, the Air Ministry was not interested.
While the Air Staff initially found the proposal to have some attraction, it was eventually decided to favour increased production rates of the rival Avro Lancaster, instead.
[27] The Short Stirling was a four-engined monoplane heavy bomber designed to provide a previously unmatched level of strategic bombing capability to the Royal Air Force (RAF).
[31] Behind the rest area, the uninterrupted deck ran across the full length of the bomb cells to the location in which the retractable ventral turret was installed upon early production aircraft; the internal area aft of this position was used to store flame floats and reconnaissance flares, as well as an escape hatch, lavatory, rear turret position, and the crew entry door on the port side.
Early Mk.III Stirlings were fitted with a 12.7 mm Browning machine gun in the rear escape hatch (behind a perspex shield) to ward off German night fighters using the Schräge Musik system.
Mk.III Stirlings were also fitted with a ventral antenna for the Blind Approach Beacon System which was a blind-landing aid and a Monica rear warning radar in the tail turret.
[4] The cantilever mid-mounted wing, which employed a two-spar structure covered by aluminium alloy sheeting that was flush-rivetted to the internal spars and ribs, was one instance of design similarity.
[35] Significant attention was paid to reducing drag – all rivets were flush headed and panels joggled to avoid edges – but camouflage paint probably negated the benefit.
The lower sides of the centre-section spar booms aligned with the main deck of the aircraft, which was supported upon the three longitudinal girders which formed the three parallel bomb cells.
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.
After a series of serious accidents and total aircraft losses involving uncontrolled ground loops on takeoff, the Royal Air Force implemented a special training and certification programme for all prospective Stirling pilots.
[42] Despite the "disappointing performance" at maximum altitude, Stirling pilots were delighted to discover that, due to the thick wing, they could out-turn the Junkers Ju 88 and Messerschmitt Bf 110 nightfighters they faced.
The Handley-Page Halifax and especially the Avro Lancaster offered better performance and when these aircraft became available in greater numbers from 1943, the Stirlings were relegated to secondary tasks.
[24][N 6] During the type's service with Bomber Command, Stirlings flew a total of 14,500 sorties, during which 27,000 tons of bombs were dropped; 582 aircraft were lost in action while a further 119 were written off.
[24] The aircraft remained in service for minelaying operations in the vicinity of German ports ("Gardening"), electronic countermeasures, dropping spies deep behind enemy lines at night and towing gliders.
Experiments with a roller-based conveyor to drop these packages faster than a dispatcher were delayed until the end of the war by concerns that this would involve too rapid a change in the aircraft's centre of gravity.
[50] From late 1944, 160 of the special transport variant Stirling Mk V were built, which had the tail turret removed and a new nose opening added; most of these were completed after the war.
In 1994 the same group looked at the possibility of raising No.196 Squadron Stirling LJ925, which crashed on 25 February 1945 in Hølen Lake, near Arendal, Norway and which had been discovered at a depth of 35 ft (11 m) buried in mud and tree bark shavings.