Modern-Aviation

The Short Stirling was born from an RAF requirement set forth in 1936 calling for a heavy four-engined bomber with suitable range and a lethal payload carrying capability. By 1938, a half-sized prototype was flying with a full-size prototype being delivered for testing in 1939. The rather conventional design made use of a forward-set flight deck, centralized internal bomb bay and tricycle undercarriage. Wings were straight and low-mounted with each assembly managing two leading edge engine nacelles. Each engine powered a three-bladed propeller. The undercarriage was retractable with the main legs left rather tall giving the Stirling bomber a rather noticeable nose-up profile when landed. The tail section was traditional, showcasing a single vertical tail fin flanked by two low-mounted horizontal planes. Typical crew accommodations included seven personnel made up of two pilots, a navigator/bombardier, nose gunner, flight engineer and two dedicated gunners. Defensive armament was 8 x 7.7mm (0.303 caliber) machine guns - 2 x in a powered nose turret, 2 x in a powered dorsal turret and 4 x in a powered tail turret. Offensively, the bomber could carry upwards of 14,000lbs of internal stores.

By 1940, the Stirling was in serial production and entered operational service the following year. In its original Mk I form, the Stirling was powered by 4 x Bristol Hercules XI radial piston engines and it would be this mark that would be available during the critical war years - holding enough range to reach the German capital of Berlin if required. The Mk II model followed in prototype form and was fitted with 4x Wright Cyclone engines - though never produced. As such, the definitive Mk III followed with its 4 x Bristol Hercules XVI powerplants and would become the principle bomber variant in the Stirling series. The Mk III series was further fitted with specialized "Pathfinder" equipment, making it useful in airborne-related paratrooper operations or directing follow-up bomber formations to the proper target in low-light.

By 1944, the Stirling had seen its best fighting days. The tide had also begun turning in favor of the Allies with gains across Africa, the Pacific, France, Italy and in the Eastern Front. The Stirling was passed up for more modern offerings and therefore relegated to secondary duties such as glider / transport tug (Mk IV) and used extensively with airborne operations through the remaining years of the war. A dedicated transport model (Mk V) was spawned as the final variant of the Short Sterling.

Beyond the British RAF, the Short Stirling was used by Belgium, Egypt and Germany. In Belgium service, these were post-war mounts used by commercial venture Trans-Air. The Egyptian Air Force procured eight ex-Belgian airframes some time later. German use was limited to recovered examples and operated to a limited extent by the specialist Luftwaffe air group known as "KG 200" ("Kampfgeschwader 200"). KG 200 was disbanded after the war in 1945.

2,383 Short Stirlings were eventually produced, these through Short Brothers, Rochester Short Brothers and Harland and Belfast Austin Motor Company.

The Short Sterling formed the backbone of British RAF heavy bomber groups beginning in January of 1941 and forged an operational existence from then through to the end of World War 2 in 1945, where it proved an obsolescent design and relegated to transport sorties. Designed from the outset as a four-engined heavy bomber (most RAF four engine bombers began life as twin-engined designs), the Stirling would reach its stride in the early 1940's through the Mk III variant as this proved the definitive principle bomber. Short Stirlings were fielded across twenty-eight total RAF bomber squadrons and certainly left their mark on the war despite the arrival of more famous mounts such as the Avro Lancaster.

The aircraft would have a crew of six; two pilots, an observer/navigator, wireless operator, and two gunners manning the nose and tail turret. Provision was also made for a remote control turret in the lower portion of the rear fuselage. Armor would be fitted along with sound proofing and even a toilet. By late 1936, the Air Staff ordered a fuselage mock-up of the design. In order to keep the takeoff and landing run within limits, Short's Chief Designer, Mr.Lipcombe, felt that the wing length should be enlarged from under 100 feet to around 112 feet. This request was rejected, with the Air Ministry stating that existing RAF hangars would not accomodate wing spans of more than 100 feet. This decision created a severe altitude and range limitation because of a decreased wing aspect ratio.

The Navigator's position was located just behind the port pilot's seat, with Navigator facing to port, and was equipped with a plotting table and light. This navigator is plotting a course using a Dalton computer, the type issued to all RAF navigators.

Short constructed a half-scale flying prototype during 1938, which was intended to reveal any aerodynamic problems. Powered by four 90 hp Pobjoy engines and constructed of plywood, the aircraft was officially designated the S31, but was better known as M4. The S31/M4 first flew on 19 September 1938 with Short's Chief Test Pilot John Lankester Parker at the controls. Within a few weeks the flight tests had been completed, while generally satisfied, RAF officials expressed concern over the prototype's takeoff and landing runs, which were felt to be excessive. The proposed solution was to almost double the wing angle. Short decided to drastically lenghten the undercarriage legs to achieve the required additional 3 degrees of wing incidence.

Fuel Tanks, Two similar, self-contained systems were carried in the wings, one on each side of the fuselage. The systems could be interconnected if necessary by operating an inter-system balance cock in the centre section. Auxiliary tanks could be fitted in the wings bomb cells for long range duties. In each system the fuel was carried in seven tanks, all tanks except those in the leading edge had self sealing covering. A total of 2692 gallons of fuel could be carried. Later aircraft had a nitrogen fire protection system fitted.

The single stage landing gear leg was discarded due to the increased length of the undercarriage rods which proved too long to be retracted into the engine nacelle wheel wells. A two stage undercarriage was built which retracted vertically and then back- wards into the nacelle. The undercarriage retraction motors were originally located inside the nacelle, but were later relocated inside the fuselage to allow for manual retraction in the event of motor failure...

The underarriage was a complicated structure, retracted or lowered in two operations by electric motors which were prone to breakdown. The undercarriage was a weak point of the Stirling, it sometimes collapsed under strong side loadings. The considerable height above ground, and the rake of the pilot's seat made it very difficult for the pilot to accurately judge touchdown attitude and precise ground position.

The powerplants were also changed from the 90 hp Pobjoy engines to 115 hp Niagara IV engines. While testing resumed with the S31/M4, construction began on two full size prototypes now officially known as the Stirling MkI/P1. Shortly after construction of the prototypes began, the Air Ministry decided to order the Stirling into production with a contract of 100 Stirling MkI's. The prototype S29 was rolled out of the company's Rochester factory on 13 May 1939.

Operators
Belgium - Trans-Air, later known as Air Transport (Post-war civilian use, a total of 10 planes, 9 of which went on to the Egyptian Air Force. The 10th (OO-XAC, ex-PK172) crashed during operations in Kunming, China)
Egypt - Egyptian Air Force
Germany - Luftwaffe, KG 200
United Kingdom - Royal Air Force
No. 7 Squadron RAF August 1940 - July 1943
No. 15 Squadron RAF April 1941 - December 1943
No. 46 Squadron RAF January 1945 - February 1946
No. 48 Squadron RAF – Stirling Mk V transport version
No. 51 Squadron RAF June 1945 - February 1946
No. 75 (New Zealand) Squadron October 1942 - March 1944
No. 90 Squadron RAF November 1942 - June 1944
No. 138 Squadron RAF June 1944 - March 1945
No. 148 Squadron RAF November 1944 - December 1944
No. 149 Squadron RAF November 1941 - September 1944
No. 158 Squadron RAF June 1945 - December 1945
No. 161 Squadron RAF April 1942 - June 1945
No. 171 Squadron RAF September 1944 - January 1945
No. 190 Squadron RAF January 1944 - May 1945
No. 196 Squadron RAF July 1943 - March 1946
No. 199 Squadron RAF July 1943 - March 1945
No. 214 Squadron RAF April 1942 - January 1944
No. 218 Squadron RAF January 1942 - August 1944
No. 242 Squadron RAF February 1945 - December 1945
No. 295 Squadron RAF July 1944 - January 1946
No. 299 Squadron RAF January 1944 - February 1946
No. 513 Squadron RAF September 1943 - November 1943
No. 525 Squadron RAF June 1944 - August 1944
No. 570 Squadron RAF July 1944 - January 1946
No. 620 Squadron RAF June 1943 - July 1945
No. 622 Squadron RAF August 1943 - December 1943
No. 623 Squadron RAF August 1943 - December 1943
No. 624 Squadron RAF June 1944 - September 1944