Editing Short Empire (section)

==Development==
===Origins===
During the 1930s, global demand for air travel was consistently and rapidly growing. Thus, keen to grow its share of this emerging market, British airline [[Imperial Airways]] was keen to expand and sought the latest technology to do so. In particular, Imperial Airways' technical adviser, Major Robert Hobart Mayo developed a specification for a new type of aircraft to serve both passenger and freight requirements throughout the world.<ref name = "norris 3">Norris 1966, p. 3.</ref> This specification sought an aircraft that would be capable of carrying up to 24 passengers in spacious comfort along with adequate room for [[airmail]] or freight while simultaneously being capable of a [[cruising speed]] of {{convert|170|mph|km/h}} and a range of at least {{convert|700|mi|km}}; the capacity for an extended range of {{convert|2000|mi|km}} to serve the North [[Atlantic]] route was also stipulated.<ref name = "norris 3"/> At the time, it was not considered possible to construct a land-based aeroplane of such size and weight which would have acceptable landing/take-off performance; thus it was determined that a flying boat would be required.<ref name = "norris 3"/>

Early on, it was apparent that Short Brothers, who had previously developed and produced several satisfactory large flying boats for Imperial Airways and the [[Royal Air Force]] (RAF), would be a frontrunner to fulfil the requirement.<ref name = "norris 3"/> However, Shorts was hesitant to build such an aircraft straight from the drawing board without the production of a preceding prototype, and thus requested to be allowed to build such an aircraft; this was rejected by Imperial Airways, who stated that such a delay was not permissible.<ref name = "norris 3"/> In 1935, Imperial Airways announced the placement of an order for 28 flying boats of an as-of-yet undesigned type, weighing 18 tonnes each; the order was reportedly hailed as being "one of the world's boldest experiments in aviation", while sceptics referred to the decision as being a gamble.<ref name = "norris 3"/>

A design team led by Arthur Gouge set about designing what would become the Empire. It was quickly determined that, in order to have sufficient clearance between the tips of the [[propeller]]s and the water, the wing would need to be in a high mounted position; initially to be housed in a hump above the fuselage for sufficient height, the fuselage depth was instead increased, providing more internal volume than required but enabling a lighter and stronger integration of the [[cantilever]] wing with the fuselage.<ref name = "norris 3"/> Shorts' own convention for wide planing bottomed hulls for its flying boats was overturned as the 18-tonne weight would generate excessive drag with such a configuration; following a series of water tank experiments, a new type of planing bottom with a reduced [[Beam (nautical)|beam]] deemed suitable.<ref name = "norris 3"/> The basic aerodynamic design was derived from the smaller [[Short Scion Senior]] floatplane, which served in all but name as a half-scale prototype for the Empire and for its sibling, the military-orientated [[Short Sunderland]].<ref name = "norris 3 4">Norris 1966, pp. 3–4.</ref>

At the time of development, the British aircraft industry had never attempted to construct an aeroplane of this size and complexity before; accordingly, many new techniques were devised to overcome problems encountered, particularly during its construction process.<ref name = "norris 4">Norris 1966, p. 4.</ref> Shorts had to develop its own machinery to produce the necessary T-shaped [[Hiduminium]] [[alloy]] lengths that comprised the main [[Spar (aeronautics)|spar]].<ref name = "norris 4"/> A specialised and patented [[Flap (aeronautics)|flap]] arrangement, known as [[Gouge flap]]s after their creator, was employed on the Empire to increase wing area with only a small increase in drag and without heavy disrupting airflow over the top of the [[airfoil|aerofoil]]; in operation, the lift coefficient of the wing could be increased by 30 percent, reducing the landing speed by 12 per cent, without employing any [[Trim tab|trimming]] to adjust.<ref name = "norris 3"/>

===Initial production===
[[File:Airplane. Captain Wilcockson Signs Autograph BAnQ P48S1P01041.jpg|thumb|Captain Arthur Wilcockson, who was in charge of the notable flight of the flying boat ''Caledonia'' from Ireland to Canada, signs an [[autograph]], 8 July 1937]]
On 4 July 1936, the first Empire flying boat to be built, G-ADHL, named ''Canopus'', conducted its [[maiden flight]], flown by Shorts' chief test pilot, [[John Lankester Parker]].<ref name = "norris 6 7">Norris 1966, pp. 6–7.</ref> Early flights of the type were relatively trouble-free, Parker declaring his satisfaction with the aircraft's performance; the new styling of the planing bottom used also quickly proved its value.<ref name = "norris 6 7">Norris 1966, pp. 6–7.</ref> On 17 September 1936, G-ADHL first flew on behalf of Imperial Airways, piloted by Major H G Brackley, Imperial Airways' air superintendent; the final delivery and proving flight of the aircraft to [[Marseille]], France took place on 22 October 1936.<ref name = "norris 7">Norris 1966, p. 7.</ref> The first series of the Short Empires, the ''S.23'', could carry five crew, 17 passengers, and 4,480&nbsp;lb (2,035&nbsp;kg) of cargo at a maximum speed of 174 knots (320&nbsp;km/h) and was powered by four {{Convert|920|hp|kW}} [[Bristol Pegasus]] Xc [[radial engine]]s.<ref>THE AEROPLANE 28 October 1936</ref>

The second Empire and the first of the long-range models to be produced, G-ADHM, named ''Caledonia'', performed her first flight on 15 September 1936 and was delivered to Imperial Airways on 4 December 1936.<ref name = "norris 7"/> From September 1936 onwards, the Empire was produced at a rate of one aircraft per month; typically, each aircraft's delivery date occurred only a few days after having performed its maiden flight, the hand-over sometimes happened immediately following the first flight.<ref name = "norris 7"/> The Empire was officially known as the C-class by Imperial Airways and each aircraft operated by them was given a name beginning with a C.

On 26 February 1938, the final three Empires of the initial order placed by Imperial Airways – ''[[Coorong, South Australia|Coorong]]'', ''[[Coogee, New South Wales|Coogee]]'' and ''[[Corio, Victoria|Corio]]'' – were diverted from the Imperial Airways order and were delivered instead to the Anglo-Australian [[Qantas Empire Airways]].<ref name = "norris 7 10">Norris 1966, pp. 7–10.</ref> In late 1937, due to Imperial Airways' satisfaction with its operational experience with the aircraft of the initial batch, the company placed a follow-on order for another 11 Empires; combined with the original order of 28 this had the distinction of being the largest single order to have ever been placed for a British civil aircraft at that time.<ref name = "norris 10 11">Norris 1966, pp. 10–11.</ref> While the first three aircraft of the additional order were of the typical S.23 class, intended for Qantas Empire Airways, the rest were manufactured to a differing design, designated as the ''S.30''.<ref name = "norris 11">Norris 1966, p. 11.</ref> A total of 42 Empires were built, all at Short's [[Rochester, Kent|Rochester]] factory.

===Further development===
The ''S.30'' series was outfitted with four [[Bristol Perseus|Bristol Perseus XIIc]] [[sleeve valve]] engines in the place of the Pegasus engines; the Perseus engines were more efficient but provided a lower power output of {{Convert|890|hp|kW}}, but the decrease in developed thrust was effectively compensated for via the adoption of smaller diameter nacelles which had resulted in a substantial reduction in drag.<ref name = "norris 11"/> It also had a strengthened airframe and used heavier gauge sheeting on the fuselage and wings; while these changes allowed the takeoff weight to be increased to {{Convert|46000|lb|kg}} with a corresponding range of {{Convert|1500|mi|km}}, the S.30 had broadly the same performance as the preceding S.23 flying boats.<ref name = "norris 11"/>

The first of the S.30 flying boats to be laid out and completed was G-AFCT, named ''Champion''.<ref name="norris 11" /> In December 1938, the second S.30 aircraft G-AFCU, named ''Cabot'' became the first aircraft of the series to conduct the first successful takeoff. The last three aircraft of this order – ''Captain Cook'', ''Clare'' and ''Aotearoa'' – were renamed and re-registered for use by [[Tasman Empire Airways Limited|TEAL]].<ref name = "norris 11"/> In 1939, a final S.30 flying boat, G-AFKZ, was ordered and delivered to Imperial Airways in late March 1940.<ref name = "norris 11"/>

A total of four flying S.30 series flying boats – ''Cabot'', ''Caribou'', ''Clyde'' and ''Connemara'' – were equipped with in-flight refuelling equipment and extra fuel tanks in order that they could be used to provide a regular transatlantic airmail service. The concept was for the aircraft to take off at lower weights and, once airborne, take on extra fuel to reach an all up weight of {{Convert|53000|lb|kg}}, giving the aircraft a range of over {{Convert|2500|mi|km}}. The extra fuel reduced the payload to {{Convert|4270|lb|kg}} against the {{Convert|6250|lb|kg}} of the standard aeroplane. The refuelling was performed by three converted [[Handley Page H.P.54 Harrow|Handley Page Harrow]] bombers, one operating out of Ireland and two out of [[Dominion of Newfoundland|Newfoundland]].

In 1939, Imperial Airways placed a further follow-on order for a modified model of the S.30, designated as the ''S.33''.<ref name = "norris 11"/> This series had the same basic construction as its immediate predecessors, the new Pegasus XI engine, a development of the powerplant used by the original S.23 series, was adopted instead. Out of these three final aircraft, only two – ''Clifton'' and ''Cleopatra'' – would be completed and delivered to the newly formed [[British Overseas Airways Corporation]] (BOAC).<ref name = "norris 11"/>

A substantial larger development of the Empire flying boat, effectively a new aircraft, was the ''[[Short S.26|S.26]]'', designated as the G-class.<ref name = "norris 13">Norris 1966, p. 13.</ref> The aircraft had similar appearance to the standard Empire, but was in fact roughly about 15 percent larger in all dimensions, as well as differing in its use of the more powerful [[Bristol Hercules]] [[radial engine]]. It adopted an improved hull design, featuring a wing span of {{Convert|134|ft|m|0}} and a length of {{Convert|101|ft|m|0}}. It was intended to be used for year-round services on the north Atlantic route.<ref name = "norris 13"/> Only a small number were built, and these were quickly impressed into military service during the Second World War.<ref name = "norris 13 14">Norris 1966, pp. 13–14.</ref>