https://en.wikipedia.org/wiki/Short_Empire
The Short Empire was a medium-range four-engined monoplane flying boat, designed
and developed by Short Brothers during the 1930s to meet the requirements of the
growing commercial airline sector, with a particular emphasis upon its
usefulness upon the then-core routes that served the United Kingdom. It was
developed and manufactured in parallel with the Short Sunderland maritime patrol
bomber, which went on to serve in the Second World War; a further derivative
that was later developed was the piggy-back Short Mayo Composite.
The development of the Short Empire had been heavily influenced by its primary
customer, Imperial Airways, who had originally developed the requirements to
which it was initially ordered and designed from. Imperial Airways, and its
successor, the British Overseas Airways Corporation (BOAC), along with Qantas
and TEAL, operated the type in commercial service. Upon entering service, the
Empire routinely flew between the British mainland and Australia and the various
British colonies in Africa and Asia, typically carrying a combination of
passenger and mail cargoes; the Empires were also used on various other routes,
such as on the service between Bermuda and New York City.
The Short Empire flying boat is a relatively clean-looking high-wing monoplane,
initially powered by an arrangement of four wing-mounted Bristol Pegasus Xc
radial engines which drove de Havilland-built variable-pitch propellers. The
Pegasus Xc engines could each produce 910 horsepower (680 kW) of thrust on
takeoff, declining to 740 horsepower (550 kW) at an altitude of 3,500ft.
Alternative engine models were installed upon various models of the aircraft,
these were of both greater and lower power outputs dependent upon intended role
and sought purpose. Initial aircraft produced were designed for a 40,500 lb
(18,400 kg) gross weight; however, by 1939, many aircraft had been strengthened
for an increased gross weight of 53,000 lb (24,000 kg). Overall, its useful load
included 600 imperial gallons (720 US gal; 2,700 L) of fuel (weighing 4,560 lb
(2,070 kg)), 44 imp gal (53 US gal; 200 L) of oil, assorted onboard equipment
(weighing 3,340 lb (1,510 kg)), along with the payload itself and a crew
compliment of five (weighing 8,200 pounds (3,700 kg)). The S.23 series achieved
a top speed of 200 miles per hour (320 km/h) at an altitude of 5,500 feet (1,700
m) along with a cruising speed of 165 miles per hour (266 km/h) and a minimum
flying speed for 73 miles per hour (117 km/h).
The 17 ft (5.2 m) deep hull accommodated a total of two decks, the upper deck
forming a lengthy compartment divided into sections to accommodate 3,000 lb
(1,400 kg) of freight and mail along with a storage space and a ship's clerks
office, this office contained controls such as electrical fuseboxes and circuit
switches, ventilation controls, and fuelcocks. The lower deck contained a large
marine compartment containing an anchor, a pair of drogues, a mooring bollard,
and a boat hook, along with a step ladder to the cockpit; aft of the mooring
compartment was the forward passenger saloon, followed by a central corridor
flanked by the toilets and galley, a mid-ship cabin, a spacious promenade cabin,
and finally an aft-cabin.
The flying crew were seated in a spacious cockpit, also referred to as the
bridge; the captain and copilot were seated side-by-side while the radio
operator sat facing rearwards behind the captain. The flight deck was relatively
well equipped for the era, including features such as an autopilot; the flying
instrumentation included a Hughes-built turn indicator, compass, and variometer,
a Sperry Corporation-built artificial horizon and heading indicator, a
Kollsman-built sensitive altimeter, a Marconi-built radio direction finder, a
Smiths-built chronometer, and an attitude indicator. The radio operator was
furnished with Marconi-built shock-proof radio sets for receiving and
transmitting across the radio spectrum; the retractable loop antenna could be
repositioned for visual or aural homing.
Role
Flying boat mail and passenger carrier
Manufacturer
Short Brothers
Designer
Arthur Gouge
First flight
3 July 1936
Introduction
Delivered 22 October 1936,
First revenue flight 6 February 1937
Retired
1946-47
Status
retired
Primary users
Imperial Airways/BOAC
Qantas Empire Airways
Royal Australian Air Force
Royal Air Force
Produced
1936-1940
Number built
42
Unit cost
Variants
Short Mayo Composite
On 8 February 1937, one of the Empire flying boats, Castor, conducted the first
regular flight, flying from Calshot, Hampshire, England to Alexandria, Egypt.
This flight, which covered a distance of roughly 2,300 miles (3,700 km)
non-stop, showing that Britain could move military materiel to its overseas
bases. On 18 February 1937, Caledonia, the first of the Empires built, flew the
same Colshot-Alexandria route; it was able to traverse the route non-stop at an
average speed of 170 MPH.
On 5 July 1937, the first crossing of the Atlantic by an Empire flying boat was
conducted. On an experimental basis, Caledonia, piloted by Captain W N Cummings,
flew a 1,993 miles (3,207 km) route from Foynes on the River Shannon west to
Botwood, Newfoundland. On the same day, an American Sikorsky S-42 flying boat
flew the opposite direction.Caledonia took just over 15 hours (including a
period spend searching for a landing spot), flying at an altitude of 1,500 to
about 130 mph (210 km/h). On its return flight, conducted on 22 July 1937,
Caledonia flew the same route in the opposite direction in a time of 12 hours;
in comparison to the competing Sikorsky S-42, the Empire was able to traverse
the overall route faster.
The Short Empire was designed to operate along the Imperial Airways routes to
South Africa and Australia, where no leg was much over 500 miles (800 km). After
the design of the Empire had been finalized and production had commenced, it was
recognised that, with some pressure from the United States, it would be
desirable to offer a similar service across the Atlantic. The range of the S.23
was less than that of the equivalent American-built counterpart in the form of
the Sikorsky S-42, and as such they could not provide a true trans-Atlantic
service. Two boats (Caledonia and Cambria) were lightened and furnished with
long-range tanks; both aircraft were used in experimental in-flight refuelling
trials in order for them to conduct the journey; these modifications came at the
cost of being able to carry fewer passengers and less cargo.
Wartime experience in operating the type at overload weights resulted in the
realization that the Empires could take off at considerably higher weights than
the conservative maxima provided by Shorts and, although the last Empire
crossings to America were made in 1940 (by Clare and Clyde), many more flights
were made on the long, demanding and vital over-water Lisbon-Bathurst flights.
Specifications (Shorts S.23)
General characteristics
Length: 88 ft (26.82 m)
Wingspan: 114 ft (34.75 m)
Height: 31 ft 9?3/4 in (9.70 m)
Wing area: 1,500 sq ft (139.35 m2)
Empty weight: 23,500 lb (10,659 kg)
Max. takeoff weight: 40,500 lb (18,370 kg)
Performance
Maximum speed: 200 mph (322 km/h)
Range: 760 miles (1,223 km)
Service ceiling: 20,000 ft (6,100 m)
*
|
|