AN ALL-METAL CANTILEVER MONOPLANE, the Empire Flying BoatCorinna measures 88 feet from nose to tail. It has a wing span of 114 feet and a wing area of 1,500 square feet. Four Bristol Pegasus radial air-cooled engines are fitted.
THE air routes of the British Empire, with their long transoceanic and transcontinental crossings, require aircraft of exceptional performance. The flying boats of the Empire type were built by Short Brothers Ltd., of Rochester, Kent, to specifications laid down by Imperial Airways after many years of experience flying to schedule on these routes.
The design of the Short Empire flying boat represents many departures from orthodox practice. The first of the fleet to be completed was named the Canopus. The ratio of her beam to her overall height (31 ft 9¾-in) is small and, despite her weight (24,000 lb unladen, 40,500 lb fully loaded), she has a take-off which lasts for only twenty-one seconds.
Her hull is designed to “unstick” with the greatest possible ease in all conditions of loading. It is designed to withstand all the shocks and strain that may be incurred through alighting on rough water, yet it has been kept as light as possible. This has been achieved partly by the use of “Alclad” planking, riveted with flush rivets to the horizontal and longitudinal girders. An all-metal cantilever monoplane, the Empire flying boat measures 88 feet from nose to tail, having a wing spread of 114 feet and a wing area of 1,500 square feet. The wings are metal throughout, the main spars being in the form of a girder box tapered in depth as well as towards the wing tips. Struts and stiffeners are covered with light metal sheets, the leading and trailing edges being built up as separate units. The four engines are mounted in the wings, with the fuel tanks behind them. The aircraft used for experimental transatlantic flights have additional tanks fitted, but the normal capacity is 600 gallons.
The interior of the hull is a masterpiece of economic design. In the forepart of the ship there are two complete decks. The upper deck contains the “bridge”, with cockpit for the Captain and First Officer. Immediately behind comes the radio operator’s cabin, then the mail compartments and an office for the ship’s clerk. This office contains also the main switchboard for all the electric lighting in the aircraft. A step-ladder leads down to the kitchen on the lower deck. The kitchen and two lavatories are situated between the smoking cabin forward and the saloon amidships. These two rooms measure 6 ft 6-in by 10 feet and are 8 feet high. In the nose of the monoplane is housed the mooring gear. Farther aft there are a large saloon known as the promenade cabin, leading to another cabin, and the large hold in the tail for freight, mail and baggage. By day the cabins, from fore to aft, can accommodate seven, three, eight and six passengers respectively; each cabin has sleeping berths for four persons. There are two separate ventilating systems in all cabins.
The engines are four Bristol Pegasus units, each developing a maximum output of 790 horse-power at 2,600 revolutions a minute. The nine-cylinder engines are of the radial air-cooled type. They give a maximum speed of 200 miles an hour at 5,500 feet, and a maximum cruising speed, with all engines throttled down, of 164 miles an hour. The rate of climb is 950 feet a minute, the ceiling being 20,000 feet. Normal range in still air is 810 miles. Three-bladed de Havilland variable-pitch airscrews are fitted.