AVIATION

Timaru Herald, Volume CXXXVII, Issue 19640, 7 November 1933, Page 12

AVIATION

BRITISH NEWS EX PE RIME NT A L MA Cl HINES LONDON. October 3. Severe tests of experimental aeroplanes built of stainless steel, except for the fabric covering of wings, fuselage and tail unit and certain minor components—have proved the worth of the metal. Twelve stainless steel ’planes—six “Nimrod” single-seater ship fighters and six “Osprey” twoseater fiighter-reconnaissance craft—are in course of construction; following trials in the hands of the Hawker test pilots they will be sent to replace older types of aircraft in the complement of the Fleet Air Arm. Since the earliest days of metal aircraft building. British chemists and metallurgists have sought ways and means of countering the corrosion demon, which more perhaps than any other single factor limits the “life” of an aeroplane and adds to maintenance charges. Metals which in themselves are not rustless arc coated with protective coverings of special varnishes; they may also be chemically treated or stove-enamelled. In these ways a high degree of resistance to corn lon is obtained. and metals treated according to established British technique show remarkable endurance even in most severe conditions., such as affect operation of s r a-going aeroplanes in the tropics. There still remains real advantage in employing a constructional metal which requires the minimum of protective treatment, and adoption of stainless steel represents a long step towards the corrosion-proof flying machine.

The first complete fuselage of stainless steel to be shown in public anywhere in the world had a place on the Hawker Company's stand at the Paris Salon late in 1032, and attracted much informed interest. It consisted in the body framework of an “Osprey” biplane. Subsequently the remainder of the structure was completed in the same material, and a “Nimrod” fighter was similarly built. Both craft were submitted to drastic tests. The “Osprey” went through weeks of exposure strapped to the gun-turret of a cruiser, where it was swept by rain, roasted in the sun. an., soaked in salt sea spray. Finally, it was lowered overboard and soaked in the water for many hours. Careful examination showed that none of the tests had exposed any serious weakness in the ability of the material to withstand all kinds of weather and treatment.

Tlie first cost of a stainless steel structure is considerably higher than that of a similar aeroplane built ol other materials, but the makers claim that the freedom from corrosion—especially important in the operation of sea-going - aircraft —with the consequential savings derived from lessened maintenance charges and longer “life” between overhauls of the rustless airframe. will more than compensate for the increase in initial expenditure. Fastest shipboard fighters yet commissioned for service in any of the world's navies, the “Nimrod’' biplanes provided the spearhead of the defence of aircraft carriers and capital ships against aerial attack in the recent seaair exercise held over an area of 1000 square miles of the North Sea. Carrying full load—and the shipboard aeroplane must lift considerably more fuel and navigational equipment than landbased craft doing similar work —the “Nimrod” attained in official test flights as long ago as October, 1931, a maximum level speed of 200 miles an hour. Its service “ceiling,” or the height at which the rate of climb has fallen off to 100 feet a minute, was 27,500 feet, and it climbed to 20,000 feet above sea-level in a little more than 11 minutes. Power was derived from a Rolls-Royce “Kestrel” watercooled motor, then rated at 480h.p.; detail improvements in design and increased power from the engii-j have since made available still better performaiVT.

The “Osprey” is equally notable for high speed and general flying efficiency. Its ma: linum attainable speed is in the neighbourhood of three miles a minute, and its cruising range is more than 500 miles. Both “Nimrod” and “Osprey” ’planes have been supplied to foreign governments as well as to the Fleet Air Arm. always abroad in the face of severe competition from foreign aircraft constructors.

Britain’s largest aeroplane, and the fastest flying-boat in the world, the Short six-engined biplane which weighs with full load on board no less than 32 tons, concluded at Felixstowe yesterday a 2000 miles’ cruise round much of the British Isles. The flight was undertaken in continuation of earlier Service trials of the big 'plane, and was especially planned to test her seaworthiness in moderately agitated seas and her behaviour at anchor in exposed moorings. Flight Lieutenant H. G. Sawyer, one of the officers attached to the marine aircraft experimental station at Felixstowe, was in command.

The flight began with a non-stop journey <of approximately 600 miles from Felixstowe to Lerwick, in the Shetland Islands, continued to Kirkwall, in the Orkneys, and then on by way of Stornoway, Londonderry, Stranraer, Oban, Pembroke Dock, and the Mountbatten seaplane base, Plymouth. Altogether the trip lasted exactly a fortnight, and much valuable information was gained. Though she is designed to carry an immense load the six-engined boat, thanks to remarkably “clean” design and the power output of her RollsRoyce "Buzzard” 825 930h.p. motors, attains in level flight a maximum speed of more than 150 miles an hour, a speed which was only just reached by many standard singe-seater fighters a few years ago. Her practical cruising range is immense, fitting her admirably for the long distance patrol and open-sea reconnaissance duties which governed her design. Her crew consists in 10 men, who have comfortable living quarters on board. In addition to formidable defensive ; rmament and elaborate navigational equipment she carries all of the paraphernalia of surface vessels; anchors, riding lights, fog-horns and so forth. _____