MAILS BY AIR

Evening Post, Volume CXII, Issue 106, 31 October 1931, Page 10

MAILS BY AIR

FAST NEW CARRIER

NON-PASSENGER MACHINE

(From "Tho Post's" Representative.) LONDON, 13th August Tho fastest British load-carrying civil aircraft yet built, an Avro mailplano capable of flying at nearly three miles a minute with full load on board, was demonstrated on 10th August at Heston Air Park, before Colonel Sholmerdine, Director of Civil Aviation, and a few privileged exports. Acceleration of air. mail services throughout the world is a subject receiving nowadays marked attention in British aviation circles, and this now craft is tho first of a number of mail carriers constructed in British works wlyich promise spectacular progress in the development of night and day aerial mail routes. The British Empire offers a field for high-speed mail operation not surpassed in potentialities by any of the other great land areas, and leading.exports consider' that the employment of rolays of machines similar to the new Avro mailplano could at once, given the essential ground organisation, reduce the time taken for the mails to travel from London to Sydney, for example, to 7A days. , The present controversy engages the protagonists of two theories, that, mails should travel with passengers, and, alternatively, that these two main classes of "aerial traffic should be separated. Supporters on tho ono side declare that the slowing down of mail transport to tho speed made necessary by the frequent halts while the passengers rest is illogical. The result, they say, is that the Indian air mail moves at* an average speed of no moro than 28 miles an hour; for two-thirds of tho journey it is stationary while passengers eat; and sleep. On the other hand, exports point triumphantly to the United States lines which, begun as "mails only" enterprises, are now rapidly turning over to the operation of aircraft carrying passengers and mails together. But there can be no doubt about the immense speeding up that would follow establishment of "mails only" services throughout the Empire, and this is work-that the Avro "mailplane" type 027 is admirably fitted to do. THREE MILES A MINUTE. Last week tho new machine completed official trials at Martlesham Heath, the Royal Ait- Force experimental station where all new British aircraft aro put through exacting tests. It recorded there a maximum speed, with 8701b of mail on board arid a full load of fuel sufficient for 600 miles non-stop, of more than 170 miles an hour, a rale of climb at ground level of no less than 1200 ft a minute, and a cruising speed at only two-thirds of.full engine power of 140 m.p.h. \These figures represent a degree of performance striking enough to' commend the mailplanes to aircraft operating companies abroad, and within the next fortnight:or so the machine will be shipped to Canada for further demonstration; actually the conditions governing mail carriage in Canada received prime consideration in working out the design. The Type 627 is a shapely biplane, a wing system chosen : by the makersto secure conveniently small overall dimensions and low cost of transporting spare wings in emergency. In every detail is perceptible the insistence iv lessening resistance to movement through, the air—the reduction of "drag," to use the' technical term— which is so marked a feature of prp-'sent-day British aircraft design. Notli'iiig is hero to disturb tho flow of air over the'structure; even the landing wheels have. streamlined casings, while every strut and wire is streamlined.: '■ ALL-METAL MACHINE. Except, for tho fabric coverings of wings and tail unit and the fuselage fairings, tho entire machine is built of metal, welded steel tubing making up the fuselage framework, high tensile corrugated steel strips, the wing spars and duralumin pressings tho wing ribs. The • engine, an Armstrong-Siddeloy " Jaguar Major," 525 h-.p.," air-cooled radial unit, is surrounded by a resist-ance-reducing Townend ring, the outlines of which merge smoothly into a streamlined exhaust manifold behind the motor and continue into the fuselage. The single pilot sits in a cockpit immediately aft of the fireproof and watertight mails compartment, which has a total capacity of 40 cubic feet. His eyes aro on a level with the upper wings, and ho has a magnificent view in every direction. Seat height and the position of the rudder bar at his feet are adjustable in flight; before him on the dashboard is an unusually large equipment of navigational apparatus to guide him by day and by night. After dark a flood-lighting device illuminates the dash and retractable landing lights are ready for instant use. To meet the rigours of fly-, ing in tempei'atuTcs far below zero the cockpit is warmed from the engine by a long' muff wrapped round a pipe at-' tached to the exhaust manifold. ;