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CONSTRUCTORS of metal aeroplanes since 1910, Messrs. Breguet have recently turned out a new machine which represents a complete breakaway from accepted practice. After acquiring a thorough experience of light alloy construction in the past ten years with their world‐known Breguet 19, they have been led to reconsider the problem of design from the very beginning and to introduce an entirely new conception.

In the description we published of the machines engaged in this year's Deutsch de la Meurthe Cup race (“Modern French Racers,” by R. J, de Marolles, AIRCRAFT ENGINEERING, Vol. VI, July 1934, pp. 179–182) brief mention was made of the Ratier and Levasseur variable pitch air‐screws employed. The Ratier type was fitted to the winining Caudron, C.450, with a 320 h.p. Renault engine, and the Levasseur to the Caudron, C.366, with a 217 h.p. Régnier engine which finished second. We are enabled, through the courtesy of the editor of “L'Aéronautique,” to reproduce here, in this and the following article, descriptions of both these interesting types of variable pilch airscrew, based mainly on articles which appeared in the July issue of that journal. We are particularly indebted to M. Douche for the loan of the originals of the illustrations.

ALL‐METAL construction is much to the fore in many countries, in various forms; some engineers still cling to fabric as a covering, relying solely on structural members to take all the stresses, while others prefer taking full advantage of the use of metal throughout, including covering, both to obtain increased durability and to make the skin take its share of the load. It appears probable that, for important machines at least, the latter school is likely to predominate in the future. But it constitutes a much more difficult task if advantages are not to be attained at the expense of other qualities, such as small cost, low weight and ease of repair, to mention but a few. Some firms are working hard in France to arrive at a satisfactory solution of the problem; amongst them, Messrs. Weymann‐Lepère are noteworthy for their recent and strikingly original efforts.

HELD as usual in the unique atmosphere of the Grand Palais building, the fourteenth “Salon de l'Aviation,” from November 16th to December 2nd, presented a most international character, the number of machines exhibited by foreign manufacturers being appreciably increased over all previous shows. Products of seven countries were displayed in the vast hall, the aeroplanes occupying the ground floor, with the engines round them, while the balcony and other rooms were devoted to accessories and the official exhibition of the Ministère de l'Air. The fourth international Exhibition of Photogrammetry formed part of the show, and not the least instructive. The success of the Salon is a just reward for its sponsors, the Chambre Syndicate des Industries Aéronautiques, of which M. Henry Potez, the well‐known aeroplane and engine manufacturer, is the present President, M. André Granet being Commissaire‐Général.

AVIATION is still young and requires more urgently than any other form of mechanical sport the incentive of pure speed competitions. Strangely enough, there have not been many of them in recent history; apart from the famous Gordon‐Bennett, Schneider, and first Deutsch de la Meurthe contests, all launched by the Aero Club de France, and the Pulitzer and Thompson Trophies in the United States, scratch races for really fast machines on a truly international scale have been rare. In actual fact, no such speed contest for landplanes has taken place in Europe since 1924. There has been only the Schneider Cup for seaplanes, the regulations of which, drawn up in 1912, provided for no limitation of any kind. The result of this, a continuous increase in power, is well known, making competition in practice a Government affair.

THE second edition of the now classic Deutsch de la Meurthe Cup race showed considerable progress over the first competition; the principle of setting a relatively low limit for the cubic capacity of the engine and giving the designers an otherwise entirely free hand is unquestionably one of the best ways towards rapid technical strides. It must be particularly stressed that the competing machines had no certificate of airworthiness of any sort; in fact, Government control was for once completely left aside and the racers allowed to take part in the contest without having been subjected to the slightest examination of officials of the Ministère de l'Air. Thus manufacturers were relieved of the customary administrative difficulties and losses of time. The result proved perfectly satisfactory; machines were rapidly built and tried, they demonstrated remarkable flying qualities and performance, and technical advances of great practical value have been attained in a very short space of time. The experience is likely to have long‐reaching and beneficial results.

THE fourth competition for the “Challenge de Tourisme International,” to give it its official spelling, met with excellent success. Five countries entered 47 machines, 34 contestants qualified at the opening on August 28th at Mokotow aerodrome, near Warsaw, 32 passed the severe preliminary trials and started for a Tour of Europe and North Africa nearly 10,000 km. long, and 19 survived the final ordeal, an all‐out race over 297 km. flown over a triangular course in the vicinity of Warsaw.

SEVERAL new types of commercial aeroplane have appeared in France recently, to meet modern requirements on the various air lines. All these machines are multi‐engined monoplanes, mostly with pure cantilever planes of metal construction. The designers have aimed at higher speed and improved life in service, while the comfort for passengers has made substantial progress.

THE rules for the 1935 Deutsch de la Meurthe Cup Race remained almost identical with those of 1933 and 1934. Briefly, the contest was open to all types of land “aerodynes”; the only limitation being that the total capacity of the engine (or engines) remained under 8 litres (488·20 cu. in.). In other directions, designers were left with an absolutely free hand—the usual Certificate of Airworthiness even being dispensed with. To avoid the participation of machines of doubtful characteristics, each competitor had to qualify between April 2 and May 2 by passing successfully the following tests: a flight of 500 km. (311 miles) in a closed circuit at a speed exceeding 300 k.p.h. (186·5 m.p.h.)—against 250 k.p.h. (155·5 m.p.h.) last year. In addition, take‐off and landing had to be performed in less than 500 metres (1,640 ft.) over a “screen” 1 metre (3·28 ft.) high—against 550 metres (1,801 ft.) last year. Actually, the “screen” took the form of two parallel ropes set at the required height and separated by an interval of 50 metres (164 ft.), so as to ensure correct execution of the test. The wind velocity had to be under 6 metres per second (19·7 f.p.s.) during the take‐off and landing tests.

CONTINUITY is a precious virtue, and in this respect no classic aeronautical competition can boast of a record approaching that of the Coupe Deutsch de la Meurthe. Regulations drawn up for the first contest, held in 1933, have since remained identical, except in some minor details. The main points—the limitation of the cubic capacity of engines to 8 litres (488.2 cu. in.), the distance of the race, 2,000 km. (1,242 miles), and the provision of a qualifying test calling both for a high average speed and for the demonstration of the ability of the machines to take‐off and land in a reasonable space after clearing an obstruction—all these characteristic features combined have proved the most remarkable incentive to technical progress ever recorded in the history of aviation.