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Aviation History
1924
1924 - 0474.PDF
JULY 31, 1924 SPAN 4~/-6' LENGTH . . . 30 -9 WING AREA473-4 Sq.pt DESCAMPS-BRUNET A2 SESQUIPLAN -400 H.R LORRAINE -DIETRICH ENGINE, THE DESCAMPS-BRUNET A.2 SESQUIPLAN ; General arrangement drawings. Both pilot and passenger have an excellent range of vision. The pilot is located beneath the trailing portion of the top plane, a section of which is cut away ior the purpose of providing a view upward, while the small dimensions of the lower plane enables the pilot to obtain a good view downwards. The gunner's or observer's cockpit is located well aft of the top plane, where he has an excellent view and range of fire in all directions. The control is independent of the fuselage and all cables are out of the wav of the pilot and observer, being; led beneath the flooring of the cockpits. The seats and controls are adjustable to suit different " sizes " of pilots or passengers. A wide-track landing gear is provided, consisting of two independent housings—or " plus fours " !—each mounted out on the lower planes and each containing a w'fteel. The wheels are also separate, and are mounted in the housings by means of Sandow shock absorbers. There is thus a clear space below the fuselage at this point for the mounting and operation of bombs. The tail-skid is pivottSI in order to facilitate steering on the ground. <•> <$> THE DEMONTY-PONCELET MONOPLANE 40 H.P. Gregoire Engine the present but few particulars have become available relating to the light 'planes taking part in the Tour de France des Avionettes, the eliminating trials for which were held at the Bleriot aerodrome at Buc on July 24, 25 and 26, and the start for which took place from the same aerodrome on Sunday, July 27. There are, it will be remembered, 15 machines entered for the competition, of which two are Dutch, two Belgian, two Czechoslovak, and the remaining nine French, except that the machine entered by the Bleriot firm is really to be regarded as a British machine, having been designed and built at Addlestone. Of the two Belgian machines, one is entered by M. Victor Simonet, who took part in last year's Lympne light 'plane competitions, while the other is a Demonty-Poncelet, designed by the two gentlemen named and built by M. Poncelet. M. Demonty is chief engineer and technical director of the Belgian S.A.B.C.A. works, while M. Poncelet is their works manager. By the courtesy of our French contemporary Lr,s Ailes, we are able to publish this week a brief description and general arrangement drawings of the Demonty-Poncelet monoplane, which shows several unusual features in its design. The machine, it will be seen, is a high-wing monoplane with strut bracing, and the chief characteristic is that the two occupants are housed inside the cabin, sitting side by side. Owing to the fact that the engine is a four-cylinder-in-line inverted Gregoire, the forward portion of the engine housing is relatively narrow on top, and allows the pilot to look forward from the cabin through windows in the sloping forward walls. Other windows in the sides of the cabin give a reasonably good view laterally, while circular celluloid windows in the roof give ian upward view and also improve the lighting of the cabin. From an aerodynamic point of view the Demonty-Poncelet is chiefly remarkable for a fuselage very deep in front, but tapering off rapidly towards the rear, where, in fact, the curves are slightly " hollow." Whether or not this feature is a good one we should not like to say. The Belgian designers are not alone in choosing it, as it will be remembered that M. Louis de Monge, the famous French designer, has em ployed these reverse curvatures in some of his machines and is, we believe, of the opinion that these concave curves improve to some extent the resistance figure. It is somewhat difficult to see exactly on what grounds this opinion is held. Structurally the Demonty-Poncelet is of straightforward type, with wood as the chief material employed. The fuselage has bulkheads of elm and three-ply, with diagonal bracing strips and longerons of elm and covering of three-ply. The latter, incidentally, is of mahogany. The frames or bulkheads in line with the wing spars are specially streng thened and reinforced. The cabin is reasonably roomy, measuring 3 ft. 7 ins. in length, 3 ft. 11 ins. in width and 4 ft. 5 ins. in height. As already mentioned, the occupants sit side by side, and, in addition to the usual seating accom modation, the cabin contains a small luggage compartment and a tool-box. It should be borne in mind that the machine is not so much a light 'plane, in the British sense of the word, as a low-power touring machine, and everything possible has been done to ensure the comfort for pilot and passenger. The monoplane wing is composed of a centre-section which is part of the fuselage structure and two wing-halves which are so attached as to be rapidly removable for transport. The spars are of spruce and the rear spar is attached to the top corner rail of the fuselage by a universal joint. The front spar is attached by two bolts, and the wings are braced by two wood struts on each side, so arranged as to take tension as well as compression stresses. At the top the two wing bracing struts are joined by a longitudinal piece, while at the lower end the struts are separately attached to the lower longerons, one in front of and one behind the wheel. For folding the wings the front spar bolts are removed, as well as the pins securing the bracing struts to the wing spars, the wing is rotated on the rear spar universal joint, and the wing is folded flat alongside the fuselage, resting with its leading edge on the tail plane. With wings folded the overall width of the machine is only 7 ft. 10 ins., so that it can be trailed behind a motor-car. The two wing halves 474
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