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Aviation History
1925
1925 - 0100.PDF
20fnn 19 17 16 15 14 12 II 10 9 8 7 6 5 4 ? !, xJ JDAR O H E STAC > i7 L TIME IN MINUTED 2 4 6 8 10 12 14 16 15 20 2 j j L l / f © \ ) / / L 110 / \ iVE V \ \ / / \ ^/ \ \ L 5PE > / \ \ 2 24 26 28 30 32 •> E.D i l.r n. 120 1 \ \ y \ \ 130 r- g X 5TANDAR C i 4- i:0 19 18 17 16 15 14 13 12 II 10 8 7 6 5 4 2 1 n ) 2 4 6 8 10 12 14- 16 18 20 22 24 26 28 30 32 34 TIME IN MINUTES THE BRISTOL VARIABLE TIMING GEAR : The curves show comparative performances of the Bristol "Bloodhound" with same all-up weight and same propeller, curves 1 relating to the standard " Jupiter " series IV engine, and curves 2 to the " Jupiter " IV with variable timing gear and Triplex carburettors. It will be seen that the performance, i.e. both speed and climb, is greatly improved. existing conventional " in-line " engines, however, this simple method of increasing power at altitude was never developed. On the Bristol " Jupiter " radial air-cooled engine it has been possible to obtain a practical solution of. the variable- FEBRUARY 19, 1925 timing engine ; firstly, owing to the patented double- epicyclic timing gear, it is quite simple to arrange that the period of opening the valves can be easily changed while the engine is running, and also owing to the stroke-bore ratio of the engine, viz., 1 -3 to 1, it has been possible to re-design the cylinder with 6-3 to 1 compression ratio without obtaining an inefficient combustion chamber. The Bristol Aeroplane Co., Ltd., have been working on this development for the last nine months, and have now obtained most excellent results both on the bench and in the air, as we recorded in one of our Paris Show articles dealing with the " Jupiter " exhibited there. From the illustration given of the gear as mounted on the nose of the " Jupiter " engine, it will be noted that it is quite simple. There is a double-worm gear controlling the stationary annulus of the timing gear." No moving parts of the engine are affected, so that the reliability of the engine is not detracted from in the least, and the additional weight to the engine is only 4 lbs. On the test bench, with the variable timing retarded, it was found that the engine maintained ground-level power at normal consumption, and that the gear could be operated quite satisfactorily throughout its whole range with a very slight effort. This engine was then mounted in the Bristol Bloodhound," a two-seater fighter, with which scry careful performance tests had previously been made when fitted with a standard " Jupiter " engine. " This machine has now been flying for the past three months, during which period an extended series of tests have been carried out by the Bristol Company's chief test pilot. The results show a marked increase in performance between the aircraft when fitted with the standard Series IV " Jupiter " engine, with 5 to 1 com- pression ratio, and when fitted with the engine with the variable-timing gear. Throughout the tests the same pilot, same weight, and same propeller were used, and all figures have been carefully corrected, so the results are strictlv comparative. The accompanying chart shows the difference in climb and speed of the machine with the standard engine, and with the variable-timing engine. It will be noted that on a climb to 18,000 ft., the time is reduced by 11 minutes by the use of the variable-timing engine, and at 15,000 ft. the increase in speed is 8 m.p.h. The addition of the variable-timing gear, for which a patent has been applied for, has thus proved a simple acd practical method ol considerably improving aeroplane per- formance at altitudes, without adding any appreciable weight, increasing head resistance, or detracting in the slightest degree from the engine relUl.ilitv. Sir Sefton Brancker Flying Home SIR SEFTON BRANCKER, Director of Civil Aviation, who arrived at Calcutta on February 9 in the D.H. 50 piloted by Alan Cobham en route for England, proceeded on February 13 for Benares. Delhi was reached in the evening of February 15. French Saharan Flight Disaster THE De Goys aerial mission to Lake Chad and Bangi, which had successfully reached Niamey, on the Niger— 2,750 miles from Paris—met with disaster when resuming the flight on February 11, in consequence of which the French Under-Secretary for Air, M. Laurent Eynac, has ordered the flight to be abandoned. One of the four-engined Bleriots, " Jean Casale," piloted by Col. Vuillemin, was just leaving the ground when it suddenly rose at a steep angle, stalled and then crashed to the ground. Col. Vuillemin was seriously injured, and the mechanic, Serj. Knecht, was also very badly iHirt, but the wireless operator, Serg. Vendelle, was killed. Capt. Dagneaux, the navigator, was less seriously injured, and is reported to be doing well. The cause of the accident is stated to be due to an incorrect setting of the tail plane. Capt. Pelletier d'Oisy, the pilot of the second Bleriot, has been instructed to return to Dakar. On behalf of Great Britain, Sir Samuel Hoare, Secretary of State for Air, sent telegrams to the French Minister of War and Air Minister, expressing regret at the disaster to the Jean Casale." Madrid-Las Palmas Air Mail ACCORDING to The Times correspondent, a Royal Decree authorises the Director-General of Communications, a branch of the Ministry of the Interior, to issue, after consulta- tion with the Council'of State, a call for tenders from Spanish companies for the establishment of an aerial postal service between Seville and the Canary Islands. A concession for ten years, renewable for a similar period, will be granted to the selected company. The service is to consist ;>t first of one journey both ways each week, to be increased according to the requirements of the traffic. The aeroplanes must have at least two engines and be fitted with wirele^ apparatus. The minimum speed is to bo 85 miles an hour, the radius of action six hours, and the carrying capacity for mail-. 1,32(1 lbs. The flight will be in five stages : Seville-I.araiche, 91 miles ; Laraiche-Mogador or Agadir, about 210 miles ; Mogador or Agadir to Cape Juby, 226 miles ; Cape Juby-La I'almas and Las Parmas-Teneriffe, 31 miles. Although during the last three years concessions for air lines have been granted all over the Peninsula, the only concession which has, so far, materialised under Spanish enterprise has been the Seville- Larakhc service, which employs British machines and pilots. It is calculated that, unless the official bodies which have been asked to report on the new proposed line show most unusual activity, about one year must elapse before the line will be opt?n for use. French Parachute Disaster A TERRIBLE accident occurred at Villacoubl;«y last week, when A. Kuppert set out on a Liore et Olivier monoplane lor an attempt to beat the world's height record. When at about 2,000 ft. one of the wings of his machine gave way, and as the machine dived to earth the pilot was seen to jump with his parachute. The latter, however, failed to function, and the pilot fell straight to the ground nnd was instantly killed. The Royal Infant Orphanage THE half-yearly election for the admission of fatherless children to thie Royal Infant Orphanage, Wanstead, E 11, will be held in May next. Children are received from birth up to seven years of age and maintained and educated until sixteen. Application should be made as early as possible to the Secretary at the Orphanage, Wanstead, London, E. 11. 100
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