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Aviation History
1923
1923 - 0682.PDF
w'r^^SSi NOVEMBER 8. 1923 1 it ft y / —— — •• i— — — A y ~ -. 7 3= / 7~ X © y ?^ / y --— •£— > © ffi 1 4 SO ft! X ID R.PM. Power curves of a standard Bristol " Jupiter " Engine :In the above graph throttle curves 1 indicate readings taken with dynamometer set at 90 per cent, of therated horse-power, i.e. 344 b.h.p. at 1,575 r.p.m. Curves 2 indicate readings taken with dynamometerset at full power at 1,575 (i.e. normal) r.p.m. Curves 3 are full throttle power curves. •;•' for the short exhaust pipes. This arrangement has beenchosen in preference to a very large fuselage, and the greater proportion of cylinder projecting has been more than made upfor by streamlining each in the manner described. Thus the fuselage itself is not much larger than necessary to make itmeet the circumference of the crank-case. The speeds attained seem to show that, contrary to general opinion, it isbetter, aerodynamically, to have a narrow body with nearly the whole of the streamlined cylinders projecting than to havea large body with the cylinder heads only, but un-streamlined, projecting. As far as can be ascertained no trouble with over-heating was experienced. Another unusual feature of the Gourdou-Leseurre mono-plane is the retiactable undercarriage. Each wheel is mounted on a fork enclosed in a streamline casing, and when themachine is in the air these forks are swung back in such a manai r that they drop into a recess in the sides of the fuselage.The principle upon which the retractable undercarriage gear vorks is very simple, and seems to have worked well inpractice. Each of the wheel forks is carried on a pair of Vee struts, of which the front ones are hinged to the lowerlongeron of the fuselage. The rear struts are secured at their upper end to a guide in the recess in the side of thefuselage. A quadrant is mounted on and moves with the Vees of the undercarriage, and extends from the top of therear strut, across the Vee, and projects slightly forward of the front strut, about two-thirds of its length down fromthe upper end. Engaging with the quadrant is a worm, operated from the pilot's seat. When this worm is rotatedit raises the quadrant, and with it the wheel. The lower ends of the wheel forks work in slots in the Vee struts, andthe upper end has a cross member resting against rubber cord shock absorbers carried on spools mounted on the frontVees and between fore and aft members across the Vee respectively. The travel obtained is not very great, butthe tests carried out so far appear to have been entirely satisfactory. It might be argued that an undercarriage ofthis type will not be very strong under side loads. While that is probably true, it should be remembered that if amachine with such high landing speed lands with even a small amount of drift, it will probably turn over anyway,and no amount of undercarriage strength against lateral loads will prevent this. That the retractable chassis on theGourdou-Leseurre does add materially to the speed is not to be doubted. The original, or normal, machine has a wing area of20 sq. m., and the speed attained with this wing was 300 km. (186-5 m.p.h.). It is estimated that the ceiling, with theservice wing fitted, will be more than 9,000 m. (29,600 ft.), so that the Gourdou-Leseurre monoplane should, in addition toits role as a racer, be a very useful type for service purposes as a single-seater fighter. The view obtained is excellent, themachine guns can easily be installed, and, finally, the radial " Jupiter " engine gives a low longitudinal moment of inertia,so that the machine should be very manoeuvrable. As rigged for the Coupe Beaumont the Gourdou-Leseurremonoplane had an overall length of 7 -2 m. (23 ft. 7 ins.) and a span of 7 -8 m. (25 ft. 7 ins.). The wing area of the racingmachine was only 12 sq. m. (130 sq. ft.), and the maximum speed must be in the neighbourhood of 240 m.p.h. The weight of the machine is given as 935 kgs. (2,060 lbs.),composed as follows : Engine installation, 345 kgs. (760 lbs.) ; pilot and instruments, 100 kgs. (220 lbs.) ; fuel, 160 kgs.(350 lbs.) ; machine, 330 kgs. (725 lbs.). The wing loading is 15 -86 lbs./sq. ft., and the power loading (on 450 h.p.)4-58 lbs./h.p. It might be mentioned that the engine speed was 1,650r.p.m., which, on this particular engine, No. 855, was equal to a power of 450 b.h.p. This engine gave 490 h.p. at 1,875r.p.m., so that when it has been thoroughly tuned and fitted with a suitable propeller to allow of its being run up to its fullpower a considerably improved performance should be obtained. While on the subject of the Bristol " Jupiter " enginereference may be made to a series of power curves recently taken on a standard " Jupiter," series IV. These tests werecarried out at a moment's notice, simply for purposes of record, and without any special preparation or tuning of anysort. In other words, the engine was one picked at random from stock. As will be seen from the accompanying curves,,the tests were eminently satisfactory. At normal speed (1,575 r.p.m.) the power at full throttle is 400 h.p. and theconsumption is 225 pints (28 gallons 1 pint) per hour, or •562 pint/h.p./hour. Sadi Gets Up to 11,000 MetresNOT content with his previously established record of 10,741 metres, Sadi Lecointe has made a further attempt, thistime reaching an altitude of 11,000 metres. This figure has not yet been homologated, but the sealed barographs havebeen submitted to the Institute of Arts et Metiers for examina- tion and correction, and their report will probably be availablein a few days. The machine used by Lecointe was a Nieuport- Delage, with Hispano-Suiza engine and Lamblin radiators. The Coupe Lamblin BAD weather having interfered with the attempts made during the last days of October by several French pilots to beat the performance of Adjutant Bonnet in the Coupe Lamblin competition, which closed for this year on October 31, Bonnet remains the holder of the Cup for 1923. The circuit over which this competition was flown was Paris-Strassburg-Lyons, adistance of 1,200 km. (744 miles). Bonnet's time was 5 hr. 54 m. 13 s., giving an average speed of 195 km. (121miles) per hour. Adjutant Bonnet receives a prize of 10,000 francs. Second in the race was Lieut. Bordes, whosetime was 5 h. 58 m. 23 -8 s. Lieut. Bordes receives a prize of 5,000 francs. Both flights were made on October 12, andhave not been beaten by any later attempts. Curiously enough, third prize (3,000 francs) goes also to AdjutantBonnet, for his flight on September 4, when his time for the circuit was 6 h. 14 m. 13 s. The -machines used by bothcompetitors were Nieuport-Delage biplanes, type 29, with 300 h.p. Hispano-Suiza engines, and are production types inactual use in the service. Needless to say, Lamblin radiators are used. ... ._......•._ .. .. 682
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