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Aviation History
1912
1912 - 0768.PDF
lAWHT r,.. « Combined Speed Climb. . r-i—if and Climb. 1-52 •57 •08 1-52 •98 1-84 •4 •0 2-99 2-07 2-88 3-I9 4-88 4'39 3'55 •37 Effective Speed Range. Hannot No. 2 . 8-8 + 6 = 1-47 Bleriot No. 4 ... 9-0 + 6=1-50 M. Farman ... 17-8 + 6 = 2-8o French Dep. ... io-i + 6 = 1-67 Cody biplane ... 23-9 + 6 = 3-90 Hanriot No. 1 ... 15-3 + 6 = 2*55 Bleriot No. 5 . 18-9 + 6 = 3-15 Bristol No. 14 ... 2-2 -*. 6 = -37 The interpretation of the above table is that the Maurice Farman Bleriot (5) sociable and the Cody score heavily in speed range, while the Hanriots and the French Deperdussin gain most marks for their climbing. It is interesting to compare these results with those published last week, in which the weight and engine power were taken into account for the purpose of gaining some idea of the efficiency of the machine as a whole, as distinct from its utility for a specific purpose, which is the object of the present discussion. Thus, if, in the following table, Ej is the ratio of V times the resistance deduced from the gliding angle, to the h.p. available, where V is the maximum flight speed, and E2 is E, plus the per centage h.p. used for the height climbs then we have :— Hanriot No. 2 Bleriot No. 4 ... M. Farman ... French Dep. No. 26. Cody biplane ... Hanriot No. I Ble'riot No. 5 ... Bristol No. 14 E,. % E2. % X. 81 105 168 74 85 198 58 75 75 80 103 138 59 75 85 73 99 172 Weight unknown Gliding angle unknown 216 In the above the Hanriot (2) and the Deperdussin score as very efficient machines on speed, while the Farman and Cody lose. The same remarks apply when the climbing is added to the absolute speed under this head but come to the fore directly the range of speed is taken into account, as it is in the preceding table. Before dismissing the subject, there is still one other factor that ought to be taken into consideration, namely, fuel and oil con sumed. Fuel is latent power, and if one machine can accomplish on a gallon what another requires two gallons to perform, there is presumably an advantage in the more economical, which ought not " Flight" Copyright. Waiting on the weather at the Army Aeroplane Trials on Salisbury Plain.—From left to right: Major F. H. Sykes, Brlg.'Gcn. D. Henderson, Mr. S. F. Cody, and Mr. Plxton. AUGUST 24, 1912. to be overlooked. In this calculation it will, perhaps, be fairer to add the lubricating oil to the petrol, since both are necessary to the running of the engine, particularly because the oil is the more expensive material to buy, and in some cases the least easy to obtain in emergency. If we allow that the numerical values in the preceding tables have the dimensions of power, as explained, then it is not without reason to introduce the fuel factor by establishing a ratio between the values given for combined speed and climb and the fuel used per hour Hanriot No. 2.. Bleriot No. 4 .. M. Farman French Dep. .. Cody biplane Hanriot No. 1 Bleriot No. 5 . in gallons. Speed Range and Climb. • 2'99 . 2-07 . 2-88 • 3'I9 . 4-88 • 4'39 • 3-55 Thus :— Fuel and Oil. Speed Range and Climb, Fuel and Oil. 0/ 8-65 + 2-1 =1075 5'35 + i7 = 7*05 7-0 + -73= 7-73 8-4 +1-3 = 97 9-0 + -42= 9-42 8-o +2-4 =10-4 6-3 +1-7 = 8-o !o 28-0 29-4 37 "2 32-8 52-0 42-0 44'5 X. 168 198 75 138 85 172 It is interesting to compare the results thus obtained with the con stant X (i.e., wt./h.p. x wt./sq. ft.), and to observe how the machines with the greatest amount of reserve power (lowest X) would appear to score most under the trial conditions, regarded solely from the point of view of doing the useful work required and ignoring the flying of the machine as a whole, save for the remarkable exceptions afforded by the Bleriot sociable and Hanriot No. 1, which score so heavily on their flexibility of speed. Nevertheless, there is some support for the prevalent idea of the practical utility and economy of the large sail area biplanes as vehicles of aerial transport and the efficiency of the modern streamline monoplane, regarded as complete machines, in the especial fields of higher speed flight and climbing. In conclusion it may be convenient to summarise the machines under the various heads that have been considered, thus :— X. Bristol 15 Bristol 14 Bleriot 4 Hanriot 1 Hanriot 2 Cody M. Farman E2. % Hanriot 2 Dep. ... Hanriot 1 Bleriot 4 Cody Farman ... 222 216 198 172 168 85 75 105 103 99 85 75 75 Speed (max.). V,T, , * , ' XV (max). m.p.h. Hanriot 1, Bristol 15 Cody Bristol 14 Dep. ... Bleriot 4... Bleriot 5... Farman... 2, 75 Bristol 15 73 Bristol 14 72 Hanriot I 70 Hanriot 2 69 Bleriot4... 61 Dep. 59, Cody ... 55 Farman ... 16,200 15,200 12,900 12,700 12,100 9.55o 6,140 4,140 Speed Range Fuel and Oil and Climb. per Hour. Cody ... Hanriot 1 Bleriot 5... Dep. Hanriot 2 Farman... Bleriot4... 4-88 Bleriot4.. 4-39 Farman .. 3-55 Bleriot5.. 3-19 Cody .. 2-99 Dep. 2-88 Hanriot 1 2-07 Hanriot 2 7-05 • 773 8-o 9-42 97 10-4 1075 EL % Hanriot 2 Dep. ... Bleriot 4... Hanriot 1 Cody Farman ... Si 80 74 73 59 58 (Speed Range and Climb): (Fuel and Oil). Cody ... Bleriot 5... Hanriot 1 Farman ... Dep. ... Bleriot ... Hanriot 2 7. 52 44 42 37 33 29 28 These figures are, of course, very much of the rough and ready order, but as the process of their calculation is given it is hoped that they may give rise to discussion, and that something useful may come of this attempt at analysis. Reverting to the subject at issue, viz., class design, it must not be forgotten that some of the machines, such as the Farman, Cody, and perhaps others, were never specially designed for the trials at all. Inasmuch, however, as the entrants in question used their everyday standard machines, they showed a good judgment and common sense that should be a lesson to some of those who may lose the opportunity of their lives by trying to get special models into action at the eleventh hour. ® ® ® ® U.S. Navy and Hydro-aeroplanes. IN response to some requests from manufacturers, the U.S. Naval authorities have issued a schedule of requirements for naval aeroplanes. This sets forth a good many points which should be borne in mind by the designer and manufacturer. It stipulates that the machine should fly for four hours, averaging 50 m.p.h., and attain a maximum speed of at least 55 m.p.h. in a series of ten runs over a measured mile, five with and five against the wind. These tests must be made with full load, i.e., fuel and oil for four hours' flight, two passengers weighing together 350 lb=., and wireless, &c, equipment. The machine will be required to turn in a circle of 400 yards diameter, make a spiral ascent to 1,500 ft., and to glide from a height of 500 ft. a horizontal distance of 2,500 ft. The machine must also be capable of riding out a 20-mile breeze on open water with engine stopped. 76S
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