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Aviation History
1911
1911 - 0024.PDF
l/Q<EL] JANUARY 14, 1911. Tabulated Results of the Trials. The first u*e in the table gives the figures laid down in the regulations for the competition. A.—Endurance tests. M "** H 1 K 5 d D. 0 — </> <*. 0 • 0 . fc 1 0 y •— a igh i) e 0 — rt £ So ".2 — g 6 S Is c 5 a- H a — O o ^3 M 1. v ~1 a v *s -a as ?! O 11 H s.8. P. s*i V f-i -C (L If 111II, e = > v a j£ g-8. ~. *> C U *~* 9 o -*J B »H.:*s. e a> a. •. Da . 3 SO J3 • B A Mji ? O •- B &i S ,> Sfl B 2^0 Wolseley M Humber Green Remarks h. m. 24 0 3 * 17 41 11 32 24 0 3 0 7 1 1 h. in. 0 30 0 0 2 18 0 2 0 10 h. <m. — 3 2 «s 23 11 30 i 23 5° 1 lbs. 24s 242 234 219 ft. lb. units. 1-17 0-13 o-6i 026 1,445 1,420 1,230 1,212 35 36-2 ?4'8 37-8 3i'5 lbs. 32-0 32-0 35-8 38-0 lbs. 60 40-0 16-7 30 lbs. 0-632 0-613 o-553 0-503 lbs. 0-082 0-115 0-251 0282 lbs. 453'2 457-2 472-9 431-6 lbs. 7 6-69 6-95 6-i8 6-96 12-52 I3-I4 12-51 13-71 Humber engine : 12J pints of oil added 7 hours after commencement of test, and 50 pints after 8 hours. Green engine : 42 pints of oil added 17 hours after commencement of test, and 21 pints after 22 hours. Note.— The petrol was supplied to the laboratory by Messrs. Carless, Capel and Leonard, and was described as their standard petrol of S.G. -700. Some notes as to the possible causes of the fluctuations occurring are given with the diagrams. These are taken from the test sheets and represent the view taken by the observer at the time, but it the oil-way to live pin was blocked up, and, further, the gudgeon- pin had moved sideways and was rubbing against the sides of the cylinder. B.—Maximum brake horse-power developed on run of seven minutes. Speed— Engine. Duration. B.I I. P. revs, per Remarks. min. Green ... 7 mins. 36-4 1,390 The following readings were obtained with throttle fully open :— Speed. B.H.P. i,295 35-o i,35o 35-8 1,390 36-2 1,470 37"i C.—Test of engine with moment of 50 ft.-lbs. applied to crank-shaft in a vertical plane, to represent the gyroscopic action of the propeller in steering. Engine. Duration. Remarks. Green ... 3 mins. No apparent effect on speed or torque. D.—Trials run with the axis of the shaft inclined at an angle of 150 to the horizontal. Engine. Conditions. Dura- Remarks. tion. f In these tests the power was absorbed by a water-cooled rope brake. The • H. P. developed was approximately 18 in each test. The engine ran quite smoothly in both trials. w 3 P«TENTS S« £n —^ : tmmt . .. . llreen Propeller end up Propeller end down 1 hr. 1 hr. Ease of starting. No starting devices were supplied to any o( the engines sent in, so that for the purpose of starting the engines the dynamo was connected to the laboratory mains and used as a motor. There was no difficulty in starting any of the engines tested, and they may be said to be equally good in this respect. Security against fire. Wolseley.—Nothing in design and construction to find fault with in this respect. No leak or accumulation of petrol observed. Humber.—Reasonable security against fire. No leak or accumu lation of petrol observed. Green.—Reasonable security against fire. Radiator mounted on wood strips. No leak or accumulation of petrol observed. Air resistance. Wohelty.—Aiv resistance somewhat high, due to honeycomb form of radiator. Humber.—Air resistance high, due to abnormal size of radiator. Grtm.—Air resistance low, due to excellent design and distri bution of radiator surfaces oblique to air current. The Autographic Records of the Speed and Torque during the 24 Hours* Trials. In the case of the Green and Humber engines, at the speeds at which the trials were made, there was more vibration of the torque pen than in the case of the Wolseley engine, which ran at a higher speed. This should be taken into account in interpreting the •diagrams. 24 Speed and torque records of Green engine. must not be assumed that in every case the supposed cause was the true or only cause of the variations. The notes are reproduced in the hope that they may be of some assistance in the interpretation of the records. The field of the generator was excited from the bus bars of the Laboratory, which were occasionally subject to changes in voltage due to throwing off machines. A few momentary fluctuations on the speed and torque curves due to this cause will be found on the diagrams, and are indicated in the notes. A line is drawn on each diagram to indicate the value of the torque, at the mean speed, corresponding to 35-h.p. Description of the Testing Plant. Under the conditions of the competition the motors were to be tested with open exhaust, and in an air current moving at approxi mately 30 miles an hour relative to the engines. The principal test was an endurance test of 24 hours' continuous running at 35-b.h.p., so that considerable care was necessary to ensure that the appliances required for producing the air current, transmitting and absorbing the power, and for measuring the torque and speed should be capable of continuous working for a run of this magnitude. The motor under test was erected on rails in a galvanised iron testing box 7 ft. by 6 ft. by 6 ft. high, one side of which communi cated with the 4 ft. by 4 ft. air duct containing the fan, and the
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