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Aviation History
1931
1931 - 0690.PDF
'FLIGHT, JULY 3. 1931 BRISTOL "JUPITER'S" 300 HOURS' FLIGHT TEST FOLLOWING upon the series of 100 hours' full-throttlebench tests carried out on the geared " F " typeBristol "Jupiter" engines, the Bristol AeroplaneCompany, Ltd., decided to submit one of their standard 490 b.h.p. Jupiter XI.F. engines to an extendedendurance flight test in order to demonstrate the reliability, smooth running and economy of these engines under flightconditions. For the purpose of the test, a standard engine, selected by the Air Ministry, was installed in the Bristoltype 109 machine, a large single-engined biplane of 50 feet span, and designed to carry a maximum all-up weight of9,000 lb. In view of the amount of information to be obtainedfrom a test of this nature, if carried out under strict supervision, the control of the test was undertaken by theRoyal Aircraft Establishment. The machine was stationed at Farnborough, and throughout the test was flown byRoyal Air Force pilots nominated by the Air Ministry. As a check on the possible replacement of components,the engine was sealed by officials of the Aeronautical Inspection Directorate in numerous places. The aircraft was delivered to the Royal Aircraft Estab-lishment on September 12, 1930, and flying was carried out daily on all possible occasions in periods varying from2 to 12 hours, as circumstances of weather and personnel permitted. Throughout the test, apart from taking off andlanding, the machine was flown at a constant throttle setting giving 90 m.p.h. and 1,850 r.p.m., under whichconditions the power output of the engine was approxi- mately 350 b.h.p. 300 hours' flying time was completed in the followingMarch, and during this time the only seals broken were on a magneto, after 232 hours, in order to replace a defectiveautomatic timing coupling (not of Bristol manufacture), and to replace a set of valve rocker gear and details, dueto a broken tie rod. Throughout the test the engine ran smoothly and well,both when cruising and at full throttle, standard Shell aviation petrol, without the addition of dope or benzole,and a standard grade of Shell mineral oil were used exclu- sively, the average fuel consumption working out at 20.6gallons per hour, and the oil consumption 6.9 pints per hour. This fuel consumption may be regarded as excep-tionally low, especially as the condition of the cylinders and valves at the end of the test gave no indication ofinjury from running in too weak a mixture. At the end of the 300 hours the aeroplane was handedover to the R.A.E. Experimental Flying Department for Certificate of Airworthiness trials, and was then flown backto Bristol, where the engine was removed for calibration, prior to stripping and detailed examination. The calibration tests on the Froude dynar.ometerrevealed that the engine had maintained its power output exceptionally well, the full-throttle power at norma; r.p.mbeing within 2 per cent, of that developed by the engine prior to the 300 hours' flight test. This ability to main-tain power after long periods of running is characteristic of Jupiter engines, and in this case was demonstratedmost satisfactorily. Finally, the seals were removed and the engine wasstripped for inspection under A.I.D. supervision. It was found to be in very satisfactory condition, with the mini-mum of wear on the major components and a marked freedom from gumming up of piston rings. The Bristol Aeroplane Company, Ltd., desire to acknow-ledge their indebtedness to the Air Ministry, to the stag at the Royal Aircraft Establishment, and to SquadronLeader W. S. Caster, M.C., the pilot responsible for flying the machine. Despite the large amount of work always inhand at the R.A.E., the 300 hours' test was carried through in short time, and considerable credit is due to allconcerned. The Bristol Jupiter XI F, 300 Hours' Flight Test Average WearComponent. during Test. Cylinder bore 0-0026Piston 0 0014 Gudgeon-pin diameter .. .. . . 0 • 0005Small-end bush bore 0 0006 Wrist-pin diameter . . . . . . 0 • 0007Wrrist-pin bush bore 0-0005 Crank-pin diameter .. .. .. 0-001Big-end bush bore 0-001 Big-end bush, outside diameter .. Nil. Master rod liner bore . . . . . . 0 • 0007 Cam-sleeve bush bore . . . . . . Nil.Crankshaft sleeve . . . . . . Nil. Eccentric gear bore 0-0001Eccentric floating bush, degrees diameter Nil. Eccentric floating bush bore . . . . Nil.Eccentric, outside diameter . . . . Nil. Crankshaft tail bearing . . . . . . Nil. Propeller-shaft arms 0-0001Bevel-pinion bushes . . . . . . 0 • 0003 Exhaust-valve stems 0 • 0007 Inlet-valve stems 0-0004Exhaust-valve guides 0-0032 Inlet-valve guides 0-0017The general condition of the engine was excellent. As shown in the above table, the amount of wear was in HO case sufficient to require replacement. o AT BUCKINGHAM PALACE •JNT Investiture was held by His Majeaty the Kingat Buckingham Palace on June 25." Amongst those present were Air Marshal Sir E. Ellington(Principal Air Aide-de-Camp) and Group Captain E. Robertson (Aide-de-Camp in Waiting). The followingwere amongst those introduced into the presence of the King, who invested 'Jiem with the Insignia of the respec-tive Divisions of tile Orders into which they have been admitted: — _ Order of the Bath . "r~ • "-'•' ' Military Division. Knight Grand Cross :—Air Chief Marshal Sir JohnSalmond. Received the honour of Knighthood, Knight Com-mander:—Air Vice-Marshal Charles Lambe. . ... Order of the British Empire Military Division. Commander :—Wing Commander William Shorten,R.A.F. Officers:—Squadron Leader George Law, R.A.F., andFlight Lieutenant Herbert Heslop, R.A.F. Members :—Flight Lieutenant Frederick Bishop, R.A.F.,and Sergeant-Major Glendor Marshall, R.A.F. His Majesty then conferred Decorations as follow : — Air Force Cross Squadron Leader Hubert Penderel, R.A.F., Flight Lieutenant James Addams, R.A.F., and Flight Lieutenant Gilbert Nicholetts, R.A.F. Royal Red Cross ASSOCIATES:—Miss Esther Hunter, Princess Mary'sR.A.F. Nursing Service, and Miss Dorothy Mansell Princess Mary's R.A F. Nursing Service. :: Albert Medal Henry Leech, in recognition of his gallantry whei.tiie Airship R.101 was wrecked near Beauvais or, October 5, 1930. Despite terrifying experiences in extri-cating himself from the blazing wreckage, Mr. Leech immediately, at grave risk, re-entered the burning massand succeeded in disentangling a companion from the network of red-hot girders and hauled him into safetyhimself sustaining burns in the process 644
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