FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1927
1927 - 0429.PDF
JUNE 16, 1927 The valve gear of the model J-5 is enclosed, thus preventing entrance of dust and dirt to the moving parts, as well as the blowing away of the lubricants from the bearing surfaces. The rocker arm has been generously increased in size, and has been provided with improved bearings and lubrication. The rocker arm roller has been enlarged, and is made of heat- resisting alloy steel, which reduces wear at this point. The valve clearance adjustment has been moved from the push rod, and is now incorporated in the rocker arm itself, where micrometer divisions provide an easy and convenient means of adjustment without the use of feelers. The push-rod ball end fits into an easily replaceable socket made of ball-bearing steel ; this socket in turn is housed in an adjusting seat screwed into the rocker arm end. The adjustment is locked in place by a suitable clamping screw on the end of the rocker arm. The push rods are made of nickel steel tubing, and are provided with ball ends, also of ball-bearing steel. These ball ends, and their sockets in the rocker arm, are twice the area of those on the model J-4B, giving a large increase in contact area. The connecting-rod assembly of the " Whirlwind " engine was described and illustrated in Mr. I.awrance's paper, and soon make their appearance, unless the engine is now as goodas it is humanly possible to make it ! Some Endurance and Overload Tests THE endurance tests on the model J-5 engine have been exceptionally severe. Three fifty-hour endurance tests have been run on this engine, in addition to approximately 100 hours of miscellaneous calibration and fuel-consumption tests. The first fifty-hour endurance test was run at 1,970 r.p.m. at full throttle, giving an average mean effective pressure of 121 lb./ sq. in. The average power developed during this test was 238 b.h.p., and the fuel consumption was -508 lb./h.p./hr. The second fifty-hour test was run at 1,827 r.p.m. at full throttle, and showed an average power of 216 b.h.p., with a fuel consumption averaging 0-458 lb./h.p./hr., and a M.E.P. of 119 lb./sq. in. The third fifty-hour endurance test was made with the object of determining the reliability of the engine under overload conditions. To this end an external supercharger was provided, arranged so as to force air into the carburettor. No other change was made in the engine itself. In spite of the fact that this test was carried out during the hottest part of the summer, with the air temperature averag- THE WRIGHT "WHIRLWIND " ENGINE: Front and back views of type J-5C and J-5CA. as far as we are able to discover, this has not been altered in the J-5 model. It consists of a master rod of H section, with link rods of tubular section. The model J-5 has also been provided with a new type of carburettor, which incorporates in a single unit three barrels supplied by a common float chamber, each barrel com- municating with three cylinders through a separate manifold. This arrangement results in improved distribution, and has had its effect on the lower fuel consumption of the engine. The average " best setting " full-throttle consumption of a large number of production engines varies from 0-49 to 0-51 lb./h.p./hr. Although the J-4 is a new model, improved modifications are already in existence. Thus the J-5C incorporates a piston of slightly different design from that used in the originalJ-5. The change permitted the use of a permanent mould in casting, and at the same time the compression ratio was altered, so as to allow of the use of a wider range of commercial petrol. In addition, the priming system of the J-5C now directs the raw fuel into the intake passages in the crank- case, thus eliminating the danger of washing the lubricant trom the cylinder walls. The changes between the models J-aC to J-5CA are of a very minor character. Fabric-covered rubber insulated ignition wire is used, and the two crankshaftr .011" bearings, are replaced by molybdenum steel ball bearings. l?01^ th 15CA i'blid b th ltt in. p y ythe 1-5C is'believed to be the latest version id'" dl ill f +i l?01"^ the 1-5C isbelieved to be the latest versiothe ' 'Whirlwind,'" although doubtless other models will ing 150° F. at the point of entrance to the carburettor, the engine ran 50 hours without difficulty, averaging 295 b.h.p. at 2,150 r.p.m., and;with a fuel consumption of 0-510 lb./h.p./hr. In May, 1927, the U.S. Navy completed a 100-hour non-stop run on a stock " Whirlwind " engine, the test being run continuously at full throttle, averaging 223 h.p., and a fuel consumption of 0-53 lbs. •'h.p./hr. and an oil consumption of 0-023 lb, 'h.p./hr. The " Whirlwind " engine fitted in the Bellanca monoplane which established a duration record of 51 hours 11 mins., had already been run for 179 hours 53 mins. During the record flight 3S5 gallons of petrol and 4-93 gallons of oil were used, corresponding to an hourly petrol consumption of 7-5 gallons and an oil consumption of rather less than a pint. Power Curves Concerning the power and propeller load curves given herewith, the makers of the Wright " Whirlwind " engine point out that these refer to the models J-5C and J-5CA, and that the curve marked " Full Throttle Power " shows the average maximum power at the speeds indicated. An individual engine may vary from two to three per cent, above or below this value. At the full rich setting of the mixture control, the fuel consumption at full throttle is indicated by the curve marked " Full Throttle Rich." The leanest position of the mixture control at which the engine turns maximum revolutions is 391
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
