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Show W LBlfMOIOfi, SIT IT IS Tho new Liberty engine which our government has fathered has remained re-mained as a closed book to the ma jority of the American people. That It was a twelvo-cylinder motor of tho V type and developed in tho neighborhood neighbor-hood of 450 horsepower, is all the information in-formation we have had concerning it. Concerning further details of the engine however, the war department now authorizes the following statement: state-ment: The designs of the parts of the Liberty Lib-erty engine were based on the follow Ing: Cylinders Tho designers of the cylinders for the Liberty engine followed fol-lowed tho practice used In tho Gor man Mercedes, English Rolls-Royco. French Lorralne-LIotrich and Italian Isotta Fraschinl before tho war and during tho war. Tho cylinders aro made of steel Inner shells surrounded by pressed steel waterjackets. Tho Packard company, by long experiment, had developed a method of applying these steel waterjackets. The valve cages are drop forglngs welded into the cyylinder head. The principal doparturo from European practice is In the location of the holding-down flange, which Is several inches above the mouth of the cyl der, and tho unique method of manu facturo evolved by tho Ford company. The output Is now approximately 1700 cylinder forgings per day. Camshaft anu vaivo mechanism above cylinder heads Tho design of tho above is based on tho Mercedes, but was improved for automatic lubrication lubri-cation without -wasting oil by the Packard Motor Car company. Camshaft drive The camshaft drive was copied almost eritirely from the Hall-Scott motor; in fact, several of, the gears used in tho first sample on- ' glues wero supplied by tho Hall -Scott Motor Car company. This type of drive is used by Mercedes, Hispano-Suiza Hispano-Suiza and others. Anglo between cylinders In the Liberty the included angle between the J cylinders Is 45 degrees; in al other existing twelve-cylinder engines it is CO degrees. This feature is now with the Liberty engine, and was ndopted for the purpose of bringing each row of cylinders nearer the vortical and closer together, so as to save width and head resistance. By tho nnrrow angle greater strength is given to the crnnk-ca80 and vibration is reduced. Electric generator and Ignition A Dolco Ignition system is U3cd. It was I especially designed for the Liberty engine en-gine to save weight and to meet the special conditions due to firing twelve cylinders with an Included angle of 45 degreotj. Pistons The pistons of tho Liberty Lib-erty eugino aro of Hall-Scott design. Connecting rods Forked or straddle-typo connecting rods, first used on tho French Do Dion car and on tho Cadillac motor car ln this country, are used. Crankshaft Crankshaft design followed fol-lowed tho standard twelve-cylinder practice, except as to Oiling. Crank-case Crank-case follows standard practice. The 45 degree angle and the flange location loca-tion on the cylinders made possible a very strong box section. Lubrication Tho first system of lubrication followed the German practice prac-tice of using one pump to keep the crank-case empty, delivering into an outside reservoir, and another pump to forco oil under pressure tothe main crank -shaft bearings. Tins lubrication lubrica-tion system also followed the German practico ln allowing the overflow in tho main bearings to travel out tho face of the crank cheeks to a scupper which collected this excess for crank-pin crank-pin lubrication. This is very economical economi-cal ln the use of oil, and is still the standard German practice. 1 The present system is similar to the first practice, except that tho oil while' under pressure, is not only fed to main bearings, but through aolea inside of tho crank cheeks to crank pins through scuppers. Tho difference between the two oiling systems consists con-sists of carrying oil for the crank pins through a hole inside the crank instead in-stead of up the outside face of the crank cheek. Propeller hub The Hall-Scott propeller pro-peller hub design was adapted to tho power of the Libcrtyengine. Water pump The Packard typo of water pump was adapted to the Lib-er'.y. Lib-er'.y. Carburetor A carburetor was developed de-veloped by the Zenith company for he Liberty engine. Bore and stroke of the Liberty engine en-gine is 55 by 7 inches, the samo as the Hall -Scott A -55 and A-7 engines, and as in tho Hall-Scott twolvc-cyliader engine. Remarks Tho idea of developing Liberty engines or 4, G, S and 12-cylinders 12-cylinders with the above characterics, was first thought of, about May 25, 191?. The idea was developed in conference con-ference with representatives of tho British and French missions. May 2S j to June 1, and was submitted in ihj form of sketches at a joint meeting of the aircraft (production) board end the joint army and navy technical board, June 4. Tho first sample was an eight -cylinder model, dellvorod to the bureau of standards July 3, 1917. Tho eight-cylinder model, however, wao never put into production, as advices ad-vices from France indicated that demands de-mands for increased power would make the eight-cylinder model obsolete obso-lete before it could be produced. Work was then concentrated on the 12 -cylinder engine, and one of tho experimental ex-perimental engines passed tho 50 -hour test August 255. 1917. After tho preliminary drawings were made, engineers from the leading engine en-gine builders were brought to tho bureau bu-reau of standards, where they inspected inspect-ed the new design and made suggestions, sugges-tions, most of which were incorporate in the final design. At the samo time export production men were making suggestions that would facilitate pro-ducion. pro-ducion. The Liberty 12 -cylinder engine passed tho 50-hour test, showing, as tho official report of August 25, 1917, records, "that tho fundamental construction con-struction is such that very satisfactory service with a long life anr high order of efficiency will be given by this new power plant, and that tho design has passed from the experimental stage into tho field of p"roven engines." An engine committee was organized organiz-ed Informally, consisting of tho engineers en-gineers and production managers of the Packard. Ford, Cadillac Lincoln, Marmon and Trego companies. This committee met at frequent Intervals, and It Is to this group of men that the final development of the Liberty, engine is largely due. |
