I-FILE Cq£Y I i t"0 0 -. - -- -- NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS REPORT No. 471 PERFORMANCE OF A FUEL-INJECTION SPARK-IGNITION ENGINE USING A HYDROGENATED SAFETY FUEL By OSCAR W. SCHEY and ALFRED W. YOUNG 1933 For sale by the Superintendent of Documents, Washington, D.C. - - _ _ - - - • • - • • Price 5 cents AERONAUTICAL SYMBOLS 1. FUNDAMENTAL AND DERIVED UNITS Metric English Symbol Unit Symbol Unit Symbol Length ______ _ l meter _________________ _ m foot (or mile) ________ _ ft. (or mi.) Timc ________ _ t second __ __ ____________ _ s second (or hour) ______ _ sec. (or hr.) Force _______ _ F weight of 1 kilogrnm _____ _ kg weight of 1 pound _____ _ lb. PoweL _ _ _ _ _ _ _ P kg./m/s _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ horscpoweL _________ _ hp. S d {km/h__________________ k.p.h. mi./hr. ______________ _ m.p.h. pee -------- ---------- m/s____________________ m .p.s. ft./scc. ______________ _ f.p .s. 2. GENERAL SYMBOLS, ETC. W, Weight = mg mP, Moment of inertia (indicate axis of the g, Standard acceleration of gravity = 9.80665 radius of gyration k, by proper sub­ m/s2 = 32.1740 ft./sec.2 script). s, Area. m, Mass = W g S"" Wing area, etc. p, Density (mass per unit volume). G, Gap. Standard density of dry air, 0.12497 (kg-m-4 b, Span. S2) at 15° C. and 760 mrn=0.002378 C, Chord. 2 ,Ob.-ft.-4 sec. ). b2 Specific weight of "standard" air, 1.2255 S' Aspect ratio. 3 3 kg/m =0.07651Ib./ft. • jJ., Coefficient of viscosity. 3. AERODYNAMICAL SYMBOLS 17, True air speed. Q, Resultant moment. n, Resultant angular velocity. q, Dynamic (or impact) pressure = ~ pP. Vl p-' Reynolds Number, where l is a linear L, Lift, absolute coefficient OL=:S J1. dimension. e. g., for a model airfoil 3 in. chord, 100 D, Drag, absolute coefficient OD= ~ mi./hr. normal pressure, at 15° C., the corresponding number is 234,000; Profile drag, absolute coefficient Do, ODO=~S or for a model of 10 em chord 40 mis, the corresponding number is 274,000. Dt, Induced drag, absolute coefficient ODt=~S 0 11 , Center of pressure coefficient (ratio of distance of c. p. from leading edge to D p , Parasite drag, absolute coefficient OD = ~S 1l chord length). 0, Cross-wind force, absolute coefficient o a, Angle of attack. OC=qS E, Angle of downwash. R, Resultant force. a o, Angle of attack, infinite aspect ratio. '/,"" Angle of setting of wings (relative to at, Angle of attack, induced. thrust line). a D, Angle of attack, absolute. '/,,, Angle of stabilizer setting (relative to (M easured from zero lift position.) thrust line). 'Y Flight path angle. - REPORT No. 471 PERFORMANCE OF A FUEL-INJECTION SPARK-IGNITION ENGINE USING A HYDROGENATED SAFETY FUEL By OSCAR W. SCHEY and ALFRED W. YOUNG Langley M emorial Aeronautical Laboratory 725-33 1 -~--~-------------.-~ - --.-- ~ .. NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS NAVY B lLDlNG, WASHINGTON, D .C. (An independent Government establishment, created by act of Congress approved March 3, 1915, for the super,ision and direction of thescienlifie study of the pr blorns of flight. Its membership was increased to 15 by act approyed 1arch 2, 1929 (Public, No. 908, 70th Congress) . It consists of members who are appointed by the President, all of whom serve as such without compensation.) JOSEPH S. A~!E S , Ph.D., Chairman, Presid ent, J ohns Hopkins University, Baltimore, Md. DA ID W . TAYLOl1, D. Eng., Vice Chairman, Washington, D.C. CHARLES G. ABBOT, c.D., Secretary, Smith onian Institution, \Yashington, D.C. LYMAN J. BRIG GS, Ph.D., Director, Bureau of tandards, Washington, D.C. ARTHUR B. COOK, Captain, United tate avy, As istant Chief, Bureau of Aeronautics, avy D partment, Washington, D.C. WILLIAM F. D URA 'D, Ph.D., Professor Emeritus of Mechanical Engineering, Stanford University, California. BEN.JAMI D. Fo LOIS, Major General, United States Army, Chief of Air Corps, War D epartment, Washington, D .C. HARRY F. GUG GENHEIJII, M.A., P ort Washington, Long Island, ew York. ERNEST J. KING, R ear Admiral, United tates avy, Chief, Bur a u of Aeronautics, Navy Department, Washington, D.C. CHARLES A. LINDBERGH, LL.D., ew York City. WILLIAM P. MA CRACKEN, Jr., Ph.B., Wa hington, D.C. CH..... RLES F. MARYlN, c. D., Chief, United tates Weather Bureau, Washington, D.C. HE 'RY C. PRATT, Brigadier General, nited States Army. Chief, MatCriel Division, Air Corp, Wright Field, Dayton, Ohio. EDWARD P. WARNER, M.S., Editor "Aviation," New York City. ORVILLE WRIGHT, c.D., D ayton, Ohio. GEORGE W. LEWI S, Director of Aeronautical Research. JOHN F. VICTORY, Secretary. HENRY J . E. REID, Engineer in Charge, Langley Al emorial Aeronautical Laboratory, Langley Field. Va. JOHN J. IDE, Technical A ssistant in Europe, Paris, France. EXECUTIVE COMMITTEE JOSEPH S. AMES, Chairman. DA\,ID IV. TAYLOH, Vice Chairman. CHARLES G. ABBOT. WILLIAM P. MA CCRA CKE N, Jr. LYMAN J. BRIGG S. CHARLES F . M ARVIN. ARTHUR B. COOK. HE RY C. PRATT. BENJAMIN D. FOULOIS. EDWARD P . WARNEll. ERNEST J. KING. ORVILLE WRIGHT. CHARLES A. LINDBERG ll. JOHN F. VICTORY, Secretary. 2 REPORT No. 471 PERFORMANCE OF A FUEL-INJECTION SPARK-IGNITION ENGINE USING A HYDROGENATED SAFETY FUEL By OSCAR W. SCHEY and ALFRED W. You G SUMMARY In France, Sabatier has reported an investigation on This report presents the perjormance oj (L single­ the u e of fuels having flash points of 100° F. and 77° cylinder test engine using a hydrogenated sajety juel. F ., obtained from coal-tar and petroleum derivative, The sajety juel has a flash point oj 1.~5° F. (Cleveland respectively (reference 1). The commercial usc of open-cup method)) which i high enough to remove mo t these fuels was restricted, if not entirely prevented, oj the fire hazard, and an octane number oj 95, which by their poor performance a compared with gasoline: permit higher compression mtio to be u eel than are the power was reduced, the fuel consumption was permissible with mo t undoped gasolines. The juel increased, starting was difficult, and increased heating was injected into the engine cylinder, except jor a few of the carburetor was nece ary. comparative runs with gasoline, when a carburetor wa The ational Advisory Committee for Aeronautics used. The te ts were made with compression mtio. oj has conducted tests with sarety fuel manufactured 5.85 and 7.0, valve timings giving 30° and 130° overlap, by the hydrogenation process (reference 2). Bec3,use inlet pressures jrom atmospheric to 6 inches oj mercury of the low volatility of the fuel it has been injected boost, and engine speeds jrom 1,250 to 2,200 r.p.m. into the engine cylinder instead of being introduced Under imilar conditions the power obtained with the through a carburetor. The first fuel investigated had sajety juel was the same as that obtwined with gasoline, a flash point of 137° F. as determined by the Cleve­ whereas the juel consumption wa jrom 5 to 10 percent land open-cup method. The fuil-throttle power higher. With a compression mtio oj 7.0, a valve overlap obtained with tIus fuel was lower than with gasoline, oj 130 crankshajt degrees, and a boost pressure oj 2 and the fuel consumption was con iderably higher. inches oj meTcury, the sajety juel gave a brake mean The second fuel tested had a flash point of 115° F. effective pressure oj 175 pounds per squcu'e inch with a With this fuel the power was as high as that with juel consumption oj 0.50 pound per brake horsepower gasoline, but the fuel consumption was from 25 to 30 hour. percent higher (reference 3). INTRODUCTION The results obtained from an investigation con­ The importance of replacing gasoline with a fuel ducted with a third fuel, which had a flash point of that would reduce or eliminate the fire hazard in air­ 125° F., are presented in this report. The object of craft has long been recognized. The use of gasoline this investigation was to detel'nune the performance is a fire hazard because inflammable vapors are given obtained with a spark-ignition engine when operating with a hydrogena,tecl safety fuel injected into the off in nearly all climates and seasons. Aviation ga 0- line has a flash point of abou t - 30° F. Those engine cylinder. As a basis for comparison the per­ acquainted with the problem of fire prevention in air­ formance was obta,ined for several comparable condi­ planes agree that the highly inflammable gasoline tions with gasoline. The tests were conducted at should be replaced by a fuel having a higher flash Langley Field, Va., in D ecember 1932 and January 1933. point, preferably over 105° F. as determined by the APPARATUS AND METHOD closed-cup method. One of the advantages of the compression-ignition Figure 1 hows the set-up of the test equipment. A engine is that it uses a fuel of such a high flash point single-cylinder 4- trok.e-cycle water-cooled test engine (approximately 175° F.) that no inflammable vapors of 5}~ -inch bore and G-inch stroke was used. The en­ are given off even in the warmest climate. Aircl'aft­ gine could be operated with either a fuel-injection engine operators, however, have con idered the advan­ system or a carburetor. A commercial fuel-injection tage of reducing thc fire hazard by u ing compre sion­ pump was driven from the engine crankshaft through ignition engines to be insufficient to off et the dis­ a reduction gear which permitted the phase of the in­ advantage of the decreased power per unit of weight jection to be changed at will.