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Viewing 43621 to 43650 of 44195
1937-01-01
Technical Paper
370026
C. M. LARSON
Since the publication of the original Classification of Transmission and Rear Axle Lubricants back in 1931, evolution has seen the development of a most complicated and varied number of gear lubricant recommendations for the millions of cars now on our highways. Each year as new features are introduced, changes are made which affect gear lubricant requirements of the past. Yet nothing is done to revise car manufacturers' lubrication charts made up previously each year. A composite grouping of gear lubricants would simplify the servicing of cars on the road. At the present time, the service station attendant is required to follow with exactness lubrication charts for each and every make and model of car if he would keep the car owner out of trouble. On the other hand, the service station needs are best filled by the smallest number of grades required for proper servicing since large inventories and especially gear lubricant dispensing equipment (metered) are costly.
1937-01-01
Technical Paper
370032
T. B. Rendel
1937-01-01
Technical Paper
370034
Ivan L. Shogran
1937-01-01
Technical Paper
370033
Robert A. Plumb
1937-01-01
Technical Paper
370036
Melville F. Peters, H. Kendall King, John P. Boston
1937-01-01
Technical Paper
370037
Melville F. Peters, George F. Blackburn, Paul T. Hannen
1937-01-01
Technical Paper
370041
Walter E. Arnoldi
1937-01-01
Technical Paper
370062
F. M. YOUNG
1937-01-01
Technical Paper
370057
Pierre Schon
1937-01-01
Technical Paper
370075
E. B. DAILEY
1937-01-01
Technical Paper
370081
B. B. Bachman
1937-01-01
Technical Paper
370089
R. J. Kretz
1937-01-01
Technical Paper
370100
S. D. Heron, A. L. Beall
SUMMARY It is stated that in cases where cylinder distortion produces exhaust valve leakage, the problem of valve burning becomes one of considerable difficulty. A flexible exhaust valve seat, which apparently conforms to the valve and produces a tight seat even though the cylinder head be distorted, has been designed and tested. Apparently complete sealing of the valve was secured in a cylinder known to be subject to exhaust valve seat distortion. This result indicates that heat dissipation through the seat is not of major importance when a tight seal of the valve is secured. The use of flexible inserts may remove some present limitations on cylinder design.
1937-01-01
Technical Paper
370095
C. M. LARSON
With the increase in horsepower output per cubic inch displacement, gasoline and Diesel engines are more susceptible to ring sticking and piston ring or cylinder liner wear. Formerly crank case oil stability (how the used oil looked when drained after 50 hours or more operation in an engine) was considered of prime importance. It was thought that the tendency of mineral oils to cause ring sticking depended largely on the degree of refinement of the lubricating oil, but this has not proven to be the case with Diesel engines or with high output gasoline engines. Highly solvent treated oils have been shown to be deficient in lubricating value and ring sticking caused by excessive blowby has resulted. Such high output gasoline and Diesel engines will operate on straight mineral oils at reduced loads; but reduced cylinder wear, freedom from ring sticking and sludge reduction can be had only with proven addition agents.
1937-01-01
Technical Paper
370097
H. C. Edwards
1937-01-01
Technical Paper
370107
O. A. Axelson
1937-01-01
Technical Paper
370104
W. W. Lowther
1937-01-01
Technical Paper
370186
Harold E. Gray
THE general discussion presented in this paper includes shielded ignition systems, covering both high-tension and low-tension sides of the magneto, generators and generator control boxes, radio power units, motors for general service, and a résumé of airplane shielding and bonding practices.
1937-01-01
Technical Paper
370169
Arnold E. Biermann
THIS paper gives the results of an analysis made to determine the proportions of aluminum and steel fins to dissipate maximum quantities of heat for several pressure differences across a finned cylinder. The power required to force the cooling air between the fins and the relative weights of the various designs are presented. The calculation of the heat flow in the fins is based on an experimentally verified, theoretical equation and the surface heat-transfer coefficients and pressure differences were taken from previously reported experiments. In particular, the analysis concerns fin proportions for minimum pressure drop, minimum power, and minimum weight.
1937-01-01
Technical Paper
370154
Charles S. Moore, John H. Collins
ENGINE-TEST results are presented for simulated altitude conditions using a displacer-piston combustion-chamber on a 5-in. by 7-in. single-cylinder compression-ignition engine operating at 2000 r.p.m. Comparison between maximum performance at altitude of the compression-ignition engine and a carburetor engine showed that the compression-ignition engine had a slight power advantage for the same conditions of inlet air. However, if the carburetor air is heated to prevent icing, the compression-ignition engine inducting the colder and more dense air of altitude will have a decided advantage over the carburetor engine. Analysis of the results for which the inlet-air temperature and pressure were varied independently indicates that maximum engine performance cannot be corrected reliably either on an inlet-air-density or weight-of-air-charge basis. Maximum engine power increases with inlet-air pressure and decreases with temperature very nearly as straight lines.
1937-01-01
Technical Paper
370017
Henry C. Hill
1937-01-01
Technical Paper
370193
Donald H. Wood
RECENT work on cowlings for air-cooled engines has been characterized by the correlation of the cooling function of the cowl with the drag-reducing function into a rational design procedure, whereas earlier work was devoted largely to drag reduction and this was a cut-and-try proceeding. The fundamental relations between the pressures and velocities of the external and internal air flows are discussed here in their relation to the quantity of air available for cooling and the effect on drag. Experimental results are outlined, and a design procedure is indicated. It is pointed out that certain factors must be determined by the engine manufacturers in order that a rational design of cowl may be laid out. The shape of the cowling nose is not critical, and the part of the drag that is subject to control is determined by the air flow out the cowl exit. For an efficient cowling and for control of the air flow, the exit is the important part.
1937-01-01
Technical Paper
370177
George J. Mead
THE rapid increase in the size of our air transports, as well as the requirements for higher cruising speeds, forewarn of the need of powerplants of decidedly greater power. The further development of the existing standard types may be relied upon to ultimately provide at least 50 per cent greater output. There is, however, definite evidence now of the need of engines of even greater power in the period immediately ahead, which need has focused attention on other types in which additional displacement may be provided through the employment of a greater number of cylinders. Studies indicate that there is an opportunity of reducing the powerplant drag sufficiently to effect a saving in fuel at least as great as is promised by further improvement in specific consumption. For this reason the form and location of the new powerplants, as well as the method chosen for cooling them, will be dictated largely by the resulting effect on operating costs.
1937-01-01
Technical Paper
370179
A. T. Gregory
WITH engine outputs continually going up it is worthy to note that the in-line air-cooled engine possesses certain inherent characteristics which make it particularly suitable as an aircraft engine of high output. Satisfactory cooling of this type of engine has been obtained at higher rated specific outputs than have yet been achieved in any other kind of air-cooled engine. A type of valve gear can be used which, in addition to being suitable for high-speed operation, permits long periods of operation without the necessity for checking valve clearances. The lubrication of this type of engine appears to be less of a problem than that of the slower speed radials. Smoothness of operation and relative quietness at high speed not only afford comfort to pilots and passengers, but also affect favorably the life of both engine and airplane. The cowling of the in-line engine is relatively simple and permits excellent visibility, combined with the possibility of reduced drag.
1937-01-01
Technical Paper
370035
E. O. Cooper
1937-01-01
Technical Paper
370171
R. F. Gagg
THE objective in determining an engine rating is to establish the limiting values for the variables in operating procedure which permit a maximum of utility in power output and economy of fuel consistent with requirements for safety and durability in the class of service for which the engine in intended. The obvious safety requirement is that no interruptions to service shall occur due to engine trouble when operations are conducted in the manner established by the rating tests. This paper consists of a discussion of testing methods to be used for the determination of engine ratings, and some suggestions for the adoption of a uniform procedure. Standardization of engine-rating procedure is thoroughly in accord with the established policy of the American aircraft industry as a means of insuring a maximum of safety to air-transport passengers.
1937-01-01
Technical Paper
370161
Weldon Worth
THIS paper presents the problem of engine lubrication from an installation and operation standpoint with respect to starting, warm-up, and stabilized flight. It describes the manner in which these problems are solved by the latest Materiel Division lubrication system, with its oil dilution, hopper-type oil-tank, viscosity-control valve and jacketed oil coolers. It also analyzes the radiator drag and shows the magnitude of unnecessary radiator drag that may exist if the radiator is not properly designed and installed. The paper then presents a practical design method and shows a sample design calculation for a 1000-hp. engine.
1937-01-01
Technical Paper
370150
Du Bois, Val Cronstedt
RAPID development and widespread use of aircraft fuels of high knock rating make advisable a study of the best means of utilizing these fuels for high specific power output. The response of an hypothetical aircraft-engine cylinder to changes in supercharger compression ratio (boost) and cylinder compression ratio is developed theoretically and outlined by means of charts. The explosion pressures are calculated and the resulting information used to establish a criterion of cylinder performance. Results of some cylinder calibrations on high-octane fuels show the calculated relations to be fairly well established. The effects of (1) high mean effective pressures and (2) high crankshaft speeds on the detail design of the engine are analyzed. The conclusion is reached that, in order to obtain a balanced design of minimum weight for extremely high specific output, it is advisable to use both speed and high mean effective pressures.
1937-01-01
Technical Paper
370153
John M. Tyler
THE reduction of vibration in aircraft structures is becoming a major problem in aircraft design. The increasing emphasis placed on vibration studies is the result of three important influences: (1) the increased loading of the structures, (2) the broadening of the operating-speed range obtained with controllable propellers, and (3) an increase in demand for more passenger comfort. In the past structural vibrations have been given attention mainly because of the danger of failure. At present to obtain the required comfort, the vibration studies must be carried out to a much greater degree of refinement. The vibrations of the aircraft engine as a whole may set up vibrations of the whole airplane, but the vibrations of parts of the engine with respect to each other are not noticeable in the cabin; in fact, they are difficult to detect except by the use of special instruments.