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SINCE “mass production” cannot be defined, our problem is to design for any specific quantity. To determine the suitability of the design for the quantity, a cost criterion is proposed. An examination of cost factors and the distribution of costs at various quantities shows the relative importance of each, so that our production design effort may be better directed. The principles of design producibility are shown to be directed toward minimizing our tooling and manufacturing problem. A detailed study of the material and assembly problems attempts to set forth the more exacting requirements of new design trends. A set of principles is set forth as a guide for more realistic production design effort. The principles emphasize the necessity for staying within the design, material, tooling, and manufacturing limitations of any organization, in other words, employ only “sure-fire design” practices.

A REVIEW of fatigue information as it applies to life expectancy calculations for aircraft is presented here. The author shows that the number of factors and the lack of data, as well as of a definite theory, make it impossible to do more than make a reasonable guess of life expectancy. He concludes that repeated load tests still [ILLEGIBLE] to be the most satisfactory method of [ILLEGIBLE] a safe life expectancy.

The paper discusses the general lubrication problems associated with operation of high-output aircraft engines. Since the paper is concerned with two types of aircraft engines, namely, turbine and reciprocating, a natural division into two parts is made. Part I deals with the problems of turbine engines, and part II deals with the problems of reciprocating engines. In part I it is indicated that the choice of a lubricant is very difficult for the turbine engine particularly, because of the wide temperature range (from -67°F to approximately 400° F). Two solutions to the problem of proper choice of a lubricant are discussed, namely (1) the use of supplemental lubricants, and (2) the use of additive lubricants. Data are presented on supplemental lubricants including the various oxides of iron, molybdenum disulfide and graphite.

THIS survey of psychological research in the field of reading aircraft and other instruments shows that the majority of serious errors cannot be eliminated by mere improvements in visibility, such as could be obtained by increases in size or illumination. Rather, it is said, we must find methods of indication that actually simplify the interpretational processes interposed between the seeing of an instrument and the making of an appropriate control action. For instance, it appears that most errors in the reading of such instruments as the altimeter can be eliminated by the use of a single-pointer instrument with a counter to indicate the number of revolutions of the pointer.

A realistic appraisal of the problem shows, the author says, that space travel is not just around the corner. He points out that we will most certainly have to await the development of high-velocity rockets with very low weights, which will be difficult to attain. Space travel will come, he feels, by the gradual process of developing better sounding rockets, longer-range rocket missiles, and eventually satellite vehicles. These last will be the first embryonic space vehicles. Only when this experience lies behind us does he believe that we will be in a position to consider the construction of a full-fledged spaceship capable of leaving the gravitational dominance of the earth.

A THOROUGH study of the problem has convinced the authors that preignition causes more aircraft-engine failures than detonation does. It has also brought them to the conclusion that the spark plug is the most common cause of this phenomenon, the combustion-chamber deposits the second cause, and the exhaust valve the least common cause.

TESTS conducted on a full-scale aircraft engine show that satisfactory engine operation can be obtained at warmed-up conditions with low-volatility fuels of the safety type. The engine used in the tests was modified for direct cylinder fuel injection, as fuels of this type are not sufficently volatile to be satisfactorily vaporized by means of a carburetor induction system. Knock-limited performance, specific fuel consumption, and oil dilution characteristics were studied in these tests.

THIS paper outlines a method for obtaining the performance of a gas turbine powerplant with a variable exhaust nozzle, based upon a graphical process for matching the turbine and compressor. The method is general in that it may be employed for all operating points at any altitude and speed. The deviations from the ideal static sea-level operation are determined on an h-s diagram from increments of entropy produced by pressure losses through the system and by pressure gains due to velocity.

DATA exist now for the design of heated wings on a fundamental wet-air basis. The design method takes into consideration three factors: 1. Meteorological and flight conditions. 2. Area of water impingement, and rate and distribution of impingement. 3. Rate of evaporation. All of the water intercepted by a wing which is to be heated only in the leading-edge region must be dispersed by evaporation. The design method provides for determining the heat required and the extent of heated area needed to evaporate the intercepted water.

DESCRIBED here is an intake metering injection system suitable for low-horsepower aircraft engines. Gasoline injection is said to have many advantages over carburetion for this class of engines, such as: 1. Complete elimination of manifold icing-one of the most troublesome problems in light engines equipped with carburetors. 2. Better idling characteristics. 3. Faster engine acceleration. 4. Lower maximum cylinder-head temperatures. 5. Better fuel economy. 6. Higher power. 7. Longer periods between overhauls. 8. Simplified engine cooling. 9. Flatter engine designs are possible.

DESIGN of stable turboprop control systems is greatly speeded up by the WAC electronic analog. This computing device simulates the physical relationship between the five prime variables involved: speed, torque, temperature, fuel flow, and propeller blade angle. Although as many as 25 design characteristics may be involved in a control system, the analog can determine the optimum values for them in the course of one day. The analog computing technique might be equally valuable in a number of other uses.

THIS discussion of the problems encountered in designing the installation for the TG-180 in the P-84 Thunderjet is presented in the hope that other engineers designing installations for other turbojets may benefit from Republic's experiences. Problems discussed include provision for quick engine replacement; reduction of losses in the long inlet duct; development of a strong, tight joint for the tail pipe and engine; choice of thermal protection for the fuselage; provision for adjusting tail pipe area; and design of the fuel system. Several suggestions are made for improving the design of the engine from the installation standpoint.

TEST results on the Allison V-1710 exhaust-turbine compounded reciprocating aircraft engine showed that compounding markedly increased power output and, at the same time, decreased specific fuel consumption. One compounded engine, the Allison Model V-1710-E27, was built and tested. Compounding boosted power from 1200 to 1530 bhp at 30,000 ft and 3200 rpm. Despite the promising test results on compounding, development was dropped. It was felt that the engineering manpower needed to develop a turbine capable of withstanding maximum exhaust-gas temperatures would be better employed on turboprop development.