THIS paper records the results obtained from operating medium-weight trucks on pneumatic tires, and points out the advantages and disadvantages experienced. An analysis is made of the claims advanced in support of the use of pneumatic tires. Certain items are specified which in the author's opinion require further development before a satisfactory solution can be reached.
THE objects to be obtained in testing tractors are listed, but field testing only is dealt with. Regardless of the attempt of the Society of Automotive Engineers to standardize the practice of drawbar horsepower rating of tractors, the practice followed by the industry is anything but uniform. Drawbar horsepower actually developed in tests at the 1918 National Power-Farming Demonstration, varied from 50 to 200 per cent of the rating. The need of more than 25 per cent reserve, as provided by S. A. E. Standard Practice, is argued. Drawbar pull is suggested as an important part of the rating. Rating of tractors by the number of plows pulled will not be satisfactory, owing to wide variation in soil conditions. To make satisfactory tests an accurate dynamometer is required. The Hyatt and Iowa instruments are described. The importance of care in making tests is emphasized. In the discussion, the Gulley and Giddings recording dynamometers are described.
ON the basis that it is impossible to state the case for either the airship or the heavier-than-air machine without some comparison of the two, the author discusses relatively features, points of merit or superiority and the fields of usefulness thus far disclosed in the rapid development of the craft. Progress since 1914 is outlined, a brief history to date is included and the way prepared for consideration of the possibilities of long-distance flight. A comparison of the features given emphasizes strongly the point that the airplane is mainly a high-speed, short-distance carrier, while the large rigid airship is essentially a medium-speed long-distance carrier. Each type has a distinct sphere of activity; the airship in transcontinental, transoceanic traffic; the airplane in feeding the terminals of the airship with passengers and, possibly, certain kinds of freight.
THE production of gasoline in this country could be increased through the following changes in refinery practice: (1) Universal adoption of a high “end-point,” or upper volatility limit for gasoline (2) General use of more efficient distillation methods and equipment (3) Recovery of gasoline now lost in refinery operation (4) Wider use of cracking processes Other possible methods of increase are not considered of sufficient importance to merit discussion in this connection. Some of the details of the four methods of increase are discussed and it is estimated on the basis of the evidence now at hand that the maximum percentage increases in production under the four heads listed are as follows: (1) 15 to 20 per cent; (2) 10 per cent; (3) 10 per cent, and (4) 100 per cent.
THE automotive industry is developing without due regard to the fuel situation. This situation is an integral part of the automotive field and should not be left out of account. Owing to the pressure of automotive demand, the supply of engine fuel is changing in character and price, with danger of precipitant alterations; there arises in consequence a fuel problem which cannot be adequately solved without the active participation of the automotive industry.
THE approaching exhaustion of the petroleum supply, from which nearly all of the available internal-combustion engine fuel is produced, raises two vital questions, upon the answers to which will depend the future of the automotive industry. These are (a) what fuels are to be available, from the point of view of the engine designer and (b) how much transportation can be secured from the fuel used. It is not certain that satisfactory engines can be developed to handle a wider range of fuels than those used at present. It is therefore not clear whether the trend of development will be toward two or more different grades of fuel, or toward a single mixed fuel to be used in all engines ultimately designed to burn it.
MEXICO achieved second place among the petroleum-producing nations of the world in 1918. This position will not soon be relinquished, judging from the study made by the author of the two general regions from which petroleum has thus far come. The Petroleum Commission of the Mexican Government has issued statistics covering the production by years since the industry started. It is confidently hoped that future production will continue, as indicated, to stop the gap, constantly increasing and critical, between production and consumption in the United States. A section of the paper is devoted to the export trade, especially with this country, which furnishes the nearest great market.
DURING the first two years of the war the author conducted in England experimental work for the British Government on the engine he describes. After brief mention of V-type water-cooled engines and the general situation as regards revolving air-cooled and radial water-cooled types, the discussion is narrowed to two distinct designs of fixed radial air-cooled engine, both of which have been tried out and seen some service. The fundamentals in which fixed radial air-cooled engines give promise of excelling are weight of powerplant per horsepower, the fuselage mounting and space required being duly considered; reliability and durability; fuel and oil consumed per horsepower-hour; streamline mounting, with armor, if desired; quick detachability of powerplant; accessibility, and freedom from certain inherent difficulties peculiar to water-cooled engines.