TABLE IV.-Number of authorized transmitters and estimated number of receivers, safety and special services, Jan. 1, 1949 TABLE V.-Number of broadcast stations and estimated aggregate original cost, as of Apr. 30, 1949 1 The cost data for FM and TV are estimated on the basis of $50,000 and $250,000 per station, respectively; for AM, the cost data are based on actual reported figures for 1,464 stations and an estimate for the remaining 521 stations on the basis of $50,000 per station. * Includes cost data applicable to stations authorized for noncommercial FM, remote pick-up, and studio transmitter link. Cost data estimates for stations authorized in the experimental TV, international, developmental, and facsimile services not available. NUMBER OF LICENSEES AND CONSTRUCTION PERMIT HOLDERS, SAFETY AND SPECIAL SERVICES, APR. 30, 1949 (ESTIMATED) NUMBER OF LICENSEES AND CONSTRUCTION PERMIT HOLDERS, SAFETY AND SPECIAL SERVICES, APR. 30, 1949 (ESTIMATED)-Continued Exclusive of the 19,000 shown above with private aircraft station licenses. 2 Exclusive of 10,000 broadcast employees. NUMBER OF AUTHORIZED STATIONS IN THE RADIO SERVICES Broadcast services: Service 100 45 15 2, 300 660 200 39, 765 80, 000 100 1 80, 000 2 364, 000 563, 865 Citizens service not organized until 1947 fiscal year. Experimental common carrier service not organized until 1947 fiscal year. TABLE 2. Data indicating work loads of Field Engineering and Monitoring Division TABLE 4.-Number of authorized stations in safety and special radio services (other 1940, actual.. 1947, actual. 1948, actual. than amateur and citizens) 9, 896 | 1949, estimated. 36, 544 1950, estimated. TABLE 5.-Growth of authorized stations in safety and special services 1 62, 745 84, 945 These tables are designed to show the growth in each of the separate services. No comparison should be made among services as to relative size because of the different scales used, and because station definitions are not comparable as among the different services. TABLE 6.-Number of authorized stations and transmitters in police radio service TABLE 7.-Television, frequency modulation, and standard broadcast services A. NUMBER OF AUTHORIZED STATIONS (ON JUNE 30) TABLE 8.-Number of authorized radio stations in common carrier TABLE 9.-Selected financial and operating data of communications common carriers (Estimated as of Dec. 31, 1948) $10, 000, 000, 000 $3, 000, 000, 000 $2,750, 000, 000 200, 000, 000 53, 000, 000, 000 2, 200, 000, 000 NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS CONTRIBUTIONS TO AVIATION 700, 000 Senator O'MAHONEY. The National Advisory Committee for Aeronautics has submitted information requested by the committee. It shall be inserted in the record at this point. (The information follows:) SOME NACA CONTRIBUTIONS TO THE PROGRESS OF AVIATION Since its establishment by act of Congress in 1915, the NACA has pioneered in scientific research on the problems of flight. NACA research has provided the major basis for virtually every improvement in airplane design. The continuing nature of the Committee's scientific research program is such as to make its results applicable to the solution of aeronautical problems generally, and so it is difficult to isolate these results in terms of specific achievements. Certain results, however, do lend themselves to assessment more easily than others and the following examples will illustrate the type of advancement that has been made possible through the Committee's efforts. The airfoil or cross-sectional shape of a wing, has been the subject of systematic research and has resulted in accepted NACA “families" of these shapes that are in use throughout the world. A product of this research was the NACA low-drag laminar-flow airfoil which cut the wind resistance of a wing in half. High lift devices which make it possible to land airplanes at safe speeds have been the subject of much NACA research. All such devices in use today have been completely or in part developed by the NACA. The famed NACA cowl, which made possible speed increases of 15 percent as early as 1928, was the result of an extensive investigation of means of reducing wind resistance of engines. The principles of the optimum location of engines in wings, and wing-fuselage filleting made attractive the use of the retractable landing gear. The combination of these three improvements at one time revolutionized the performance of aircraft the world over. As a part of the program to reduce airplane wind resistance, the NACA developed a flush riveting process that made smoother skin surfaces possible. This process furnished the basis for all commercial flush riveting processes in use today. The following figures are given as a graphic example of the success of NACA'sTM wartime efforts to reduce wind resistance of the airplane and so increase its speed: These improvements were accomplished through practical recommendations which could be carried out without affecting the prime structure or holding up production. When the number of airplanes is considered it is obvious that the dollar value of these improvements was tremendous. Every airplane in this country today has been designed on the basis of air loads research conducted by the NACA. NACA research on flying qualities or ease of flying an airplane has resulted in acceptance by the Army and Navy of NACA standards for these characteristics. As a result of research on design of airplane tails it is now possible to design an airplane that will not spin. NACA propellor research has resulted in increased efficiencies of commercial and military aircraft by 4 to 28 percent depending on the speed range encountered. Following is an illustration of what the 4 percent increase has meant to commercial aircraft in dollar value. These figures are based on the commercial fleet actually operating in January 1946. Due to added 4 percent in propeller efficiency extra revenue from added pay load_. Fuel cost saved____. Total annual gain... $8,780, 000 1, 942, 000 10, 722, 000 For comparative purposes, the total cost of the 5 years of research that resulted in these gains was about $2,500,000. The NACA has led the country in the application of thermal ice prevention systems wherein warm air is circulated through the wings and other parts of an airplane. The results of this research are currently being applied to such new transports as the Douglas DC-6, Martin 2-0-2, and Consolidated-Vultee 240. Structurally, the airplane has been improved until there is now seldom a failure that can be traced to structural design. Investigations to determine the most efficient type of construction have led to enormous dollar savings. For instance, a 1 percent weight reduction in a fleet of 500 commercial transports with an estimated life of 5 years would result in a saving of from $22,000,000 to $112,000,000. An NACA designed camera that will take 200,000 pictures per second has enabled the committee to lead the way in combustion research as applied to the reciprocating engine. NACA investigations of cylinder cooling determined the optimum fin shape and size for air-cooled engines. These data were supplied to the manufacture of these engines and made possible an increase in their output of almost 100 percent. The first controlled performance data to be obtained on a jet engine operating under altitude conditions were the results of NACA research. The NACA eight-stage axial-flow compressor which was designed and built in 1938 had the highest efficiency of any such unit at that time. Research on this compressor has served as a basis for later application of results to axialflow compressors for modern aircraft gas turbines. Research on centrifugal compressors during the war resulted in a gain of eight points in compressor performance. |