1964 NASA AUTHORIZATION TUESDAY, APRIL 2, 1963 HOUSE OF REPRESENTATIVES, COMMITTEE ON SCIENCE AND ASTRONAUTICS, SUBCOMMITTEE ON SPACE SCIENCES AND ADVANCED RESEARCH AND TECHNOLOGY, Washington, D.C. The subcommittee met, pursuant to adjournment, at 10 a.m., in room 304, Old House Office Building, Hon. Joseph E. Karth (chairman of the subcommittee) presiding. Mr. KARTH. The meeting will come to order. Dr. Bisplinghoff, I understand that today, Mr. Charles Zimmerman who is the Director of Aeronautical Research Division of your office would like to present a statement to the committee. I would like to suggest, as I did to you privately about 10 minutes ago, that Mr. Zimmerman give us a 10 or 15 minute summation of his prepared statement and then the members may have questions. The reason I suggest this is because I recall that on the aeronautical research section of your presentation we went into considerable detail. Dr. BISPLINGHOFF. Yes, sir. Mr. KARTH. There was a good deal of interest on the part of the subcommittee members, and I think, perhaps, they are fairly familiar with it. If there are no objections on the part of you or Mr. Zimmerman we will proceed in that way. Dr. BISPLINGHOFF. We will be glad to proceed in any way you see fit. Mr. KARTH. Mr. Zimmerman. STATEMENT OF CHARLES H. ZIMMERMAN, DIRECTOR OF AERONAUTICAL RESEARCH, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Mr. Chairman and members of the subcommittee, the NASA is conducting research in aeronautics with the following broad goals which are in accordance with the national interest and consistent with the policies set forth in the National Aeronautics and Space Act of 1958 and in the President's message on transportation of April 4, 1962. Our goals are to provide the research and advanced technology which will 1. Enable our aircraft industry to produce aircraft which will, to the greatest practicable extent, make the convenience and speed of air transportation available, and economically feasible; to the people of this country; 2. Enable our armed services, working with our industry, to develop military aircraft superior in performance, in utility, and in requirements for logistics and manpower support to those of any other country. In working toward these goals, we coordinate our efforts closely with the Federal Aviation Agency, the Department of Defense, and other government agencies. We maintain liaison with these agencies and with the aircraft manufacturers and their customers not only through personal contacts at all levels and numerous ad hoc groups and panels set up from time to time to deal with special problems, but also through a system of committees. Our aeronautical program is regularly reviewed, criticized and augmented by committees on aircraft_aerodynamics, operating problems, structures, and air-breathing propulsion. These committees are made up of qualified experts from the aircraft industry, the airlines, the Federal Aviation Agency, and the Department of Defense. Before going into a discussion of our program, I would like to make a few general comments. Aviation no longer offers the glamour and excitement which so strongly influenced its growth in its early years. We are not striving for speed and altitude records. Men have circled the Earth at orbital speeds. The X-15 has flown practically out of the atmosphere. Our objective now is transportation, economically feasible transportation for commercial purposes, militarily superior transportation for military purposes. I would like for you to consider our program as directed toward maintenance and enhancement of our leadership in air transportation. In order to assist you in your assessment of our program, I will discuss it in terms of four aircraft categories, as shown on figure 172, page 2074. 1. Conventional subsonic aircraft. 2. Supersonic aircraft. 3. Hypersonic aircraft. 4. Vertical and short take-off and landing aircraft. SUBSONIC AIRCRAFT There is a tendency to assume that, since our present jet transport aircraft operate across the continent and around the world with apparent ease, the problems associated with such aircraft have all been solved. This is far from true and one of the principal areas of research in the aeronautical program is directed toward aiding in the solution of some existing problems. Major problems include the provision of better flying and handling qualities, the alleviation of engine noise, the multiple aspects of flight safety, all-weather operations, and other environmental aspects and flight instrumentation accuracy. In addition, a reasonable level of research support is maintained to provide aerodynamic data which will make possible improvements in performance and efficiency in this speed range. Many continuing programs support the subsonic aircraft effort. Among these is the NASA VGH (V for velocity, G for acceleration, H for altitude) data collection program which has provided research information on operational practices and environmental parameters for several types of commercial turbine-powered transports. This information has provided a basis for assessing the adequacy of current design criteria and also a body of information applicable to the design of future transports. Current and projected programs are aimed at extending the scope of the measurements to cover new types of commercial transports, cargo airplanes and light airplanes in the personal category. The data to be obtained will provide statistical information on airspeed-operating practices, ground and flight loads experienced, and pertinent environmental parameters, such as the atmospheric turbulence encountered. The integration of this information into design criteria will result in improved and more efficient airplane structures and operating practices. In another program of great importance in the subsonic aircraft field, the NASA in late 1961 assisted the FAA in conducting full-scale tests to determine the drag on a jet transport operating on a runway covered with slush or standing water. Additional supporting tests were carried out at the NASA's Langley landing loads track. The slush drag problem and its importance can be visualized by figure 173, page 2075, where the effect of runway surface condition on aircraft stopping distance is illustrated. The results are for a large jet transport using basic data obtained from friction coefficients determined during the aforementioned FAA NASA slush-drag program. For a touchdown speed of 150 miles per hour, it is seen that this particular airplane requires 1,800 feet to stop on a dry runway, 2,800 feet on a wet runway and 4,800 feet on a runway covered with one-half inch of slush. Research on various types of landing gears and into basic means of improving braking under adverse conditions will be continued in fiscal year 1964 at the Langley track. An area of aircraft operations generally recognized as one of great potential danger, is the traversing of the wingtip vortex field of one aircraft by another. The CAB recently has attributed three fatal light-aircraft accidents which occurred in a 4-month period to such a probable cause. The NASA has done some experimental and theoretical work in this field which has pointed up the magnitude of the danger and offered some relatively simple operational procedures for pilots to follow. Somewhat less well recognized has been the potential danger to light aircraft traversing the vortex field generated by helicopters. Recent flight tests have been made with the results illustrated by figure 174, page 2076. The upper portion of the figure (which is not to scale) shows the tip vortex cones generated from the outer edges of a helicopter rotor disk and the flight path of the penetrating test airplane. As the test airplane gradually crossed the helicopter wake from 1,000 feet behind and 100 feet below, the airplane response was such as to cause it to roll violently first to the left and then to the right. These motions had to be counteracted by the use of full aileron control. In fact, as the lower portion of figure 174, page 2076, indicates, the stick was against the stop for a short period of time. If the test aircraft had been lighter or the weight of the helicopter greater, the maneuver would have been uncontrollable. The test program graphically demonstrated the dangers to light aircraft and resulted in a wide dissemination of cautionary advice to pilots. Studies in this area will be continued and assistance will be given to the FAA as further operational aspects are explored. The aircraft engine noise problem will be attacked on two fronts in fiscal year 1964: (a) an investigation of the noise source, i.e., the engine components, to obtain basic information to ferret out any engine-design techniques that might reduce engine noise, and (b) the investigation of operational techniques to move the source of the noise farther away from the people on the ground. Modifications are being made to the noise research facilities at Langley which will permit the evaluation of various means of reducing the noise from ducted fans and compressors and the correlation of these results with engine performance data. The noise generated by the ducted fan engines used by the modern jet transports is an important factor in community planning. To illustrate this, figure 175, page 2077, shows the noise level on the ground below an aircraft as it proceeds along an instrument landing approach path. It will be noted that even 5 miles out the level is 97 decibels, while within 1 mile of the touchdown point it has increased to 125 decibels. Any level above about 112 decibels can be considered as intolerable. If the approach angle can be raised to 15 degrees, there will be a noise decrease ranging from 24 decibels 5 miles out to 14 decibels 11⁄2 miles from touchdown. These are significant improvements since a 14-decibel decrease means that the noise intensity is 25 times lower and a 24-decibel change is equivalent to decreasing the noise intensity by a factor of 250. Figure 175, page 2077, has indicated the improvements which could be effected by using steep approach techniques. The development of such techniques applicable to V/STOL and transport aircraft for the purposes of noise abatement and also airspace conservation is part of the NASA aeronautical research program for fiscal year 1964. Present effort includes work with helicopters to represent V/STOL-type aircraft and a variety of fixed-wing aircraft. Future work is planned using a variable-stability fixed-wing aircraft to represent additional aircraft types including supersonic transport designs. SUPERSONIC AIRCRAFT Supersonic aircraft have advanced to the point where military fighter and bomber aircraft are currently in operational status; however, these aircraft are somewhat deficient with regard to range and endurance and are uneconomical to operate. Research must therefore be directed toward improving the state of the art in aerodynamics, structures, materials, and propulsion. Advancements in the state of the art will not only permit the improvement of existing aircraft but will also show the way to new advanced military and civil aircraft. In the military field significant achievements have recently been accomplished that effectively illustrate the value of a continuing fundamental research program. The research conducted by our research centers, and in particular the Langley Research Center since 1959 culminated recently when General Dynamics was selected to develop the variable-sweep F-111 biservice tactical fighter. We described some of our goals and work in this area last year, and I have here a model of one of the promising configurations we investigated. The F-111 will serve both the Air Force and Navy and will provide extreme versatility. This aircraft is a direct result of the NASA's aeronautical research program. When our research program in this area was initiated, there was no specific requirement for such an aircraft, since it was not realized that such versatility was possible. Now our effort in this area must turn to the problems of the specific F-111 design to assist the military in obtaining a vehicle to meet its mission requirements. In this regard our work in fiscal year 1964 will increase in this area to provide required information in sufficient depth of detail to assure that the military agencies acquire the best possible vehicle for the defense of the country. In the civil area, as part of the joint FAA/NASA/DOD national program of assistance to the industry for the development of a commercial supersonic transport airplane, the NASA role is to provide technical support and conduct the basic necessary research. For about 4 years, we have been engaged in applying our current technology to demonstrate the broad technical feasibility of an aircraft meeting anticipated requirements of the airlines, financial interests, and the public. A concentrated research effort involving the Ames, Langley, Lewis, and Flight Research Centers on the problems posed by the supersonic transport has brought this project to the stage where industry will very soon have sufficient information to choose among several design possibilities. When the designers' choices are narrowed, the NASA effort will concentrate on the problems related to the specific chosen design and research will necessarily increase in depth of detail in all technical areas. Many supersonic transport configurations have been investigated in the past 2 years. These investigations have allowed us to conclude that at least on the basis of wind-tunnel tests and analytical studies, four basic design concepts appear capable of providing the characteristics required of an efficient, economical, safe, and reliable supersonic transport aircraft. The four basic design concepts are shown in the next chart, figure R63-941. These four, the arrow-wing, two variable-sweep configurations, and the CanardDelta are currently under study by the aircraft industry to determine their practicability as design concepts and to define any problems in need of further research. The aerodynamic problem is to achieve cruise efficiency with adequate range and reasonable operating cost and still achieve good takeoff, landing, climb, A supersonic propulsion system which will meet the economic and reliability requirements of commercial aviation is not presently available. The next chart, figure 176, page 2082, illustrates types that appear to satisfy these requirements, the turbofan, the turbojet, and a composite engine. The problems associated |