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Engine noise control involves well-known methods and procedures, and the methods applied successfully to automotive situations can be applied with equal success to nonautomotive equipment. Three case histories are given in which a problem is solved with existing standard equipment by exerting control at the source, along the transmission path, and to the receiver.

The mechanism of structural noise in internal combustion engines is defined, and its abatement is considered. Structural noise is shown to dominate the other sources of engine noise at high frequencies. The abatement of engine structural noise by employing the fundamentals of isolating high-frequency vibrations, reducing the radiation efficiency of finite panels, and damping resonant vibrations is discussed.

The current and future regulation of product noise levels required by federal, state, and local authority has been surveyed. Probable effects on product design are presented and discussed, with consideration given to specific problems such as: cost/benefit; enforcement, noise-monitoring networks; lead time; technological feasibility; and design concept changes. All these problems are present and must be considered in any coordinated approach to product noise control.

Presented in this paper is a discussion of the details of the General Motors air cushion restraint system and of specific technical problems of system development and of implementing a production build program. The details of the General Motors system include a description of the components of the driver's and front passenger's systems, crash sensing, and “variable inflation.” The discussion of specific technical problems includes performance considerations; such as: Occupant rebound, child-size occupants, out-of-position occupants, non-barrier type crashes, and the function of the appearance cover. Also included is a discussion of the toxicity potential, noise risk, sensor development, reliability considerations, and field service requirements.

The Association PEUGEOT-RENAULT has explored several paths, technological as well as theoretical, regarding deployable methods of restraint. The first work was carried out using various kinds of American-made devices. At the same time, the Association PEUGEOT-RENAULT is actively participating in the development of French devices. This communication explains the present stage of these technological solutions, analyzes the performances obtained, and allows comparison of the latter with those obtained using seat belts.

This paper summarizes the work done on air bag systems under Volkswagen's restraint system development program. The paper first presents theoretical considerations, both generally and then specifically applied to small cars. Based on this, some typical design parameters for the Volkswagen air bag systems are given. Then, sensor considerations and various air bag system concepts and configurations are discussed. The solutions chosen for the VW are presented, followed by some typical test data from sled tests and full scale crash tests. It is also pointed out that acceptable small-car systems cannot be expected simply by scaling down large car systems, mainly because of the differences in vehicle deceleration characteristics and passenger compartment layout between large and small cars.

Many anxieties have been generated concerning the introduction of an air cushion passive restraint system in automobiles for a variety of reasons; but, one of the most prevalent anxieties stems from the common lack of understanding relative to the functioning characteristics and safety of the inflator which is to contain some quantity of pyrotechnic material - this inflator becoming a permanent fixture in the passenger compartment of the vehicle. This presentation discusses in understandable detail the physical and functional characteristics of the basic pyrotechnically augmented inflator and how each of its major components contribute to form a controllable system which can be varied to meet various systems demands. It further discusses a proposed marriage of inflator and sensor in a system totally restricted from functioning by any other mode than the properly prescribedcrash energy signature.

Part I of this paper discusses a computer model of a hybrid air cushion inflator which models existing systems to a high degree of accuracy. Gas generator size and ballistic properties, stored gas composition, storage pressure, volume, temperature, and receiving tank parameters can be varied to accurately predict the effects of system changes on inflator performance. In Part II, an approach for analytically obtaining equations of motion for torsos during contact with gas cushions in frontal collisions and subsequent ride-down characteristics is developed. From these equations, calculations of torso “g” forces, cushion pressures and other system parameters can be made. It is then possible to optimize these parameters in terms of desired torso response under a variety of design criteria as a guide to system design and experimental verification.

The initial air cushion research by Ford and suppliers has primarily involved full-sized cars. Technical approaches for these cars in packaging, kinematics, sensing and deployment are presented. Also, efforts to meet the requirements of the potential restraint standard as well as to resolve “real world” problems are discussed.

One of the sub-systems of air bag passive restraint systems presently under examination for automotive application is the energy source sub-system. The function of the energy source is to provide, release, and control a volume of gas at a rapid rate to inflate the air bag. Three basic types of energy sources will be described, these being stored gas, generated gas, and hybrid sources. Both liquid cooled and gas cooled hybrid sources are mentioned. The automotive requirements for application of energy sources are discussed in terms of performance objectives for passive restraints, particularly for front seat passenger air bags. The requirements include minimum package size and weight, ability to perform in hot and cold as well as normal environments, freedom from degradation during the service life, high reliability, controlled toxicity and heat, and ability for safe disposal during vehicle recycling. Two new types of inflation systems which are to improve versatility are mentioned.

Development of reliable, low-cost inflators without toxic exhaust products is the key to successful inflatable occupant restraint systems. The characteristics and performance of gas generators and aspirator inflators are presented, together with cushion gas characteristics. Toxicity considerations, including both gaseous and aerosol constituents, are discussed. Results indicate that inflators can be produced that will meet stringent, yet realistic, toxicity requirements. The feasibility of the aspirator inflator has been established, and this unique device offers distinct and significant advantages over conventional direct inflation devices.

Gas generators for filling auto air cushions have been developed in several compact sizes and configurations. All-solid chemical-generating compositions have been developed to give nearly pure nitrogen gas. Other compositions developed give mainly carbon dioxide. Gas cushions ranging in size from 1-12 ft3 have been inflated. Deployment time, bag temperature, and sound level are within safe limits. Toxicity tests have been performed on dogs without harmful effects being observed.

Electroforming produces close tolerance and nonporous tools, and offers savings in time and investment in capital equipment. Tools made by electroforming are not as limited as tools of high-temperature plastic construction which, because of repeated heat cycling, have reduced accuracy after long use. Tools fabricated from aluminum stock can be economically produced only if the shape, contours, and curves can be achieved by rolling, braking, or welding the aluminum stock. Hand finishing operations are expensive and time-consuming.

The need for adequate reciprocating-engine installation data is discussed. Techniques for obtaining reliable installation data and methods for their application to assure efficient, minimum drag installation design is presented. Aircraft performance gains to be expected from improved engine cooling characteristics are included. The testing was performed on a Lycoming TIGO-541-GIAD, a 6-cyl, horizontally opposed, aftercooled engine rated at 450 bhp with operational capability beyond 30,000 ft.

A design analysis is carried out to compare the performance of a telescoping wing airplane with a fixed-wing type. The increase in wing weight required by the telescoping wing is taken into account. Marked improvement in range performance is obtained with the telescoping wing. Optimum design values of cruise velocity are obtained for each landing speed. A preliminary design of an 8-place turbofan amphibian aircraft is carried out to show the relation of component weights to a fixed-wing design. Performance of the example aircraft is marginal.

STOL aircraft obtain their unique performance by incorporating in their design any one or all of three design aspects: increase of the powerplant size to minimize the weight-tothrust ratio, increase of the wing area to reduce the wing loading, and/or increase of the maximum obtainable lift coefficient. A special powered STOL light aircraft wing has been developed at West Virginia University. This wing combines several STOL features such as: circulation control through blowing around a circular trailing edge, boundary layer control through suction, leading edge modification and slats, 20% increase in chord length in the STOL mode, blown and drooped ailerons, and fences for maximum spanwise lift distribution. This wing was designed at West Virginia University and is based on the results of theoretical analysis and wind tunnel tests of several other configurations. The wing has been built and is to be test flown in spring 1973 on a light aircraft called the Technology Demonstrator.

The NASA Flight Research Center awarded a contract to Astronautics Corp. of America to develop a low-cost flight director system for general aviation. The system that was designed is expected to cost the consumer less than $3000-a reduction of nearly 70% in the total cost of available systems. The features that permit lower cost without excessive degradation in performance are: use of belt drives, high-volume-production standard parts, single-box construction including gyros, and post-plate construction techniques.

The history of aeronautical research efforts within NACA/NASA is briefly traced to identify the foundation for the current NASA general aviation technology programs. Future program trends are discussed in general terms emphasizing relevance to the industry requirements. An appendix summarizes the research reports that have been generated under the current program.

Stall/spin airplane accidents result in a significant number of fatalities each year within the general-aviation community. The most effective method of reducing this type of accident is to prevent airplane stalls. The device described in this report has been shown to be effective in preventing stall of a Piper PA-18, 150 airplane, and it should also be effective on other airplanes. The system incorporates a small spoiler mounted on the under surface of the stabilizer near the elevator hinge line. The spoiler is deployed automatically by means of a servo system that receives its commands from an angle of attack sensor mounting in the wing leading edge. Thus, the operation of the system is independent of pilot reactions. The spoiler deploys to limit tail power near the wing stall angle of attack, thereby preventing the wing from reaching the angle of attack required for stalling.

The present paper discusses the NASA Langley Research Center stall/spin research program to improve the design and the evaluation techniques relative to stall/spin characteristics of general-aviation aircraft. The program encompasses model wind-tunnel tests, spin-tunnel and radio-control model tests, and full-scale airplane spin tests. Initial spin-tunnel results on models with several tail designs representative of light airplanes and several testing techniques are discussed.