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This paper deals with the development of a steel spar/epoxy-glass envelope rotor blade for the Sud-Aviation SA-330 helicopter. It presents the reasons for this selection of materials instead of some of the more advanced fibers. It also points out how and why a transition into boron or carbon fibers might be made in a later version of the same blade.

Studies of the potential for minimization of structural weight in large launch vehicles of the future through the use of composite materials are described. Previous structural weight minimization techniques for composites are reviewed and extended. Typical structural efficiency charts are presented. Significant weight saving through the application of an efficiently stiffened composite structure is demonstrated.

Weight-critical design involves closer than usual tolerances. Precision machine shop tolerances are usually impractical in a production shop. However, combinations of present techniques, along with some new innovations, result in further reduction of redundant weight. Tolerance optimization, probability of structural integrity and higher than usual rejection rates of detail parts are involved in design tradeoff. Manufacturing philosophy is critical, making “machine-it-to-nominal-and-above” passé. Weight incentive programs, coupled with close supervision, can be made to be successful. The engineer must consider all aspects of rejection rate/weight/strength/time/cost, if his design is to be successful.

Increased air travel and new larger capacity aircraft, along with their planned counterpart super terminals, are demanding new terminal luggage handling systems. The airlines, at a time when their revenues are up and profits down, are looking for cost reduction in their ground handling operations. Airport planners, in attempting to handle the anticipated passenger loads, provide the airlines with efficient terminals, and at the same time make it easier for passengers to negotiate the terminals, are looking for new high speed automated luggage handling systems. The concept of placing luggage in individual containers that can be coded and directed around the terminals at high speeds is a viable answer to future luggage handling, offering the ability to completely automate air terminal luggage handling, adequately handling peak loads, while at the same time providing added passenger convenience.

An automated transportation system has been developed which can be used efficiently for both passenger and commodity transportation. It is particularly adaptable to short-run applications, such as between a remotely located parking lot and an airline terminal building. Preprogrammed stops are selected by the passengers by means of a push button within the vehicle. The system can be programmed at several levels of operation to accommodate varying predicted load requirements.

In examining forward area air cargo systems, this paper compares externally loaded helicopters with ground transport, fixed wing, and high speed VTOL. The operation at Khe Sanh, Vietnam is used as an illustration. There is a need for a series of helicopters of various sizes -- compatible with other transport systems, and designed for standard intermodal cargo containers. The need is being partly filled at present. From present experience, future designs are projected. To exploit the full potential of this new supply concept, however, involves more than the air vehicle itself. Aerial resupply capability at the retail level will depend ultimately on load sizes and shapes, delivery frequency, number of delivery personnel, locations of forward area supply centers, fixed wing-rotary wing transfer systems, and upon the force available to protect delivery routes. When the forward area aerial resupply system is in full use, logistics problems will no longer restrict Army mobility.

Cost effective design does not allow for rejection of spacecraft hardware because it cannot be inspected adequately. An actual example of an uninspectable part is presented together with its impact. The rationale of the design-inspection interface is discussed. Some of the influences this interface can have, if not one of complete understanding and cooperation, are: part uninspectable, part costly to inspect, inspection results subject to interpretation, parts cannot be tested nondestructively, part rejection because out of tolerance, part failure, and no accessibility for inspection.

The technological requirements and the development program required in producing a spacecraft have significant effects on the manufacturing operations of an aerospace corporation, particularly when there is no prospect of follow-on production. The spacecraft’s internal and external environment considerations, weight controls, reliability, traceability, and limited production are reviewed with respect to their influence on manufacturing costs, schedules, operations, skill levels, and training requirements. The importance of visibility into, and control of, day-to-day operations is highlighted. Some salient management problems that result from the spasmodic nature of the development program are discussed.

The purpose of this paper is to emphasize the need for accessibility in the assembly and maintenance of spacecraft. This is especially pertinent because accessibility to subsystems for replacement, repair, and maintenance has proven to be one of the more costly phases of preflight preparation. The most successful programs in this day and age have been when the design and manufacturing engineers work side by side around a mockup where solutions to the problems can be visually seen and solved, keeping in mind the assembly as related to accessibility. Therefore, it will be shown that in order to overcome the difficulties, designers should adapt a hard, fast ground rule that each unit must be accessible and individually removable without disturbing the other units.

Two large anesthetized chimpanzees were exposed to −150 Gx (“eyeballs out”). Both were restrained by contour supports of synthetic foam material. Both survived the experience with minor injuries, demonstrating the increased tolerance to impact provided by whole body restraint systems.

A program for investigating frontal force accidents has been underway for approximately 2 years at Wayne State University. It differs from most investigations in that each accident was analyzed in detail. Accidents in which the cause of injury could not be accurately ascertained were eliminated. Thus, a limited number of cases were investigated in detail rather than depending on statistics from a large number of accidents. It was necessary to establish a comprehensive scale for the detailed investigations because available rating scales did not provide fine enough injury increments. A degree of injury scale has been devised which can be modified as new data on injury are acquired. The scale ranges from very minor injuries to fatalities with the following six major categories of injury in increasing order of severity: minor, moderate, moderate-severe, severe,critical, fatal. Each category has several subdivisions with a detailed description of each.

A knowledge of the state of the physical properties of cadaver material is important if such material is utilized for impact studies. Experiments were designed to evaluate changes in elastic and strength properties of bone in the experimental animal in the course of its transition from live to recent death to embalmed conditions. Results indicate less than 5% change from the live to the fresh condition. In progressing to the embalmed wet condition variable degrees of stiffening are observed averaging around 8%. Drying of embalmed bone further increases stiffness about 24% and remoistening reconstitutes some of the initial flexibility.

Three human male cadaver heads were statically loaded along anteroposterior, posterioanterior, side to side, and vertex to base lines of action, while simultaneously measuring skull deflections at four or five locations and intracranial volume changes. Volume changes due to loading along the long (A-P) axis were small and either increased or decreased, while loads transverse to the A-P axis decreased the volume. Transverse loads produced volume changes on the order of 10 times larger than those due to A-P forces. Two skulls loaded to fracture in the A-P direction, failed at 1150 and 2200 lb, respectively, into the right orbit. These magnitudes and linear fracture direction correspond to four fractures produced by impact to the frontal bone of intact cadavers in previous work.

The objective of designing vehicle structure to minimize restrained occupant responses to multicar collisions requires a detailed study of all elements of the vehicle-occupant system. Two mathematical models, an 8 deg of freedom three-dimensional occupant and a 1500 deg of freedom vehicle structure, have been developed to allow such a detailed investigation. How these two models may be combined into a total system is described, along with initial validation efforts. The validations of the occupant model and the vehicle structure model will be supported by static load tests and two-car vehicle crash data for the particular case of side impact. Validation of the models merely establishes the feasibility of the approach, which is the principal conclusion to be derived from the analytical development to this point.

Forces necessary for fracture under localized loading have been obtained experimentally for a number of regions of the head. Three of these, the frontal, temporoparietal, and zygomatic, have been studied in sufficient detail to establish that the tolerances are relatively independent of impulse duration, in contrast with the tolerance of the brain to closed-skull injury. Significantly lower average strength has been found for the female bone structure. Other regions reported upon more briefly are mandible, maxilla, and the laryngotracheal cartilages of the neck. Pressure distribution has been measured over the impact area, which has been 1 sq in. in these tests, and the relationship between applied force as measured and as predicted from a head accelerometer is examined.

Various modes of head support systems were studied in conjunction with optimum body containment by exposing guinea pigs to abrupt deceleration in the ±Gx orientations. Nonsurvivability and the incidence of cerebral hemorrhage were used as indexes of impact tolerance. The effects of impacts up to 600 G were studied at entrance velocities of 40, 60, and 80 ft/sec. The head support system evolved from a thin, flat pad of resilient foam to a contoured, nonresilient foam support. As the head support system improved there was a general increase in survivability and a decrease in the incidence of cerebral hemorrhage until high G levels were reached where no additional protection seemed achievable.

The types and mechanisms of head injury are reviewed, and then the findings of a UCLA study on the electrophysiology of primate concussion is presented. It was found that g loadings, as measured by a triaxial accelerometer attached to the skull of an impacted monkey, correlated well with severity of concussion. Deep and superficial cerebral electrodes were implanted to monitor electroencephalographic and impedance changes after concussion. Resistance dropped and capacitance rose in the impedance electrodes in direct proportion to the severity of concussion. Deep electroencephalographic recordings showed a high amplitude low frequency charfge in the reticular formation areas after impact. Superficial electroencephalographic recordings did not correlate with clinical states. Applications of these data are presented as they relate to the prevention and treatment of head injury.

The new high-safety glazing is superior to that currently in use. The total thickness is reduced by half, which results in greater lightness, flexibility, and reduction of the effects of inertia. It offers very high resistance to rupture and penetration caused by external impacts by small projectiles and even repeated impacts. In the event of breakage by these exterior impacts, total visibility is maintained. In the event of internal shocks of light or moderate energy, the high resistance to rupture combined with light inertia and great flexibility means that the human tolerance limit is never reached. When these internal shocks are of high energy, progressive deceleration and considerably heightened resistance to penetration is evident, compared to the high-impact sheeting of ordinary thick glass as prescribed by USAS Z26.1. The danger of cuts is practically eliminated and the guillotine effect is totally eliminated.

The exchange of energy between bodies involved in an impact depends upon the elastic properties of the bodies and, owing to the sequence of the dynamic reaction during the impact, upon the shape of the impact bodies. In the case of ball and plate, the conditions in this respect are extreme ones. With regard to the forces of reaction caused by the impact of a passenger against the fastened windshield, the different reactions of the various types of safety glass have to be taken into account. In particular, the forces of reaction and the reaction times occurring must remain within human tolerance limits. New windshield systems are presented which take into account the human tolerance values of the cervical spine.

A versatile acceleration facility is described which accelerates and decelerates a sled or a modified automobile on its own wheels. The same propulsion and snubber systems are used for both the sled and the vehicle configurations with less than an hour required between runs. Accelerations and decelerations up to 60 g, velocities up to 60 mph, onsets of 200-2000 g/sec, acceleration distances up to 10 ft and deceleration distances up to 6 ft are available with excellent reproducibility. Extensive safety features for the operating personnel are provided.