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A three-engine, two-fan arrangement for an advanced vertical and short takeoff and landing (V/STOL) lift/cruise multimission aircraft has many advantages. With three engines, sufficient engine-out thrust is available for safe operation, over the range of multimission emergency landing requirements. The flexibility offered by being able to shut down one engine for loiter and cruise results in a fuel-conserving aircraft. The capability to add the power of the third engine provides a high-speed vehicle when the mission requires. A two-fan system with fans under each wing provides for smooth transition from vertical flight to forward flight and return. Minimum-distance STOL performance is achievable because all of the thrust is available to accelerate the aircraft during the takeoff ground roll and to interact with the wing during climbout.. In shaft-driven systems, clutching horsepower can be drastically reduced or eliminated. Fans can be made interchangeable.

A two-engine, three-fan V/STOL airplane was designed to fulfill naval operational missions. Use of interconnected variable pitch fans led to a good balance between the requirements for high thrust and responsive control at low speed, and efficient thrust at cruise speeds. Engine-out requirements, integration of propulsion and aerodynamic controls, and the propulsion installation were the major factors influencing the configuration. An airplane with a multimission capability from both vertical and short takeoff was conceived.

Lift Fan Multimission V/STOL aircraft provide new capabilities which could revolutionize Naval and Marine aviation but the design concept as well as the design philosophy must be carefully selected. Since the propulsion system is the crux of any V/STOL aircraft this is of primary importance followed by secondary design considerations such as fuselage sizing to accommodate the multimission requirements.

The smoke production of aircraft gas turbine engines is currently characterized by the SAE smoke number and, to a lesser extent, the exhaust transmittance. Quantitative relationships are developed between these characterizations and the optical properties of the engine smoke particles for use in subsequent visibility calculations. These optical properties are the particulate mass concentration and the specific projected particle extinction area. The SAE smoke number is both the most common smoke characterization and the one farthest removed from optical properties. The inherent stained filter technique is first treated in general, then specifically in terms of the SAE requirements. A relation between the smoke number and the optical properties is achieved. It is shown that the SAE interpolation procedure is unsuitable at low smoke numbers, and an alternative procedure is suggested.

The rapid and dramatic growth of aviation over the past several decades is a matter of history with which we are all quite familiar. Integral to that growth has been the mushrooming progress in powerplant technology which, by necessity, is the lead factor in the development of aircraft systems. This paper highlights some of the major milestones that have influenced the course of developments in gas turbine powerplants. It traces its origins in work done on turbosuperchargers, with discussion of the stimuli and shifts in requirements that resulted in various types of jet engines leading up to today's high-bypass turbofans. The natural quest to fly higher, faster and further has reached a point of relative maturity in technology so that today's efforts can now be directed more towards improvements in efficiency, reliability and ecological consciousness. The future holds new challenges. It calls for new ways to control the spiraling costs of development and production of powerplants.

This paper presents the results of a design study of a low cost Jet Fuel Starter (JFS). The JFS is a small free turbine turboshaft engine with a peak output of 150 horsepower. The design concentrates on high output per unit volume and weight, and on low cost. A low speed, four stage axial compressor design results in a compact, lightweight starter. Die castings and a radial pin construction for both the static structure and the compressor rotor provide the most significant cost savings over conventional gas turbine fabrication methods. The low speed concentric shaft design (approximately 70 percent of usual design practice) permits a simple two bearing shaft suspension for both rotors. The resulting close coupling of the turbines reduces the number of expensive hot end components to only five parts.

An Aerodynamic Torque Converter (ATC) which operates as a high speed coupling device between a single shaft auxiliary power unit (APU) and the accessory loads has been designed and built, and is in the latter stages of its testing program. The ATC operates at APU speeds and temperatures while maintaining favorable power-to-weight and power-to-volume ratios.

An automatic takeoff and landing system has been developed for remotely piloted vehicles (RPV) operating from prepared runways. This system consists of a scanning beam microwave landing guidance system and a high performance flight control system. Interfaced with the automatic system is a remote operator, who, using a special control station, monitors system performance, evaluates approach quality and may remotely control the vehicle in the event of contingencies. This paper describes briefly the RPV Automatic Takeoff and Landing (Autoland) system development program: the design approach, simulation and flight test results, and conclusions.

By accurately reconstituting accidents whose parameters are well known from multidisciplinary accident investigation, it is possible to associate forces and accelerations values with injuries sustained by occupants involved in in-the-field accidents. In this study, two in-the-field accidents, their reconstruction conducted by using dummies as occupants, and their reconstruction then with human cadavers are analysed. These accidents reconstructions allow to associate and compare accident occupants injuries with acceleration forces, injuries criteria values measured on dummies, and, on the other hand, accelerations, injuries criteria values, injuries sustained by cadavers during the second accident reconstruction.

The head, chest and femurs of three Hybrid II dummies were impacted with a ballistic pendulum at various angles to determine what differences in accelerometer and femur load cell output would result for a constant energy input. Also evaluated were suspicious tension loads in the femur load cell output when the legs were subjected to obvious off-center impacts during crash tests. It was found that the dummy legs can be subjected to very high torsion and bending loads which can have a significant effect on the femur load cell axial load outputs.

Our aim is to show that today's safety standards (FMVSS 208, EC-Proposals) are inadequate in the present state to ensure optimum protection for belted passengers. These standards do not take into account motion sequence during impact. The postulated tolerance limits - HIC, SI, forward displacements etc. - cannot describe the dynamic behaviour adequately. We emphasize the importance of motion sequence to ensure optimum biomechanic conditions, because motion sequence is the necessary prerequisite for any discussion about biomechanical tolerance limits. First results of our current belt-accident investigations indicate that this is an important problem. By applying experience from crash tests and accident investigations, we try to define simple and well-controllable criteria for motion sequence.

Data on towaway accidents involving 1973- and 1974-model American passenger cars were collected according to a systematic sampling plan in order to measure 1974 restraint system performance. The data on 5,138 drivers and right front passengers were collected by three organizations: Calspan Corporation, Highway Safety Research Institute, and Southwest Research Institute. Analysis of the data showed that the 1974 ignition interlock system increased full restraint system usage by a factor of 10 over 1973 cars. The 1974 full restraint system (lap and upper-torso belts) also demonstrated a greater reduction in severe injuries (AIS≥2) than the 1973 lap-belt-only system. Paradoxically, little reduction in 1974-model severe injuries was found when the two model years were compared, although no attempt was made to control for confounding factors in the accident cases.

Injuries produced by standard three point restraint systems with retractors will be compared between cadavers in laboratory simulated collisions at 30 mph barrier equivalent speed and lap and shoulder belted front seat occupants in real world frontal collisions of '73-'75 full sized cars. Tests conducted at SwRI with belted, unembalmed, fresh cadavers have resulted in extremely severe thoracic and cervical injuries, including multiple rib fractures, fractures of the sternum, clavicle and cervical vertebrae. On the other hand, injury data from a national accident investigation study to evaluate the effectiveness of restraints in late model passenger cars indicates that such injuries in real world crashes of equivalent severity are not always observed. The reasons possible for these differences are discussed. Both programs at SwRI are funded by the National Highway Traffic Safety Administration.

Unembalmed cadavers restrained with a three point harness were exposed to a deceleration environment of 20, 30 and 40 mph BEV.* Injuries were tabulated from detailed autopsies. The results Indicate an AIS-1 injury at 25.5 mph, an AIS-2 injury at 31.5 mph and an AIS-3 injury at 34.5 mph. The AIS-3 injury level is recommended as the maximum acceptable injury. The cadavers sustained the same types of injury that have been reported in medical literature including bruises, abrasions, lacerations, fractures and viscera ruptures, but injury severities were greater in the cadavers than in living humans at a given collision severity. Also, there is a wide spread in the degree of injury between cadavers due to differences in age and physical condition. The threshold of cadaver rib fracture is 30 mph and the threshold of cadaver vertebral fracture is between 30 and 40 mph for the environment utilized. More numerous and severe abdominal injuries were observed.

The purpose of this paper is the comparison of the protection efficiency between three-point belt and air bag systems under various crash conditions. Dynamic tests have been performed with subcompact vehicles (Renault R 12) in which two dummies were restrained, either by three-point belts with load limiting devices, or by air bags consisting of solid gas generators and bags including porous outlets (the driver's knees were protected by a collapsable structure). Three types of crashes were chosen: frontal barrier crash at 50 km/h (13,9 m/s) head-on crash between two vehicles with overlap at 50 km/h (13,9 m/s) crash against a guardrail at 80 km/h (22 m/s) with 30° angle of incidence. The comparison drawn from commonly used biomechanical indices shows that the three-point belt ensures a protection in each analysed crash type but it should be improved in order to reduce head deceleration.

Occupant response to side-impact collisions is studied with a mathematical vehicle/occupant model, the MVMA Two-Dimensional Crash Victim Simulator. A primary goal is the investigation of head-torso relative motion and neck forces and moments. Computer simulations were performed in conjunction with a study on properties of the neck in lateral motion (not reported on here) involving 96 subjects. The subject pool consisted of six carefully defined population segments which represented young, middle-age, and elderly male and female adults of average stature. The side-impact simulations make use of much pertinent data resulting from the volunteer subject testing program, including head-neck lateral bend range of motion, sternomastoid muscle group strength, reflex time, and anthropometry.

This paper describes the injury relations which result when car-to-car crashes are analyzed using a computerized accident reconstruction procedure. The results of the study are presented in the form of graphical relations between injury severity and crash severity. Effects of factors such as impact location, seating position and vehicle weights are discussed. THIS PAPER EXPLORES the use of a relatively new tool for accident reconstruction - Simulation Model of Automobile Collisions (SMAC). The capability of this program to simulate a wide variety of crashes is described in detail elsewhere (1,2,3)*. This study is limited to the reconstruction of side impact collisions in which two passenger vehicles are involved. The need for redesigning vehicles based on an understanding of this crash condition is amply demonstrated by the fact that 28 percent of passenger car occupant fatalities and 41 percent of passenger car occupant injuries are caused by side impacts (4).

Currently used criteria based on functions of spinal acceleration obtained from crash test dummies are shown to be invalid indicators of chest injuries in blunt frontal impacts. Cadaver impact data are analyzed; and injury is found to be a statistically significant function of chest deflection, chest depth, and cadaver age at death. Based on the resulting regression equations, injury-limiting chest deflections are recommended for various size test dummies. The recommendations apply only to test dummies that have significant thoracic biofidelity for blunt frontal impact. They are valid for environments which include signigicant blunt frontal impact. Their extension to other environments has not been validated.

Tests were conducted to provide information on the mechanics of child restraint with a five-point harness system. For anatomical reasons, the juvenile chimpanzee was chosen as the best approximation to the human child. Sedated juvenile male chimpanzees withstood frontal deceleration tests in a five-point harness at crash speeds of 32.2, 40.2, and 48.3 km/h (20, 25, and 30 mph) without skeletal bone fractures or evidence of soft tissue injury. Injury assessment was by X-ray and blood serum enzyme analysis as well as ECG readings and post-test observations of the animals' behavior. While this animal model does not fully guarantee the identical performance of a five-point harness system with humans, these results support the opinion that the protection offered a child occupant in a five-point system is comparable to that available to adult passengers in conventional automotive restraint systems.

Our tests with fresh human cadavers were continued (cf. proceedings, 18th Stapp Car Crash Conference). Presented herewith are the results of 103 tests evaluated so far. While the severity of injuries showed an increase with advancing age, it is not obviously dependent upon weight or sex. Under the conditions chosen by us, the 12 to 30-year age group reached the thorax tolerance level at an impact velocity of still below 50 km/h with a stopping distance of 40 cm, the 30 to 50-year age group of below 40 km/h, and the age group beyond 50 years below 30 km/h. A comparison of our results with volunteer tests (Ewing et al., 29) and with evaluated real accidents (Patrick et al., 22) as well as with similar cadaver tests (Tarriere et al., 19) is made. When introducing safety testing regulations for vehicles in the light of dummy tests, the broad spectrum of the respective age groups has to be considered. The thorax injuries may be slightly mitigated due to a lessening of the surface pressure.