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This paper describes the results of the first step of a planned development program to produce a family of split path hydro-mechanical transmissions for military applications. The HMT-250 hydromechanical transmission has given superior performance, unlimited ability to change ratio without affecting service life, and a control system with the advantages of variable ratio. The control system and testing programs are described in detail.

Previous studies had demonstrated the economic and technical feasibility of producing high-quality forgings for aircraft turbine engine parts from hot-isostatically pressed (HIP) Rene 95 powder billets. The present program was aimed at developing a production practice for making HIP + forged turbine discs. The major goal was improved product fabricability and reliability with minimum cost. The program was conducted using argon atomized Rene 95 powder. Experimental studies were conducted to evaluate the effect of powder characteristics, HIP parameters, preform design, and forging conditions on forgeability, microstructure, and mechanical properties. The results of these studies were incorporated into a pilot production run in which 10 disc forgings were made and evaluated. The selected process involved the consolidation of -60 mesh powder to full density by hot-isostatic pressing at a temperature above the γ' solvus temperature.

The advantages of infinitely variable ratio steering and propulsion for track laying vehicles are well known. Studies and demonstrator programs in the past decade have indicated that the hydromechanical transmission has the most promise of providing infinitely variable ratio for military vehicles. In 1966 the Army launched a program to develop the hydromechanical transmission to “production ready” status. This paper describes that program, the transmission selected, and some of the problems encountered in the transition from the demonstrator stage to one of readiness for military application.

THE CONCEPT of an electric motor mounted inside the rim of a large wheel provides several advantages: flexibility, weight and cost reductions, and adaptability to established operating and maintenance patterns. A heavy-duty traction motor drive has been designed that eliminates the need for mechanical drive lines, differentials, and hydraulic torque converters. This paper describes the gear train, lubrication system, brakes, and ventilation of such a drive. Also discussed is the engine-generator set for an electric wheel motor.*

Measurement of dimensional characteristics of airfoil parts is primarily a manual, labor intensive operation. It employs a wide variety of gages that vary from very expensive optical comparitors to inexpensive pin gages. An automatic non-contacting inspection gage capable of measuring most dimensional characteristics would be cost effective, simplify inspection operations, consolidate a number of gages into one, and improve overall inspection reliability by minimizing human involvement. This paper presents the results of the design and development of a demonstrator semi-automatic laser gage dimensional inspection system that addresses this problem.

If the labyrinth seal designer can first determine the nature, cause, and resolution of previous problems, he can then better judge what to do and how to do it for today's engines. The designer of long-life labyrinth seals is primarily interested in those design features and design criteria which have been substantiated by actual service experience. If the design features or criteria are too recent to have had significant service experience, component or factory engine tests may provide valuable substantiation.

A new silicone rubber formed-in-place gasketing concept has been developed which has greatly reduced the incidence of warranty oil leaks in engine and drive train components. This concept utilizes a combination of joint configuration and unique cured properties of the silicone formed-in-place gasketing material to achieve leak-free performance over the life of the component.

An acceleration of metal replacement to reinforce thermoplastic composites is positioned to impact the transportation markets through a joint venture between PPG Industries and GE Plastics, called AZDEL, Inc. The strength of both companies' strong technological base in glass and engineering thermoplastic resins is the key. The resulting long continuous glass thermoplastic composites have high strength to weight ratios, provide tough durable products, facilitate combining functions in design, and because of its high speed manufacturing processes, is cost effective. In addition, these materials can be post fabricated during the assembly phase, easily repaired and conveniently recycled. Value added secondary operations for both the captive or custom molders provide another avenue for cost reductions.

Reliability can be improved by the careful definition of the mechanical properties of engineering materials. Methods to define these properties for design functions by the use of statistics and probability concepts are presented. In addition, methods will be presented for quantitatively measuring the effects of specification screening on the improved properties of the acceptable materials. By selection of the proper design allowables based on required failure rate, reliability can be designed into components using the techniques discussed and illustrated.

The term “SP-100” is synonymous with a set of technologies that can be utilized to provide long lifetime, reliable, safe space power over the range of kilowatts to megawatts [1] using a nuclear reactor as the heat source. This paper describes recent development progress in a number of technology areas such as fuel, materials, reactivity control mechanisms and sensors. Without exception, excellent technical progress is being accomplished in all areas under development to optimize spacecraft performance characteristics.

This paper describes the design, implementation, and performance test results of an engineering model of the Position Multiplexer (MUX)-Analog Input Processor (AIP) System for the transmission and continuous measurements of Reflector Control Drive position in SP-100. The specially tailored MUX-AIP combination multiplexes the sensor signals and provides an increase in immunity from low frequency interference by translating the signals up to a higher frequency band. The modulated multiplexed signals are transmitted over a single twisted shielded cable pair from the reflector drives located near reactor to the AIP located at the power conditioning/system controller end of the space craft boom. There the signals are demultiplexed and processed by the AIP, eliminating the need for individual cables for each of the twelve position sensors across the boom.

The SP-100 Space Reactor Power System is being developed by GE, under contract to the U.S. Department of Energy, to provide electrical power in the range of 10's to 100's of kW. The system represents an enabling technology for a wide variety of earth orbital and interplanetary science missions, nuclear electric propulsion (NEP) stages, and lunar/Mars surface power for the Space Exploration Initiative (SEI). An effective infrastructure of Industry, National Laboratories and Government agencies has made substantial progress since the 1988 System Design Review. Hardware development and testing has progressed to the point of resolving all key technical feasibility issues. The technology and design is now at a state of readiness to support the definition of early flight demonstration missions. Of particular importance is that SP-100 meets the demanding U.S. safety, performance, reliability and life requirements.

System level design studies of space applications ranging in power from 77 kWt to 200 MWt have indicated no practical limit to the thermal power that can be reliably generated by a space reactor system based on the technologies being developed in the SP-100 program. These technologies include uranium nitride fuel, PWC-11/rhenium bonded fuel cladding, PWC-11 structural material for the lithium coolant boundary, electromagnetic coolant pumps, safety and reactivity control drive mechanisms, sensors, shielding materials, etc. at operating temperatures up to 1400K. The physical arrangements and characteristics of the nuclear reactor materials are described. The physical size of components and the arrangement of components change, but the basic technologies required are generally the same, irrespective of the total power output.

Standard laboratory immersion tests show silicone rubber to be stable in ASTM #1, #3 oils and in unused engine lube oils. However, new test data have shown that silicone rubber will degrade when exposed to engine lube oil which has functioned in lubricating a diesel engine for many hours of service. Special silicone rubber compounds have greatly improved the resistance to degradation as shown by laboratory tests and diesel engine tests of cylinder liner seals. These silicone rubber materials should also better the seal performance in other engine applications requiring low temperature flex, high temperature and petroleum base oil resistance.

Researchers now have the means to evolve complex manned and unmanned space missions using all of their complex support systems in a fully adaptive visual environment. The expected interactive nature of space missions requires powerful, flexible and comprehensive simulation hardware and software to develop and verify concepts, systems, and procedures. Correlation of visual, sensor, and radar imagery is essential due to new sensor blending and fusion techniques that characterize complex systems and missions. Only through total visual, non-visual and mission environment simulation, combined with analytical tools, can reliable systems and missions be developed. The same can be said of the simulation-based training programs that must be developed for ground and flight mission crews. If maximum situational awareness cannot be trained through simulation, it may be too risky, too expensive or even too late to acquire during a mission.

The effects of transmission selection on the performance and fuel economy of a gas turbine powered automobile are analyzed. Both single-shaft and two-shaft turbines are considered. Examples are given of fuel economy for an urban cycle, and performance of these engines with an infinitely variable transmission and with a power shift automatic transmission. The primary conclusions are that the infinitely variable transmission is necessary for a single-shaft engine and highly desirable for a two-shaft engine, and the use of an infinitely variable transmission with the single-shaft turbine eliminates any need for the wider output speed range of a two-shaft engine.