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Use of a wave rotor as a topping cycle for a gas turbine engine can improve specific power and reduce specific fuel consumption. Maximum improvement requires the wave rotor to be optimized for best performance at the mass flow of the engine. The optimization is a trade-off between losses due to friction and passage opening time, and rotational effects. An experimentally validated, one-dimensional CFD code, which includes these effects, has been used to calculate wave rotor performance, and find the optimum configuration. The technique is described, and results given for wave rotors sized for engines with sea level mass flows of 4,26, and 400 lb/sec.

Recent computer-based improvements in excavator-type machines have addressed fuel economy and power delivery to the implement for various types of tasks. Although some developments have been made in task-specific bucket control, the basic pattern of hand control motions for operating these machines has remained little changed over many years. This paper reports on a hand control interface, its computer-based hydraulic control system and the results of human factors studies carried out on a Cat 215B-based log loader. By means of a set of real-time excavator simulator studies, a new approach to directing the control of the implement motion has been developed. A testbed machine was made available by Caterpillar and the control system was implemented on an excavator, a log loader and at present is also being implemented on a feller-buncher. A commercial version of the concept has also been successfully implemented on grapple yarders.