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Continued growth of general-aviation over the next 10-15 years is dependent upon continuing improvement in aircraft safety, utility, performance, and cost. Moreover, these advanced aircraft will need to conform to expected government regulations controlling propulsion system emissions and noise levels. An attractive, compact, low-noise propulsor concept, the Q-FAN, when matched to reciprocating or rotary combustion engines, opens up the exciting prospect of new, cleaner airframe designs for the next generation of general-aviation aircraft, which will provide these improvements and meet the expected noise and pollution restrictions of the 1980 time period. In this paper, Q-FAN propulsion system performance, weight, noise, and cost trends are discussed. The impact of this propulsion system on the complete aircraft is investigated for two representative aircraft size categories. Examples of conceptual designs for Q-FAN/engine integration and aircraft installations are presented.

Within the next few years tighter restrictions on general aviation aircraft noise are expected. It is anticipated that these noise restrictions, like those imposed on larger transport aircraft now certified under Federal Aircraft Regulations, will be revised downward over a period of time. While it is expected that initial restrictions can be met by the current propeller technology, the larger lower tip speed propellers necessary to meet succeedingly more stringent restrictions may prove difficult to accept. In this paper an alternative to the propeller as a propulsor for general aviation aircraft is discussed. This is the subsonic tip speed low-pressure ratio fan which can be mated to turboshaft, rotary combustion, or reciprocating engines to provide a low noise propulsor in a small package. Information is presented which shows tradeoffs among noise, weight, size, cost, and performance.

Catalytic decomposition of hydrazine and hydrazine blend propellants has been recognized as an efficient means of providing warm gas for direct thrust or auxiliary power in many current and future applications. In most of these applications, the dynamics which relate propellant inlet flow to gas output flow have a significant influence on the overall system design. It therefore becomes essential that these dynamics be predicted and tailored for each system. In general, the approach to date to this problem has been from two extremes: the empirical evaluation of specific configuration and the analytical study of a completely distributed parameter microscopic model. The first approach does not lend itself to tailoring of the reaction chamber for specific systems. The second approach could produce both prediction and tailoring capability if accurate values of reaction and diffusion rates as a function of numerous environmental and geometric parameters were available.

Integration of propulsion controls can simplify the task of aircraft power management. Not only can integration ease the pilot's problem of adjusting engine power settings according to the flight mode, but it also enables improved propulsion system performance to be achieved and extends the regions of safe and stable operation. Such improvements to the inlet/engine compatibility by themselves warrant the use of control system integration, but once the controls are adapted for ease of data exchange they can easily accommodate power management functions and the processing of parameters for a maintenance monitor. One possible method of implementation is described utilizing state-of-the-art hardware.

Aircraft propellers normally operate at extremes of environmental temperature. Specification of lubricants for these highly stressed and precision machined mechanisms has evolved over the past forty years, with the requirements for each generation of propellers becoming increasingly stringent. Experience with aircraft propellers is applicable to comparable mechanisms exposed to similar environments.

This paper describes the influence of aircraft and installation characteristics on the design of propellers in the 500-1000 SHP class. These characteristics have a significant effect on propeller performance, weight, and stress levels. Specifically, the effects of aircraft geometry and flight conditions on propeller blade selection and pitch change system design will be considered. Sample aircraft installations will be presented along with a brief description of propeller operation.

The term programmed engine and accessory testing systems implies a variety of design options that are available to the activity contemplating computer assisted test operations. Implementation of such systems may be restricted to one specific option or may be a combination of several options. Final design configuration will reflect the results of trade-off studies involving economics, reliability, and the functional nature of the individual test to be conducted. A total testing system complex pertaining to post-overhaul engine test cells and accessories test stands is selected and described.