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Wallhagen, R. E.

Publications and source records attributed to Wallhagen, R. E..

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Application of fluidics to new control components

The inherent tolerance for nuclear radiation makes fluidic devices candidates for nuclear rocket control systems. Also, they are being considered for supersonic jet engine inlet control because of their high temperature and vibration tolerance. Three new control components being considered for these applications are described. A fluidic circuit to control a pneumatic stepping motor for nuclear rocket control drum actuation is discussed. An all-fluidic sensor being developed for determining the position of the normal shock in the inlet of a supersonic jet engine is outlined. A new vortex valve configuration is developed to prevent supersonic jet engine inlet unstarts by regulating bypass flow.

Dustin, M. O.↗
NASA NTRS1974

Self-teaching digital-computer program for fail-operational control of a turbojet engine in a sea-level test stand

The design and evaluation are described of a digital turbojet engine control which is capable of sensing catastrophic failures in either the engine rotor speed or the compressor discharge static-pressure signal and is capable of switching control modes to maintain near normal operation. The control program was developed for and tested on a turbojet engine located in a sea-level test stand. The control program is also capable of acquiring all the data that are necessary for the fail-operational control to function.

Wallhagen, R. E.↗
NASA NTRS1973

Dynamic response of Mach 2.5 axisymmetric inlet with 40 percent supersonic internal area contraction

Results of experimental tests conducted on a supersonic, mixed compression, axisymmetric inlet are presented. The inlet is designed for operation at Mach 2.5 with a turbofan engine (TF-30). The inlet was terminated with either a choked-orifice plate or a long pipe with variable area choked exit plug. Frequency responses were obtained for selected static pressures in the diffuser. These pressures were selected as potential control signals for terminal shock control. Frequency responses were obtained for the Mach 2 and 2.5 conditions for different terminations. Responses also were obtained with and without cowl bleed. Internal disturbances were produced by sinusoidally varying the inlet overboard bypass doors at frequencies out to 100 hertz.

Baumbick, R. J.↗
NASA NTRS1972

Sea-level evaluation of digitally implemented turbojet engine control functions

The standard hydromechanical control system of a turbojet engine was replaced with a digital control system that implemented the same control laws. A detailed discussion of the digital control system in use with the engine is presented. The engine was operated in a sea-level test stand. The effects of control update interval are defined, and a method for extending this interval by using digital compensation is discussed.

Arpasi, D. J.↗
NASA NTRS1972

Dynamics of a supersonic inlet-engine combination subjected to disturbances in fuel flow and inlet overboard bypass airflow

An axisymmetric mixed-compression supersonic inlet and a single-spool turbojet engine were dynamically tested at Mach 2.5. The propulsion system was subjected to sweep-frequency sinusoidal disturbances of either inlet overboard bypass airflow. The disturbances were at a logarithmic sweep rate of 1 decade per minute. Dynamic responses were taken of signals throughout the propulsion system. Selected signals were reduced relative to the prime propulsion system parameters. The experimental data are presented in Bode plots. Most of the plots are for a frequency range of 1.0 to 50 hertz.

Wallhagen, R. E.↗
NASA NTRS1971

Determination of normal-shock position in a mixed compression supersonic inlet

Methods of determining inlet normal shock position from wall static pressure profiles were investigated. By using methods investigated in this report, it should be possible to control an inlet with less stability margin. Variation in inlet angle-of-attack caused drastic changes in pressure profile shape and wide variations in the angle of the shock plane with respect to the inlet axis. Thus, four sensors located around the circumference may be required to handle angle-of-attack and sideslip variations. One criterion would determine the shock position by comparing individual statics to a properly selected reference pressure.

Dustin, M. O.↗
NASA NTRS1970

Flueric-controller pneumatic stepping motor system

Nutating stepping motor consists of an output rotating gear and a nutating gear. A flueric logic circuit controls the nutating motor. The complete system constitutes a reliable, open loop actuator system with inherently high output stiffness, reasonable slewing speeds and small step size.

Dustin, M. O.↗