Engineering Commons^™

Sidestick Controllers During High Gain Tasks, Brian J. Goszkowicz

Masters Theses

This research attempts to demonstrate the feasibility of a sidestick controller in a high gain environment. The research is assembled from several historical precedents and various projects.

New technologies have re-ignited interest in the use of sidestick controllers for commercial and military aircraft. There are many advantages and disadvantages utilizing a sidestick in fighter aircraft. Many pilots prefer the feel of a centerstick controller and the designer only needs to develop a few sets of command gradients or gearings to produce adequate handling qualities. However, centersticks require more cockpit room due to their larger size and range of motion. Consequently, …

The Correlation Of Pedal Position To Tail Rotor Power Requirement On The Oh-58a+, Kan-Wai Tong

Masters Theses

Every mechanical component has a finite failure life. Excessive usage of a component may cause damage. Therefore, life determination is essential to safe operation. Replacement of mechanical components prior to the end of useful life results in higher costs of maintenance. Monitoring rotating components is not always reliable or cost effective. This thesis attempts to solve this problem for a helicopter tail rotor. The development of an algorithm to calculate the loads on a component using stationary measurements can eliminate the need for rotating measurement equipment.

The purpose is to predict the tail rotor power requirement of a helicopter throughout …

Integration Of The Control Display Navigation Unit (Cdnu) Into The Ea-6b Block 89a Aircraft And Its Impact On Navigation Operations, Robert Donald Croxson

Masters Theses

This thesis was to evaluate the attributes of the recent modification and installation of the Control Display Navigation Unit (CDNU) into the EA-6B aircraft. The author conducted multiple ground and flight test events during a three year evaluation of the EA-6B Block 89A aircraft.

The Block 89A modification included an embedded Global Positioning System (GPS)/ Inertial Navigation System (INS) (EGI), enhanced functionality with the recent GPS system modification, and the ability to control the navigation, weapon, and communication on one control panel. This modification was an attempt to replace a failing attitude system and also allow for additional capability. The …

A Study Of The Chemistry Between Fast Atomic Oxygen And Silver-Coated Qcm Crystals, Juan Carlos Valer

Masters Theses

Atomic Oxygen (AO) is the main constituent of Low Earth Orbit (LEO), and it is responsible for chemical reactions on spacecraft materials that may degrade the performance or terminate the usefulness of them, and eventually accelerate the end of the life of the vehicle. This situation has make it clear the need to simulate the AO flux of LEO in a ground laboratory, to better understand the mentioned interactions.

MSRI and a UTSI team lead by Dr. Frank Collins have heavily modified an atomic oxygen generator originally fabricated by Dr. Gar Hoflund that promises to at least duplicate the AO …

Computational Investigation Of The Discharge Coefficient Of Bellmouth Flow Meters In Engine Test Facilities, Charles Lynn Sebourn

Doctoral Dissertations

In this thesis computation of the discharge coefficient of bellmouth flow meters installed in engine test facilities is presented. The discharge coefficient is a critical parameter for accurately calculating flow rate in any flow meter which operates by means of creating a pressure differential. Engine airflow is a critical performance parameter and therefore, it is necessary for engine test facilities to accurately measure airflow.

In this report the author investigates the use of computational fluid dynamics using finite difference methods to calculate the flow in bellmouth flow meters and hence the discharge coefficient at any measurement desired.

Experimental boundary layer …

An Investigation Of The Effects Of Relative Winds Over The Deck On The Mh-60s Helicopter During Shipboard Launch And Recovery Operations, Dominick J. Strada

Masters Theses

Vertical replenishment (VERTREP) of underway fleet naval vessels by helicopter is the primary mission of the MH-60S helicopter and is absolutely critical to sustaining fleet combat readiness at sea. The effectiveness of the MH-60S helicopter in conducting this crucial mission is directly dependent upon its ability to launch from and recover to the delivery ship under a wide range of wind-over-deck (WOD) conditions.

This thesis is an investigation of the effects of relative winds over the deck on the MH-60S helicopter documented during shipboard launch and recovery operations conducted during the initial MH-60S shipboard testing and launch and recovery wind …

Neural Network Model Of Unsteady, Nonlinear Aerodynamics, Amy Pearsall Henderson

Masters Theses

Many flight control systems are developed from aerodynamic measurements obtained from static wind tunnel testing. These control systems frequently inadequately handle unsteady, nonlinear flight conditions. Dynamic roll angle measurements made in a wind tunnel have been obtained. This aerodynamic data presents a nonlinear, unsteady dynamical system. The roll angle trajectories have been successfully approximated with multilayer feedforward backpropagation neural networks.

Flight Testing Amateur-Built Helicopters, Jeffrey Scott Bender

Masters Theses

Test-flight procedures for the amateur-built helicopter are presented. Test methods were acquired from acceptable practices for flight testing Normal Category Rotorcraft, Amateur-Built Aircraft and Ultralights. These acceptable practices were modified to overcome the challenges faced by the amateur-built helicopter test pilot. These challenges include limited in-flight instrumentation. A significant modification of procedures was to establish a methodology of flight testing using collective control stick position as an indicator of power during performance testing. Additionally, this procedure provides a method structured to overcome limited instrumentation during testing of stability and control. In-flight test data of a United States Army OH-58 was …

Handling Qualities Evaluation Of A Variable Stability Navion Airplane (N66ut) Using Frequency Domain Test Techniques, Randy Lee Bolding

Masters Theses

General aviation small aircraft handling quality certification has predominately been accomplished using traditional time-domain test techniques. This thesis investigates the handling quality characteristics of the variable stability Navion airplane, tail number N66UT, using frequency-domain test techniques. N66UT is configured with conventional flight controls at the copilot's station and a fly-by-wire set of flight controls at the pilot's station. Time delays between the fly-by-wire and conventional flight controls were determined to be minimal. Evaluation of handling qualities of the aircraft were compared to the fixed wing flying qualities speci fied in M IL-HDBK- 1 797. Analysis of flight test was conducted …

Mach Number Uniformity In A 16-Foot Supersonic Wind Tunnel At Arnold Engineering Development Center, David H. Smith

Masters Theses

Mach number uniformity in a 16-foot-square supersonic wind tunnel (Tunnel 16S) at the Arnold Engineering Development Center's Propulsion Wind Tunnel Facility was evaluated. Tunnel 16S is a continuous-flow, closed-circuit tunnel with a 101-foot-long, flexible-wall, Laval nozzle that can provide test-section Mach numbers from 1.50 to 4.75. It has been hypothesized that the observed Mach number nonuniformity is, at least partially, a result of two discontinuous regions in the nozzle contours. These discontinuous regions are a result of the nozzle-plate "lap joints", vertical seams in the nozzle walls. A 2-D, time-dependent, inviscid Euler code, NAP, was used to compute Mach number …

A Methodology For Acoustic Measurement And Separation Of Background Noise, Sekhar Radhakrishnan

Masters Theses

An attempt is made at developing experimental methods for the acoustic measurement and separation of background noise in a wind tunnel. To this end, an array beamforming technique known as delay-and- sum beamforming is identified and tested.

The theory underlying delay-and-sum beamforming is discussed. Two linear arrays, the seven microphone linear array and the four microphone minimum redundancy array, are designed. A driver is designed based on Helmholtz resonator theory to provide a source of monochromatic sound. Also, the concept of partial coherence as applicable to the separation of background noise from signal noise is investigated.

Array beamforming results show …

An Investigation Of Unsteady Vortex Flow Over A Maneuvering Delta Wing, Harry James Kowal

Doctoral Dissertations

An investigation of the vortex breakdown phenomenon using flow visualization qualitatively and quantitatively was conducted with a 70° delta wind under conditions of steady and unsteady pitch, roll and combinations of pitch and roll. Testing was carried out in the water tunnel located in the Mechanical Engineering Department of the Royal Military College of Canada, Kingston, Ontario.

Steady state roll experiments with the delta wing pitched at 30° showed that the behavior of vortex breakdown as a function of roll angle could be considered linear over the front half of the delta wing; however, the behavior beyond a certain critical …

Force Diagnostics Of Aerodynamic Bodies Based On Wake-Plane Data, Bohus Ondrusek

Masters Theses

The conventional method of using a balance to measure lift and drag on a model in a wind tunnel only provides information about the total quantities of these force components. Wake-survey analysis is a different technique developed for determining aerodynamic force on a body. Compared with the balance measurement, it provides a great deal of information about decomposed constituents and it clarifies the source of the aerodynamic force, but it also requires considerable work. In 1989, J.Z. Wu and J.M. Wu developed a unique theory, based on vorticity, for determining sources of aerodynamic force on a body from wake-plane data. …

High Angle Of Attack Handling Qualities Rating Scales, Chris A. Hadfield

Masters Theses

Aircraft handling qualities rating scales have traditionally been developed for closed-loop handling tasks at moderate angles-of-attack (AOA). The latest fighter aircraft, using fly-by-wire flight controls and vectored thrust, are capable of sustained maneuvers at very high AOA. A pitch control margin test (Lackey, 1991) was performed using a specially developed rating scale, which evolved as an element of tests investigating controllability at high AOA, progressing through conceptualization, simulation, and eventual flight test. This pitch control margin test is analyzed in this thesis as a case study in the development of handling qualities rating scales to evaluate high AOA flying qualities. …

Cryogenic Line Quench Experiment In Microgravity, Kanishkan Sathasivam

Masters Theses

This experiment was designed to provide a visual understanding of the nature of saturated liquid nitrogen flow boiling in a microgravity environment. This was undertaken by obtaining visual records of the flow patterns on film, and qualitatively analyzing them to form a definitive picture of the flow. An experimental apparatus was designed and built to obtain these visual records in microgravity. Liquid nitrogen was supplied from a dewar to an accumulator, from which it was then delivered to a test section. The accumulator was home-built and made of stainless steel. It contained a metal bellows vessel within it. Gaseous helium …

A Proposed Solution To The Longitudinal Instabilities Of The Ball-Bartoe Jetwing Through The Addition Of A Thin, Fixed Slat To The Horizontal Tail, Steven L. Sisterman

Masters Theses

The Ball-Bartoe Jetwing research aircraft was developed as a STOL demonstrator vehicle employing single engine powered lift by means of upper surface blowing. Unfortunately, the aircraft has been plagued by longitudinal instabilities since the first flight. These instabilities have prevented an exploration of the full STOL potential of the aircraft since the problem becomes more severe during low airspeed flight.

A review of the historical data indicated that the instabilities may be attributed to the downwash flow that blanketed the horizontal tail in certain flight conditions. As the blown flaps were deflected to increase lift at low airspeeds, the resulting …

Effects Of Coefficient Errors On The Performance Predictions Of A Typical Fighter At Medium Altitude, John D. Cloyd

Masters Theses

Performance prediction is one of the primary uses of wind tunnel data. Uncertainties in the tunnel data are therefore directly related to errors in performance predictions. The objective of this study was to examine the effects of aerodynamic coefficient errors on the point performance predictions for a typical fighter at medium altitude and subsonic velocity. The point performance parameters were formulated as functions of the aerodynamic coefficients. A computer program was written to calculate the selected performance parameters for 121 cases, each case representing a different combination of coefficient errors. The result was the correlation of the percentage error in …

An Experimental Investigation Of The Air Drag On Monofilament Fibers And Flowfield Behavior Resulting From Two Convergent High Velocity Jets: Melt Blowing Application, Bryan David Haynes

Masters Theses

An extensive experimental investigation has been conducted in order to better understand the air drag phenomena of a monofilament fiber in a free jet flowfield. The resulting flowfield was generated from two convergent high velocity jets. This particular arrangement is similar to the meltblown configuration used in the production of nonwoven materials. The experimental data in the results show how the fiber drag varies with stagnation pressure, air injection angle, fiber length, test section orientation, die setback, and exit velocity. A Fanno flow analysis was used to model the flow in the injection nozzles to determine the exit velocity.

The …

The Effect Of Particle Dynamics On Turbulence Measurements With The Laser Doppler Velocimeter, Robert H. Nichols

Doctoral Dissertations

The laser velocimeter (LV) is currently being used by many researchers to nonintrusively obtain velocity data in complex flow fields. The LV measures the velocity of small particles entrained in the flow field of interest. The fluid velocity and turbulent velocity correlations are then inferred from statistical analysis of these particle velocity measurements under the assumption that the particles exactly reproduce the motion of the fluid. This assumption needs careful evaluation since it is fundamental to the application of the LV.

The particle equation of motion was carefully analyzed to determine what form is required for evaluating the turbulence response …