Date of Award:

5-2016

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Mechanical and Aerospace Engineering

Committee Chair(s)

Stephen A. Whitmore

Committee

Stephen A. Whitmore

Committee

Rees Fullmer

Committee

David Geller

Committee

Ling Liu

Abstract

The ability for an aircraft-based launch platform to place an orbital payload onto a nominal launch trajectory at a higher energy state -- altitude, velocity, flight path angle, and azimuth --using highly-efficient air breathing propulsion instead of a much lower-efficiency rocket system, offers the potential for a significantly smaller launch vehicle. An airborne platform also provides the ability to launch from multiple locations and allows for significantly increased "system responsiveness." The NASA Armstrong Flight Research Center’s Towed Glider Air-Launch System (TGALS) is a small-scale flight research project investigating the feasibility for a remotely-piloted, towed, glider system to act as a versatile air launch platform for nano-scale satellites. Removing the crew from the launch vehicle means that the system does not have to be human rated, and offers a potential for considerable cost savings. A small throttled "stage zero" rocket system is being designed to allow the TGALS platform to achieve the required launch point flight path angle, a condition that the TGALS cannot achieve without external propulsion. Throttling is required in order to achieve and sustain the proper launch attitude without structurally overloading the airframe. A hybrid rocket motor using gaseous oxygen and a solid ABS fuel as propellants was chosen for this project due to the inherent "green" and safe nature of the propellants. This thesis summarizes the development and testing campaign, and presents results from the clean-sheet design through ground-based static fire testing. Development of the closed-loop throttle control system is presented. The throttle control system uses chamber pressure as a system feedback and throttle control is actuated through an actively modulated ball valve that restricts the oxidizer flow into the system. Presented ground test results demonstrate that the throttle control system was able to follow the thrust profile in a predictable manner, allowing for a repeatable throttle response to a pilot-prescribed input command.

Checksum

6fbf7c59bf9969086e91d899ac1e9d8b

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .