Miniature Turbojet Development at Hamilton Sundstrand: The TJ-50, TJ-120 and TJ-30 Turbojets

As military needs shift from large, expensive, manned weapons platforms toward more dependence on small, inexpensive, high-volume, unmanned systems, the need for propulsion of these small systems forces a re-calibration of how engine manufacturers approach design and production. Traditional designs and manufacturing methods no longer apply and design/development timelines are compressed drastically to keep up with new weapons development. Hamilton Sundstrand Power Systems (HSPS), over the past 15 years, has developed a family of miniature turbojet engines. These turbojet engines were developed to meet the needs of small, lowcost weapons sytem such as targets, decoys and mini cruise missiles. The paper describes key parts of the development effort. Engine performance is presented, along with design features and needs/considerations for future systems. 1 Mark M. Harris, Technical Program Manager and Principal Engineer, Propulsion Engines, Hamilton Sundstrand Power Systems Anthony C. Jones, Chief Engineer of Propulsion Engines, Hamilton Sundstrand Power Systems Eric J. Alexander, Program Manager and Principal Engineer, Hamilton Sundstrand Power Systems THE SENGAP CHALLENGE In the early 1990’s, the Defense Advanced Research Projects Agency (DARPA) created a program called the Small Engine Advanced Program (SENGAP). As a contractor in this effort HSPS developed the first of its high performance, miniature turbojets, the TJ-50. The DARPA contract called for an ultra-low-cost, 4-inch diameter, air-breathing engine capable of providing 50 lbf net thrust at Sea Level/Mach .8. The requirements included an engine throttling capability such that future air vehicles could maximize range for a given fuel load, yet fly at high subsonic speeds to simulate fighter/bomber missions. The engine had an altitude start goal of 15,000 ft and needed to operate reliably up to 30,000 ft with a nominal 30-minute mission time. THE TJ-50: A STRONG FOUNDATION At the completion of its development in the late ‘90s, the TJ-50, Figure 1, demonstrated a performance capability beyond any engine of its size, meeting or exceeding all DARPA’s performance objectives. Key to the engine’s success is efficient mixed flow turbo-machinery, high rotating speed capability (130000 RPM) and a short residence time combustor. The turbomachinery maximizes the thrust for a given diameter and the combustor is capable of starting and stable operation at high loadings. The TJ-50 SENGAP program provided valuable technical design information/experience for all of the followon engines. Nominal performance of the TJFigure 1. TJ-50 Miniature Propulsion System 2nd AIAA "Unmanned Unlimited" Systems, Technologies, and Operations — Aerospac 15 18 September 2003, San Diego, California AIAA 2003-6568 Copyright © 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. American Institute of Aeronautics and Astronautics 2 50 is compared to the original SENGAP goals in Table 1. Objective Demonstrated