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Proceedings Paper

Shape memory alloy actuation for a variable area fan nozzle
Author(s): Nancy Rey; Gregory Tillman; Robin M. Miller; Thomas Wynosky; Michael J. Larkin; Jeffrey D. Flamm; Linda S. Bangert
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Paper Abstract

The ability to control fan nozzle exit area is an enabling technology for next generation high-bypass-ratio turbofan engines. Performance benefits for such designs are estimated at up to 9% in thrust specific fuel consumption (TSFC) relative to current fixed-geometry engines. Conventionally actuated variable area fan nozzle (VAN) concepts tend to be heavy and complicated, with significant aircraft integration, reliability and packaging issues. The goal of this effort was to eliminate these undesirable features and formulate a design that meets or exceeds leakage, durability, reliability, maintenance and manufacturing cost goals. A Shape Memory Alloy (SMA) bundled cable actuator acting to move an array of flaps around the fan nozzle annulus is a concept that meets these requirements. The SMA bundled cable actuator developed by the United Technologies Corporation (Patents Pending) provides significant work output (greater than 2200 in-lb per flap, through the range of motion) in a compact package and minimizes system complexity. Results of a detailed design study indicate substantial engine performance, weight, and range benefits. The SMA- based actuation system is roughly two times lighter than a conventional mechanical system, with significant aircraft direct operating cost savings (2-3%) and range improvements (5-6%) relative to a fixed-geometry nozzle geared turbofan. A full-scale sector model of this VAN system was built and then tested at the Jet Exit Test Facility at NASA Langley to demonstrate the system's ability to achieve 20% area variation of the nozzle under full scale aerodynamic loads. The actuator exceeded requirements, achieving repeated actuation against full-scale loads representative of typical cruise as well as greater than worst-case (ultimate) aerodynamic conditions. Based on these encouraging results, work is continuing with the goal of a flight test on a C-17 transport aircraft.

Paper Details

Date Published: 14 June 2001
PDF: 12 pages
Proc. SPIE 4332, Smart Structures and Materials 2001: Industrial and Commercial Applications of Smart Structures Technologies, (14 June 2001); doi: 10.1117/12.429677
Show Author Affiliations
Nancy Rey, United Technologies Research Ctr. (United States)
Gregory Tillman, United Technologies Research Ctr. (United States)
Robin M. Miller, United Technologies Research Ctr. (United States)
Thomas Wynosky, Pratt and Whitney, Retired (United States)
Michael J. Larkin, Pratt and Whitney (United States)
Jeffrey D. Flamm, NASA Langley Research Ctr. (United States)
Linda S. Bangert, NASA Langley Research Ctr. (United States)

Published in SPIE Proceedings Vol. 4332:
Smart Structures and Materials 2001: Industrial and Commercial Applications of Smart Structures Technologies
Anna-Maria Rivas McGowan, Editor(s)

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