Specialty Materials, Inc.
F-16 LANDING BRACE
SP aerospace (Geldrop, The Netherlands) has developed a titanium metal matrix composite (MMC) lower drag brace for the landing gear on a Royal Netherlands Air Force F-16. It is the first application of an MMC landing gear part.
The materials for the highly loaded drag brace were supplied by Specialty Materials, Inc. (formerly Textron Systems Composite Products Group, Lowell, MA USA). Flat MMC prepreg sheet was produced, using monofilament fibers made by chemical vapor deposition of silicon carbide on a carbon fiber core, combined with titanium in a plasma spray process. The prepreg was wound onto a steel mandrel and consolidated in a hot isostatic press under fluid pressure. The “blanks” were shipped to SP, where they were machined to final dimensions.
The part was designed using ProEngineer three-dimensional design software (PTC, Needham, MA, USA and ABAQUS non-linear finite element analysis methods (Hibbit, Karlsson & Sorenson, Pawtucket, RI USA). Coupons and finished parts were extensively tested to determine A-basis design allowables. The F16 that flight tested the part was outfitted with sensors to monitor the part’s performance during taxiing, gear retraction and, finally, at increasing landing speeds.
The MMC replacement braces weighs 40 percent less than the original, which is fabricated with high-strength steel. Additionally, the MMC material has better corrosion and fatigue resistance than either steel or aluminum, says SP. The SP technology demonstration program for the MMC drag brace was funded in part by the Dutch Government. A carbon composite landing gear component also fabricated by SP aerospace was recently certified for the NH90 helicopter (see HPC March 2003, p.44)