No Trouble "ADAPTing" to Better SUAV Production Option

  • Published
  • By Heyward Burnett
  • Materials and Manufacturing
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  An Air Force Research Laboratory Manufacturing Technology-managed program produced a new small unmanned air vehicle production method to replace notably laborious and costly processes that have heretofore diminished the capacity to leverage sensor and payload advances of great potential benefit to warfighters. The program--aptly dubbed ADAPT, for the Automated Disposable Airframe Production Technology sought--demonstrated the viability of fused deposition modeling as an efficient, lower-cost alternative to the labor- and tool-intensive hand layup techniques currently used for some SUAV manufacturing. The polymer-based direct manufacturing approach generated by the ADAPT effort enables rapid design modifications, which are an essential part of meeting ever-changing warfighter needs.

Funded through a Broad Agency Announcement for Unmanned Aircraft Systems Manufacturing and managed by AFRL ManTech, the ADAPT program originated from the realization that the manufacture of SUAV airframes via FDM (a Stratasys, Inc., patented technology) might provide significant advantages, not only in cost but in capability (e.g., payload versatility). Accordingly, a then newly formed ADAPT team identified a wing design suitable for use as a SUAV baseline geometry. Based on the small UAS Stalker platform, this chosen geometry provided the team a foundation for SUAV wing assembly design, performance trade analysis, and cost comparison activities. The researchers' creation of a baseline wing model facilitated subsequent performance predictions regarding Ultem 9085, the highest-strength polymer available from Stratasys for the FDM process.

Having identified the best-available polymer for the task at hand, the ADAPT team performed two trade studies: one on an unmodified wing design, wherein the outer mold line and all mating features were kept constant, and the other on an optimized design, wherein both inner and outer mold lines and all mating features were enhanced via Ultem 9085. The polymer-optimized design accommodated changes (leaving the wing only slightly heavier than the baseline configuration) and, further, demonstrated equivalent endurance. The optimized design then underwent finite element analysis, which calculated the wing's deflection and buckling points. Stratasys' FORTUS, a highly portable production system encouraging on-demand use, ultimately enabled the ADAPT team's fabrication of a full-wing structure for around $8,000--a substantial price reduction compared to the cost of wings produced using conventional methods.

The researchers next subjected their newly manufactured wing to proof test at the Lockheed Martin Aeronautics Laboratory (Palmdale, California) in order to verify the finite element analysis models. While the wing's performance during this testing verified the model for downward deflection, it was unable to do so for upward deflection (i.e., the wing deflected more than that model initially predicted). Based on lessons learned throughout the ADAPT program, development of a process improvement roadmap identifying specific material and manufacturing improvements to FDM-oriented SUAV production is now under way.