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M A Y 2 0 1 4 | 4 3 WORK IN PROGRESS L E A R N M O R E @ w w w. c o m p o s i t e s w o r l d . c o m Read this article online at short.compositesworld.com/Aeroscraft. See a video of the Dragon Dream's frst fight and other video documentation at http://aeroscraft.com/videos/4575674029. trolled via the helium's tank vs. envelope balance. The system renders ground teth- ering crews and ballasting unnecessary, and opens the way for cargo transport to remote and unimproved locations. Key to the concept's success is the craft's rigid internal structure, which must support not only the weight of the cargo, but the heavy COSH helium pump, compressors and storage tanks. Early trade studies showed that carbon/epoxy tubes in various diameters, assembled to form an airy truss skeleton (see photo, p. 41), could provide suffcient support at minimal weight. To shave cost during the demonstrator phase, some anodized alu- minum tubing is used with the carbon, but Aeros intends to feld future airships with all-carbon trusses. "We ultimately determined that a truss design was the best way to handle bend- ing loads, after multiple design itera- tions," says Kenny. "We have divided the truss into sections, similar to a bridge design." Carbon fber/epoxy tubes in a range of diameters from 0.5 inch/12.5 mm up to 4 inches/100 mm, as well as some heftier square tube profles, are assembled, together with the aluminum tubing, to form truss sections. The larger tubing is used, he explains, where loads are heavier, under the compressor equip- ment and engines, and where lifting or bending loads are anticipated to be the greatest. Sections are connected by com- plex tubular aluminum joints — the ad- hesive layer isolates the carbon and alu- minum, preventing galvanic corrosion. Aeros used Solidworks software from Dassault Systèmes (Waltham, Mass.) for the truss design, and conducted fnite el- ement analysis (FEA) of the entire struc- ture under cargo-loading and bending conditions, using Nastran FEA software from NEi Software (Westminster, Calif.). A new way to carry cargo The majority of the composites comprise the truss structure, but other composite elements include the instrument panel, honeycomb-cored glass and carbon fber cockpit foor panels and abrasion-resis- tant aramid fber-reinforced compos- ite fabrics on the craft's ground-contact pads. Kenny reveals that in the full-scale airships, the outer skin might be made with more durable, rigid, lightweight composite panels, rather than the mylar flm employed in the demonstrator. The Dragon Dream successfully lifted off in 2013, says Aeros' director of communi- cations John Kiehle. Since then, Aeros has inked four memoranda of under- standing with cargo transporters Pacifc Airlift, Cargolux Airlines, Air Charter Ser- vice and Bertling Logistics, to explore shipping possibilities — Aeros intends to lease, not sell, the craft and will act as feet operator. Target markets include oil and gas and wind energy (transport of blades and towers). The goal, says Kieh- le, is FAA certifcation by 2016, and an active feet soon thereafter. 707 Fulton Ave. • Rockford, IL 61103 USA afpm@ingersoll.com • 815-987-6000 0514HPC WIP-OK.indd 43 4/22/2014 3:12:27 PM