A membrane bag in the general shape of a wing, filled with foam beads, can be loosely shaped into a suitable airfoil and then fixed (drawn taught) by pulling a partial vacuum. A partially embedded spar would comprise a structural stiffening spine to step as a mast or use as a wing-root.

The shaping phase could be as basic as hand forming by trowelling strokes or simple molding, for varied complex profiles to test or match to conditions. Partial vacuum would allow sensitive trim-plasticity, before "locking" the form. The shaping process is reversible by releasing the vacuum. Many tricks can be devised to extend the basic capabilities, including live-morphing during operation (like tacking the sail camber to port or starboard). Internal airbags could actuate trim inputs.

Wingsails on this principle could be light and robust. Most mishaps would be fully corrected by just patching holes and/or resetting the form.

• CC BY NC SA     ~Dave Santos    30Nov2013          Discuss at:  AirborneWindEnergy10687
• In response to DaveC's call for a DIY wingsail pattern-language, the vacuum-bead method emerged as an option. Lets call this unusual structural material "Vacutanium". The term is hereby reserved to the public domain as a generic descriptor.
  
  Vacutanium is "programmable matter" with the potential to make vast ultralight structures. Vacuum-packed beads jam together to form tough rigid structure in most any shape desired. Its an interesting study to compare with known inflated structure, with complementary properties and composite synergies (like airbags as giant beads in megascale vacuum-bags). Vacutanium absorbs excess loadings and impact forces by deforming reversibly. To reconfigure a form, just relax the vacuum and reset.
  
  An attractive source of plastic beads are the ocean "trash gyres". Beads mined from this waste should earn subsidies. Large floating cities of Vacutanium might be enabled. A ready source of experimental membranes are the well-known vacuum bags to compact and store knitted goods. Foam packing "peanuts" and crumbled foams of many kinds are easy to salvage as beads. Larger heatsealed polythene membranes could be a basis for "instant" curaches, pirogues, and even wingsails.
  
  CC BY NC SA
  
  Related Prior Art-
  http://creativemachines.cornell.edu/jamming_gripper?q=jamming_gripper

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