Alan Ball sent along this concept that is based on our recent design meeting at John Baron's shop. This design separates two morphing arms to make the rear frame more 3D, instead of the earlier designs that essentially have the frame all in one vertical plane. The idea is to get better torsional rigidity and reduce weight. This design is based on using an NEMSHPEC gravity reduction system. (NEMSHPEC stands for Nylon Encased Multi-Strand High-Performance Elastic Cord ... or to most consumers "bungee" cord.) Instead of the gas springs of our earlier designs, this vehicle will actually use a multistrand shock cord to provide the morphing lift. We've tested it, and it works great. Its also much easier to adjust than a gas spring, and it will be lighter and less expensive. I also belive it will be more reliable. At New England Handcycles, we used shock cord for seat components, and for the centering spring. The cords are waterproof, tough, and seemed not to care about sun exposure, even over long periods of time. (years)
The cords are not shown in this early mock up.
See earlier posts that led to this design: Photos: http://morphhc.posterous.com/photos-of-the-morphing-handcycle-test-rig and Video: http://morphhc.posterous.com/morphing-handcycle-important-breakthroughs-se-0
Here is the e-Drawings file for the SolidWorks model: You'll need the free e-Drawings Viewer (for Mac or PC)