the premise behind the "turtle" design
First, it is patently impossible to "build" an airship out of fabric; no such craft can be constructed in sizes large enough, nor durable enough for more than fair weather operations, nor strong enough to carry engines that are more numerous or powerful. Regrettably, it is what virtually all current blimp companies continue to do.
Second, the greatest challenge facing any airship design is not buoyancy, or flight, or even how it is constructed. It is the ground handling. A cursory glance at any blimp will show it's rounded lower hull, which cannot be placed upon the ground securely enough to control it. And yet, again, most airship companies continue to build in just this manner.
the Turtle is quite different.
When Lockheed Martin and Aeros Worldwide presented their airship concepts or designs to DARPA, those historic problems were readily apparent. Walrus was folded because of this.
Lockheed and Aeros, both have tried to design a sort of "hovercraft" landing system that is supposed to "suck" the airship down onto the landing area and so eliminate past ground handling problems. The idea flies in the face of logic, let alone practicality. The reason that a "hovercraft" operates at all, is because the weight of the vehicle it is supporting pushes it downward, while the air it is blowing underneath it lifts it off the ground. That weight is absolutely critical. And yet, these two companies proudly tout that their lighter-than-air craft can use it. Complete nonsense. Even when ballasted to a "heavy" condition, there still is to little weight.
There are further flawed design issues if one considers all the extra weight and controls for such a hovercraft landing system; and, it seems they completely discount any notion of FOBs (Foreign OBjects) being "sucked" into the system as well. Utter folly. (Concord tragedy, as example?)
Turtle Airship, RE: lift. We focus on pure aerostatic lift supplied from lifting gasses. Any so called "hybrid airship" (WALRUS, Lockheed's P-791, Aeros' "Aeroscraft", SkyCat, Ohio-Airships' "DynaLifter", etc), all need a runway. Period. Of short length perhaps, ungroomed, less likely (see FOBs note)...but a runway. A "hybrid airship" is nothing more really than a very large, lightweight airplane. Susceptible to all the cross winds that any other airplane has to deal with in landing or take off; plus with the addition of really immense "sail" area. Again, folly.
The Turtle Airship does use directed thrust and common control surfaces to generate lift and control. As also, using varied buoyancy via dumping ballast or venting gases; and, of course, use of a "lifting body" design. Nevertheless, it is a true Lighter-than-Air airship.
RE: Carbon and Aluminum as structural materials:
Turtle proposes to use rigid carbon fiber "threads" to connect an interior, aluminum wall, and exterior carbon wall or outer surface of the airships' hull. It is very strong, very lightweght, similar to a bird's bone. We are also looking into marrying this with simple Aerogel-like materials. Of course, this is the hull material; which is then supported via the geodesic construction and other interior framing.
As always, I'm pleased to discuss these things with persons who may then take the information to work with, so that we might ALL become active partners in creating a new airship industry