Thanks for asking, Mirek! To answer the "cloth" question first...I haven't actually textured it yet (the "canvas" setting in Photoshop's Texturizer scaled way down gives the right effect).
If you're asking how I did the basic shape of the hull, I can certainly answer that! In case you're not aware, airships of this type are NOT "blimps". A blimp is basically a soft balloon with a gondola and motor. The pressure of the gas itself keeps the "shape" of the blimp. The largest blimps ever built were just over 400' in length. Most blimps one sees today (as, for example, at sporting events) are maybe 120 or so feet long (30-35 meters, give or take). What I am doing is an example of a "rigid" airship. These had a rigid framework (aluminum or "duralumin", a stronger aluminum alloy) which determined the basic shape of the craft, and inside were a dozen or more gas bags filled with hydrogen or helium which provided the lift. Rigid airships were huge almost from day one (a WWI era rigid was about 650 feet long; the "Hindenburg", the largest ever built, was 804' long, and plans were made for airships well over 1000' long, though none were ever built).
The hull started as a NURBS sphere with 36 sections along the "z" axis and was scaled to match the basic shape. Isoparms were added as necessary. The NURBS object was then converted to a Poly. Faces were cut vertically as necessary, and then (to get the "look" of the girders under the cloth covering) a bevel was added along the length of the 36 horizontal sections.
As for scale, I used a reference drawing based on US Navy blueprints. The original USS Akron was 785' long and 135' wide at its widest point. I cut the drawing in half and added a section which would make my own version (a fictional lengthened version) approximately 950' by 150'. You can see the gap in the drawing where I added the extra length!
"Ad astra per aspera..."