Hybrid envelopes

Haven't been able to find this anywhere else so I apologize if I'm resurrecting a dead horse. 

Has anyone thought of lining a nylon shell with aluminized mylar? The mylar would act as a membrane to hold the lifting gas and the nylon would allow for polypropylene webbing to be sewn in as "hard points" for attaching a frame and or gondola. It would also add some durability to the mylar. 

The original idea called for several 16ft diameter spheres to be lined up and anchored inside a semi-rigid frame like the skyacht (http://www.personalblimp.com/).Having multiple smaller envelopes allows for modular design and it means that if one goes you don't lose all your lifting gas. 

The nylon and aluminized mylar both come in various thicknesses, weight to square foot ratios, and UV tolerance ratings. 

 The   thing is  cost  using  these  materials  such as proper  Sewing, cutting  and  shaping  the nylon  ,   and  also the  "mylar"  which has other dependability  issues  of being a thin film  such as  its   seaming   method  ,  laminating  quality  , and over all  ware quality .  Securing  widths and  lengths   in  rolls   to  actually   be  useful , seem   to  be   very hard  to  find  unless  you  buy tens of   thousands of  linear  feet.   The  suppliers  are not  end user  friendly  at  all . 
 See  the   Kitchen Foil  thread  for  a  "Mylar on  steroids"  option that  I personally  like  a lot .  

We plan to use a polyethylene outer bag and a "mylar" type inner bag. It helps if the material comes very wide. We have sourced PE film that comes over 40 ft wide. If you know of any other materials that come over 40 ft wide, please post them. 

I like PE because you can work on it with cheap hobby irons. 

With the small weight margins of LTA craft in general and this ultralight project in particular, you need to have every component pull as much double duty as possible. So you need to have your envelope material at least gas tight to maintain integrity and shape, even if you have other lift gas balloonetes.

Not that it isn't worth trying. If you can get a weigh saving by using a nylon silk-weigh fabric  and a thin mylar film to make a composite that is stronger and lighter than PE alone...

http://smallblimps.lefora.com/2010/03/09/scratch-built-blimp/

This entire post series dealt with multilayered plastics. The upshot is , they're better, more expensive , and harder to work with.

Are you sure you linked to the right thread?

That thread talked about heptax and then delved into adhesives and someone's RC blimps...

Are you sure you linked to the right thread?

-jamesg

If all the envelope stuff is under envelopes as a thread, and if all the engine stuff is under an engine thread where someone new can review the time sequence of the decisions made, then we can get to closure...a final product.

If everytime we get new members we spawn a bezillain new threads we will always be divergent.