Airship Storage

We have talked about the concept of storage in several different threads. But this thread will be dedicated to discussion of airship storage. 

Do we need a hanger? Or can we moor outside safely? What about an inflatable building that is somewhere between the two?

Here is such an inflatable storage building that might meet our needs. It can be used with big "clamshell" doors. What do yall think?http://www.tectoniks.com/clear-spans.php

An 8X20 cargo trailer costs a little over five grand and will hold a break-down Personal Ultralight Dirigible airframe. It has an aluminum body on a steel frame so it's not too heavy for a car to maneuver. See the Doolittle Trailer site.

Also has room for the envelope, a generator and a H2 electrolyzer. Just park it at an under-used county airstrip and start the 110V generator and bring out the inflated lift bags now and then and place them inside the envelope. Don't have to advertise exactly what the gas is.

In other words it is a portable airship station. Maybe even could have a bunk or hammock in there! 

I think strong moorings can be developed to hold down a PUD in all but the worst storms, in which case the dirigible should fly away to calmer locations which is what normal airplanes do anyway. Actually, a system for handling mooring stresses should be designed into the frame at the first git-go.

It's so CHEEP and easy to get UP!

Some of you  are planing a typical Airship.  Some  are looking at  some type of Inflated  Airfoil shape. An Airship  has  the better  wind  resistance  The  air foil  would need some  serious  thinking  to  Keep it  down without  damage, If your storing  outside, or  just parking  between flights.
  Inflated structures  require  constant  power ,Some  are inflated pillows  that join together  ,  With the constant pressure type  being  the better  as they  stay  constant.  where the inflated type  will  vary  pressures  with temp  and atmospheric change resulting in  a  "flabby"  building  catching  wind  instead of  repelling it.  BUT  the  constant pressure type   will have problems keeping up   when you open  the  barn door  to get the  airship out.  So its  6  and 6  .
   A  2 x 4 or 6  ,    or   conduit tubing  frame of  a   Conjoined  string of  geodesic  domes could  provide the  shelter you need .   There  are  many  "V" configurations. that  could  accommodate  your  shape the best. Covering   options  are many,  from poly  tarp,  to foam panels, even   with   Chicken  wire  and  Stucco . A lot of the  materials  could be  salvaged   as  they  will  not be  standard  lumber, sheeting , or tubing  manufactured  sizes to help offset the cost a grate deal. 
    And the other option  is to  look  at  Agricultural and commercial  quonset huts  from Steel Master .
  As they  are  simple to  erect  with the aid of a  Sky trac or boom truck.   
I  Really like  the  trailer /  Filling station .  But how long does it take to  fill the  Airship? Whats your production  Volume per Hr  in  something you  can fit in a trailer  WITH  the  stored  Airship   too  ?  Or  are you  using bottled gas ?   
          

The advantage of any hybrid lift airship, is that it will be heavy on the ground so it will be less likely to blow away. So storage should be easier than a traditional airship. There is an added advantage that hybrid airships are usually smaller and shorter. 

In our Skype conferences we agreed that we need a design that can be moved by trailer. I think it will require more effort to make the airship trailer friendly than to make the trailer airship friendly. The concerns that I have about the trailer are that it needs big waterproof doors and it needs to be free of any edges and must be smooth enough to avoid damaging the envelope. I believe that a 30 foot trailer would hold my design with only minor envelope deflation (I would guess < 10%). A shorter trailer would work, but would need greater deflation.

That said, if we are going to design for a trailer, we might as well use it for our main storage. But when away from base, I would want a lightweight restraint system that I could throw over the airship to secure it and protect it from the weather. 

Maximum trailer dimensions for most states are: 

8.5 ft wide
13 ft tall
53 ft long

So I am looking at how I can fit my airship in these dimensions. It is lenticular so it isn't a good shape from the start for trailering. I was thinking of using a nurse bag to take out enough gas to make the envelope flexible enough to fit in a rectangular space. Then stuff them both in a trailer. 

Has anyone figured out how to get 8,000 cubic feet of lifting gas into a small, portable steel tank?   A 2,000 gallon propane tank on a big truck could hold a lifting gas at 240 psi or so, and that's about the size tank you will need.  Or maybe 50 or 60 small  high pressure tanks, either way you will need a separate truck to carry the tanks.   I believe it will be cheaper to build a hanger to store it in and an extra thick cover to help retain gas.

See post:

http://smallblimps.lefora.com/2011/03/16/quad-rotor-rescue-hovercraft-small-blimp/#post12

It will take 28 Helium cylinders to provide 8000 cf.

You won't be able to use propane equipment to store Helium. Even if you could it would only hold 465 cf. so it would take 17+ trucks to do this...... not cost effective.

 A lot of  what your considering  calls for  re tanking  the  lift gas  under pressure . 
 In  theory  you could use a 10  CFM scuba compressor  and run  the intake port  on it  to  the  balloons  dump  vent .  These Compressors  are not  cheep, but wont  allow outside air entrainment ,  and  the  cylinders  aren't ether .  In math  it would  take  12 hours + to  do it.  Realistically  it  would take  2 to 3  days  to  move  8000 cu  ft  to  allow  for compressor cool off time  and  tank  connecting . 
   Dude  may have  the  best  option of  dumping  gas into  a  nurse bag  or more   then trying  to  get  the  ship   and nurse bag  in  a LARGE  trailer   with out  hurting both . Maybe  a large set of  PODs  type  moving  service  storage containers  ( drop off and  pick up and  deliver might  help ..? )   
 Heres what I'm  thinking with  the Pods ,  you have a known  size,   build  the  nurse bags  to  fit  it .  install  the bags  collapsed and  completely  evacuated of any air  ,   and  then  fill them  .  Re fill envelope at  the  new location  then  remove  the bags  for  re use.  Leave as little gas in  the envelope as possible  so  to make it  very  easy  to  handle and maybe  pack in your  own personal  trailer so   the likelihood of  damage is  drastically  reduced ,   
 Moving  the gas  could be done   by  building  a large  ( or  several large ) fire place  bellows type pumps  that could be operated  with a  standard air compressor  ,  air ram cylinder and control  valve  to  collapse  and  expand the bellows mechanically  to  move  the gas and  maybe  be able to develop  "some" pressure at least   .  At least  it would not get firecracker hot  like a  scuba compressor would. Given  the  time it would take  the  Bellows option  would  / could  make  the  best  option using  truck  size  inner tubes as the  flexible membrane and  the larger polyfastener  as  the  way  to  attach it to  the  plates.  
 A larger version of  this
 .

Lets say  build a few to  move a half cubic yard  18 cubic  ft at a 1 min  cycle time . Thats  moving  pretty slow , but large  deep  breaths .   Thats  ruffly   the size of a  truck inner tube  if you  cut it  around the equator on  the inside and allowed it  to  become a rubber tube.  the  Flow restriction at  the  exit port would  determine the pressure you could have . Ideally  at  the  start  you  would not  want  any pressure  to  move as much  as quickly as you could .  But  later  the  flow  will slow by envelope pressure  and  that  would only be  dictated by an amount  to not rupture  the  inner tube and  slowing  the  air rams cycle time to  force  the gas in slow until it  reaches a point of  equilibrium . I  will  guess here  and say  1 maybe  2 PSI  is  all  you  could get  out of it .  BUT  you  did move  99.9 % of  the volume !  .     

I can just see Dude going over the scales at the truck stop. "But son, your trailer only weighs fifty pounds, that's impossible!"

P.S. T-shirt arrived, thanx. It's great!

Dude's large trailer is only about 5200 cubic feet, he will need a separate trailer for the nurse bag.   I have another idea, along Nav's plan to assemble his ship, he was thinking of having the lift bags stored in a shed until assembly time, so it only makes sense that if he had to trailer his ship he would simply pull out as many lift bags as needed to make the ship manageable.   So if we design a small ship with a larger air lock than previously thought of, we could pull out some key lift bags, put them in a separate trailer and then you might, after taking some frame parts loose squeeze a ship into a 5,000 cubic foot trailer with no more gas loss or transfer.
.   Also, if you want to transfer lifting gas from the inner bags to an outer bags it would be efficient to use a ducted fan like what is used in an RC jet plane with a brushless motor and mount it inline, inside your duct to inflate the other bag.  I believe the cfm is hundreds if not thousands so it would be very quick.

 True Inv 47.  A in-line  fan  may  solve  the  transfer  problem .  But  anything  running at  high speed  in  a helium  atmosphere  is  gonna get hot  just like  the  problem  with  the scuba compressor .  Thats  why  the  bellows  would  be optimal  in  performance  and longevity using a  large volume and  slow  motions keeps   it  cool . 
 However   this  10 inch in-line  fan  may  work at  a rated 790 CFM     http://www.growwurks.com/vortex-inline-duct-blower-10-powerfan-790-cfm.aspx  Dont know  how much less CFM  would happen   running in  a helium environment . Also the  placement of the envelopes   deflation port  would make  a lot of difference too . If  the deflation port is on top,  the natural force of  the gas  will  help  push  the gas  into  a storage bag .  if  the  deflation port is on  bottom of the envelope  ,  the  fan  will  be working  extra hard  to  try  to  pull gas  against  its natural lift of  20  ft per second   and into  the  storage bag.   if  you  can  flip  flop  the envelope  to  take advantage of  the natural  upward motion   of lift gas , your good to go . Otherwise  you  are going to need 2 ports.  A fill at  the bottom  and  evac at the top. .
 The bellows  system  can overcome this  problem  of  natural lift  because of a large  vacume chamber  created  when  the   bellows  starts  to  expand .  But  it  will  work  a lot better  with  the  evac  port on  top   too .   

The pressure needed in my envelope will be about 1/300 of an atmosphere. 1 psi is more than enough. 

By my calculations. My nurse bag and trailer will need to be about 8.5 x 13 x 48. That is a tractor tailer. Huge...

I can go taller or wider, but I would need a permit to drive anywhere. Not an attractive prospect. I'm thinking filling on location is a cheaper option in the short term.

Option  #2 ,  fly it there !

Notes:

1. Why trailer a 8000 cu ft nurse bag when you're just going to use it to fill an 8000 cu ft blimp which you're also trailering?

2. Seriously?

A nurse bag helps you get a square peg into a round hole. The peg being a lenticular airship and the hole being a rectangular trailer. I wasn't thinking of totally emptying the gas into the nurse bag, just enough to make the envelope conform to the trailer space. 

Unless we find a cheap way to compress gas, that is the only way trailering is going to work. The volume is just too big and awkward.

The other option is to design the airship totally around the shape of the trailer space. That rules out lenticular from the start and sends us back to the drawing board.

 We kind of  shifted gears here  from  storage  to  transporting . 
 I  will  attempt  to  right  the course  and try to  tie  storage  and transport togather .

#1  Smaller  manageable  bags  that make up  make  the 8000  CUFT required .

# 2   Yep , only Bigger,  18 cu ft per gulp   and  air  ram cylinder operated . Wont get  extremely hot  and melt down like  recep's compressors will . Most recep's in gas plants   are  water cooled  using  refrigerated  water 
 This is A low pressure  version of  the   helium diaphragm compressor.  that  actually  compresses  helium  up to  and over  2500 psi for cylinder  filling .   Hey ,  its  a  way  at least  that  can  be  home made to  transfer  gas  . It  may  be  needed  if  you  develop a problem  with  your  envelope  that  would  require  removing  the  gas   to  fix it without  loosing  the  gas  by  just  dumping it . A  simple in-line duct  fan  may  work,   But nether  has  been  tested  yet ether.   

 BUT !  I like  3#  the best  because  WHAT are  we building  these personal airships  for  anyway ...?

 #3   Fly it  there !  May  be  the  best  all around   way . AND  the most  public  exposure  way !   You  would  use  a  chase  car / truck  and  trailer /  to  follow  the route  and  stay in contact so  your  not  alone and to  carry  equipment  you may  need  like proper  tie down  and cover  for parking over night,  ( use  the  car  / truck & trailer for   secure  tie down !  )  Extra gas,  food  water, clothing , shelter  ,  and so on .  There  have  been  many successful  cross country  flights  in  Ultralights  and all using  chase  cars  to  support the mission . Couldn't  have been done  otherwise. Plan  the  route  using  FAA   maps to  stay out of  restricted  airspace . Will need  a  aircraft band  radio.    
 
  Only  2 options really  exist  for a  portable  hanger  if  this  is   what  we're looking  for in  this  thread .
 It is  assumed here  that  you  will fly  from location to location  and  the  chase  vehicle  will prepare  the next  LZ .  
 A..  Outfit your  trailer  (20 ft min)  to  become  the  main  structure support ( side wall)  for a quonset  or  Geo dome   type frame  work  . It has  the mass and  weight  ( or  weight  can be added) to  make  a  structure not  easily prone to  wind  damage .  Normally can  withstand  anything  less than  a F 0  tornado  or  tornado  force  winds .  .  Can  be easily  home made using  the polyfastener system  to  make  a  secure  covering for it .  If  this  is  something  you  plan  to  do   a lot .  Outfit  the  trailer  to  become a  custom comfortable Camper  /  work station. And  the  main  support  for  the hanger     
 B.   Inflatable  air rib building with  water  ballast ground weight  chambers  .  Very  expensive.  
 
 YMMV . but  this is how I see it happening .  The  Air Ventures  Zeppelin NT based in  Ca.   uses  a chase truck  complete  with  mobile  gantry  crane  as  a  way  to  facilitate  landings   away  from   home port . 
 In  a  way,  we will be no  different,  Except  that  we  are  smaller   and  might  able  to  take our  hanger  with us . We're  building  to  FLY  !  Lets  FLY!
                     IM.           

Flying it "there" and leaving it inflated  isn't really an option for most people since most live in cities where airspace is usually restricted. Think of the customers!!!1!

You are going to need a compressor as part of your ground equipment regardless unless you want to dump that expensive lift gas each time, as mentioned before. Ideally you would want a small lightweight compressor and a light "pony bottle" size tank with which to trim buoyancy with (in lieu of carrying ballast)
I'm thinking a something like the little 12v compressors that they sell as roadside emergency kit, but which can develop the higher pressures required. Two of them tied together to maintain envelope equilibrium between the lift bags and internal pressure.  You wouldn't use them for filling (yes I digressed) For filling/defilling operations, you use your heavy duty ground compressor and main storage tank.

 Wow   and   that  main  tank  and compressor  is   just   going  to  knock  the  price tag  right over  the  fence for  any  "tank-able " pressure system.  You  could  realistically  buy  a  Cessna  for  what  you  will pay   for  a  real helium compressor and tanking  system.     . 
    This is  airships   and  as  such   each  customer  will need  to  assess their   situation  for  compatibility  .  It  wont  fit  a wide spectrum  of  demographics  or  back yards or  garrages like  a  UL  trike   or  even  a powered paraglider  will.  .  However   in  a lot of  areas   there  are  privately owned   recreational  flying  sites  and  grass strip  fields   That  would   welcome  an  airship   and its  hanger .  Usually  these sites   have  a live on site  owner who  are  the  'watch dogs"  over   his  members  aircraft   that  are parked  there . Some have  small hangers for  the  UL's  ,  some  dont . 
  If  you  had  a  reasonable mobile hanger  system  for  your  airship   such  a  a trailer  mounted  structure  and  could show  it was  sturdy  enough  to  withstand   weather and not  poise a danger  to other  aircraft  . I'm  sure  that you and  your  rig  would be  very  welcome   to become a Due paying member  and  join  their  flying  site .  Problem   solved  on more  that one front .  These  privet  flying  sites  are    everywhere ,   you  will  just  have  to  do some  research  to  find one  close  enough   to  be  doable .

I donno about you but I want to be able use this for years and years.
Think of the long term costs of the loss of gas from either leaving it inflated or just dumping when you need to do envelope maintenance.  Go price a building large enough to house an inflated ship.