[balloon-makers] plastic bag balloons- update

[Mark Caviezel]

All: 
Not a whole lot of traffic here on the list recently,
I hope everyone is having a great holiday. 

An update on my plastic bag cluster balloon project: 
Current plan is fifty small, 900 cubic foot balloons,
methane filled, each providing about 20 pounds net
buoyancy, individually tied off to Don's Body Helmet
gondola.   I have almost half of the lift cells built
and ready to go.  Discussions with the local FAA has
been initially positive for getting airworthiness
certificate for this set up.  Each cell will have a
small valve for vernier buoyancy adjustments, a rip
panel to loose all of the cell's lift gas, and
provision to cut away individual cells in an emergency
situation. 

I've conducted an air inflation test and two methane
inflation tests- with favorable results.   The second
methane inflation test was conducted over a 4.5 day
period with minimal leakage.  It was pleased and
surprised for this successful test because it was tied
off to a 20 pound cinder block and allowed to sway in
the breeze.  The 2nd test was terminated only because
of high winds developing after 108 hours.  The balloon
material is 0.00075 inches thick, about .5 oz per
square yard.  This is the same plastic that I use for
my scientific high altitude balloons.  Although this
lightweight material is fragile on the ground, it has
potential to be a part of a real high performance
competitive gas balloon envelope- only about 150
pounds total weight for 1000 cubic meters.  (And low
leakage, and low solar heating)  
  

I'll send a link to the photos of the inflation tests
for those who want to look.  

I'm still looking for a good launch site.   The local
airport would be fine, but the airport commission has
been stalling on my request to launch from there.  
I'll continue to work that angle but if anyone has a
better option within 500 miles of Oklahoma, I'd love
to hear from you. 

best regards, 

- Mark Caviezel 


 
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