Re: [balloon-makers] Introduction

[Donald L Piccard <private e-mail address>]

Hi Greg,

Although there were some independent submarine flotation devices designed
at Goodyear Rubber Company to get the maximum volume with the minimum
vertical dimension, the bulbous gore balloon was invented to provide
flexibility under dynamic load without having wrinkles that could
overheat the fabric.

My father's sphere on cone, and later Upson and Melton's "Natural Shape",
were designed to be only partially inflated at the surface.  They would
only be full, and tight, at altitude where there would be little dynamic
load.

Raven used a Sigma Zero pattern for the hot air balloons, presumably
because that was the way their stratosphere balloons were built.  I
observed several structural failures of natural shape hot air balloons
under dynamic load  as  a result of Ram air pressure against the crown
and Bernoulli vacuum at the equator due to rapid ascent and searched for
a design to eliminate the stress.  My first attempt entailed a high sigma
natural shape, (for Decat in France) but the fabric formed several
"Ropes" where all the excess circumferential material congregated.  The
inner portions of these ropes would hang into the central area and be
exposed to excess heat.  The balloon had to be re cut and rebuilt for a
delayed delivery - CATASTROPHE !

Then I studied the deployment of fabric in balloon spinnakers with a
horizontal cut and together with Rudy Aurez of Hanna Sailmakers in Cost
Mesa, California lofted the first "Lobular" balloon for Dale Gates of
Cleveland, Ohio (who had been referred to me by Raven who had terminated
their hot air sport balloon business earlier.)  I called it the DLP,
using my initials, for "Distributed Load Pattern"  but as other people
accepted the  invention, it came to be known as the bulbous gore.  I was
able to base the curve on a Sigma Five without any rope forming.

If you would like the FAA approved type design procedure for lofting
patterns for my design, which would be too extensive to include here, I
would be happy to send it to you.  I think you would find it a little
more expensive to construct according to that than "researching" some cut
corner copies on the market.  They are not quite Camera Copies.

On Wed, 4 Apr 2001 08:44:47 -0500 Greg_Winker@Dell.com writes:
> SNIP> 
> Jonathan has prompted me to final get around to asking a question 
> about
> balloon design.  I see (most) everybody using either the Smalley or 
> Boland
> envelope design.  These are both basically smooth surfaced balloons, 
> ala the
> Cameron N type.  I have always found the bulbous gores more pleasing 
> to the
> eye, my favorite being the Thunder & Colt Series II.  But have never 
> found
> anyone describing how you modify (or develop) a gore pattern for 
> this type
> of bag.  I took a look at a local Cameron Viva a few months ago and 
> was
> surprised at how the individual panels were cut.  Has anyone spent 
> any time
> on this?
> 
> Good Floating!
> 
> Greg Winker
> 
> 

Don Piccard, Balloon@Juno.Com,
1445 East River Parkway
Minneapolis, MN 55414-3625
http://balloon.freeyellow.com/Homepage.html  www.thepiccardsociety.com
612/333-6912
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