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Foil Balloons
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With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD 0 Attachment
Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 
> Sig
> The Original Rolling Ball Clock
> Idle Tyme
> IdleTyme.com
> http://www.idletyme.com 0 Attachment
Joe,
I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).
A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?
Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.
I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.
Anybody else have any advice for us mylar newbies?
Chuck / KG5CA
 In GPSL@yahoogroups.com, <nss@...> wrote:
With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD 0 Attachment
Mike,
Thanks for point out that patent. They did an amazing job!
Chuck / KG5CA
 In GPSL@yahoogroups.com, <mrmanes@...> wrote:
Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 
> Sig
> The Original Rolling Ball Clock
> Idle Tyme
> IdleTyme.com
> http://www.idletyme.com 0 Attachment
Chuck,Here are the basic equations for a regular tetrahedron with edges of length a (from http://www.vitutor.com/geometry/solid/tetrahedron.html)Surface Area of a Regular Tetrahedron
Volume of a Regular Tetrahedron
The ratio of Volume/Surface Area is about 0.068a for the tetrahedron. This ratio is not as favorable as other regular shapes:For the sphere, Volume/Surface Area is 0.33r (where r is the radius)For an ideal cylinder with radius equal to height (the optimal condition), Volume to Surface Area is 0.25r.For a cube, Volume/Surface Area is 0.17a (where a is the edge length).However, the simplicity of construction of the tetroon, with fewer straight seams, makes it a very attractive shape.You are correct that the float altitude can be calculated for the superpressure balloon. You need to know the mass of the payload, balloon fabric, and other attachments (parachute, cut down device??). You also need to know the density and initial volume of the lifting gas. The float altitude will be where the buoyant force of the lifting gas equals the weight of everything that is being floated.I agree that floating above 60 kft is desirable for a long duration flight.Howard, KC9QBNwww.tinyurl/basedepauw
From: "cgoldsmith@..." <cgoldsmith@...>
To: GPSL@yahoogroups.com
Sent: Sunday, September 22, 2013 10:14 PM
Subject: [GPSL] RE: Foil Balloons
Joe,I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.Anybody else have any advice for us mylar newbies?Chuck / KG5CA In GPSL@yahoogroups.com, <nss@...> wrote:
With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD 0 Attachment
I've done a lot of work on superpressure balloons in particular and will try to write more on the subject later today or tonight. At the moment I'll just say that I don't recommend using a tetroon for a firsttry at a superpressure flight. The faces of a tetroon have a huge effective radius compared to a sphere or cylinder of comparable volume. In the superpressure role, they were really only used for lowaltitude (tropospheric) flights using rather thick (24 mil) bilaminated film. And they were only used in this role at all because of the simplicity of fabricating a large number of tetroons at low cost for use as Lagrangian trackers. My tetroons have all been solar Montgolfieres or zeropressure helium.That said, if you're talking about an extremely lightweight payload (as we recently saw in Europe) then the allowable margin of error is a lot greater and you might be able to use a tetroon with little difficulty. In my personal experience, the greatest problem you will face will be finding a way to make a gasproof, pressureworthy envelope out of film with adhesive on a single side. You'll see what I mean as your experiments move along. Pinholes will be another problem, but if you're only talking about a weeklong flight they shouldn't be much of an issue. My alternative to bilamination was a coating of polyvinyl alcohol, although this has to be on the inside of the envelope due to the hygroscopic nature of PVA.And finally (for now anyway), the free lift that you have at ground  calculated relative to the total system mass (including gas in the envelope)  will be directly converted into superpressure at float (assuming a perfectly nonextensible balloon). So if you want 5% superpressure at float, you would fill your balloon so that you have a free lift of 5% at launch.More later... Students on the way! :)Regards,RobertKC8UCH
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo GloriaOn Sat, Sep 21, 2013 at 9:10 PM, Mike Manes <mrmanes@...> wrote:Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI> Sig
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 

Yahoo! Groups Links
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 0 Attachment
Thanks Robert.
Now a tetroon may not be the best,
I assume the better would be of course a sphere, but good luck making that. I'm now thinking cylinder.
I can of course make a very easy 1 seam one. A long tube more or less, that would be simple.
But I wonder what way would be best? A single LONG one. or multiples s in cluster one?
Joe
On 9/23/2013 8:24 AM, Robert Rochte wrote:
I've done a lot of work on superpressure balloons in particular and will try to write more on the subject later today or tonight. At the moment I'll just say that I don't recommend using a tetroon for a firsttry at a superpressure flight. The faces of a tetroon have a huge effective radius compared to a sphere or cylinder of comparable volume. In the superpressure role, they were really only used for lowaltitude (tropospheric) flights using rather thick (24 mil) bilaminated film. And they were only used in this role at all because of the simplicity of fabricating a large number of tetroons at low cost for use as Lagrangian trackers. My tetroons have all been solar Montgolfieres or zeropressure helium.That said, if you're talking about an extremely lightweight payload (as we recently saw in Europe) then the allowable margin of error is a lot greater and you might be able to use a tetroon with little difficulty. In my personal experience, the greatest problem you will face will be finding a way to make a gasproof, pressureworthy envelope out of film with adhesive on a single side. You'll see what I mean as your experiments move along. Pinholes will be another problem, but if you're only talking about a weeklong flight they shouldn't be much of an issue. My alternative to bilamination was a coating of polyvinyl alcohol, although this has to be on the inside of the envelope due to the hygroscopic nature of PVA.And finally (for now anyway), the free lift that you have at ground  calculated relative to the total system mass (including gas in the envelope)  will be directly converted into superpressure at float (assuming a perfectly nonextensible balloon). So if you want 5% superpressure at float, you would fill your balloon so that you have a free lift of 5% at launch.More later... Students on the way! :)Regards,RobertKC8UCH
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo Gloria
On Sat, Sep 21, 2013 at 9:10 PM, Mike Manes <mrmanes@...> wrote:Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI> Sig
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 

Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/GPSL/
<*> Your email settings:
Individual Email  Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/GPSL/join
(Yahoo! ID required)
<*> To change settings via email:
GPSLdigest@yahoogroups.com
GPSLfullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
GPSLunsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
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 0 Attachment
ok what happens with a cylinder vs length?
If a 4 foot circumference cylinder was made, (4 foot is the width of the material so only 1 seam)
what changes if the cylinder is 10 feet long 20 feet long 100 feet long?
Joe WB9SBD
On 9/23/2013 7:54 AM, BASE wrote:
Chuck,
Here are the basic equations for a regular tetrahedron with edges of length a (from http://www.vitutor.com/geometry/solid/tetrahedron.html)Surface Area of a Regular Tetrahedron
Volume of a Regular Tetrahedron
The ratio of Volume/Surface Area is about 0.068a for the tetrahedron. This ratio is not as favorable as other regular shapes:For the sphere, Volume/Surface Area is 0.33r (where r is the radius)For an ideal cylinder with radius equal to height (the optimal condition), Volume to Surface Area is 0.25r.For a cube, Volume/Surface Area is 0.17a (where a is the edge length).
However, the simplicity of construction of the tetroon, with fewer straight seams, makes it a very attractive shape.
You are correct that the float altitude can be calculated for the superpressure balloon. You need to know the mass of the payload, balloon fabric, and other attachments (parachute, cut down device??). You also need to know the density and initial volume of the lifting gas. The float altitude will be where the buoyant force of the lifting gas equals the weight of everything that is being floated.
I agree that floating above 60 kft is desirable for a long duration flight.
Howard, KC9QBN
From: "cgoldsmith@..." <cgoldsmith@...>
To: GPSL@yahoogroups.com
Sent: Sunday, September 22, 2013 10:14 PM
Subject: [GPSL] RE: Foil Balloons
Joe,I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.Anybody else have any advice for us mylar newbies?Chuck / KG5CA
 In GPSL@yahoogroups.com, <nss@...> wrote:
With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD
 0 Attachment
Hi Joe.I have a spreadsheet all set up for cylindrical superpressure balloons and will send to you when I find it (it's in my Google Drive somewhere). It will let you plug in your numbers for areal density, film thickness, float altitude, etc, and will calculate the rest of the design. It's not pretty, because I only made it for my own use  but I think you'll find it helpful.With regard to a cluster, just consider that the failure of any one envelope will bring your cluster to the ground. The advantages of the original Piccard Pleiades (mostly eliminating the Upson ring problem and thus the need for a cap) are lost on a superpressure cluster in most cases. I've tried working out the numbers using a cluster of small spheres, but for anything other than a fleasized payload there just isn't any benefit. In fact, most of the designs that I came up with wouldn't get off the ground due to the mass penalty of extra fittings, etc.R
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo GloriaOn Mon, Sep 23, 2013 at 9:46 AM, Joe <nss@...> wrote:Thanks Robert.
Now a tetroon may not be the best,
I assume the better would be of course a sphere, but good luck making that. I'm now thinking cylinder.
I can of course make a very easy 1 seam one. A long tube more or less, that would be simple.
But I wonder what way would be best? A single LONG one. or multiples s in cluster one?
Joe
On 9/23/2013 8:24 AM, Robert Rochte wrote:I've done a lot of work on superpressure balloons in particular and will try to write more on the subject later today or tonight. At the moment I'll just say that I don't recommend using a tetroon for a firsttry at a superpressure flight. The faces of a tetroon have a huge effective radius compared to a sphere or cylinder of comparable volume. In the superpressure role, they were really only used for lowaltitude (tropospheric) flights using rather thick (24 mil) bilaminated film. And they were only used in this role at all because of the simplicity of fabricating a large number of tetroons at low cost for use as Lagrangian trackers. My tetroons have all been solar Montgolfieres or zeropressure helium.That said, if you're talking about an extremely lightweight payload (as we recently saw in Europe) then the allowable margin of error is a lot greater and you might be able to use a tetroon with little difficulty. In my personal experience, the greatest problem you will face will be finding a way to make a gasproof, pressureworthy envelope out of film with adhesive on a single side. You'll see what I mean as your experiments move along. Pinholes will be another problem, but if you're only talking about a weeklong flight they shouldn't be much of an issue. My alternative to bilamination was a coating of polyvinyl alcohol, although this has to be on the inside of the envelope due to the hygroscopic nature of PVA.And finally (for now anyway), the free lift that you have at ground  calculated relative to the total system mass (including gas in the envelope)  will be directly converted into superpressure at float (assuming a perfectly nonextensible balloon). So if you want 5% superpressure at float, you would fill your balloon so that you have a free lift of 5% at launch.More later... Students on the way! :)Regards,RobertKC8UCH
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo Gloria
On Sat, Sep 21, 2013 at 9:10 PM, Mike Manes <mrmanes@...> wrote:Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI> Sig
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 

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Cool looking forward to it.
Joe
On 9/23/2013 9:16 AM, Robert Rochte wrote:
Hi Joe.I have a spreadsheet all set up for cylindrical superpressure balloons and will send to you when I find it (it's in my Google Drive somewhere). It will let you plug in your numbers for areal density, film thickness, float altitude, etc, and will calculate the rest of the design. It's not pretty, because I only made it for my own use  but I think you'll find it helpful.With regard to a cluster, just consider that the failure of any one envelope will bring your cluster to the ground. The advantages of the original Piccard Pleiades (mostly eliminating the Upson ring problem and thus the need for a cap) are lost on a superpressure cluster in most cases. I've tried working out the numbers using a cluster of small spheres, but for anything other than a fleasized payload there just isn't any benefit. In fact, most of the designs that I came up with wouldn't get off the ground due to the mass penalty of extra fittings, etc.R
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo Gloria
On Mon, Sep 23, 2013 at 9:46 AM, Joe <nss@...> wrote:Thanks Robert.
Now a tetroon may not be the best,
I assume the better would be of course a sphere, but good luck making that. I'm now thinking cylinder.
I can of course make a very easy 1 seam one. A long tube more or less, that would be simple.
But I wonder what way would be best? A single LONG one. or multiples s in cluster one?
Joe
On 9/23/2013 8:24 AM, Robert Rochte wrote:I've done a lot of work on superpressure balloons in particular and will try to write more on the subject later today or tonight. At the moment I'll just say that I don't recommend using a tetroon for a firsttry at a superpressure flight. The faces of a tetroon have a huge effective radius compared to a sphere or cylinder of comparable volume. In the superpressure role, they were really only used for lowaltitude (tropospheric) flights using rather thick (24 mil) bilaminated film. And they were only used in this role at all because of the simplicity of fabricating a large number of tetroons at low cost for use as Lagrangian trackers. My tetroons have all been solar Montgolfieres or zeropressure helium.That said, if you're talking about an extremely lightweight payload (as we recently saw in Europe) then the allowable margin of error is a lot greater and you might be able to use a tetroon with little difficulty. In my personal experience, the greatest problem you will face will be finding a way to make a gasproof, pressureworthy envelope out of film with adhesive on a single side. You'll see what I mean as your experiments move along. Pinholes will be another problem, but if you're only talking about a weeklong flight they shouldn't be much of an issue. My alternative to bilamination was a coating of polyvinyl alcohol, although this has to be on the inside of the envelope due to the hygroscopic nature of PVA.And finally (for now anyway), the free lift that you have at ground  calculated relative to the total system mass (including gas in the envelope)  will be directly converted into superpressure at float (assuming a perfectly nonextensible balloon). So if you want 5% superpressure at float, you would fill your balloon so that you have a free lift of 5% at launch.More later... Students on the way! :)Regards,RobertKC8UCH
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo Gloria
On Sat, Sep 21, 2013 at 9:10 PM, Mike Manes <mrmanes@...> wrote:Hi Joe,
Talk to Robert Rochte KC8UCH about how to fab a tetroon from flat
sheet stock. He demoed that process at the GPSL in Omaha some time
ago (until the room started rotating  whole 'nother story!). He
used big box thin poly drop cloth stock and Scotch tape for his
solar ZPs and coats the inside surface with carbon black to get
solar absorptivity up  not necessary for a SP, nor is the Al
coating.
NOAA's small SP's with Irridium met beacons have used 'em with good
results.
Here's a link to Huch's 1962 patent on tetroon fab:
http://www.google.com/patents/US3047252?dq=3047252
Click on the Images to see details.
Huch is better known for his "Huch Clutch"  a means to clamp off
a portion of a plastic balloon during fill, and improved upon by
Norm Kjome's "Kjome Clutch", which EOSS has used.
I think the key to success in making a SP bag is in the seam strength.
This can be tested for burst pressure easily on the deck using
compressed air, I'd think. The huge SPs being developed by NOAA &
Winzen use fiberglass load tapes, IIRC, but those are for their
typical "Buick and 4 scientists" payloads.
GL es 73 de Mike W5VSI> Sig
On 9/21/13 9:29 AM, Joe wrote:
> With the recent success of these foil balloons, it has made me somewhat
> interested in them and their possibilities for long duration flights.
> Their ability to"Superpressure"
>
> Now I wonder, what would be the better way to go? See I have literally
> thousands of feet if not miles of an aluminized mylar in rolls that are
> in varying widths from only 2 feet wide to almost 4 feet wide.
>
> Now this also has the heat sensitive adhesive backing on it too. I just
> cut a large square of it, and weighed it to see what it weighs, and it
> comes in at 0.1768 oz per sq ft.
>
> Now everyone what configuration think would be best?
>
> Many small balloons, like a cluster balloon system?
>
> A long cylinder
> or
> a like tetroon type?
>
> Thoughts?
>
> Joe WB9SBD
> 

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Joe,The simple answer is that the performance, as compared to a spherical shape enclosing the same volume gets worse.Here are some quick numbers:The circumference of the cylinder is 4 feet. This makes the radius of the cylinder 0. 64 feet.Cylinder height (ft) Cylinder Volume(cu. ft) Cylinder Surface Area(sq.ft) Equal Volume Sphere S.A.(sq.ft)4 5.1 18.6 14.36 7.6 26.6 18.710 12.7 42.6 26.220 25.5 82.6 41.4100 127.3 402.6 119.6Short height cylinders are not much worse than the sphere, but as the height increases things you have a lot more surface for equal volumes.Howard
From: Joe <nss@...>
To: BASE <hlbrooks@...>
Cc: BASE <basedepauw@...>; "cgoldsmith@..." <cgoldsmith@...>; "GPSL@yahoogroups.com" <GPSL@yahoogroups.com>
Sent: Monday, September 23, 2013 9:49 AM
Subject: Re: [GPSL] RE: Foil Balloons
ok what happens with a cylinder vs length?
If a 4 foot circumference cylinder was made, (4 foot is the width of the material so only 1 seam)
what changes if the cylinder is 10 feet long 20 feet long 100 feet long?
Joe WB9SBD
On 9/23/2013 7:54 AM, BASE wrote:
Chuck,
Here are the basic equations for a regular tetrahedron with edges of length a (from http://www.vitutor.com/geometry/solid/tetrahedron.html)Surface Area of a Regular Tetrahedron
Volume of a Regular Tetrahedron
The ratio of Volume/Surface Area is about 0.068a for the tetrahedron. This ratio is not as favorable as other regular shapes:For the sphere, Volume/Surface Area is 0.33r (where r is the radius)For an ideal cylinder with radius equal to height (the optimal condition), Volume to Surface Area is 0.25r.For a cube, Volume/Surface Area is 0.17a (where a is the edge length).
However, the simplicity of construction of the tetroon, with fewer straight seams, makes it a very attractive shape.
You are correct that the float altitude can be calculated for the superpressure balloon. You need to know the mass of the payload, balloon fabric, and other attachments (parachute, cut down device??). You also need to know the density and initial volume of the lifting gas. The float altitude will be where the buoyant force of the lifting gas equals the weight of everything that is being floated.
I agree that floating above 60 kft is desirable for a long duration flight.
Howard, KC9QBN
From: "cgoldsmith@..." <cgoldsmith@...>
To: GPSL@yahoogroups.com
Sent: Sunday, September 22, 2013 10:14 PM
Subject: [GPSL] RE: Foil Balloons
Joe,I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.Anybody else have any advice for us mylar newbies?Chuck / KG5CA
 In GPSL@yahoogroups.com, <nss@...> wrote:
With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD
 0 Attachment
It's not just volumetric efficiency, though  the cylindrical superpressure will have twice the skin stress of a sphere the same diametre. For small envelopes, the tradeoff of greatly simplified construction may be worth it. On the other hand, precisely weighingoff (remember, free lift turns into superpressure!) and then launching a 75 foot long tube is not a lot of fun (AMHIK). R
Robert Rochte, Director of Technology
The Grosse Pointe Academy
+1 3133780525 Mobile
Soli Deo GloriaOn Mon, Sep 23, 2013 at 10:42 AM, BASE <basedepauw@...> wrote:Joe,The simple answer is that the performance, as compared to a spherical shape enclosing the same volume gets worse.Here are some quick numbers:The circumference of the cylinder is 4 feet. This makes the radius of the cylinder 0. 64 feet.Cylinder height (ft) Cylinder Volume(cu. ft) Cylinder Surface Area(sq.ft) Equal Volume Sphere S.A.(sq.ft)4 5.1 18.6 14.36 7.6 26.6 18.710 12.7 42.6 26.220 25.5 82.6 41.4100 127.3 402.6 119.6Short height cylinders are not much worse than the sphere, but as the height increases things you have a lot more surface for equal volumes.Howard
From: Joe <nss@...>
To: BASE <hlbrooks@...>
Cc: BASE <basedepauw@...>; "cgoldsmith@..." <cgoldsmith@...>; "GPSL@yahoogroups.com" <GPSL@yahoogroups.com>
Sent: Monday, September 23, 2013 9:49 AM
Subject: Re: [GPSL] RE: Foil Balloons
ok what happens with a cylinder vs length?
If a 4 foot circumference cylinder was made, (4 foot is the width of the material so only 1 seam)
what changes if the cylinder is 10 feet long 20 feet long 100 feet long?
Joe WB9SBD
On 9/23/2013 7:54 AM, BASE wrote:
Chuck,
Here are the basic equations for a regular tetrahedron with edges of length a (from http://www.vitutor.com/geometry/solid/tetrahedron.html)Surface Area of a Regular Tetrahedron
Volume of a Regular Tetrahedron
The ratio of Volume/Surface Area is about 0.068a for the tetrahedron. This ratio is not as favorable as other regular shapes:For the sphere, Volume/Surface Area is 0.33r (where r is the radius)For an ideal cylinder with radius equal to height (the optimal condition), Volume to Surface Area is 0.25r.For a cube, Volume/Surface Area is 0.17a (where a is the edge length).
However, the simplicity of construction of the tetroon, with fewer straight seams, makes it a very attractive shape.
You are correct that the float altitude can be calculated for the superpressure balloon. You need to know the mass of the payload, balloon fabric, and other attachments (parachute, cut down device??). You also need to know the density and initial volume of the lifting gas. The float altitude will be where the buoyant force of the lifting gas equals the weight of everything that is being floated.
I agree that floating above 60 kft is desirable for a long duration flight.
Howard, KC9QBN
From: "cgoldsmith@..." <cgoldsmith@...>
To: GPSL@yahoogroups.com
Sent: Sunday, September 22, 2013 10:14 PM
Subject: [GPSL] RE: Foil Balloons
Joe,I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.Anybody else have any advice for us mylar newbies?Chuck / KG5CA
 In GPSL@yahoogroups.com, <nss@...> wrote:
With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD
 0 Attachment
On Mon, Sep 23, 2013 at 7:49 AM, Joe <nss@...> wrote:
> ok what happens with a cylinder vs length?
Well, when you increase the length of the cylinder, it obviously gets
>
> If a 4 foot circumference cylinder was made, (4 foot is the width of the material so only 1 seam)
>
> what changes if the cylinder is 10 feet long 20 feet long 100 feet long?
longer, and you have more volume enclosed.
Take a trip back to junior high school math:
http://math.about.com/od/formulas/ss/surfaceareavol_3.htm
Your surface area to volume ratio decreases as you get further and
further away from a sphere.

James
VE6SRV 0 Attachment
Well yeah Duh? I was meaning, envelope stresses, envelope area vs volume, etc.
Joe WB9SBDOn 9/23/2013 11:15 AM, James Ewen wrote:
On Mon, Sep 23, 2013 at 7:49 AM, Joe <nss@...> wrote:
ok what happens with a cylinder vs length? If a 4 foot circumference cylinder was made, (4 foot is the width of the material so only 1 seam) what changes if the cylinder is 10 feet long 20 feet long 100 feet long?
Well, when you increase the length of the cylinder, it obviously gets longer, and you have more volume enclosed. Take a trip back to junior high school math: http://math.about.com/od/formulas/ss/surfaceareavol_3.htm Your surface area to volume ratio decreases as you get further and further away from a sphere.
 0 Attachment
On Mon, Sep 23, 2013 at 10:22 AM, Joe <nss@...> wrote:
> Well yeah Duh? I was meaning, envelope stresses, envelope area vs volume, etc.
I guess you never bothered to follow the link then... it gave you the
basic calculations for area vs. volume.
Envelope stresses were never covered in junior high school. If you do
hang a lot of mass from a tie off point at one end of the cylinder,
you will pinch the end down to a point, changing the shape.
At some point, you could potentially tear the end off the cylinder
once your mass exceeds the strength of the material. I doubt however
that you would ever get to that point with a 4 foot circumference
cylinder. The law of diminishing returns would keep your total payload
mass too low.

James
VE6SRV 0 Attachment
Hi Chuck,
While researching tetroons, I found a link on Wikipedia that
detailed the surface area, volume & mass of a tetrahedral balloon
envelope  but sadly, I can't pull it back. Might give it a shot
yourself. Most of the tetroon stuff I found was related to hot air
balloons, but same principles should work for a gas balloon.
73 de Mike W5VSI
On 9/22/13 8:14 PM, cgoldsmith@... wrote:
> I wonder if anybody has worked out the volume/surface area of the tetroon? 0 Attachment
Joe,I visitied Vin Lally at NCAR in the late 1980's and he gave me a reprint of his detailed article about designing and performance of Tetroons. I'll look for that article since it was a good one. You might be able to find it in the NCAR archives somewhere. Try searching for Vin Lally Tetroon. Bill WB8ELKChuck,Here are the basic equations for a regular tetrahedron with edges of length a (from http://www.vitutor.com/geometry/solid/tetrahedron.html)Surface Area of a Regular Tetrahedron
Volume of a Regular Tetrahedron
The ratio of Volume/Surface Area is about 0.068a for the tetrahedron. This ratio is not as favorable as other regular shapes:For the sphere, Volume/Surface Area is 0.33r (where r is the radius)For an ideal cylinder with radius equal to height (the optimal condition), Volume to Surface Area is 0.25r.For a cube, Volume/Surface Area is 0.17a (where a is the edge length).However, the simplicity of construction of the tetroon, with fewer straight seams, makes it a very attractive shape.You are correct that the float altitude can be calculated for the superpressure balloon. You need to know the mass of the payload, balloon fabric, and other attachments (parachute, cut down device??). You also need to know the density and initial volume of the lifting gas. The float altitude will be where the buoyant force of the lifting gas equals the weight of everything that is being floated.I agree that floating above 60 kft is desirable for a long duration flight.Howard, KC9QBN
From: "cgoldsmith@..." <cgoldsmith@...>
To: GPSL@yahoogroups.com
Sent: Sunday, September 22, 2013 10:14 PM
Subject: [GPSL] RE: Foil BalloonsJoe,I was also thinking along the same lines. If you want something to float for days, the mylar balloon foils have been optimized for strength and low gas diffusion, and are not bothered by UV. I have been checking out the Balloonkts.com website, where they have some decentsized rolls of foil at inexpensive prices. Gary Felix, the guy that runs the site, says their foil is 48 gauge (12 um), 29g/sq yard, pull strength of 4 lbs/linear inch, and only loses 4% helium per year (can that be true?  amazing).A sphere is always optimal in terms of volume/surface area ratio, but it is pretty hard to construct from long rectangles/strips of material. A cylinder can come close to the same performance if the radius of the cylinder is large. I wonder if anybody has worked out the volume/surface area of the tetroon?Mike is right, there seems to be a good number of videos on assembling tetroons, I like http://www.youtube.com/watch?v=_cVp8EKtgTA The simplicity of assembly seems to make it quite popular.I was wondering if it is straightforward to calculate the altitude that the balloon will float? I imagine the altitude where the gas expands to occupy the max volume of the envelope must be close to where it will cease to be buoyant and float. My concern in building a large mylar floater is that it needs to travel well above the aircraft lanes. Having a balloon drift for days at aircraft altitudes, being visible on radar (metallized mylar right?) would not be a career advancing event.Anybody else have any advice for us mylar newbies?Chuck / KG5CA
 In GPSL@yahoogroups.com, <nss@...> wrote:With the recent success of these foil balloons, it has made me somewhat interested in them and their possibilities for long duration flights. Their ability to"Superpressure"
Now I wonder, what would be the better way to go? See I have literally thousands of feet if not miles of an aluminized mylar in rolls that are in varying widths from only 2 feet wide to almost 4 feet wide.
Now this also has the heat sensitive adhesive backing on it too. I just cut a large square of it, and weighed it to see what it weighs, and it comes in at 0.1768 oz per sq ft.
Now everyone what configuration think would be best?
Many small balloons, like a cluster balloon system?
A long cylinder
or
a like tetroon type?
Thoughts?
Joe WB9SBD 0 Attachment
this one?
http://en.wikipedia.org/wiki/Tetrahedron
Joe WB9SBD
On 9/23/2013 1:36 PM, Mike Manes wrote:
Hi Chuck, While researching tetroons, I found a link on Wikipedia that detailed the surface area, volume & mass of a tetrahedral balloon envelope  but sadly, I can't pull it back. Might give it a shot yourself. Most of the tetroon stuff I found was related to hot air balloons, but same principles should work for a gas balloon. 73 de Mike W5VSI On 9/22/13 8:14 PM, cgoldsmith@... wrote:
I wonder if anybody has worked out the volume/surface area of the tetroon?
 Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/GPSL/ <*> Your email settings: Individual Email  Traditional <*> To change settings online go to: http://groups.yahoo.com/group/GPSL/join (Yahoo! ID required) <*> To change settings via email: GPSLdigest@yahoogroups.com GPSLfullfeatured@yahoogroups.com <*> To unsubscribe from this group, send an email to: GPSLunsubscribe@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://info.yahoo.com/legal/us/yahoo/utos/terms/
 0 Attachment
A fairly recent development in foil balloon film technology that claims to reduce He leakage by 3 to 5 times, not simply due to the impervious nature of the film, but from better seam bonding. Trade name is Anagram XL (XtraLife), film manufacturer is Toray Plastics, balloon manufacturer using it is Anagram. I believe patent US8236399 at Google Patent server describes it:
http://tinyurl.com/k43wfom
Anagram responded to my email and said they do produce plain silver 36" diameter round (not spherical) foil balloons. I have no idea how to go about obtaining sheets of this material in hobbyist quantities. 0 Attachment
Hi guys,
One advantage of the tetroon is that it's simple to figure out
where to attach the beacon load; not so simple for a cylinder, where
the load would tend to collapse the bottom of the cylinder unless it
were reinforced with a spreader ring.
re making one that floats above the NAS (above 60K'): that will require
an envelope volume about 10X that of the fill, and that may get pretty
heavy.
The tough part in making any SP balloon is getting adequate seam
strength to tolerate peak gas pressure during the day while remaining
fully inflated overnight. The thermodynamics boggles ...
73 de Mike W5VSI
On 9/23/13 8:42 AM, BASE wrote:
> Joe,
>
> The simple answer is that the performance, as compared to a spherical
> shape enclosing the same volume gets worse.
>
> Here are some quick numbers:
>
> The circumference of the cylinder is 4 feet. This makes the radius of
> the cylinder 0. 64 feet.
>
> Cylinder height (ft) Cylinder Volume(cu. ft) Cylinder Surface
> Area(sq.ft) Equal Volume Sphere S.A.(sq.ft)
> 4 5.1 18.6
> 14.3
> 6 7.6
> 26.6 18.7
> 10 12.7 42.6
> 26.2
> 20 25.5 82.6
> 41.4
> 100 127.3 402.6
> 119.6
>
> Short height cylinders are not much worse than the sphere, but as the
> height increases things you have a lot more surface for equal volumes.
>
> Howard
> 0 Attachment
Yeah, that's where I started. The details on volume, mass, area and
heat transfer may be in one of those links or its references.
 Mike
On 9/23/13 1:19 PM, Joe wrote:
> this one?
>
> http://en.wikipedia.org/wiki/Tetrahedron
>
> Joe WB9SBD
> Sig
> The Original Rolling Ball Clock
> Idle Tyme
> IdleTyme.com
> http://www.idletyme.com
> On 9/23/2013 1:36 PM, Mike Manes wrote:
>> Hi Chuck,
>>
>> While researching tetroons, I found a link on Wikipedia that
>> detailed the surface area, volume & mass of a tetrahedral balloon
>> envelope  but sadly, I can't pull it back. Might give it a shot
>> yourself. Most of the tetroon stuff I found was related to hot air
>> balloons, but same principles should work for a gas balloon.
>>
>> 73 de Mike W5VSI
>>
>> On 9/22/13 8:14 PM,cgoldsmith@... wrote:
>>> I wonder if anybody has worked out the volume/surface area of the tetroon?
>>
>