In article , Mike Coslo
writes:
Len Over 21 wrote:
Have you looked at Federal Air Regulations in regard to such
high altitudes? This isn't like hot-air ballooning at low altitudes
where manned free balloons have rights of way over all others.
Yes, I have. They are surprisingly accommodating.
"Accommodating" whom? You didn't sumarize, compose a precis
or anything else. What does the FAR SAY?
Back in the 60s the weather folks used to loft a quarter million or
so weather balloons per year...with little transmitters in them and
telemetry done with extremely low-cost electronics. Good example
of doing things simply and for low cost per launch.
And they still are. One big difference is that they don't attempt to
get their payloads back. They do have a return address on them, and
there is about a 20 percent return rate. That surprised me a bit.
They are? How do you know?
You need to consult some (free for the asking) density values of
the atmosphere and some back-of-the-envelope figuring first. Note
that you have to allow for the lifting gas expansion with altitude. It
is far from the same at 100 kilofeet versus sea level.
Welp, since you didn't really look, here's a capsule from an on-line
calculator:
At 1000 feet, temp 55.4 F, 14.17 PSI, density 1.1896 Kg/cubic meter.
At 10K feet, temp 23.3 F, 10.11 PSI, density 0.9046 Kg/cubic meter.
At 100K feet, temp -50.8 F, 0.1581 PSI, density 0.0167 Kg/cubic meter.
Notice how the DENSITY drops off at a remarkable rate past 10,000
feet. [Density is going to be very important since it will determine
the limit of buoyancy of the whole balloon]
Two words: Payload weight.
You can't get up in the blue sky with lack-of-detail blue sky ideas.
Quite seriously, I was making a mini pitch here on the newsgroup. To
think that I gave the entirety of my knowledge on the subject is, well,
wrong.
Tsk. I didn't see much of any "knowledge" displayed, or any sort of
hard science. The Standard Atmosphere has been public for over a
half century, most countries. While the 1976 model has been revised
a couple times since, the basic data is mostly in refinement.
If it were that easy, lots and lots of folks would have done so a
half century ago.
Back when we had those coal burnin' GPS satellites!
Many, MANY balloons have been lofted (other than rawinsondes)
BEFORE the precursor to GPS, NAVSTAR, was first launched.
That was around 1971 or better than 33 years ago.
Neither GPSS nor NAVSTAR nor GLONASS used "coal" to burn
for anything.
The experiments vary. One of the favorite devices for the grade and
middle school kids is something called a pongsat. This is an experiment
that can be anything that will fit inside a ping-pong ball. Sounds
weird, but there are plenty of small scale experiments that fit the
bill... er, ping-pong ball.
The balloon lifts the payload to the predetermined altitude, and
bursts. The payload drops, and the Ham comms can continue during
descent, although the first few moments after burst can be pretty weird
as the payload often does some pretty strange gyrations until the
parachute can grab some atmosphere. Drops like the proverbial rock.
All this time, the GPS is keeping track of the whereabouts of the
payload. Then at landing, it turns into a foxhunt as the hams use the
beacon transmissions to find the payload. With the advent of us getting
used to the software and the precision with which the GPS can determine
the location, it is not too uncommon for the recovery team to witness
the landing.
Launch of one of these things does not take as much bureaucratic red
tape as most people think.
You've done that? You are going to the edge of the stratosphere and
think you can do so freely? Ain't quite that easy.
With all due respect:
http://www.eoss.org/faq/faa_liaison.htm
Sorry, sport, but 100 kilofeet of altitude is something you will NOT
do with some surplus "latex weather balloons."
10 kilofeet maybe.
It has to do with BUOYANCY. As the density drops, so does the
"lifting power" of the displaced air (from the balloon itself).
Worse yet, as the altitude increases, the pressure drops but the
lifting gas inside the balloon remains at the same pressure...which
will drop depending on the expansion capability of the balloon
material. At some point, the differential pressure can exceed the
strength of the balloon material. Pop goes the balloon.
Could you cite where you got your information?
Yes, I can. Old stuff, really. You can do a search under "standard
atmosphere" and get a whole pot of hits, from NASA through
ordinary-folk sites (some having on-line calculators). There's
enough material in basic text books on atmosphere plus gasses.
And it can be done for surprisingly little money.
"Surprisingly little" is a highly subjective term. Real projects have
quite objective, finite budgets.
And you expect me to post my budget here? "Suprisingly little" is
precise enough for general notes in here.
So far, you've been only as concrete as a pipe dream. Ambiguous
statements.
Now you get all hurt because I post some HARD science figures which
WILL come and bite your project's butt if you don't start getting some
non-ambiguous numbers.
Sounds like you've already filled the "executive" position. :-)
Yes I have. I do this kind of stuff. Some years ago, I organized and
pulled off one of the premier star parties in the Northeast. That
actually took much more red tape than this project. The party is still
going on, although under the new management, it is not as profitable,
despite growing numbers of attendees.
I like organizing groups of people that share a common task.
Wanna help?
"Help" who? Mike Coslo making a name for hisself?
Sorry, in that I am definitely NOT involved.
Balloons have been launched from USA soil for over 200 years.
"New" they are NOT.
This is real stuff. This might spark the interest in science in some
youngster. And that is not only a career choice, but a service to the
country. American scientists are becoming pretty rare.
Tsk. Those "rare" American scientists are still being awarded
Nobel Prizes. Even this year.
"Becoming pretty rare?" Not quite as any visit to academia will
show but feel free to get opinionated.
Heh, Better check the citizenship of those engineering students.
Its great publicity for Amateur radio.
Is it? The globe has been circumnavigated by balloon, millions of
those radio-carrying rawinsondes have been launched and tracked
(by radio, no GPS needed) since they were started. Kids can get
balloons as giveaways in larger stores...or are given out at parties.
It will get ham radio noticed, but what is written up by journalists
may not be what you expect.
Free ballooning has been going in the USA since 9 January 1793,
the first American flight by Frenchman Jean-Pierre Blanchard,
lifting off from the Walnut Street Prison in colonial Philadelphia.
That was witnessed by none other than President Washington.
[from "Lighter Than Air Flight" by Lt. Col. C. V. Glines, USAF,
Franklin Watts Inc., NYC, 1965, data from pp 29-35] That's over
two centuries of time...
Thanks for the balloon history.
Tsk. LOTS more "history" available. I just picked a book from the
shelf at home. Got more on lighter-than-air-flight.
And we can innovate and experiment. Radio is a pretty mature science
now. It's doubtful that any of us are going to invent a grand new
communication scheme, or an antenna that does DC to daylight, or even
one that is a whole lot better than what we have now. So What we need to
do is to integrate what we have now, and do some innovation with it. We
also need (or at least should) prove our worth to the community.
That we can do it while having fun is a real bonus.
You can have all your innovative fun doing many, many things.
Until you find out what helium costs to lift the total balloon (the
balloon itself, its payload, its carrying structure, its all going to
be a pipe dream having no more basis than enthusiasm.
Wanna help?
Sorry, I'm not "involved."
Too much "hot air" being generated on this "idea" and it hasn't
"lifted" me.
Read the links (just a suggestion - I know you don't like being told
what to do) Check out the links. Do a little homework.
"Do a little 'homework?'" Will there be a "test?"
I've been involved in basic atmospheric data at work for decades
AND have done a bit of lighter-than-air flight experiments as a
hobby...including some careful measurements of structures and
gas bag material, lifting power versus temperature and local
pressure, etc.
I usually give you a pass on most things. But dozens of amateurs are
doing this. Now, with real payloads, inexpensively.
You are very, very wrong.
You are very, very petulant.
You give some ambiguous phraseology to the group with a bad "sell"
image and try to flummox someone with the "it's all for ham radio!"
spiel. Not a good way to get a project started.
HARD NUMBERS will give the story's baseline...followed by some
kind of estimate of project cost. The best way is to have some kind
of "rep" behind you.
Case example: Maynard Hill was the builder and trier-outer of the
TAM project (Trans-Atlantic Model). He had been setting model
records (recorded by FAI) for a mere 35 years, mostly in R/C flying
(altitude way up to the 20s of kilofeet, distance better than 750
miles to name two). His local club knew it and formed the "STAR"
group to get in on the TAM. It took OVER two dozen airframes
(built by Hill) to get to the 2003 record breaker after two prior years
of all involved footing their own bills to reach Newfoundland and
Ireland. By the way, amateur radio WAS involved in that effort.
Hill didn't have a big "salesman" pitch. He isn't the type. He
tries...and doesn't make a big noise about it whether winning or
losing...but he generally WINS much more than losing. No blue
skies approach with ambiguous numbers and amorphous
statements..."here's what I think it can do..." followed by some
estimates which were based on lots and lots of past performance.
Now NONE of that model flying thing has any relation to ham
radio (other than ham radio being a help in it) but it DOES serve
to demonstrate that a purely hobby pursuit CAN do things...based
on the can-do types having shown that they can in the past.
So, you want "help?" When you can't even cite some stuff from
the Standard Atmosphere that's been around for longer than half
a century? Not likely from me.