On Mar 2, 11:03*pm, Jim Logajan wrote:
"Paul Remde" wrote:
I was planning on including a parachute
so it won't land hard if all the balloons pop,

I presume the parachute (or perhaps a simple cloth drogue?) would already
be deployed - it'd hang limp (most of the time) till needed.

But I don't want to do it if it is not safe, or not legal, etc. *I
don't want to "take my chances" that it will be safe - unless the
risks are miniscule.

As far as I can tell it can be done legally since a SPOT allegedly weighs
only 209 gms (~7.4 oz) and the smallest surface is ~4.7 in^2, or ~1.6
oz/in^2 -- well under the 3 oz/in^2 specified by 101.1(a)(4)(i). (Numbers
extracted from the specs on the SPOT web site.)

I'd be mindful of 101.7 when determing when and where to launch. I'd launch
in clear weather and use 101.33 as a guideline (even though it isn't
applicable to such a small balloon.) So if the worst happens I'd have shown
intent to not launch in a hazardous manner.

I don't know what the probability is of it causing an accident, but I'd
guestimate it is indeed miniscule. Infinitesimal probability of a
collision, multiplied by a small amount of damage, multiplied by the
probability that small amount of damage yields fatalities.

Bottom line is I would not personally have any issue if such a balloon were
launched while I was in any sort of aircraft in the same area.

With the right size balloon you might be able to fit the Spot inside
the balloon envelope. I'm guessing that would reduce the chances of it
striking anything directly as the upwash ahead of any moving object
would tend to deflect it - plus you get a built-in airbag. Anyone
who's seen a balloon on a freeway can understand that.

As to the turbofan scenario - jet engines are designed to eat birds up
to 5 lbs (as Capt Sully found out to his dismay, geese are bigger). I
can't imagine a Spot is any tougher than a duck. You'd get some damage
I'd bet, but I doubt it'd be catastrophic.

With a little effort you could balance things so the balloon didn't
get into the Class A. For instance a small pinhole would allow helium
out at a rate to ensure that the balloon didn't get too high or go too
far - how long a chase do you want anyway? If you release it away from
and downwind of any significant terminal areas your odds of hitting
anything are infinitesimal.

Given all the time lags associated with Spot messages I doubt you'll
be able to track the thing close enough to actually see it until it's
already on the ground. Also, you'd have to worry about lakes and maybe
forests as possible unhappy endings. Without a good wide area wireless
connection you will have trouble tracking it in real time from the
road, so you'll have to wait for it to land, get a fix and go find it.

Overall it sounds a bit like you've run out of ways to entertain
yourself over the winter. ;-)

9B