> http://uk.news.yahoo.com/4/20100325/tuk-british-balloon-man-s-amazing-spa=
ce-dba1618.html

> This free-floating one goes to 21 miles. The balloon expands to 22m
> and eventually pops. The camera parachutes back down and he tracks
> a transmitter to recover it. Sounds like a fun day out

Reminds me of a line of thought I had a few months ago when i was
wondering if I could send notes etc to my children by such a means.

Adding two pivotable drag fins at 90 degrees a bit of anti spin
finning should allow you to achieve basic guidance. Fly home to launch
site, or somewhere else, without two much effort. Std GPS stops
working at I-forget metres so you may have to get clever with
topographical recognition, but that should not be too too hard, and a
compass would be enough for direction and the simplest of radio
beacons give you approximate "where am I " capability until GPS was
usable. If you were aiming at substantial; cross range then RDF on eg
a televsion transmitter until the GPS returned would be enough.

At 20 miles / 100,000 feet / ~30 km a 1:1 glide ratio gives you 1:1
downrange range.

Drop a suitably wingy glider at apogee with a 10:1 glide ratio and you
start to go places.

According to me in December 2007
http://old.nabble.com/U2-flight-to-70,000-feet---superb-td14453905.html
a U@ achieved 28:1 glide ratio for 200 miles glide range from 70,000 feet.

To reach my son from here I'd need about 50:1 glide ratio
(Christchurch NZ) which is hardly seriously doable and to send
brochures to my daughter needs about 100:1 + (Canberra Oz) . So both
seem safe from this form of missive delivery.

English Channel type ranges would be very doable.

Model-glider + balloon launch systems could be a lot of fun - and GPS
would be available at all sensible altitudes.

It would be interesting to see what sort of return accuracy GPS would
allow with simple guidance. Possibly too interesting :-(. =A0Presumably
many people have though of this and similar already.


=A0 =A0 =A0R

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