[chbot] Sundays balloon-adventure, report please

[Chris Hellyar]

Just looking at the pictures.
 
I went a different way for the payload.  I had a rigid blue foam 'box' with Aluminium foil stuck to the outside using spray adhesive.  Seemed to the the lightest way to get a box that wouldn't freeze, and the tinfoil made it look cool. :-)
 
On your slow ascent and bearing in mind this is from vague memory.. I think I needed an 8ft diameter balloon to lift 750gm fast enough to guarantee not getting into controlled airspace launching from up near Springfield. I found a rate of ascent vs payload vs air temp vs gas volume vs burst height formula somewhere on the web.
 
Hmm, I'm gonna have to stop reading this.  I already have waaaayyy to may projects on the go!
 
Cheers, Chris H.
 
-----Original Message-----
From: "André Geldenhuis" <andre.geldenhuis at gmail.com>
Sent: Tuesday, 8 January, 2013 23:34
To: "Christchurch Robotics" <chchrobotics at lists.linuxnut.co.nz>
Subject: Re: [chbot] Sundays balloon-adventure, report please





On Tue, Jan 8, 2013 at 9:25 PM, Chris Hellyar <[mailto:chris at trash.co.nz] chris at trash.co.nz> wrote:


900gm is good going for all that gear       without getting very specialised, especially with two cameras in       the mix.

 Without digging out all my olds notes my weight budget was 750gm       and the 3W TX which was the guts of a miniature handheld was about       80gm, so 80x the weight of your TX!! :-).

 I was only planning one camera but at the time I was having       problems finding a tracker/GPS that would work at high altitude       and something else shiny caught my eye...  I've still got the bits       in a box somewhere.

That's a good weight :)  I really recommend the Venus GPS units, I really like them and they do work about 60f feet.  There is also a high dynamics firmware available for them which I am keen to test out on a rocket some time.

Andre
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