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Launch 3

This page tracks Launch 3, planning in progress, a foil balloon launch.

Bill of Materials


Just the one: HABTRK


Single Energiser Lithium AA or AAA

  • AA - 3,000 mah, 15g
  • AAA - 1,250 mah, 8g

Going to use a single AA for my first flight - the voltage drop from a AAA whilst the GPS is getting a fix is quite high and the boost converter I am using fails to maintain the voltage required to the GPS and it resets after a couple of hours in the freezer.


36” Qualatex silver “foil” balloon

Approximate weight of 37g, approximate internal volume of 0.1cu m before envelope stretching.

This means they can lift payloads of approx. 60g (or slightly more if you allow for stretching). However experimenters typically aim for payloads of the order of 20 - 40g per balloon in order to attempt to make them float.





Tracker including aerial - 13.8g

Battery including lead - 16.2

Insulation ~ 7

Total = 39g


Looking through the data here:[]=foil

and modifying the predictor from here:

with a balloon weight of 37g, a burst diameter of about 0.70m is the best estimate I could make for a 'if it bursts' flight path with a Descent rate of 5m/s.

Based on a 39g payload, to get an ascent rate of 1m/s = 3.5g free lift

Flight Document

Flight Document created

Doc ID: c5c392ef5958c9dce8ffd58920297444 Document: {“type”:“flight”,“approved”:false,“name”:“G7PMO Launch 2”,“start”:“2013-08-07T00:00:00+01:00”,“end”:“2013-08-07T23:59:59+01:00”,“launch”:{“time”:“2013-08-07T10:00:00+01:00”,“timezone”:“Europe/London”,“location”:{“latitude”:52.3,“longitude”:-0.7}},“metadata”:{“location”:“Wellingborough, Northamptonshire, UK”,“project”:“G7PMO”,“group”:“Kevin Walton”},“payloads”:[“e55cc3ffb42062c70087dae3d9520903”]}

Launch Announcement

Launching Wednesday 7th August around 10am a single tracker foil launch, from a site near Wellingborough (Northants).

Primary tracker: RFM22B based, $$HABTRK, 434.150Mhz (434138400 on my rx), USB, RTTY, 470Hz Shift, ASCII-7, 50 Baud, Parity none, 1 Stop bit

$$HABTRK, id, time, lat, lon, alt, sats, vinmv, rfm_temp.

Documentation is here:

Track it here: or

Predictor based on Marston launch here: or anywhere or

Burst predictors are linked from here:

projects/jimbob/launch3.txt · Last modified: 2013/08/07 07:41 by kevwal

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