U3B-12 uses callsign VE3KCL and telemetry channel 04. The balloon was launched on 03-Dec-2017. The map below shows live tracking, but there is no tracking available after dark and when the battery has discharged. There also be no tracking if the balloon travels far enough North that the winter sun is not high enough in the sky to provide sufficient light for the solar panels to charge the battery. About 8 degrees above the horizon is expected to be required.
Some progress North-East...
Dave successfully launched U3B-12 and it climbed to around 9,000m. The predicted trajectory (see below) takes it over Iceland, the noon sun in winter does not get more than 2-3 degrees above the horizon. This is probably not enough light to charge the batteries, so there may be no reports from the balloon tomorrow and until it travels further south. Dave writes:
"Heading for Iceland which has no sun at noon 2-3 degrees and then down into Europe so there could be a blackout tomorrow.
100mah battery charged to full in about 3 hrs today from lowest of 3.7v
It barely got over freezing in the foam today... and this is not great for charging lipos"
A few notes from Dave on the U3B-12 flight:
"used a chinese clear balloon with terrible seals so had to redo them with a sealer
Stretched the balloon to 118% with air, then sucked out the air and put in hydrogen
Used .45psi air to stretch the balloon
At float about 9km now, the internal pressure is .35 psi approx if the balloon expands that internal pressure should go down.
These Chinese balloons do no like to stretch in the cold
From data it looked like the solar panels started helping at about 6 degrees of sun elevation
I was looking for 8 degrees to run the thing... we will know tomorrow with a dead battery to be charged"