We are using a 1200g balloon, which will have a 28′ diameter when it finally bursts. Our payload capsule, fully loaded with 2x SainSonic AP510 APRS tracker, 1x SPOT tracker, 10x GoPro cameras and the Rocketman 4ft parachute is weighing a little over 2.1kg.
Velocity, altitude and Gas details
Assuming a 2100g weight and a 6.5m/sec ascent rate, our calculations show us that we should be able to reach 29,700 meters of altitude in 78 minutes (does not include descent time) using 196 cubic ft of helium with a total lift of 4500g.
We will be using a Sainsonic AP510 APRS Ham radio tracker as our primary tracking mechanism (KF7LKI-11). This will be configured to broadcast location, altitude and temperature every 1 minute for the duration of the flight. As a backup, we are including another APRS tracker (KF7LKI-12) and a Spot GPS Satellite tracker that will report a location every 5 minutes.