Trajectories of Rubber Balloons used in Balloon Releases: Theory and   Application
  Balloon releases are one of the main attractions of many fairs. Helium filled rubber balloons are released to carry postcards over preferably long distances. Although such balloons have been considered in atmospheric sciences and air safety analysis, there is only scarce literature available on the subject. This work intends to close this gap by providing a comprehensive theoretical overview and a thorough analysis of real-life data. All relevant physical properties of a rubber balloon are carefully modelled and supplemented by weather observations to form a self-contained trajectory simulation tool. The analysis of diverse balloon releases provided detailed insight into the flight dynamics and potential optimisations. Helium balloons are found to reach routinely altitudes above 10 km. Under optimal conditions, they could stay more than 24 hours airborne while reaching flight distances close to 3000 km. However, external weather effects reduce the typical lifetime to 2-5 hours. 
Patrick Glaschke
physics.pop-ph physics.ao-ph