The Blimp Envelope



The physical implementation of the robot uses a lighter than air vehicle (LTAV) in the form of a helium filled balloon (blimp). The blimp consists of a two-panel metalised nylon envelope 96.5cm in diameter uninflated, which once filled has the shape of a squashed sphere 0.75m in diameter. The envelope has a small non-return valve to facilitate inflation with the desired lifting gas; this valve can be opened using a tube to allow the envelope to be deflated for storage or replenishment of the gas. If the envelope is split or damaged it can be easily repaired using cellophane tape or 'Sellotape'. The volume of the envelope is approximately 0.3m3 giving a net lifting capacity of 93g when filled with Helium/Air balloon gas, this gas is only 93% Helium making it much cheaper than pure Helium with a negligible difference in its lifting capacity. Using Hydrogen would only give a slight improvement in the payload capacity over Helium but would be potentially very dangerous, as Hydrogen is an explosive gas. A spark from one of the motors could ignite any Hydrogen leaking from the envelope, having disastrous consequences.