noun

• A separate gas- or air-filled compartment within the main envelope of a balloon or airship, designed for the maintenance or adjustment of the envelope's shape, buoyancy, or orientation.

  ‘The helicopter is fitted with ballonet flotation devices for emergency landing on water.’

  More example sentences

  • ‘As a rule, such airships have a soft structure of a ballonet and consequently a considerable drag.’
  • ‘This triggers an automatic mechanism that pumps air into the ballonet compartment to compensate.’
  • ‘The envelope is a helium gas cell, with an air ballonet which is pressurized by a ballonet fan.’
  • ‘The altitude at which all air has been removed from the ballonet is referred to as the pressure altitude.’
  • ‘Prior art methods of pressurizing and filling the ballonets typically involved the use of ram air scoops.’
  • ‘Besides, it is possible to go to the fore and aft set of the ballonets and into the gas volume.’
  • ‘As a rigid airship, it had no need of ballonets, which are used only in pressure airships, or blimps.’
  • ‘The pressure inside the ballonet acts on the helium inside the envelope to maintain the shape.’
  • ‘Unless perfectly synchronized, dual ballonets tend to tip the craft toward the tail or nose.’
  • ‘The pilot controls the ballonet, so there is no need to ‘valve off’ the expensive helium gas.’
  • ‘Therefore ballonets are needed for semi-rigid airships to keep the envelope pressure constant.’
  • ‘That latitude is provided in the form of collapsible air bags, called ballonets, inside the helium envelope.’
  • ‘The pressure of the helium in the envelope is adjusted by changing the amount of air in the ballonets.’
  • ‘The ballonet is an airtight bag which allows the density of the blimp to be adjusted by adding or releasing air.’
  • ‘The initial design of the ballonet size will determine an individual airship's maximum change of altitude capability.’
  • ‘When the ballonets are filled with air, the dense air contained within different balloons but the same envelope as the helium has an effect on the buoyancy.’
  • ‘The two air chambers inside the envelope called ballonets can be expanded and contracted to add or subtract weight from the nose or the tail, trimming the airship.’
  • ‘Air is pumped in to or out of these ballonets to adjust the helium pressure.’
  • ‘Air is squeezed out of the ballonets as the gas expands with increasing altitude and forced back in again as the helium contracts when the airship descends.’