Airship & method of operation

Abstract

This invention relates to the field of buoyant aircraft and operation thereof, in particular, airships with improved stability. The present invention is directed to non-rigid, non-spherical airships having an envelope contained within the airship and at least one further envelope contained therein for holding a volume of lifting gas.

1 . A non-rigid, non-spherical airship comprising:
 a first envelope defining a hull having a first volume;   a second envelope contained within the first volume and the second envelope defining a second volume; and   a third envelope contained within the second volume and defining a third volume for holding a volume of lifting gas.   
   
   
       2 . The airship of  claim 1  wherein a fourth envelope is contained within the second volume of the second envelope. 
   
   
       3 . The airship of  claim 2  wherein the fourth envelope substantially arrests the movement of the third envelope within the second envelope. 
   
   
       4 . The airship of  claim 3  wherein the airship is capable of aerobatic flight. 
   
   
       5 . The airship of  claim 1  wherein the first envelope provides for fluid communication between the first volume and an exterior of the airship. 
   
   
       6 . The airship of  claim 5  wherein the second envelope provides for fluid communication between the second volume and the first volume. 
   
   
       7 . The airship of  claim 6  wherein the third envelope is sized to accommodate expansion of the volume of the lifting gas contained within the third envelope as the airship ascends. 
   
   
       8 . The airship of  claim 7  wherein a portion of the second volume not containing the third envelope decreases with the expansion of the volume of the lifting gas contained within the third envelope while the total of the portion of the second volume not containing the third envelope and the volume of the third envelope remains generally constant. 
   
   
       9 . The airship of  claim 7  wherein the expansion of the lifting gas is up to approximately 19 fold. 
   
   
       10 . The airship of  claim 9  wherein the airship has a service ceiling of greater than 10,000 ft. above mean sea level. 
   
   
       11 . The airship of  claim 9  wherein the airship has a service ceiling of greater than 18,000 ft. above mean sea level. 
   
   
       12 . The airship of  claim 9  wherein the airship has a service ceiling of greater than 40,000 ft. above mean sea level. 
   
   
       13 . The airship of  claim 9  wherein the airship has a service ceiling of greater than 60,000 ft. above mean sea level. 
   
   
       14 . (canceled) 
   
   
       15 . (canceled) 
   
   
       16 . (canceled) 
   
   
       17 . (canceled) 
   
   
       18 . (canceled) 
   
   
       19 . A ballonet for an airship comprising:
 a first envelope having a first volume;   a second envelope contained within the first volume and having a second volume for holding a volume of lifting gas, the second envelope sized to accommodate an expansion of the volume of the lifting gas contained in the second envelope such that the volume of the second envelope expands as the volume of the lifting gas expands; and   wherein a portion of the first volume not containing the second envelope decreases with the expansion of the second envelope while the sum of the portion of the first volume not containing the second envelope and the volume of the second envelope remains generally constant.   
   
   
       20 . The ballonet of  claim 19  wherein the first envelope provides for fluid communication between the first volume and an exterior of the first envelope to maintain the sum of the portion of the first volume not containing the second envelope and the volume of the second envelope generally constant. 
   
   
       21 . An airship having the ballonet of  claim 19 .