US2008264952A1PendingUtilityA1

Envelope For Lighter-Than-Air Aircraft

40
Individually held — no corporate assignee on recordPriority: Apr 27, 2007Filed: Apr 27, 2007Published: Oct 30, 2008
Est. expiryApr 27, 2027(~0.7 yrs left)· nominal 20-yr term from priority
Inventors:Adam N. Chu
B64B 1/14
40
PatentIndex Score
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Cited by
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References
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Claims

Abstract

An envelope is disclosed for holding gas in a lighter-than-air aircraft. The envelope includes a shell having upper and lower hemispheres. The upper hemisphere has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii and a polar radius. The lower hemisphere has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii and a polar radius. The lower hemisphere is inverted compared to the upper hemisphere. The equatorial radii of the upper hemisphere are equal to the equatorial radii of the lower hemisphere. The upper hemisphere is joined with the lower hemisphere at their respective equators. The volume of the upper hemisphere is greater than the volume of the lower hemisphere. The height of the shell is less than the diameter of the shell at the joined equators.

Claims

exact text as granted — not AI-modified
1 . An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
 a shell including
 an upper hemisphere having the shape of a hemisphere of a first generally oblate spheroid defined by first and second equatorial radii and a polar radius and 
 a lower hemisphere having the shape of a hemisphere of a second generally oblate spheroid defined by first and second equatorial radii and a polar radius, wherein the lower hemisphere is inverted compared to the upper hemisphere, the equatorial radii of the upper hemisphere are equal to the equatorial radii of the lower hemisphere, and the upper hemisphere is joined with the lower hemisphere at their respective equators, 
   wherein the volume of the upper hemisphere is greater than the volume of the lower hemisphere, and   wherein the height of the shell is less than the diameter of the shell at the joined equators.   
   
   
       2 . The envelope of  claim 1  wherein the polar radius of the first generally oblate spheroid is less than the equatorial radii of the first generally oblate spheroid and the polar radius of the second generally oblate spheroid is less than the equatorial radii of the second generally oblate spheroid. 
   
   
       3 . The envelope of  claim 1  wherein the first and second equatorial radii of the first generally oblate spheroid are about equal and the first and second equatorial radii of the second generally oblate spheroid are about equal. 
   
   
       4 . The envelope of  claim 3  wherein the ratio of the smaller of the first and second equatorial radii of the first generally oblate spheroid to the larger of the first and second equatorial radii of the first generally oblate spheroid is between 0.75 and 1. 
   
   
       5 . The envelope of  claim 7  wherein the ratio of the smaller of the first and second equatorial radii of the second generally oblate spheroid to the larger of the first and second equatorial radii of the second generally oblate spheroid is between 0.75 and 1. 
   
   
       6 . The envelope of  claim 1  wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4. 
   
   
       7 . The envelope of  claim 1  wherein the ratio of the diameter of the shell to the height of the shell is between 2.5 and 5. 
   
   
       8 . The envelope of  claim 1  wherein the angle of the shell is less than or equal to 40 degrees. 
   
   
       9 . An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
 a shell generally including
 an upper hemisphere having the shape of a hemisphere of an ellipsoid defined by first and second equatorial radii and a polar radius, wherein the first and second equatorial radii are about equal and the polar radius is less than the first and second equatorial radii and 
 a lower hemisphere having the shape of a hemisphere of an ellipsoid defined by first and second equatorial radii and a polar radius, wherein the first and second equatorial radii are about equal and the polar radius is less than the first and second equatorial radii and less than the polar radius of the upper hemisphere. 
   
   
   
       10 . The envelope of  claim 9  wherein the ratio of the smaller of the first and second equatorial radii of the upper hemisphere to the larger of the first and second equatorial radii of the upper hemisphere is between 0.75 and 1. 
   
   
       11 . The envelope of  claim 9  wherein the ratio of the smaller of the first and second equatorial radii of the lower hemisphere to the larger of the first and second equatorial radii of the lower hemisphere is between 0.75 and 1. 
   
   
       12 . The envelope of  claim 9  wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4. 
   
   
       13 . The envelope of  claim 9  wherein the ratio of the diameter of the shell to the height of the shell is between 2.5 and 5. 
   
   
       14 . The envelope of  claim 9  wherein the angle of the shell is less than or equal to 40 degrees. 
   
   
       15 . An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
 a generally oblate spheroid shaped shell having upper and lower hemispheres   wherein at least one cross section of the shell traversing the upper and lower hemispheres includes a half of a first ellipse divided along its major axis, defining the shape of the upper hemisphere, and a half of a second ellipse divided along its major axis, defining the shape of the lower hemisphere, wherein the major axes of the ellipses are equal, the semi-minor axes of the ellipses are unequal, and the ellipse halves are joined at their major axes.   
   
   
       16 . The envelope of  claim 15  wherein the volume of the upper hemisphere is greater than the volume of the lower hemisphere. 
   
   
       17 . The envelope of  claim 17  wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4. 
   
   
       18 . The envelope of  claim 15  wherein the semi-minor axis of the upper hemisphere is greater than the semi-minor axis of the lower hemisphere. 
   
   
       19 . The envelope of  claim 17  wherein the ratio of the semi-minor axis of the upper hemisphere to the semi-minor axis of the lower hemisphere is between 1.2 and 4. 
   
   
       20 . The envelope of  claim 15  wherein the semi-major axes are greater than the sum of the semi-minor axes. 
   
   
       21 . The envelope of  claim 20  wherein the ratio of the semi-major axes to the sum of the semi-minor axes is between 2.5 and 5. 
   
   
       22 . The envelope of  claim 15  wherein a cross section through the equator of the shell is generally elliptical. 
   
   
       23 . The envelope of  claim 22  wherein the shape of the generally elliptical cross section is defined by a major axis and a minor axis and the ratio of the minor axis to the major axis is between 0.75 and 1. 
   
   
       24 . The envelope of  claim 15  wherein the angle of the shell is less than or equal to 40 degrees.

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