SVT BALLON TEST

The SVT (Simulated Variable Thickness) was a balloon design introduced by Raven Industries in mid 1960's decade. Its purpose was to better carry the meridional load on each gore across the envelope apex to its diametrically-opposite gore without abrupt changes in fabric thickness. This was achieved by shaping each gore with a minimum constant width at its upper end, overlapping the excess material progressively and thus creating the equivalent of a gradual buildup of fabric thickness toward the apex of the envelope.

The design emerged from the recognition that tapes on balloons, while necessary for increased lift capabilities, were a problematic solution. Traditional tapeless balloons could support substantial loads when fully inflated at ceiling altitude but struggled with lift capacity at lower altitudes in partially inflated states. The rigid tape strips seemed incompatible with the light, flexible, and somewhat elastic films they were attached to, particularly with the lighter gauge films used in high-altitude applications.

The design's key advantage was that it offered the load capabilities of taped balloons at a cost only slightly higher than conventional tapeless balloons. Altought the SVT design has proven versatile, working effectively with both thin and heavy films, as well as reinforced materials some manufacturing-related challenges were encountered that finally led to the abandonment of the idea.

Balloon launched on: 4/22/1964
Launch site: Joe Foss field, Sioux Falls, South Dakota, US  
Balloon launched by: Raven Industries Inc.
Balloon manufacturer/size/composition: Zero Pressure Balloon 9.000.000 cuft (0.75 Mil.)
End of flight (L for landing time, W for last contact, otherwise termination time): ??/??/1964
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 1 h
Payload weight: 476 pds.

• The Flight Record Scientific Ballooning Nº 15, July 1964
• The Flight Record Scientific Ballooning Nº 15, July 1964