Wind-tunnel tests were carried out for the Department of the Environment to develop a balloon filling shelter with improved airflow characteristics compared to the rectangular structures currently in use. The new structure was to be rotatable for alignment into wind, and model tests were therefore confined to one wind direction. An initial series of tests was carried out on a large number of 1:55 scale cardboard models, using nylon streamers to indicate local flow directions and balsa wood models of the balloons to assess the effectiveness of the various designs, 'A model of the existing shelter was used as a standard for comparison with the various designs. Porther tests were carried out on a It24 scale model of the most promising design which had an elliptical-nosed platform. A variety of devices intended to improve the flow were tested and found ineffective. Finally tests were carried out on a 1112 scale model of the elliptical-nosed planform design. A helium-filled toy balloon was used to assess-the effect of the airflow on handling and launching, and to establish the effect of overall length of the structure. The shorter-aided version of this model was used as a basis for the full-scale design.
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