Reel Down System

The first flight of the Reel Down system took place on 15 September 1982 from the National Scientific Balloon Facility in Palestine, Texas. When the balloon was properly positioned for the descent phase of the experiments, a pin locking the suspended instrument cluster to the winching system was pulled and the controlled descent phase was initiated by releasing a magnetically controlled brake. Descent velocity was selectable by command from the ground. A line velocity of 7 1 m/sec was used for the experiment reported here. A full treatment of mechanical and electronic systems, as well as the data analysis regarding the dynamics of the system, appears elsewhere [19]. 

Fig. 12. Rendering of the Reel Down platform with associated suspended payload. This system is capable of vertical scans of greater than 10 km from a balloon floating at or below 40 km.

Success of the Reel Down approach hinges on the stability of the system under stratospheric conditions (characterized by low pressures, but potentially large horizontal wind fields). Oscillatory motion developed in any axis of the suspended experiment cluster can compromise experimental control and thus the quality of the observations. A prototype system was constructed to test the feasibility of such a system in the stratosphere. Technical details are described in detail elsewhere [19]. 

The wet end—where in an unwind stand the reel of paper is supported and fed under suitable tension controls into a bath of resin at controlled temperature. In many cases, instead of total immersion, the paper is wetted on one side only—to allow the resin to penetrate, force air out, and give a fully saturated sheet. To allow time enough for the required penetration a skying system of variable rollers is used, as shown in Figure 55 this transports the web upwards and then down again before a final immersion in the resin, followed by metering. 

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