The Roswell Report: Fact vs. Fiction in the New Mexico Desert

Operation of the instrument may be described as follows: The instrument is inserted in the load line just above the ballast assembly by attaching the load line to the upper ring (A) and the rigging from the ballast assembly to the lower ring (B). A cantilever spring (F) is set into an adjustable base (K), which may be adjusted for various empty ballast-assembly weights by changing the setting of the adjusting screw (L). The lower ring is attached to the cantilever spring, but can be adjusted for different ballast weights by sliding along the spring (from G to $ G_{1} $ , for instance). For light ballast weights the lower ring is moved away from the base (K) (to the right on the diagram), and for heavy ballast weights it is moved toward the base. Adjustments are made on the adjusting screw (L) and the lower ring (G) before each flight according to the weights of the ballast assembly and the ballast.

The cantilever spring is attached to the connecting bar (E) at (H). Thus the deflection of the lower ring is transferred through the cantilever spring to the connecting bar and then to the pen arm (C), which is pivoted about a fixed point (D). The deflection is recorded by the pen on a rotating smoked drum (B). In order to prevent the pen from going off the drum, an adjustable stop is set at (J).

The unit should be calibrated for maximum load (pen arm at $ C_{1} $ ), a medium load (pen arm at C) and minimum load (pen arm at $ C_{2} $ ) before each flight. A trace of ballast function will start at the top of the drum and as ballast is discarded will fall toward the bottom of the drum. By measuring the deflection at any time and comparing with the calibration, the amount of ballast left in the assembly at any time can be determined. Since this instrument is a part of the baro-thermograph, the trace obtained upon recovery will contain information concerning altitude, temperature, and ballast functioning over the complete flight. After proper correction for time displacement of the three pens has been made, the three types of information can be correlated to give a fairly complete picture of the balloon flight, including reasons for various types of motion.

It is expected that this instrument will be extremely valuable in determining ballast control operation over a long period of time, especially after the balloon system is out of radio reception range. It also will give information that could not be obtained if there were any failure of the automatic siphon meter or the transmitter during launching or flight. The chief drawback of the instrument is that information is dependent on recovery.

At the time of writing of this report the instrument has not been flight tested. Preliminary laboratory tests indicate that the instrument will live up to the high expectations placed upon it. Since the instrument actually records the tensile force in the load line during flight, it may also be valuable in analysis of the acceleration forces induced during periods of balloon oscillation in the atmosphere.