James McCampbell:Detailed reports and documents
June 12, 1981; W. of Alice, Texas
Early afternoon. Robert Gomez was driving a "vacuum" truck west of Alice, Texas when he encountered a hovering disc-shaped, and brightly-glowing object. As his truck slowed down, he depressed the accelerator to maintain speed and reported that the exhaust stacks were blowing smoke. The truck seemed to be about 1 ft. above the road. His AM radio failed but he was able to report to his dispatcher on a CB. The AM came back on when the UFO disappeared into some clouds. Gomez was carrying 165 gallens of water under no pressure at the time of the sighting but the tank was later found to be pressurized to 55 psi. Upon attempting to drain the tank, no water came out. Only steam. From thermodynamic relations it can be established that the temperature of the water and vapor in the tank had been increased to about 303 degrees F. Upon opening the drain, he reduced the pressure at the exit to 14.7 psi, one atmosphere. As the vapor pressure of the hot water was 69.7 psi absolute, it would suddenly flash to steam and that process would continue until the tank was empty.
articles/UFOs: More Engine Effects [Diesals Too].pdf (James McCampbell, 1985)