Project Skyfire: Preventing Forest Fires with Cloud Seeding
The Project Skyfire cloud-seeding generator is designed to produce silver iodide nuclei for experiments performed in devising techniques for lightning suppression. This generator produces freezing nuclei by volatilizing a silver iodide-acetone solution in a propane flame.
Several different types of silver iodide smoke generators were used during exploratory field programs. During 1956 an airborne string-type generator, designed for Skyfire operations and mounted in a Cessna 180 aircraft, was operated for about 60 hours. In addition, three ground-based string-type generators were employed several times near Flagstaff, Arizona and Missoula, Montana. Late in the 1956 field season a network of 10 acetone-burning generators was used at the Montana test site.
The two general types of generators tested, string- and acetone burning, differ mainly in the manner in which the silver iodide is injected into the flame to form a smoke of silver iodide crystals. In the acetone burning type, silver iodide is first dissolved in a solution of acetone and sodium iodide. The resulting solution is then sprayed into a flame by propane gas pressure through an internal-raixing paint spray nozzle (fig. 1). The mixture of propane gas and acetone solution burns in a flame holder.