DC-6 aircraft used in hurricane research from 1960 to 1975. DC-6 aircraft participated in the first experiment under the Global Atmospheric Research Project in the summer of 1974. This massive 20-nation effort examined the tropical waves that come off the west African coast each year, which spawn the Cape Verde hurricanes. The experiment's datasets are still being researched to this day for information on how the tropical Atlantic interacts with the global climate.