The U.S. Weather Bureau's National Hurricane Research Project aircraft
In 1961, the Research Flight Facility was created to maintain and operate the U.S. Weather Bureau’s (forerunner the U.S. NWS) National Hurricane Research Project aircraft, including two specially instrumented Douglas DC-6 aircrafts.
DC-6s were replaced in 1977 by two NOAA WP-3D Orion Hurricane Hunters, NOAA42 "Kermit" in 1976 and NOAA43 "Miss Piggy".