August 15?, 1947 — Rapid City AFB, South Dakota
9:30 p.m. Maj. Elmer H. Hammer of the 28th Bombardment Wing at Rapid City Army Air Base [now Ellsworth AFB] near Box Elder, South Dakota, sees 12 objects flying at 6,000–10,000 feet in a tight diamond formation at 300–400 mph. The objects level off at approximately 5,000 feet and make a gentle large-radius turn of about 110° to the right about 4 miles away. They start climbing at an angle of 30–40° and appear to accelerate rapidly in the climb. The objects are approximately 100 feet long and have a brilliant yellow-white luminous glow. [Eberhart]
Checklist:
Report:
Additional details given to 1st Lt. Clarence Glasebrook:
Sources:
J Allen Hynek, The Hynek UFO Report, p. 40-42;
Brad Sparks, Blue Book Unknowns Catalogue, Case 50, p. 26;
Michael D. Swords, “The Lost Words of Edward Ruppelt,” IUR 20, no. 2 (Mar./Apr. 1995): 14–15;
Jerome Clark, The UFO Encyclopedia, 3rd Ed., p. 437;
Jerome Clark, The UFO Encyclopedia, 4th Ed., p. 482;
NICAP, “12 B-29-Sized Elliptical Objects Seen”;
Hammer, Jr., Elmer H., Col