Tests Dinghies For Superfort Crews -- Airman First Class Jerry L. Robertson, 300 Wayland St., Vinton, Va., gives a flotation test to one-man life rafts worn by U.S. Air Force B-29 combat crews of the Japan - based 98th Bomb Wing. Since the 98th Superforts make a round trip over the Japan sea on each bombing mission over North Korea, they do more flying over water than over land. In two and a half years of Korean operations. the 98th has flown over 5,800 combat sorties, or 11,600 one-way trips ov