sentences:  Some aircraft were modified to act as testbeds; one carried the Kawasaki Ki-148 guided missile intended for use on the Kawasaki Ki-102 in late 1944, and one was modified to test a Ne-0 pulsejet engine in late 1944-early 1945.The fact that all models continued in service until 1945 reflects that many Ki-48s survived more often than not.This was due to the use of small ship formations (3–10 aircraft) escorted by large numbers of fighters (25–75), typically Nakajima Ki-43s.