sentences:  During a series of static experiments, an exploding JATO did significant damage to the rear fuselage of an Ercoupe; one observer optimistically noted that "at least it wasn't a big hole", but necessary repairs delayed their efforts.The military ordered a flight test using liquid rather than solid fuel in early 1942.Upon the United States' entry into the Second World War in December 1941, the Group realized they could be drafted directly into military service if they failed to provide viable JATO technology for the military.