Does CPL or PPL help to study aeronautical engineering?
Generally not. Only a basic understanding or aircraft design and construction is taught with more focus on generic aircraft systems.
A CPL and PPL syllabus are essentially the same the CPL covering subjects to greater depths and the difference in the laws etc.
As one progresses to different types of aircraft, especially the more complex and sophisticated types, you will attend specific courses relevant to the in depth knowledge needed to operate that aircraft.
If you are attending a college or university for a degree in an aviation major which includes a pilot license then you will get closer to the engineering side of things.
Name of Robert Goddard's first liquid fueled rocket?
There really isn't a name for his rocket, though it launched it on March 16, 1926 in Auburn, Mass.