One of the additions to the HistoryKat site is the Historical register of officers of the Continental Army during the war of the revolution, April 1775, to December, 1783 by Francis Heitman.
Part of the screen image from HistoryKat is shown in this post, along with the entry for Angus Rucker, a distant relative. This book is available as part of the HistoryKat collection and is searchable by name.
Of course, research never ends and I remembered that Footnote.com is also working on digitizing and indexing Revolutionary War Pensions as a part of their American Revolutionary War Collection
The Rucker pens
Using several websites in tandem with each other results in more raw data and more information about the desired family.
Subscriptions to HistoryKat or to Footnote.com are reasonably priced.