The collection is divided into two series, each representing a separate donation.

Series I, comprising the 2004 donation of papers, to a large extent retains the original order in which it was received, though some minor changes have been made for the sake of consistency. The majority of the collection, consisting of subject files, is arranged alphabetically by topic. Phillips' formal reports are arranged chronologically. The arrangement and file titles of a few folders have been changed to provide consistency to the alphabetical order. The materials have been divided among five subseries:

Subseries A: Subject Files. The files were originally housed in four cabinets, later transferred to six boxes by the donor, and finally transferred to permanent boxes during archival processing. The contents of each original cabinet had been arranged in a generally alphabetical order, but there was no overall arrangement among the individual cabinets. Thus, the alphabetical order of the original Cabinet 1 comprises Boxes 1-5; of Cabinet 2, Boxes 5-11; of Cabinet 3, Boxes 11-21; and of Cabinet 4, Boxes 21-25.

Subseries B: NACA and NASA Reports. Arranged chronologically, this subseries contains files on reports and talks given by Phillips related to his professional research.

Subseries C: Other Writings and Lectures by Phillips. This subseries includes drafts, notes, and other materials relating to writings and lectures by Phillips. It is arranged alphabetically by topic and includes a draft of Phillips' autobiography, detailing his personal and professional life.

Subseries D: Lectures and Courses Presented by Others. Originally found in no particular order, this set of files from lectures and courses presented by those other than Phillips is now arranged by name of presenter.

Subseries E: Oversize Materials. These materials were found separated from the rest of the materials in the collection and consist of "Typical Printouts from the Eppler Program."

Series II, the 2010 donation, contains the same types of materials found in Series I. These papers had no original arrangement but instead consisted mostly of loose papers together with a few individual folders and printed materials. The materials have been divided among seven subseries:

Subseries A: Writings and Lectures. Included in this subseries are files relating to the output of Phillips' research, both in a professional capacity and as a model aircraft enthusiast. The files include not only drafts and published works, but background materials and correspondence. Arranged alphabetically by title or subject.

Subseries B: Subject Files. Arranged alphabetically, this subseries contains materials gathered by Phillips in the course of his research on various topics and his involvement in various professional- and hobby-related activities. Much of the material relates to Phillips' interest in model aircraft.

Subseries C: Correspondence Files. Though personal matters are sometimes discussed, the correspondence in these files relates largely to Phillips' work and his pursuits in model aircraft design, building, and testing. Arranged alphabetically by correspondent.

Subseries D: Photographs. Nearly all of the photos in this series are of Phillips individually or include him at various events.

Subseries E: Personal Life, Education, and Career. Included in this series are materials relating to Phillips' education at Belmont High School and the Massachusetts Institution of Technology. Also here are records and mementos from his NACA / NASA career, including his many awards. Documenting Phillips' personal life is a set of diaries that he maintained throughout his adult life.

Subseries F: Oversize Materials contains large photographs, awards, and Phillips's high school diploma.