1. The document summarizes an internship at the Naval Research Laboratory working on the electromagnetic railgun. The internship involved maintaining the railgun and conducting research on wear of different armature designs. 2. As part of the internship, the author assisted in maintenance tasks like cleaning the catch tank after shots and replacing rails. The author also approximated wear on armature legs by comparing mid-flight x-rays to original outlines. 3. The calculations on leg wear proved instrumental in determining the most efficient armature design. A powerpoint series detailing wear per design created by the author will be briefed to NRL researchers.

1. Marjorie Ellen Ferrone
19 August 2012
MEMORANDUM
From: MIDN 3/C Ferrone (152118)
To: Associate Director of Research and Scholarship for Internships & Technology Transfer
Via: (1) Associate Professor Andrew Neil Smith, Mechanical Engineering Department
(2) Assistant Professor Luksa Luznik, Division Internship Coordinator
Subj: ELECTROMAGNETIC RAILGUN INTERNSHIP, SUMMER 2012
Ref: (a) COMDTMIDN/ACDEANINST 1531.73A
A. Information:
1. Internship details:
Location: Naval Research Laboratory (NRL) –
Plasma Physics Division
Dates: 25 June – 20 July 2012
Host Mentor’s full name: Dr. Robert Meger
Host Mentor’s professional title: Head of the Charged Particle Physics
Branch
Host Mentor’s contact information: meger@ccs.nrl.navy.mil
202-767-0332
USNA Faculty Point of Contact
for the internship: Professor Andrew Neil Smith
B. Research:
1. Title of Project: Rail and Armature Wear of the Electromagnetic Railgun
2. Abstract: The purpose of this research was to test which armature (projectile) design best
upheld its structure’s integrity while creating the least wear on the inner conducting rails of the
Railgun. The less the contact point on the outer face of the armature wore, the better contact it
would maintain with the rails throughout flight in the “barrel” of the gun. This produced less
magnetic arcing and increased efficiency of the Lorentz forces. The less the rails wore, the more
rounds could be successfully fired. It was determined that the most efficient armature design is
composed of certain materials which simultaneously upholds its own structure and that of the
rails, producing a more efficient gun.
3. Approach: I was the only midshipmen working on the Railgun, though there were four other
interns ranging from rising sophomores in high school to rising seniors in college. We worked
together to turn over (clean) the catch tank after every shot and maintain the gun properly.

2. Marjorie Ellen Ferrone
4. My Contributions to the Project: As part of the group of interns, I contributed to the
maintenance and research of the Railgun. Some of the maintenance jobs I completed include:
sanding the G-10 Fiberglass Tees to search for fragmentation after a ten-shot run, turning over
the flight capture tank by removing pulverized targets and inserting a new target after each shot,
assembling new targets to keep a consistent supply, replacing the air-tight film in the flight tube,
assisting to dismantle the Railgun and replace the parallel conducting rails, video-recording the
barrel of the gun to analyze rail wear-progression, and running the X-Ray machine to capture
pictures of the armature mid-flight. During the latter two weeks, I assisted Dr. Scott Douglass
with his research. My assignment was to approximate the wear on the armature legs. By using
geometric shapes on Power Point, I compared each mid-flight X-Ray of a worn armature to its
original outline.
5. Accomplishments: During summer, the number of shots per day drastically increased because
the interns provided invaluable help. Additionally, my calculations on the leg wear proved
instrumental in determining which armature design is most efficient.
6. Presentations: The Power Point series which I created, and which details armature wear per
design, will be briefed to the Charged Particle Physics Branch of the Naval Research Laboratory
as well as NRL researchers involved with the Railgun.