In the Lockheed Model 10, circumferential frames and bulkheads, known as “stations,” are numbered in inches rearward from the nose of the aircraft. Station #222, for example, is 222 inches from the tip of the nose. Note that most of the stations are 15 inches apart. Diagram based on technical drawings by William F. Harney. © W.F. Harney & TIGHAR, 2003. Used by permission. All rights reserved.