The United States Air Force Stability and Control Digital DATCOM is a computer program that implements the methods contained in the USAF Stability and Control DATCOM to calculate the static stability, control and dynamic derivative characteristics of fixed-wing aircraft. Digital DATCOM requires an input file containing a geometric description of an aircraft, and outputs its corresponding dimensionless stability derivatives according to the specified flight conditions. The values obtained can be used to calculate meaningful aspects of flight dynamics. History In February 1976, work commenced to automate the methods contained in the USAF Stability and Control DATCOM, specifically those contained in sections 4, 5, 6 and 7. The work was performed by the McDonnell Douglas Corporation under contract with the United States Air Force in conjunction with engineers at the Air Force Flight Dynamics Laboratory in Wright-Patterson Air Force Base. Implementation of the Digital DATCOM concluded in November 1978. The program is written in FORTRAN IV and has since been updated; however, the core of the program remains the same. A report was published, separated into three volumes, which explains the use of Digital DATCOM. The report consists of Volume I, User's Manual Volume II, Implementation of DATCOM Methods Volume III, Plot Module Inputs Section 3 of the USAF Digital DATCOM Manual Volume I defines the inputs available for modeling an aircraft. The inputs are categorized by namelists to facilitate reading the file into FORTRAN. Flight conditions and options The FLTCON Namelist describes the flight conditions for the case. A maximum of 400 Mach-altitude combinations can be run at once, with up to 20 angles of attack for each combination. The user can specify whether the Mach number and altitude varies together, the Mach number varies at a constant altitude, or the altitude varies at a constant Mach number. Both subsonic and supersonic analysis can be run in Digital DATCOM. The OPTINS Namelist defines the reference parameters for the aircraft. The theoretical wing area, mean aerodynamic chord, and wing span are input along with a parameter defining the surface roughness of the aircraft. Synthesis parameters The SYNTHS Namelist allows the user to define the positions of the center of gravity and apexes of the wings. The X- and Z- coordinates are needed for the wing, horizontal tail, and vertical tail in order for the aircraft to be synthesized correctly. DATCOM does not require that the origin for the aircraft has to