This system computes forces and moments due to added/virtual mass. The model is based on [Max M. Munk, "Aerodynamic forces on airship hulls", NACA report 184, 1924] and the introduction in [Christopher J. Atkinson, Robert G. Urso, "Modeling of Apparent Mass Effects for the Real-Time Simulation of a Hybrid Airship", AIAA Modeling and Simulation Technologies Conference, Aug 2006]. Usage: Define the following properties: aero/constants/volume-ft3 aero/constants/length-diameter-ft2 (length^2 + diameter^2) aero/constants/added-mass/k-axial (all three are positive but aero/constants/added-mass/k-transverse can be entered as negative aero/constants/added-mass/k-rotational for backwards compatibility) aero/constants/added-mass/tweak-factor (1.0 is the standard value) aero/constants/added-mass/k-traverse (old misspelling, can be given to work with older FlightGear) Define the following external forces and moments: { AERORP } 1.0 0.0 0.0 { AERORP } 0.0 1.0 0.0 { AERORP } 0.0 0.0 1.0 0.0 1.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0 The old deprecated force based external moment implementation below is still supported. AERORP X AERORP Y AERORP Z - 0.3048 1.0 0.0 0.0 AERORP X AERORP Y AERORP Z + 0.3048 1.0 0.0 0.0 AERORP X AERORP Y - 0.3048 0.0 1.0 0.0 0.0 AERORP X AERORP Y + 0.3048 0.0 1.0 0.0 0.0 aero/constants/added-mass/tweak-factor 0.0 simulation/sim-time-sec 2.0 aero/constants/added-mass/k-transverse aero/constants/added-mass/k-traverse aero/constants/added-mass/k-transverse NE 0.0 aero/constants/added-mass/k-traverse NE 0.0 -1.0 aero/added-mass/active atmosphere/rho-slugs_ft3 aero/constants/added-mass/k-axial aero/constants/volume-ft3 accelerations/udot-ft_sec2

external_reactions/added-mass-bx/magnitude

-1.0 aero/added-mass/active atmosphere/rho-slugs_ft3 aero/constants/added-mass/k-transverse-final aero/constants/volume-ft3 accelerations/vdot-ft_sec2

external_reactions/added-mass-by/magnitude

-1.0 aero/added-mass/active atmosphere/rho-slugs_ft3 aero/constants/added-mass/k-transverse-final aero/constants/volume-ft3 accelerations/wdot-ft_sec2

external_reactions/added-mass-bz/magnitude

aero/added-mass/active -0.05 atmosphere/rho-slugs_ft3 aero/constants/added-mass/k-rotational aero/constants/volume-ft3 aero/constants/length-diameter-ft2 accelerations/qdot-rad_sec2 aero/added-mass/active -0.05 atmosphere/rho-slugs_ft3 aero/constants/added-mass/k-rotational aero/constants/volume-ft3 aero/constants/length-diameter-ft2 accelerations/rdot-rad_sec2 aero/added-mass/pitch-moment-lbsft 1.0

external_reactions/added-mass-pitch/magnitude-lbsft

aero/added-mass/pitch-moment-lbsft -0.5

external_reactions/added-mass-pitch[0]/magnitude

aero/added-mass/pitch-moment-lbsft 0.5

external_reactions/added-mass-pitch[1]/magnitude

aero/added-mass/yaw-moment-lbsft 1.0

external_reactions/added-mass-yaw/magnitude-lbsft

aero/added-mass/yaw-moment-lbsft -0.5

external_reactions/added-mass-yaw[0]/magnitude

aero/added-mass/yaw-moment-lbsft 0.5

external_reactions/added-mass-yaw[1]/magnitude