X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;ds=sidebyside;f=src%2FFDM%2Fflight.hxx;h=a09520f2d44148b147b76bd20a317f4b4e471d90;hb=98b90a2a377108dd645449224b4f2430f436cbde;hp=5afc060c40c4c1a5e21c97e8c37c5943767c2a8e;hpb=c90db01dc8d5462a3da22771ffa7c96f5ea31217;p=flightgear.git

diff --git a/src/FDM/flight.hxx b/src/FDM/flight.hxx
index 5afc060c4..a09520f2d 100644
--- a/src/FDM/flight.hxx
+++ b/src/FDM/flight.hxx
@@ -25,9 +25,9 @@
 #define _FLIGHT_HXX
 
 
-#ifndef __cplusplus                                                          
+#ifndef __cplusplus
 # error This library requires C++
-#endif                                   
+#endif
 
 
 /* Required get_()
@@ -81,70 +81,528 @@
  */
 
 
+#include <simgear/compiler.h>
+
 #include <math.h>
 
-#include <Time/timestamp.hxx>
+#include <list>
+#include <vector>
+#include <string>
 
-#ifndef __cplusplus                                                          
-# error This library requires C++
-#endif                                   
+#include <simgear/constants.h>
+#include <simgear/timing/timestamp.hxx>
+
+#include <Main/fgfs.hxx>
+
+SG_USING_STD(list);
+SG_USING_STD(vector);
+SG_USING_STD(string);
 
 
 typedef double FG_VECTOR_3[3];
 
 
+class FGEngInterface {
+
+private:
+
+    // inputs
+    double Throttle;
+    double Mixture;
+    double Prop_Advance;
+
+    // outputs
+    double RPM;
+    double Manifold_Pressure;     //inches
+    double MaxHP;
+    double Percentage_Power;      //HP
+    double EGT;                   //deg F
+    double CHT;                   //deg F
+    double prop_thrust;           //lbs
+    double Fuel_Flow;             //Gals/hr
+    
+    /* others...
+    double PercentN1,N1;  //GE,CFM
+    double PercentN2,N2;
+    double EPR;  //P&W, RR?
+    double FuelFlow;
+    bool AfterBurner;
+    double InletAngles[3];
+    double InletPosition[3];
+    double ThrustVector[3];
+    */
+
+public:
+    FGEngInterface(void);
+    ~FGEngInterface(void);
+    
+    inline double get_Throttle() const { return Throttle; }
+    inline double get_Mixture() const { return Mixture; }
+    inline double get_Prop_Advance() const { return Prop_Advance; }
+    inline double get_RPM() const { return RPM; }
+    inline double get_Manifold_Pressure() const { return Manifold_Pressure; }
+    inline double get_MaxHP() const { return MaxHP; }
+    inline double get_Percentage_Power() const { return Percentage_Power; }
+    inline double get_EGT() const { return EGT; }
+    inline double get_CHT() const { return CHT; }
+    inline double get_prop_thrust() const { return prop_thrust; }
+    inline double get_Fuel_Flow() const { return Fuel_Flow; }
+
+    inline void set_Throttle( double t ) { Throttle = t; }
+    inline void set_Mixture( double m ) { Mixture = m; }
+    inline void set_Prop_Advance( double p ) { Prop_Advance = p; }
+    inline void set_RPM( double r ) { RPM = r; }
+    inline void set_Manifold_Pressure( double mp ) { Manifold_Pressure = mp; }
+    inline void set_MaxHP( double hp ) { MaxHP = hp; }
+    inline void set_Percentage_Power( double p ) { Percentage_Power = p; }
+    inline void set_EGT( double e ) { EGT = e; }
+    inline void set_CHT( double c ) { CHT = c; }
+    inline void set_prop_thrust( double t ) { prop_thrust = t; }
+    inline void set_Fuel_Flow( double f ) { Fuel_Flow = f; }
+
+};
+
+typedef vector < FGEngInterface > engine_list;
+
+
 // This is based heavily on LaRCsim/ls_generic.h
-class FGInterface {
+class FGInterface : public FGSubsystem {
+
+private:
+  
+    // periodic update management variable.  This is a scheme to run
+    // the fdm with a fixed delta-t.  We control how many iteration of
+    // the fdm to run with the fixed dt based on the elapsed time from
+    // the last update.  This allows us to maintain sync with the real
+    // time clock, even though each frame could take a random amount
+    // of time.  Since "dt" is unlikely to divide evenly into the
+    // elapse time, we keep track of the remainder and add it into the
+    // next elapsed time.  This yields a small amount of temporal
+    // jitter ( < dt ) but in practice seems to work well.
+
+    double delta_t;		// delta "t"
+    SGTimeStamp time_stamp;	// time stamp of last run
+    long elapsed;		// time elapsed since last run
+    long remainder;		// remainder time from last run
+    int multi_loop;		// number of iterations of "delta_t" to run
+
+    // Pilot location rel to ref pt
+    FG_VECTOR_3 d_pilot_rp_body_v;
+
+    // CG position w.r.t. ref. point
+    FG_VECTOR_3 d_cg_rp_body_v;
+
+    // Forces
+    FG_VECTOR_3 f_body_total_v;
+    FG_VECTOR_3 f_local_total_v;
+    FG_VECTOR_3 f_aero_v;
+    FG_VECTOR_3 f_engine_v;
+    FG_VECTOR_3 f_gear_v;
+
+    // Moments
+    FG_VECTOR_3 m_total_rp_v;
+    FG_VECTOR_3 m_total_cg_v;
+    FG_VECTOR_3 m_aero_v;
+    FG_VECTOR_3 m_engine_v;
+    FG_VECTOR_3 m_gear_v;
+
+    // Accelerations
+    FG_VECTOR_3 v_dot_local_v;
+    FG_VECTOR_3 v_dot_body_v;
+    FG_VECTOR_3 a_cg_body_v;
+    FG_VECTOR_3 a_pilot_body_v;
+    FG_VECTOR_3 n_cg_body_v;
+    FG_VECTOR_3 n_pilot_body_v;
+    FG_VECTOR_3 omega_dot_body_v;
+
+    // Velocities
+    FG_VECTOR_3 v_local_v;
+    FG_VECTOR_3 v_local_rel_ground_v; // V rel w.r.t. earth surface
+    FG_VECTOR_3 v_local_airmass_v;    // velocity of airmass (steady winds)
+    FG_VECTOR_3 v_local_rel_airmass_v;  // velocity of veh. relative to airmass
+    FG_VECTOR_3 v_local_gust_v;       // linear turbulence components, L frame
+    FG_VECTOR_3 v_wind_body_v;        // Wind-relative velocities in body axis
+
+    FG_VECTOR_3 omega_body_v;         // Angular B rates
+    FG_VECTOR_3 omega_local_v;        // Angular L rates
+    FG_VECTOR_3 omega_total_v;        // Diff btw B & L
+    FG_VECTOR_3 euler_rates_v;
+    FG_VECTOR_3 geocentric_rates_v;   // Geocentric linear velocities
+
+    // Positions
+    FG_VECTOR_3 geocentric_position_v;
+    FG_VECTOR_3 geodetic_position_v;
+    FG_VECTOR_3 euler_angles_v;
+
+    // Miscellaneous Quantities
+    FG_VECTOR_3 d_cg_rwy_local_v;     // CG rel. to rwy in local coords
+    FG_VECTOR_3 d_cg_rwy_rwy_v;       // CG relative to rwy, in rwy coordinates
+    FG_VECTOR_3 d_pilot_rwy_local_v;  // pilot rel. to rwy in local coords
+    FG_VECTOR_3 d_pilot_rwy_rwy_v;    // pilot rel. to rwy, in rwy coords.
+
+    // Inertias
+    double mass, i_xx, i_yy, i_zz, i_xz;
+
+    // Normal Load Factor
+    double nlf;
+
+    // Velocities
+    double v_rel_wind, v_true_kts, v_rel_ground, v_inertial;
+    double v_ground_speed, v_equiv, v_equiv_kts;
+    double v_calibrated, v_calibrated_kts;
+
+    // Miscellaneious Quantities
+    double t_local_to_body_m[3][3];   // Transformation matrix L to B
+    double gravity;                   // Local acceleration due to G
+    double centrifugal_relief;        // load factor reduction due to speed
+    double alpha, beta, alpha_dot, beta_dot;  // in radians
+    double cos_alpha, sin_alpha, cos_beta, sin_beta;
+    double cos_phi, sin_phi, cos_theta, sin_theta, cos_psi, sin_psi;
+    double gamma_vert_rad, gamma_horiz_rad;  // Flight path angles
+    double sigma, density, v_sound, mach_number;
+    double static_pressure, total_pressure, impact_pressure;
+    double dynamic_pressure;
+    double static_temperature, total_temperature;
+    double sea_level_radius, earth_position_angle;
+    double runway_altitude, runway_latitude, runway_longitude;
+    double runway_heading;
+    double radius_to_rwy;
+    double climb_rate;                // in feet per second
+    double sin_lat_geocentric, cos_lat_geocentric;
+    double sin_longitude, cos_longitude;
+    double sin_latitude, cos_latitude;
+    double altitude_agl;
+    double Tank1Fuel;             // Gals
+    double Tank2Fuel;             // Gals
+
+    double daux[16];		// auxilliary doubles
+    float  faux[16];		// auxilliary floats
+    int    iaux[16];		// auxilliary ints
+
+    // Engine list
+    engine_list engines;
+
+    // SGTimeStamp valid_stamp;          // time this record is valid
+    // SGTimeStamp next_stamp;           // time this record is valid
+
+protected:
+
+				// deliberately not virtual so that
+				// FGInterface constructor will call
+				// the right version
+    void _setup();
+
+    void _busdump(void);
+    void _updatePosition( double lat_geoc, double lon, double alt );
+    void _updateWeather( void );
+
+    inline void _set_Inertias( double m, double xx, double yy, 
+			      double zz, double xz)
+    {
+	mass = m;
+	i_xx = xx;
+	i_yy = yy;
+	i_zz = zz;
+	i_xz = xz;
+    }
+    inline void _set_CG_Position( double dx, double dy, double dz ) {
+	d_cg_rp_body_v[0] = dx;
+	d_cg_rp_body_v[1] = dy;
+	d_cg_rp_body_v[2] = dz;
+    }
+    inline void _set_Accels_Local( double north, double east, double down ) {
+	v_dot_local_v[0] = north;
+	v_dot_local_v[1] = east;
+	v_dot_local_v[2] = down;
+    }
+    inline void _set_Accels_Body( double u, double v, double w ) {
+	v_dot_body_v[0] = u;
+	v_dot_body_v[1] = v;
+	v_dot_body_v[2] = w;
+    }
+    inline void _set_Accels_CG_Body( double x, double y, double z ) {
+	a_cg_body_v[0] = x;
+	a_cg_body_v[1] = y;
+	a_cg_body_v[2] = z;
+    }
+    inline void _set_Accels_Pilot_Body( double x, double y, double z ) {
+	a_pilot_body_v[0] = x;
+	a_pilot_body_v[1] = y;
+	a_pilot_body_v[2] = z;
+    }
+    inline void _set_Accels_CG_Body_N( double x, double y, double z ) {
+	n_cg_body_v[0] = x;
+	n_cg_body_v[1] = y;
+	n_cg_body_v[2] = z;
+    }
+    void _set_Nlf(double n) { nlf=n;  }
+    inline void _set_Velocities_Local( double north, double east, double down ){
+	v_local_v[0] = north;
+	v_local_v[1] = east;
+	v_local_v[2] = down;
+    }
+    inline void _set_Velocities_Ground(double north, double east, double down) {
+	v_local_rel_ground_v[0] = north;
+	v_local_rel_ground_v[1] = east;
+	v_local_rel_ground_v[2] = down;
+    }
+    inline void _set_Velocities_Local_Airmass( double north, double east, 
+					      double down)
+    {
+	v_local_airmass_v[0] = north;
+	v_local_airmass_v[1] = east;
+	v_local_airmass_v[2] = down;
+    }
+    inline void _set_Velocities_Wind_Body( double u, double v, double w) {
+	v_wind_body_v[0] = u;
+	v_wind_body_v[1] = v;
+	v_wind_body_v[2] = w;
+    }
+    inline void _set_V_rel_wind(double vt) { v_rel_wind = vt; }
+    inline void _set_V_ground_speed( double v) { v_ground_speed = v; }
+    inline void _set_V_equiv_kts( double kts ) { v_equiv_kts = kts; }
+    inline void _set_V_calibrated_kts( double kts ) { v_calibrated_kts = kts; }
+    inline void _set_Omega_Body( double p, double q, double r ) {
+	omega_body_v[0] = p;
+	omega_body_v[1] = q;
+	omega_body_v[2] = r;
+    }
+    inline void _set_Euler_Rates( double phi, double theta, double psi ) {
+	euler_rates_v[0] = phi;
+	euler_rates_v[1] = theta;
+	euler_rates_v[2] = psi;
+    }
+    inline void _set_Geocentric_Rates( double lat, double lon, double rad ) {
+	geocentric_rates_v[0] = lat;
+	geocentric_rates_v[1] = lon;
+	geocentric_rates_v[2] = rad;
+    }
+#if 0
+    inline void _set_Radius_to_vehicle(double radius) {
+	geocentric_position_v[2] = radius;
+    }
+#endif
+    inline void _set_Geocentric_Position( double lat, double lon, double rad ) {
+	geocentric_position_v[0] = lat;
+	geocentric_position_v[1] = lon;
+	geocentric_position_v[2] = rad;
+    }
+    inline void _set_Latitude(double lat) { geodetic_position_v[0] = lat; }
+    inline void _set_Longitude(double lon) { geodetic_position_v[1] = lon; }
+    inline void _set_Altitude(double altitude) {
+	geodetic_position_v[2] = altitude;
+    }
+    inline void _set_Altitude_AGL(double agl) {
+	altitude_agl = agl;
+    }
+    inline void _set_Geodetic_Position( double lat, double lon, double alt ) {
+	geodetic_position_v[0] = lat;
+	geodetic_position_v[1] = lon;
+	geodetic_position_v[2] = alt;
+    }
+    inline void _set_Euler_Angles( double phi, double theta, double psi ) {
+	euler_angles_v[0] = phi;
+	euler_angles_v[1] = theta;
+	euler_angles_v[2] = psi;
+    }
+    inline void _set_T_Local_to_Body( int i, int j, double value) {
+	t_local_to_body_m[i-1][j-1] = value;
+    }
+    inline void _set_T_Local_to_Body( double m[3][3] ) {
+	int i, j;
+	for ( i = 0; i < 3; i++ ) {
+	    for ( j = 0; j < 3; j++ ) {
+		t_local_to_body_m[i][j] = m[i][j];
+	    }
+	}
+    }
+    inline void _set_Alpha( double a ) { alpha = a; }
+    inline void _set_Beta( double b ) { beta = b; }
+    inline void _set_Cos_phi( double cp ) { cos_phi = cp; }
+    inline void _set_Cos_theta( double ct ) { cos_theta = ct; }
+    inline void _set_Gamma_vert_rad( double gv ) { gamma_vert_rad = gv; }
+    inline void _set_Density( double d ) { density = d; }
+    inline void _set_Mach_number( double m ) { mach_number = m; }
+    inline void _set_Static_pressure( double sp ) { static_pressure = sp; }
+    inline void _set_Static_temperature( double t ) { static_temperature = t; }
+    inline void _set_Sea_level_radius( double r ) { sea_level_radius = r; }
+    inline void _set_Earth_position_angle(double a) {
+	earth_position_angle = a;
+    }
+    inline void _set_Runway_altitude( double alt ) { runway_altitude = alt; }
+    inline void _set_Climb_Rate(double rate) { climb_rate = rate; }
+    inline void _set_sin_lat_geocentric(double parm) {
+	sin_lat_geocentric = sin(parm);
+    }
+    inline void _set_cos_lat_geocentric(double parm) {
+	cos_lat_geocentric = cos(parm);
+    }
+    inline void _set_sin_cos_longitude(double parm) {
+	sin_longitude = sin(parm);
+	cos_longitude = cos(parm);
+    }
+    inline void _set_sin_cos_latitude(double parm) {
+	sin_latitude = sin(parm);
+	cos_latitude = cos(parm);
+    }
+
+    inline void _set_daux( int n, double value ) { daux[n] = value; }
+    inline void _set_faux( int n, float value ) { faux[n] = value; }
+    inline void _set_iaux( int n, int value ) { iaux[n] = value; }
 
 public:
+  
+    FGInterface();
+    FGInterface( double dt );
+    virtual ~FGInterface();
+
+    virtual void init ();
+    virtual void bind ();
+    virtual void unbind ();
+    virtual void update ();
+    virtual bool update( int multi_loop );
+    virtual bool ToggleDataLogging(bool state) { return false; }
+    virtual bool ToggleDataLogging(void) { return false; }
 
     // Define the various supported flight models (many not yet implemented)
     enum {
-	// Slew (in MS terminology)
-	FG_SLEW = 0,
-	
+	// Magic Carpet mode
+	FG_MAGICCARPET = 0,
+
 	// The NASA LaRCsim (Navion) flight model
 	FG_LARCSIM = 1,
 
 	// Jon S. Berndt's new FDM written from the ground up in C++
 	FG_JSBSIM = 2,
 
+	// Christian's hot air balloon simulation
+	FG_BALLOONSIM = 3,
+
+	// Aeronautical DEvelopment AGEncy, Bangalore India
+	FG_ADA = 4,
+
 	// The following aren't implemented but are here to spark
 	// thoughts and discussions, and maybe even action.
-	FG_ACM = 3,
-	FG_SUPER_SONIC = 4,
-	FG_HELICOPTER = 5,
-	FG_AUTOGYRO = 6,
-	FG_BALLOON = 7,
-	FG_PARACHUTE = 8,
+	FG_ACM = 5,
+	FG_SUPER_SONIC = 6,
+	FG_HELICOPTER = 7,
+	FG_AUTOGYRO = 8,
+	FG_PARACHUTE = 9,
 
 	// Driven externally via a serial port, net, file, etc.
-	FG_EXTERNAL = 9
+	FG_EXTERNAL = 10
     };
 
-/*================== Mass properties and geometry values ==================*/
+    // time and update management values
+    inline double get_delta_t() const { return delta_t; }
+    inline void set_delta_t( double dt ) { delta_t = dt; }
+    inline SGTimeStamp get_time_stamp() const { return time_stamp; }
+    inline void set_time_stamp( SGTimeStamp s ) { time_stamp = s; }
+    inline void stamp() { time_stamp.stamp(); }
+    inline long get_elapsed() const { return elapsed; }
+    inline void set_elapsed( long e ) { elapsed = e; }
+    inline long get_remainder() const { return remainder; }
+    inline void set_remainder( long r ) { remainder = r; }
+    inline int get_multi_loop() const { return multi_loop; }
+    inline void set_multi_loop( int ml ) { multi_loop = ml; }
+
+    // Positions
+    virtual void set_Latitude(double lat);       // geocentric
+    virtual void set_Longitude(double lon);    
+    virtual void set_Altitude(double alt);  // triggers re-calc of AGL altitude
+    virtual void set_AltitudeAGL(double altagl); // and vice-versa
+    virtual void set_Latitude_deg (double lat) {
+      set_Latitude(lat * SGD_DEGREES_TO_RADIANS);
+    }
+    virtual void set_Longitude_deg (double lon) {
+      set_Longitude(lon * SGD_DEGREES_TO_RADIANS);
+    }
+    
+    // Speeds -- setting any of these will trigger a re-calc of the rest
+    virtual void set_V_calibrated_kts(double vc);
+    virtual void set_Mach_number(double mach);
+    virtual void set_Velocities_Local( double north, double east, double down );
+    inline void set_V_north (double north) { 
+      set_Velocities_Local(north, v_local_v[1], v_local_v[2]);
+    }
+    inline void set_V_east (double east) { 
+      set_Velocities_Local(v_local_v[0], east, v_local_v[2]);
+    }
+    inline void set_V_down (double down) { 
+      set_Velocities_Local(v_local_v[0], v_local_v[1], down);
+    }
+    virtual void set_Velocities_Wind_Body( double u, double v, double w);
+    virtual void set_uBody (double uBody) { 
+      set_Velocities_Wind_Body(uBody, v_wind_body_v[1], v_wind_body_v[2]);
+    }
+    virtual void set_vBody (double vBody) { 
+      set_Velocities_Wind_Body(v_wind_body_v[0], vBody, v_wind_body_v[2]);
+    }
+    virtual void set_wBody (double wBody) {
+      set_Velocities_Wind_Body(v_wind_body_v[0], v_wind_body_v[1], wBody);
+    }
+    
+    // Euler angles 
+    virtual void set_Euler_Angles( double phi, double theta, double psi );
+    virtual void set_Phi (double phi) {
+      set_Euler_Angles(phi, get_Theta(), get_Psi());
+    }
+    virtual void set_Theta (double theta) {
+      set_Euler_Angles(get_Phi(), theta, get_Psi());
+    }
+    virtual void set_Psi (double psi) { 
+      set_Euler_Angles(get_Phi(), get_Theta(), psi);
+    }
+    virtual void set_Phi_deg (double phi) { set_Phi(phi * SGD_DEGREES_TO_RADIANS); }
+    virtual void set_Theta_deg (double theta) {
+      set_Theta(theta * SGD_DEGREES_TO_RADIANS); 
+    }
+    virtual void set_Psi_deg (double psi) { set_Psi(psi * SGD_DEGREES_TO_RADIANS); }
+    
+    // Flight Path
+    virtual void set_Climb_Rate( double roc);
+    virtual void set_Gamma_vert_rad( double gamma);
+    
+    // Earth
+    virtual void set_Sea_level_radius(double slr);
+    virtual void set_Runway_altitude(double ralt);
+    
+    virtual void set_Static_pressure(double p);
+    virtual void set_Static_temperature(double T);
+    virtual void set_Density(double rho);
+    
+    virtual void set_Velocities_Local_Airmass (double wnorth, 
+					       double weast, 
+					       double wdown );
+
+    // Consumables
+    inline void set_Tank1Fuel( double f ) { Tank1Fuel = f; }
+    inline void set_Tank2Fuel( double f ) { Tank2Fuel = f; }
+
+    inline void reduce_Tank1Fuel( double f ) { 
+        Tank1Fuel -= f;
+        if(Tank1Fuel < 0)
+	    Tank1Fuel = 0;
+    }
+    inline void reduce_Tank2Fuel( double f ) { 
+        Tank2Fuel -= f;
+        if(Tank2Fuel < 0)
+	    Tank2Fuel = 0;
+    }  
+
+    
+    // ========== Mass properties and geometry values ==========
 
     // Inertias
-    double mass, i_xx, i_yy, i_zz, i_xz;
     inline double get_Mass() const { return mass; }
     inline double get_I_xx() const { return i_xx; }
     inline double get_I_yy() const { return i_yy; }
     inline double get_I_zz() const { return i_zz; }
     inline double get_I_xz() const { return i_xz; }
-    inline void set_Inertias( double m, double xx, double yy, 
-			      double zz, double xz)
-    {
-	mass = m;
-	i_xx = xx;
-	i_yy = yy;
-	i_zz = zz;
-	i_xz = xz;
-    }
-    
+
     // Pilot location rel to ref pt
-    FG_VECTOR_3 d_pilot_rp_body_v;
-    // inline double * get_D_pilot_rp_body_v() { 
-    //  return d_pilot_rp_body_v; 
+    // inline double * get_D_pilot_rp_body_v() {
+    //  return d_pilot_rp_body_v;
     // }
     // inline double get_Dx_pilot() const { return d_pilot_rp_body_v[0]; }
     // inline double get_Dy_pilot() const { return d_pilot_rp_body_v[1]; }
@@ -156,20 +614,13 @@ public:
     } */
 
     // CG position w.r.t. ref. point
-    FG_VECTOR_3 d_cg_rp_body_v;
     // inline double * get_D_cg_rp_body_v() { return d_cg_rp_body_v; }
     inline double get_Dx_cg() const { return d_cg_rp_body_v[0]; }
     inline double get_Dy_cg() const { return d_cg_rp_body_v[1]; }
     inline double get_Dz_cg() const { return d_cg_rp_body_v[2]; }
-    inline void set_CG_Position( double dx, double dy, double dz ) {
-	d_cg_rp_body_v[0] = dx;
-	d_cg_rp_body_v[1] = dy;
-	d_cg_rp_body_v[2] = dz;
-    }
 
-/*================================ Forces =================================*/
+    // ========== Forces ==========
 
-    FG_VECTOR_3 f_body_total_v;
     // inline double * get_F_body_total_v() { return f_body_total_v; }
     // inline double get_F_X() const { return f_body_total_v[0]; }
     // inline double get_F_Y() const { return f_body_total_v[1]; }
@@ -180,7 +631,6 @@ public:
 	f_body_total_v[2] = z;
     } */
 
-    FG_VECTOR_3 f_local_total_v;
     // inline double * get_F_local_total_v() { return f_local_total_v; }
     // inline double get_F_north() const { return f_local_total_v[0]; }
     // inline double get_F_east() const { return f_local_total_v[1]; }
@@ -191,7 +641,6 @@ public:
 	f_local_total_v[2] = z;
     } */
 
-    FG_VECTOR_3 f_aero_v;
     // inline double * get_F_aero_v() { return f_aero_v; }
     // inline double get_F_X_aero() const { return f_aero_v[0]; }
     // inline double get_F_Y_aero() const { return f_aero_v[1]; }
@@ -202,7 +651,6 @@ public:
 	f_aero_v[2] = z;
     } */
     
-    FG_VECTOR_3 f_engine_v;
     // inline double * get_F_engine_v() { return f_engine_v; }
     // inline double get_F_X_engine() const { return f_engine_v[0]; }
     // inline double get_F_Y_engine() const { return f_engine_v[1]; }
@@ -213,7 +661,6 @@ public:
 	f_engine_v[2] = z;
     } */
 
-    FG_VECTOR_3 f_gear_v;
     // inline double * get_F_gear_v() { return f_gear_v; }
     // inline double get_F_X_gear() const { return f_gear_v[0]; }
     // inline double get_F_Y_gear() const { return f_gear_v[1]; }
@@ -224,9 +671,8 @@ public:
 	f_gear_v[2] = z;
     } */
 
-    /*================================ Moments ================================*/
+    // ========== Moments ==========
 
-    FG_VECTOR_3 m_total_rp_v;
     // inline double * get_M_total_rp_v() { return m_total_rp_v; }
     // inline double get_M_l_rp() const { return m_total_rp_v[0]; }
     // inline double get_M_m_rp() const { return m_total_rp_v[1]; }
@@ -237,7 +683,6 @@ public:
 	m_total_rp_v[2] = n;
     } */
 
-    FG_VECTOR_3 m_total_cg_v;
     // inline double * get_M_total_cg_v() { return m_total_cg_v; }
     // inline double get_M_l_cg() const { return m_total_cg_v[0]; }
     // inline double get_M_m_cg() const { return m_total_cg_v[1]; }
@@ -248,7 +693,6 @@ public:
 	m_total_cg_v[2] = n;
     } */
 
-    FG_VECTOR_3 m_aero_v;
     // inline double * get_M_aero_v() { return m_aero_v; }
     // inline double get_M_l_aero() const { return m_aero_v[0]; }
     // inline double get_M_m_aero() const { return m_aero_v[1]; }
@@ -259,7 +703,6 @@ public:
 	m_aero_v[2] = n;
     } */
 
-    FG_VECTOR_3    m_engine_v;
     // inline double * get_M_engine_v() { return m_engine_v; }
     // inline double get_M_l_engine() const { return m_engine_v[0]; }
     // inline double get_M_m_engine() const { return m_engine_v[1]; }
@@ -270,7 +713,6 @@ public:
 	m_engine_v[2] = n;
     } */
 
-    FG_VECTOR_3    m_gear_v;
     // inline double * get_M_gear_v() { return m_gear_v; }
     // inline double get_M_l_gear() const { return m_gear_v[0]; }
     // inline double get_M_m_gear() const { return m_gear_v[1]; }
@@ -281,75 +723,45 @@ public:
 	m_gear_v[2] = n;
     } */
 
-    /*============================== Accelerations ============================*/
+    // ========== Accelerations ==========
 
-    FG_VECTOR_3    v_dot_local_v;
     // inline double * get_V_dot_local_v() { return v_dot_local_v; }
-    // inline double get_V_dot_north() const { return v_dot_local_v[0]; }
-    // inline double get_V_dot_east() const { return v_dot_local_v[1]; }
-    // inline double get_V_dot_down() const { return v_dot_local_v[2]; }
-    /* inline void set_Accels_Local( double north, double east, double down ) {
-	v_dot_local_v[0] = north;
-	v_dot_local_v[1] = east;
-	v_dot_local_v[2] = down;
-    } */
+    inline double get_V_dot_north() const { return v_dot_local_v[0]; }
+    inline double get_V_dot_east() const { return v_dot_local_v[1]; }
+    inline double get_V_dot_down() const { return v_dot_local_v[2]; }
 
-    FG_VECTOR_3    v_dot_body_v;
     // inline double * get_V_dot_body_v() { return v_dot_body_v; }
-    // inline double get_U_dot_body() const { return v_dot_body_v[0]; }
-    // inline double get_V_dot_body() const { return v_dot_body_v[1]; }
-    // inline double get_W_dot_body() const { return v_dot_body_v[2]; }
-    /* inline void set_Accels_Body( double u, double v, double w ) {
-	v_dot_local_v[0] = u;
-	v_dot_local_v[1] = v;
-	v_dot_local_v[2] = w;
-    } */
+    inline double get_U_dot_body() const { return v_dot_body_v[0]; }
+    inline double get_V_dot_body() const { return v_dot_body_v[1]; }
+    inline double get_W_dot_body() const { return v_dot_body_v[2]; }
 
-    FG_VECTOR_3    a_cg_body_v;
     // inline double * get_A_cg_body_v() { return a_cg_body_v; }
-    // inline double get_A_X_cg() const { return a_cg_body_v[0]; }
-    // inline double get_A_Y_cg() const { return a_cg_body_v[1]; }
-    // inline double get_A_Z_cg() const { return a_cg_body_v[2]; }
-    /* inline void set_Accels_CG_Body( double x, double y, double z ) {
-	a_cg_body_v[0] = x;
-	a_cg_body_v[1] = y;
-	a_cg_body_v[2] = z;
-    } */
+    inline double get_A_X_cg() const { return a_cg_body_v[0]; }
+    inline double get_A_Y_cg() const { return a_cg_body_v[1]; }
+    inline double get_A_Z_cg() const { return a_cg_body_v[2]; }
 
-    FG_VECTOR_3    a_pilot_body_v;
     // inline double * get_A_pilot_body_v() { return a_pilot_body_v; }
-    // inline double get_A_X_pilot() const { return a_pilot_body_v[0]; }
-    // inline double get_A_Y_pilot() const { return a_pilot_body_v[1]; }
-    // inline double get_A_Z_pilot() const { return a_pilot_body_v[2]; }
-    /* inline void set_Accels_Pilot_Body( double x, double y, double z ) {
-	a_pilot_body_v[0] = x;
-	a_pilot_body_v[1] = y;
-	a_pilot_body_v[2] = z;
-    } */
+    inline double get_A_X_pilot() const { return a_pilot_body_v[0]; }
+    inline double get_A_Y_pilot() const { return a_pilot_body_v[1]; }
+    inline double get_A_Z_pilot() const { return a_pilot_body_v[2]; }
 
-    FG_VECTOR_3    n_cg_body_v;
     // inline double * get_N_cg_body_v() { return n_cg_body_v; }
-    // inline double get_N_X_cg() const { return n_cg_body_v[0]; }
-    // inline double get_N_Y_cg() const { return n_cg_body_v[1]; }
-    // inline double get_N_Z_cg() const { return n_cg_body_v[2]; }
-    /* inline void set_Accels_CG_Body_N( double x, double y, double z ) {
-	n_cg_body_v[0] = x;
-	n_cg_body_v[1] = y;
-	n_cg_body_v[2] = z;
-    } */
+    inline double get_N_X_cg() const { return n_cg_body_v[0]; }
+    inline double get_N_Y_cg() const { return n_cg_body_v[1]; }
+    inline double get_N_Z_cg() const { return n_cg_body_v[2]; }
 
-    FG_VECTOR_3    n_pilot_body_v;
     // inline double * get_N_pilot_body_v() { return n_pilot_body_v; }
     // inline double get_N_X_pilot() const { return n_pilot_body_v[0]; }
     // inline double get_N_Y_pilot() const { return n_pilot_body_v[1]; }
     // inline double get_N_Z_pilot() const { return n_pilot_body_v[2]; }
-    /* inline void set_Accels_Pilot_Body_N( double x, double y, double z ) {
-	n_pilot_body_v[0] = x;
-	n_pilot_body_v[1] = y;
-	n_pilot_body_v[2] = z;
-    } */
+    // inline void set_Accels_Pilot_Body_N( double x, double y, double z ) {
+    //    n_pilot_body_v[0] = x;
+    //    n_pilot_body_v[1] = y;
+    //    n_pilot_body_v[2] = z;
+    // }
+
+    inline double get_Nlf(void) { return nlf; }
 
-    FG_VECTOR_3    omega_dot_body_v;
     // inline double * get_Omega_dot_body_v() { return omega_dot_body_v; }
     // inline double get_P_dot_body() const { return omega_dot_body_v[0]; }
     // inline double get_Q_dot_body() const { return omega_dot_body_v[1]; }
@@ -361,63 +773,47 @@ public:
     } */
 
 
-    /*============================== Velocities ===============================*/
+    // ========== Velocities ==========
 
-    FG_VECTOR_3    v_local_v;
     // inline double * get_V_local_v() { return v_local_v; }
     inline double get_V_north() const { return v_local_v[0]; }
     inline double get_V_east() const { return v_local_v[1]; }
     inline double get_V_down() const { return v_local_v[2]; }
-    inline void set_Velocities_Local( double north, double east, double down ) {
-	v_local_v[0] = north;
-	v_local_v[1] = east;
-	v_local_v[2] = down;
-    }
+    inline double get_uBody () const { return v_wind_body_v[0]; }
+    inline double get_vBody () const { return v_wind_body_v[1]; }
+    inline double get_wBody () const { return v_wind_body_v[2]; }
 
-    FG_VECTOR_3    v_local_rel_ground_v; // V rel w.r.t. earth surface  
-    // inline double * get_V_local_rel_ground_v() { return v_local_rel_ground_v; }
+    // inline double * get_V_local_rel_ground_v() {
+    //     return v_local_rel_ground_v;
+    // }
     // inline double get_V_north_rel_ground() const {
-    //	return v_local_rel_ground_v[0];
-    //    }
+    //     return v_local_rel_ground_v[0];
+    // }
     // inline double get_V_east_rel_ground() const {
-    //	return v_local_rel_ground_v[1];
-    //    }
+    //     return v_local_rel_ground_v[1];
+    // }
     // inline double get_V_down_rel_ground() const {
-    //	return v_local_rel_ground_v[2];
-    //    }
-    /* inline void set_Velocities_Ground(double north, double east, double down) {
-	v_local_rel_ground_v[0] = north;
-	v_local_rel_ground_v[1] = east;
-	v_local_rel_ground_v[2] = down;
-    } */
+    //    return v_local_rel_ground_v[2];
+    // }
 
-    FG_VECTOR_3    v_local_airmass_v;   // velocity of airmass (steady winds)
     // inline double * get_V_local_airmass_v() { return v_local_airmass_v; }
-    // inline double get_V_north_airmass() const { return v_local_airmass_v[0]; }
-    // inline double get_V_east_airmass() const { return v_local_airmass_v[1]; }
-    // inline double get_V_down_airmass() const { return v_local_airmass_v[2]; }
-    /* inline void set_Velocities_Local_Airmass( double north, double east, 
-					      double down)
-    {
-	v_local_airmass_v[0] = north;
-	v_local_airmass_v[1] = east;
-	v_local_airmass_v[2] = down;
-    } */
+    inline double get_V_north_airmass() const { return v_local_airmass_v[0]; }
+    inline double get_V_east_airmass() const { return v_local_airmass_v[1]; }
+    inline double get_V_down_airmass() const { return v_local_airmass_v[2]; }
 
-    FG_VECTOR_3    v_local_rel_airmass_v;  // velocity of veh. relative to
     // airmass
     // inline double * get_V_local_rel_airmass_v() {
-	//return v_local_rel_airmass_v;
-    //}
+    //   return v_local_rel_airmass_v;
+    // }
     // inline double get_V_north_rel_airmass() const {
-	//return v_local_rel_airmass_v[0];
-    //}
+    //   return v_local_rel_airmass_v[0];
+    // }
     // inline double get_V_east_rel_airmass() const {
-	//return v_local_rel_airmass_v[1];
-    //}
+    //   return v_local_rel_airmass_v[1];
+    // }
     // inline double get_V_down_rel_airmass() const {
-	//return v_local_rel_airmass_v[2];
-    //}
+    //   return v_local_rel_airmass_v[2];
+    // }
     /* inline void set_Velocities_Local_Rel_Airmass( double north, double east, 
 						  double down)
     {
@@ -426,7 +822,6 @@ public:
 	v_local_rel_airmass_v[2] = down;
     } */
 
-    FG_VECTOR_3    v_local_gust_v; // linear turbulence components, L frame
     // inline double * get_V_local_gust_v() { return v_local_gust_v; }
     // inline double get_U_gust() const { return v_local_gust_v[0]; }
     // inline double get_V_gust() const { return v_local_gust_v[1]; }
@@ -438,23 +833,12 @@ public:
 	v_local_gust_v[2] = w;
     } */
     
-    FG_VECTOR_3    v_wind_body_v;  // Wind-relative velocities in body axis
     // inline double * get_V_wind_body_v() { return v_wind_body_v; }
-    // inline double get_U_body() const { return v_wind_body_v[0]; }
-    // inline double get_V_body() const { return v_wind_body_v[1]; }
-    // inline double get_W_body() const { return v_wind_body_v[2]; }
-    /* inline void set_Velocities_Wind_Body( double u, double v, double w)
-    {
-	v_wind_body_v[0] = u;
-	v_wind_body_v[1] = v;
-	v_wind_body_v[2] = w;
-    } */
-
-    double    v_rel_wind, v_true_kts, v_rel_ground, v_inertial;
-    double    v_ground_speed, v_equiv, v_equiv_kts;
-    double    v_calibrated, v_calibrated_kts;
+    inline double get_U_body() const { return v_wind_body_v[0]; }
+    inline double get_V_body() const { return v_wind_body_v[1]; }
+    inline double get_W_body() const { return v_wind_body_v[2]; }
 
-    // inline double get_V_rel_wind() const { return v_rel_wind; }
+    inline double get_V_rel_wind() const { return v_rel_wind; }
     // inline void set_V_rel_wind(double wind) { v_rel_wind = wind; }
 
     // inline double get_V_true_kts() const { return v_true_kts; }
@@ -466,33 +850,23 @@ public:
     // inline double get_V_inertial() const { return v_inertial; }
     // inline void set_V_inertial(double v) { v_inertial = v; }
 
-    // inline double get_V_ground_speed() const { return v_ground_speed; }
-    // inline void set_V_ground_speed( double v) { v_ground_speed = v; }
+    inline double get_V_ground_speed() const { return v_ground_speed; }
 
     // inline double get_V_equiv() const { return v_equiv; }
     // inline void set_V_equiv( double v ) { v_equiv = v; }
 
     inline double get_V_equiv_kts() const { return v_equiv_kts; }
-    inline void set_V_equiv_kts( double kts ) { v_equiv_kts = kts; }
 
-    // inline double get_V_calibrated() const { return v_calibrated; }
-    // inline void set_V_calibrated( double v ) { v_calibrated = v; }
+    //inline double get_V_calibrated() const { return v_calibrated; }
+    //inline void set_V_calibrated( double v ) { v_calibrated = v; }
 
-    // inline double get_V_calibrated_kts() const { return v_calibrated_kts; }
-    // inline void set_V_calibrated_kts( double kts ) { v_calibrated_kts = kts; }
+    inline double get_V_calibrated_kts() const { return v_calibrated_kts; }
 
-    FG_VECTOR_3    omega_body_v;   // Angular B rates     
     // inline double * get_Omega_body_v() { return omega_body_v; }
     inline double get_P_body() const { return omega_body_v[0]; }
     inline double get_Q_body() const { return omega_body_v[1]; }
     inline double get_R_body() const { return omega_body_v[2]; }
-    inline void set_Omega_Body( double p, double q, double r ) {
-	omega_body_v[0] = p;
-	omega_body_v[1] = q;
-	omega_body_v[2] = r;
-    }
 
-    FG_VECTOR_3    omega_local_v;  // Angular L rates     
     // inline double * get_Omega_local_v() { return omega_local_v; }
     // inline double get_P_local() const { return omega_local_v[0]; }
     // inline double get_Q_local() const { return omega_local_v[1]; }
@@ -503,7 +877,6 @@ public:
 	omega_local_v[2] = r;
     } */
 
-    FG_VECTOR_3    omega_total_v;  // Diff btw B & L      
     // inline double * get_Omega_total_v() { return omega_total_v; }
     // inline double get_P_total() const { return omega_total_v[0]; }
     // inline double get_Q_total() const { return omega_total_v[1]; }
@@ -514,84 +887,55 @@ public:
 	omega_total_v[2] = r;
     } */
 
-    FG_VECTOR_3    euler_rates_v;
     // inline double * get_Euler_rates_v() { return euler_rates_v; }
-    // inline double get_Phi_dot() const { return euler_rates_v[0]; }
-    // inline double get_Theta_dot() const { return euler_rates_v[1]; }
-    // inline double get_Psi_dot() const { return euler_rates_v[2]; }
-    /* inline void set_Euler_Rates( double phi, double theta, double psi ) {
-	euler_rates_v[0] = phi;
-	euler_rates_v[1] = theta;
-	euler_rates_v[2] = psi;
-    } */
+    inline double get_Phi_dot() const { return euler_rates_v[0]; }
+    inline double get_Theta_dot() const { return euler_rates_v[1]; }
+    inline double get_Psi_dot() const { return euler_rates_v[2]; }
 
-    FG_VECTOR_3    geocentric_rates_v;     // Geocentric linear velocities
     // inline double * get_Geocentric_rates_v() { return geocentric_rates_v; }
     inline double get_Latitude_dot() const { return geocentric_rates_v[0]; }
     inline double get_Longitude_dot() const { return geocentric_rates_v[1]; }
     inline double get_Radius_dot() const { return geocentric_rates_v[2]; }
-    inline void set_Geocentric_Rates( double lat, double lon, double rad ) {
-	geocentric_rates_v[0] = lat;
-	geocentric_rates_v[1] = lon;
-	geocentric_rates_v[2] = rad;
-    }
-    
-    /*=============================== Positions ===============================*/
 
-    FG_VECTOR_3    geocentric_position_v;
+    // ========== Positions ==========
+
     // inline double * get_Geocentric_position_v() {
     //    return geocentric_position_v;
     // }
     inline double get_Lat_geocentric() const {
 	return geocentric_position_v[0];
     }
-    inline double get_Lon_geocentric() const { 
+    inline double get_Lon_geocentric() const {
 	return geocentric_position_v[1];
     }
     inline double get_Radius_to_vehicle() const {
 	return geocentric_position_v[2];
     }
-    inline void set_Radius_to_vehicle(double radius) {
-	geocentric_position_v[2] = radius;
-    }
-
-    inline void set_Geocentric_Position( double lat, double lon, double rad ) {
-	geocentric_position_v[0] = lat;
-	geocentric_position_v[1] = lon;
-	geocentric_position_v[2] = rad;
-    }
 
-    FG_VECTOR_3    geodetic_position_v;
     // inline double * get_Geodetic_position_v() { return geodetic_position_v; }
     inline double get_Latitude() const { return geodetic_position_v[0]; }
-    inline void set_Latitude(double lat) { geodetic_position_v[0] = lat; }
     inline double get_Longitude() const { return geodetic_position_v[1]; }
-    inline void set_Longitude(double lon) { geodetic_position_v[1] = lon; }
     inline double get_Altitude() const { return geodetic_position_v[2]; }
-    inline void set_Altitude(double altitude) {
-	geodetic_position_v[2] = altitude;
+    inline double get_Altitude_AGL(void) const { return altitude_agl; }
+
+    inline double get_Latitude_deg () const {
+      return get_Latitude() * SGD_RADIANS_TO_DEGREES;
     }
-    inline void set_Geodetic_Position( double lat, double lon, double alt ) {
-	geodetic_position_v[0] = lat;
-	geodetic_position_v[1] = lon;
-	geodetic_position_v[2] = alt;
+    inline double get_Longitude_deg () const {
+      return get_Longitude() * SGD_RADIANS_TO_DEGREES;
     }
 
-    FG_VECTOR_3 euler_angles_v;
     // inline double * get_Euler_angles_v() { return euler_angles_v; }
     inline double get_Phi() const { return euler_angles_v[0]; }
     inline double get_Theta() const { return euler_angles_v[1]; }
     inline double get_Psi() const { return euler_angles_v[2]; }
-    inline void set_Euler_Angles( double phi, double theta, double psi ) {
-	euler_angles_v[0] = phi;
-	euler_angles_v[1] = theta;
-	euler_angles_v[2] = psi;
-    }
+    inline double get_Phi_deg () const { return get_Phi() * SGD_RADIANS_TO_DEGREES; }
+    inline double get_Theta_deg () const { return get_Theta() * SGD_RADIANS_TO_DEGREES; }
+    inline double get_Psi_deg () const { return get_Psi() * SGD_RADIANS_TO_DEGREES; }
 
 
-    /*======================= Miscellaneous quantities ========================*/
+    // ========== Miscellaneous quantities ==========
 
-    double    t_local_to_body_m[3][3];    // Transformation matrix L to B
     // inline double * get_T_local_to_body_m() { return t_local_to_body_m; }
     inline double get_T_local_to_body_11() const {
 	return t_local_to_body_m[0][0];
@@ -620,34 +964,24 @@ public:
     inline double get_T_local_to_body_33() const {
 	return t_local_to_body_m[2][2];
     }
-    inline void set_T_Local_to_Body( double m[3][3] ) {
-	int i, j;
-	for ( i = 0; i < 3; i++ ) {
-	    for ( j = 0; j < 3; j++ ) {
-		t_local_to_body_m[i][j] = m[i][j];
-	    }
-	}
-    }
 
-    double    gravity;            // Local acceleration due to G 
     // inline double get_Gravity() const { return gravity; }
     // inline void set_Gravity(double g) { gravity = g; }
-    
-    double    centrifugal_relief; // load factor reduction due to speed
-    // inline double get_Centrifugal_relief() const { return centrifugal_relief; }
-    // inline void set_Centrifugal_relief(double cr) { centrifugal_relief = cr; }
 
-    double    alpha, beta, alpha_dot, beta_dot;   // in radians  
+    // inline double get_Centrifugal_relief() const {
+    //   return centrifugal_relief;
+    // }
+    // inline void set_Centrifugal_relief(double cr) {
+    //   centrifugal_relief = cr;
+    // }
+
     inline double get_Alpha() const { return alpha; }
-    inline void set_Alpha( double a ) { alpha = a; }
     inline double get_Beta() const { return beta; }
-    inline void set_Beta( double b ) { beta = b; }
     // inline double get_Alpha_dot() const { return alpha_dot; }
     // inline void set_Alpha_dot( double ad ) { alpha_dot = ad; }
     // inline double get_Beta_dot() const { return beta_dot; }
     // inline void set_Beta_dot( double bd ) { beta_dot = bd; }
 
-    double    cos_alpha, sin_alpha, cos_beta, sin_beta;
     // inline double get_Cos_alpha() const { return cos_alpha; }
     // inline void set_Cos_alpha( double ca ) { cos_alpha = ca; }
     // inline double get_Sin_alpha() const { return sin_alpha; }
@@ -657,13 +991,10 @@ public:
     // inline double get_Sin_beta() const { return sin_beta; }
     // inline void set_Sin_beta( double sb ) { sin_beta = sb; }
 
-    double    cos_phi, sin_phi, cos_theta, sin_theta, cos_psi, sin_psi;
-    // inline double get_Cos_phi() const { return cos_phi; }
-    // inline void set_Cos_phi( double cp ) { cos_phi = cp; }
+    inline double get_Cos_phi() const { return cos_phi; }
     // inline double get_Sin_phi() const { return sin_phi; }
     // inline void set_Sin_phi( double sp ) { sin_phi = sp; }
-    // inline double get_Cos_theta() const { return cos_theta; }
-    // inline void set_Cos_theta( double ct ) { cos_theta = ct; }
+    inline double get_Cos_theta() const { return cos_theta; }
     // inline double get_Sin_theta() const { return sin_theta; }
     // inline void set_Sin_theta( double st ) { sin_theta = st; }
     // inline double get_Cos_psi() const { return cos_psi; }
@@ -671,26 +1002,18 @@ public:
     // inline double get_Sin_psi() const { return sin_psi; }
     // inline void set_Sin_psi( double sp ) { sin_psi = sp; }
 
-    double    gamma_vert_rad, gamma_horiz_rad;    // Flight path angles  
     inline double get_Gamma_vert_rad() const { return gamma_vert_rad; }
-    inline void set_Gamma_vert_rad( double gv ) { gamma_vert_rad = gv; }
     // inline double get_Gamma_horiz_rad() const { return gamma_horiz_rad; }
     // inline void set_Gamma_horiz_rad( double gh ) { gamma_horiz_rad = gh; }
 
-    double    sigma, density, v_sound, mach_number;
     // inline double get_Sigma() const { return sigma; }
     // inline void set_Sigma( double s ) { sigma = s; }
-    // inline double get_Density() const { return density; }
-    // inline void set_Density( double d ) { density = d; }
+    inline double get_Density() const { return density; }
     // inline double get_V_sound() const { return v_sound; }
     // inline void set_V_sound( double v ) { v_sound = v; }
-    // inline double get_Mach_number() const { return mach_number; }
-    // inline void set_Mach_number( double m ) { mach_number = m; }
+    inline double get_Mach_number() const { return mach_number; }
 
-    double    static_pressure, total_pressure, impact_pressure;
-    double    dynamic_pressure;
-    // inline double get_Static_pressure() const { return static_pressure; }
-    // inline void set_Static_pressure( double sp ) { static_pressure = sp; }
+    inline double get_Static_pressure() const { return static_pressure; }
     // inline double get_Total_pressure() const { return total_pressure; }
     // inline void set_Total_pressure( double tp ) { total_pressure = tp; }
     // inline double get_Impact_pressure() const { return impact_pressure; }
@@ -698,41 +1021,35 @@ public:
     // inline double get_Dynamic_pressure() const { return dynamic_pressure; }
     // inline void set_Dynamic_pressure( double dp ) { dynamic_pressure = dp; }
 
-    double    static_temperature, total_temperature;
-    // inline double get_Static_temperature() const { return static_temperature; }
-    // inline void set_Static_temperature( double t ) { static_temperature = t; }
+    inline double get_Static_temperature() const { return static_temperature; }
     // inline double get_Total_temperature() const { return total_temperature; }
     // inline void set_Total_temperature( double t ) { total_temperature = t; }
 
-    double    sea_level_radius, earth_position_angle;
     inline double get_Sea_level_radius() const { return sea_level_radius; }
-    inline void set_Sea_level_radius( double r ) { sea_level_radius = r; }
     inline double get_Earth_position_angle() const {
 	return earth_position_angle;
     }
-    inline void set_Earth_position_angle(double a) { 
-	earth_position_angle = a;
-    }
 
-    double    runway_altitude, runway_latitude, runway_longitude;
-    double    runway_heading;
     inline double get_Runway_altitude() const { return runway_altitude; }
-    inline void set_Runway_altitude( double alt ) { runway_altitude = alt; }
     // inline double get_Runway_latitude() const { return runway_latitude; }
     // inline void set_Runway_latitude( double lat ) { runway_latitude = lat; }
     // inline double get_Runway_longitude() const { return runway_longitude; }
-    // inline void set_Runway_longitude( double lon ) { runway_longitude = lon; }
+    // inline void set_Runway_longitude( double lon ) {
+    //   runway_longitude = lon;
+    // }
     // inline double get_Runway_heading() const { return runway_heading; }
     // inline void set_Runway_heading( double h ) { runway_heading = h; }
 
-    double    radius_to_rwy;
     // inline double get_Radius_to_rwy() const { return radius_to_rwy; }
     // inline void set_Radius_to_rwy( double r ) { radius_to_rwy = r; }
 
-    FG_VECTOR_3    d_cg_rwy_local_v;       // CG rel. to rwy in local coords
     // inline double * get_D_cg_rwy_local_v() { return d_cg_rwy_local_v; }
-    // inline double get_D_cg_north_of_rwy() const { return d_cg_rwy_local_v[0]; }
-    // inline double get_D_cg_east_of_rwy() const { return d_cg_rwy_local_v[1]; }
+    // inline double get_D_cg_north_of_rwy() const {
+    //   return d_cg_rwy_local_v[0];
+    // }
+    // inline double get_D_cg_east_of_rwy() const {
+    //   return d_cg_rwy_local_v[1];
+    // }
     // inline double get_D_cg_above_rwy() const { return d_cg_rwy_local_v[2]; }
     /* inline void set_CG_Rwy_Local( double north, double east, double above )
     {
@@ -741,7 +1058,6 @@ public:
 	d_cg_rwy_local_v[2] = above;
     } */
 
-    FG_VECTOR_3    d_cg_rwy_rwy_v; // CG relative to rwy, in rwy coordinates
     // inline double * get_D_cg_rwy_rwy_v() { return d_cg_rwy_rwy_v; }
     // inline double get_X_cg_rwy() const { return d_cg_rwy_rwy_v[0]; }
     // inline double get_Y_cg_rwy() const { return d_cg_rwy_rwy_v[1]; }
@@ -753,17 +1069,16 @@ public:
 	d_cg_rwy_rwy_v[2] = h;
     } */
 
-    FG_VECTOR_3    d_pilot_rwy_local_v;  // pilot rel. to rwy in local coords
     // inline double * get_D_pilot_rwy_local_v() { return d_pilot_rwy_local_v; }
     // inline double get_D_pilot_north_of_rwy() const {
-	//return d_pilot_rwy_local_v[0];
-  //  }
+    //   return d_pilot_rwy_local_v[0];
+    // }
     // inline double get_D_pilot_east_of_rwy() const {
-//	return d_pilot_rwy_local_v[1];
-//    }
+    //   return d_pilot_rwy_local_v[1];
+    // }
     // inline double get_D_pilot_above_rwy() const {
-	//return d_pilot_rwy_local_v[2];
- //   }
+    //   return d_pilot_rwy_local_v[2];
+    // }
     /* inline void set_Pilot_Rwy_Local( double north, double east, double above )
     {
 	d_pilot_rwy_local_v[0] = north;
@@ -771,7 +1086,6 @@ public:
 	d_pilot_rwy_local_v[2] = above;
     } */
 
-    FG_VECTOR_3   d_pilot_rwy_rwy_v;   // pilot rel. to rwy, in rwy coords.
     // inline double * get_D_pilot_rwy_rwy_v() { return d_pilot_rwy_rwy_v; }
     // inline double get_X_pilot_rwy() const { return d_pilot_rwy_rwy_v[0]; }
     // inline double get_Y_pilot_rwy() const { return d_pilot_rwy_rwy_v[1]; }
@@ -783,27 +1097,15 @@ public:
 	d_pilot_rwy_rwy_v[2] = h;
     } */
 
-    double        climb_rate;           // in feet per second
     inline double get_Climb_Rate() const { return climb_rate; }
-    inline void set_Climb_Rate(double rate) { climb_rate = rate; }
 
-    FGTimeStamp valid_stamp;       // time this record is valid
-    FGTimeStamp next_stamp;       // time this record is valid
-    inline FGTimeStamp get_time_stamp() const { return valid_stamp; }
-    inline void stamp_time() { valid_stamp = next_stamp; next_stamp.stamp(); }
+    // inline SGTimeStamp get_time_stamp() const { return valid_stamp; }
+    // inline void stamp_time() { valid_stamp = next_stamp; next_stamp.stamp(); }
 
     // Extrapolate FDM based on time_offset (in usec)
     void extrapolate( int time_offset );
 
     // sin/cos lat_geocentric
-    double sin_lat_geocentric;
-    double cos_lat_geocentric;
-    inline void set_sin_lat_geocentric(double parm) {
-	sin_lat_geocentric = sin(parm);
-    }
-    inline void set_cos_lat_geocentric(double parm) {
-	cos_lat_geocentric = cos(parm);
-    }
     inline double get_sin_lat_geocentric(void) const {
 	return sin_lat_geocentric;
     }
@@ -811,52 +1113,62 @@ public:
 	return cos_lat_geocentric;
     }
 
-    double sin_longitude;
-    double cos_longitude;
-    inline void set_sin_cos_longitude(double parm) {
-	sin_longitude = sin(parm);
-	cos_longitude = cos(parm);
-    }
     inline double get_sin_longitude(void) const {
 	return sin_longitude;
     }
     inline double get_cos_longitude(void) const {
 	return cos_longitude;
     }
-	
-    double sin_latitude;
-    double cos_latitude;
-    inline void set_sin_cos_latitude(double parm) {
-	sin_latitude = sin(parm);
-	cos_latitude = cos(parm);
-    }
+
     inline double get_sin_latitude(void) const {
 	return sin_latitude;
     }
     inline double get_cos_latitude(void) const {
 	return cos_latitude;
     }
+
+    // Auxilliary variables
+    inline double get_daux( int n ) const { return daux[n]; }
+    inline float  get_faux( int n ) const { return faux[n]; }
+    inline int    get_iaux( int n ) const { return iaux[n]; }
+
+    // Consumables
+    inline double get_Tank1Fuel() const { return Tank1Fuel; }
+    inline double get_Tank2Fuel() const { return Tank2Fuel; }
+
+    // engines
+    inline double get_num_engines() const {
+	return engines.size();
+    }
+
+    inline FGEngInterface* get_engine( int i ) {
+	return &engines[i];
+    }
+
+    inline void add_engine( FGEngInterface e ) {
+	engines.push_back( e );
+    }
 };
 
 
-extern FGInterface cur_fdm_state;
+typedef list < FGInterface > fdm_state_list;
+typedef fdm_state_list::iterator fdm_state_list_iterator;
+typedef fdm_state_list::const_iterator const_fdm_state_list_iterator;
 
 
-// General interface to the flight model routines
+extern FGInterface * cur_fdm_state;
 
-// Initialize the flight model parameters
-int fgFDMInit(int model, FGInterface& f, double dt);
 
-// Run multiloop iterations of the flight model
-int fgFDMUpdate(int model, FGInterface& f, int multiloop, int jitter);
+// General interface to the flight model routines
 
 // Set the altitude (force)
-void fgFDMForceAltitude(int model, double alt_meters);
+void fgFDMForceAltitude(const string &model, double alt_meters);
 
 // Set the local ground elevation
-void fgFDMSetGroundElevation(int model, double alt_meters);
-
+void fgFDMSetGroundElevation(const string &model, double alt_meters);
 
-#endif // _FLIGHT_HXX
+// Toggle data logging on/off
+void fgToggleFDMdataLogging(void);
 
 
+#endif // _FLIGHT_HXX