Flight model: ApplyFlightModel (Part 4 of 7)

       Name: ApplyFlightModel (Part 4 of 7)                          [Show more]
       Type: Subroutine
   Category: Flight model
    Summary: Calculate the dxTurn and xLinear vectors, and the slipRate
  Deep dive: The flight model
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 This part does the following:

   * Call the ApplyTurnAndThrust routine to:

       * Set the dxTurn vector as follows:

         [ dxTurn ]   [ xMomentsSc ]   [ xControlsSc ]
         [ dyTurn ] = [ yMomentsSc ] + [ yControlsSc ]
         [ dzTurn ]   [ zMomentsSc ]   [ zControlsSc ]

                      [  yGravity  ]   [      0      ]
                    + [      0     ] - [      0      ]
                      [      0     ]   [ zSlipMoment ]

       * Set the xLinear vector, depending on the turning moments and the
         forces from the engine:

         If zVelocityPHi >= 48 (so forward speed >= 500 mph), we calculate:

           [ xLinear ]   [       0      ]   [   xLiftDragSc   ]
           [ yLinear ] = [ yFlapsLiftSc ] - [   yLiftDragSc   ]
           [ zLinear ]   [       0      ]   [ (&EA zLinearLo) ]

         If zVelocityPHi < 48 (so forward speed < 500 mph), we calculate:

           [ xLinear ]   [       0      ]   [ xLiftDragSc ]   [    0    ]
           [ yLinear ] = [ yFlapsLiftSc ] - [ yLiftDragSc ] + [    0    ]
           [ zLinear ]   [       0      ]   [ zLiftDragSc ]   [ zEngine ]

         where zEngine is 0 if the engine is off, or the following if the
         engine is on:

           zEngine = max(0, thrustScaled - (max(0, zVelocityP) / 16))
                     * airDensity / 512

         and:

           airDensity = ~yPlaneHi * 2

         and thrustScaled is the thrust in (thrustHi thrustLo), but:

           * Doubled if thrust >= 1024

           * Doubled if zVelocity is in the range 512 to 1023

       * Retract the flaps if we are going too fast.

   * Set the slip rate shown on the slip indicator as follows:

       slipRate = -int(xLinear / 256)


.fmod3

 JSR ApplyTurnAndThrust \ Set the dxTurn and xLinear vectors, depending on
                        \ the turning moments and the forces from the engine

 LDA xLinearLo          \ Set the C flag to bit 7 of xLinearLo, flipped, to
 EOR #%10000000         \ round the slip rate in the following calculation to
 ASL A                  \ the nearest integer

 LDA #0                 \ Set slipRate = 0 - xLinearHi - (1 - C)
 SBC xLinearHi          \              = -int(xLinear / 256)
 STA slipRate