Curt noticed a while back that YASim was producing alpha and sideslip

values that were angles between the aircraft's orientation and the
global velocity vector, not the airflow velocity.  So the HUD velocity
vector was wrong when the wind was non-zero.  Fix that.

diff --git a/src/FDM/YASim/Glue.cpp b/src/FDM/YASim/Glue.cpp
index 8922363da0a83720b596bfc0b8a3753ea91d6795..90e9fdb249efe32262ec770009b9a74595034e97 100644 (file)
--- a/src/FDM/YASim/Glue.cpp
+++ b/src/FDM/YASim/Glue.cpp
@@ -2,11 +2,12 @@
 #include "Glue.hpp"
 namespace yasim {
 
-void Glue::calcAlphaBeta(State* s, float* alpha, float* beta)
+void Glue::calcAlphaBeta(State* s, float* wind, float* alpha, float* beta)
 {
     // Convert the velocity to the aircraft frame.
     float v[3];
-    Math::vmul33(s->orient, s->v, v);
+    Math::sub3(s->v, wind, v);
+    Math::vmul33(s->orient, v, v);
 
     // By convention, positive alpha is an up pitch, and a positive
     // beta is yawed to the right.

diff --git a/src/FDM/YASim/Glue.hpp b/src/FDM/YASim/Glue.hpp
index dd621e12db50158b91cea2bbdf8613db54a9839c..12f2f8349f8dc6ab941b0ec8ca3fe2b61139a6a1 100644 (file)
--- a/src/FDM/YASim/Glue.hpp
+++ b/src/FDM/YASim/Glue.hpp
@@ -10,7 +10,7 @@ namespace yasim {
 // out the middle of the western hemisphere.
 class Glue {
 public:
-    static void calcAlphaBeta(State* s, float* alpha, float* beta);
+    static void calcAlphaBeta(State* s, float* wind, float* alpha, float* beta);
 
     // Calculates the instantaneous rotation velocities about each
     // axis.

diff --git a/src/FDM/YASim/YASim.cxx b/src/FDM/YASim/YASim.cxx
index 924399afea10e55a0d115c4ada7732c4abbdf985..27fcbff6d64672baa49f822b3daa06ef74b7f9d6 100644 (file)
--- a/src/FDM/YASim/YASim.cxx
+++ b/src/FDM/YASim/YASim.cxx
@@ -441,7 +441,7 @@ void YASim::copyFromYASim()
 
     // orientation
     float alpha, beta;
-    Glue::calcAlphaBeta(s, &alpha, &beta);
+    Glue::calcAlphaBeta(s, wind, &alpha, &beta);
     _set_Alpha(alpha);
     _set_Beta(beta);