Blindingly stupid ground effect bug. It interpolated in the wrong direction

(zero at ground, maximum at 1-span!)

diff --git a/src/FDM/YASim/Airplane.cpp b/src/FDM/YASim/Airplane.cpp
index 53df465421ad5f3165130c84b5348c2fcc4c3db7..f2be3e0dc2612cf738e114eaa1e0e58671c35319 100644 (file)
--- a/src/FDM/YASim/Airplane.cpp
+++ b/src/FDM/YASim/Airplane.cpp
@@ -582,7 +582,7 @@ void Airplane::compile()
     // Ground effect
     float gepos[3];
     float gespan = _wing->getGroundEffect(gepos);
-    _model.setGroundEffect(gepos, gespan, 0.3f);
+    _model.setGroundEffect(gepos, gespan, 0.15f);
 
     solveGear();
     solve();

diff --git a/src/FDM/YASim/Model.cpp b/src/FDM/YASim/Model.cpp
index 1a098358cb4a87f8081efa94a3c868a9cf301fb2..8cc50c9d03aaff659d98847940bd68b2d7764694 100644 (file)
--- a/src/FDM/YASim/Model.cpp
+++ b/src/FDM/YASim/Model.cpp
@@ -260,8 +260,9 @@ void Model::calcForces(State* s)
     float dist = ground[3] - Math::dot3(ground, _wingCenter);
     if(dist > 0 && dist < _groundEffectSpan) {
        float fz = Math::dot3(faero, ground);
-       Math::mul3(fz * _groundEffect * dist/_groundEffectSpan,
-                  ground, faero);
+        fz *= (_groundEffectSpan - dist) / _groundEffectSpan;
+        fz *= _groundEffect;
+       Math::mul3(fz, ground, faero);
        _body.addForce(faero);
     }