Make sure the friction forces are positive, otherwise they will push the aircraft...

diff --git a/src/FDM/JSBSim/FGLGear.cpp b/src/FDM/JSBSim/FGLGear.cpp
index fb374821114175f67ff5fc85a50690c4865f83bf..3de603f40e7b82e702b06ff8b96dafc06c18fd2f 100644 (file)
--- a/src/FDM/JSBSim/FGLGear.cpp
+++ b/src/FDM/JSBSim/FGLGear.cpp
@@ -403,6 +403,11 @@ FGColumnVector3& FGLGear::Force(void)
         FCoeff = dynamicFCoeff*fabs(WheelSlip)/WheelSlip;
       }
 
+      // A negative force coefficient will result in a force pulling the wheel(s)
+      // back instead of trying to stop them from moving.
+      if (FCoeff < 0.0)
+          FCoeff = 0.0;
+
 // Compute the vertical force on the wheel using square-law damping (per comment
 // in paper AIAA-2000-4303 - see header prologue comments). We might consider
 // allowing for both square and linear damping force calculation. Also need to