From: andy <andy>
Date: Thu, 1 Dec 2005 21:06:25 +0000 (+0000)
Subject: Swap signs of the twist and incidence values to match the
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=d71a5418377157890e2523cf167b4da664891ca9;p=flightgear.git

Swap signs of the twist and incidence values to match the
documentation and author expectations.  Positive just wants to mean
"up", no matter what the axis conventions have to say.
---

diff --git a/src/FDM/YASim/FGFDM.cpp b/src/FDM/YASim/FGFDM.cpp
index 3bf8c8079..9fdbecd61 100644
--- a/src/FDM/YASim/FGFDM.cpp
+++ b/src/FDM/YASim/FGFDM.cpp
@@ -583,8 +583,12 @@ Wing* FGFDM::parseWing(XMLAttributes* a, const char* type)
     w->setTaper(attrf(a, "taper", 1));
     w->setDihedral(attrf(a, "dihedral", defDihed) * DEG2RAD);
     w->setCamber(attrf(a, "camber", 0));
-    w->setIncidence(attrf(a, "incidence", 0) * DEG2RAD);
-    w->setTwist(attrf(a, "twist", 0) * DEG2RAD);
+
+    // These come in with positive indicating positive AoA, but the
+    // internals expect a rotation about the left-pointing Y axis, so
+    // invert the sign.
+    w->setIncidence(attrf(a, "incidence", 0) * DEG2RAD * -1);
+    w->setTwist(attrf(a, "twist", 0) * DEG2RAD * -1);
 
     // The 70% is a magic number that sorta kinda seems to match known
     // throttle settings to approach speed.