Tune up the starter torque to match the recent changes to engine

friction.  We should get these better calibrated at some point...

diff --git a/src/FDM/YASim/PistonEngine.cpp b/src/FDM/YASim/PistonEngine.cpp
index 8c28d62f044966b160743978034e6a1099549dfc..9635f2ea4d691d1677eb5831c575daf86047e3a1 100644 (file)
--- a/src/FDM/YASim/PistonEngine.cpp
+++ b/src/FDM/YASim/PistonEngine.cpp
@@ -191,10 +191,12 @@ void PistonEngine::calc(float pressure, float temp, float speed)
     float power = _power0 * burned/_f0;
     _torque = power/speed;
 
-    // Figure that the starter motor produces 20% of the engine's
-    // cruise torque.
+    // Figure that the starter motor produces 60% of the engine's
+    // cruise torque.  That sounds like a lot to me, but it's
+    // necessary to produce the right acceleration.  Someone should
+    // find a good reference for this...
     if(_cranking && !_running)
-       _torque += 0.20f * _power0/_omega0;
+       _torque += 0.60f * _power0/_omega0;
 
     // Also, add a negative torque of 10% of cruise, to represent
     // internal friction.  Propeller aerodynamic friction is too low