JSBSim Thrusters: Difference between revisions

JSBSim Thrusters (view source)

1,155 bytes added , 1 November 2011

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          </tank>
      </propulsion>
+=== Starter speed ===
+There is a somewhat complex relationship among the power coefficient, the maxrpm, and idlerpm.  Both maxrpm and idlerpm are set in the engine xml file.
+The power of the starter motor is proportional to maxrpm.  The minimum RPM needed to start the engine is 80% of the idlerpm.  The greater the power coefficient (for J near 0), the more power the propeller will require to spin when starting the engine with the aircraft at rest.
+If your propeller will not spin fast enough to start, you can try some combination of:
+* Increase maxrpm (increases the power of the starter motor)
+* Decrease idlerpm (decreases the minimum RPM needed to start the engine)
+* Decrease the power coefficient in the C_POWER table, for values of J close to (or equal to) 0.  This will reduce the amount of power it takes for the propeller to spin at a given RPM where J is close to 0 (which is the typical situation when starting the engine and the aircraft is at a dead stop).
+You can open the property tree and watch the value of J (/fdm/jsbsim/propulsion/engines/advance-ratio) to get an idea of which values you need to change in the C_POWER table.
 === Notes ===