JSBSim Engines: Difference between revisions

Jump to navigation Jump to search
1,599 bytes removed ,  23 August 2018
No edit summary
Line 408: Line 408:


=== Starting the engine ===
=== Starting the engine ===
In a [[YASim]] aircraft you need to simulate the spool-up of the engine in a [[Nasal]] script. For an example see lines 498-529 of [{{fgaddon aircraft url|b1900d|Nasal/systems.nas|l=498}} systems.nas] from the [[B1900d]].
Unlike [[YASim]], JSBSim simulates the startup of Turbine engines.


JSBSim however spools the engine up automatically when certain conditions are met. According to my experience the process is the following:
# Set the [[property]] <code>/controls/engines/engine[~n~]/starter</code> to <b>true</b>.
 
# JSBsim will begin to crank the engine spinning it up to around 5% N1, and about 25% N2.
# The [[property]] <code>/engines/engine[~n~]/cutoff</code> has to be <b>true</b>.
# You can set the property <code>/engines/engine[~n~]/cutoff</code> to <b>true</b> at any point.
# Set the property <code>/controls/electric/engine[~n~]generator</code> to <b>true</b>.
# If the engine is above 15% N2, and the cutoff property is set to true, JSBsim will introduce fuel to the engine, and the engine will spin up.
# Set the property <code>/controls/engines/engine[~n~]/starter</code> to <b>true</b> as well.
# <code>/engines/engine[~n~]/n1</code> will increase further until it stabilizes at the value which is defined in <code>idlen1</code> in the [{{fgaddon aircraft url|707|Engines/RCo12.xml|l=42}} engine definition file].
# As result, <code>/engines/engine[~n~]/starter</code> and <code>/engines/engine[~n~]/starting</code> will be set to <b>true</b> and <code>/engines/engine[~n~]/n1</code> will increase which means that the engine is spooling up. In JSBSim <code>n1</code> represents the rotation speed of the turbine shaft which is significantly higher than the propeller speed.
# [[Nasal]] can be used to automate this process, allowing any number of engine start simulations. Various JSBsim aircraft will do this differently, depending on how the real plane functions, and how the author implemented it.
# <code>/engines/engine[~n~]/n1</code> stabilizes at a specific value which is defined in <code><startern1></code> in the engine definition file of the FDM (see the table above or as an example the [{{fgaddon aircraft url|b1900d|Engines/PT6A67D.xml|l=11}} engine file] of the B1900d).
# When <code>/engines/engine[~n~]/n1</code> rises above <b>15</b> (at least I think), you can set <code>/engines/engine[~n~]/cutoff</code> to <b>false</b> which simulates that the engine now gets supplied with fuel.
# This sets <code>/engines/engine[~n~]/starting</code> to <b>false</b> and <code>/engines/engine[~n~]/cranking</code> to <b>true</b>.
# Now you may set <code>/engines/engine[~n~]/starter</code> to <b>false</b> without interrupting the starting process.
# <code>/engines/engine[~n~]/n1</code> will increase further until it stabilizes at the value which is defined in <code>idlen1</code> in the [{{fgaddon aircraft url|b1900d|Engines/PT6A67D.xml|l=5}} engine definition file].
# Finally <code>/engines/engine[~n~]/cranking</code> will be set to <b>false</b> and <code>/engines/engine[~n~]/running</code> to <b>true</b> which means that the engine is now running.
 
 
 
Pleas note that the above described process is only an assumption based on my experiences with trying to create a JSBSim FDM for the [[Twin Otter]] which is equipped with turboprop engines, and unfortunately I cannot guarantee the correctness. If something is wrong here feel free to correct it.
: [[User:Dg-505|Dg-505]] ([[User talk:Dg-505|talk]]) 13:53, 5 December 2016 (EST)


== FGRocket ==
== FGRocket ==
1,414

edits

Navigation menu