How to start any aircraft?

[seung-cha]

I have been playing with JSBSim on multiple platforms (flight gear, unreal engine and raw) and can't get any other aircraft to run except C172X.
Is there a universal property that, once turned on, bypasses all the complicated procedures and powers the aircraft?
If not, how can I figure out what to do to start an aircraft?

[agodemar]

@seung-cha Looks like your question comes from a gamer mindset.
JSBSim, a software library, implements the physical-mathematical model of a flying vehicle, which is fully defined by the data you provide across a set of XML configuration files. Defining an aircraft is not the simplest thing in the world; it can be made simple, but not too much. The answer to your question is: No, there isn't a universal property to bypass all necessary data authoring tasks—at least, not yet.
To model an aircraft from scratch, one should have a flight-dynamicist mindset. A basic knowledge of aircraft anatomy, aerodynamics, and propulsion will help.

[bcoconni]

@seung-cha, the aircraft start procedure differs from one aircraft to the other so unfortunately there is no universal property for that purpose. However setting the property propulsion/set-running to 1 sometimes works, but this is not guaranteed to succeed on every aircraft.

In the case where propulsion/set-running does not work, the XML scripts of JSBSim are a great source of information to find the start procedures of our models.

[seung-cha]

Judging by how FlightGear and Unreal Engine support one button to start the engine running, I was under the impression that JSBSim inherently supports a property that enables such a procedure.

For aircraft without a .XML script file (e.g ah1s), how can I figure out the procedures to start the engine?
I've been looking at the aircraft file for c172x to find a clue but it looks like the procedures aren't explicitly defined.

[bcoconni]

For aircraft without a .XML script file (e.g ah1s)

The ah1s helicopter does have a script : scripts/ah1s_flight_test.xml

[andgi]

For FlightGear it is something that is, for those aircraft that are close to real, implemented per aircraft (to larger or smaller degree). /Anders

[seanmcleod70]

@seung-cha take a look at #1266 and #1264.

As mentioned in the discussion I came across the issue where propulsion/set-running = -1 worked for the 737, C172x but no the C172p. There if a fix for that issue now regarding piston engine aircraft.

Having said that, I don't want to over promise. This should be a simple one liner to start aircraft in stand-alone JSBSim aircraft. However it may not work with aircraft with more complex system modelling, e.g. some aircraft in FlightGear where there may be logic implemented in their systems which require some additional steps otherwise the engine may cut-out.