Howto:Aerial refueling: Difference between revisions

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Howto:Aerial refueling (view source)

Revision as of 21:53, 28 August 2010

271 bytes added ,  28 August 2010
It does look like AAR is broken with Git. I'll do some tests.
(It does look like AAR is broken with Git. I'll do some tests.)
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== What's possible ==
'''Aerial refueling''', also called '''air refueling''', '''in-flight refueling''' ('''IFR'''), '''air-to-air refueling''' ('''AAR''') or '''tanking''', is the process of transferring fuel from one [[aircraft]] (the tanker) to another (the receiver) during flight.
At present, there are two tanker [[aircraft]] ([[Boeing KC-135E|KC135-E]] and KA6-D) and several receiving aircraft ([[Douglas A4 Skyhawk|A4F]], [[Grumman A-6E|A-6E]], [[Fairchild A-10|A-10]], [[Grumman F-14 Tomcat|F-14 Tomcat]], [[English Electric Lightning|Lightning]],[[F-117 Nighthawk|F-117 Nighthawk]] and [[Northrop T-38|T38]]) capable of in-air refuelling.  When flying one of these aircraft in the default scenery area, one can locate the tanker aircraft using air-air [[TACAN]] and/or radar and then receive a full or partial load of fuel by flying in close formation behind the tanker.  Refuelling is also possible between aircraft in a [[Howto: Multiplayer|Multiplayer]] session. The KC135 is a boom refueller, while the KA6 has a hose. The A4F and Lightning are both fitted with a probe for hose refuelling while the T38 is fitted with a boom receiver. At the moment, either type can refuel from any tanker, but in the future it is likely that the correct type will have to be used (this has been implemented in CVS).


It is not possible to control the boom position yet.
== What is possible ==
At present, there are two tanker [[aircraft]] and several receiving aircraft capable of in-air refuelling:
 
{| class="prettytable" border="1px" cellspacing="0" cellpadding="2"
!Aircraft
!Can be refueled by
|-
|[[Douglas A4 Skyhawk]]
|rowspan="5"|KA6
|-
|[[English Electric Lightning]]
|-
|[[F-8 Crusader]]
|-
|[[Grumman A-6E]]
|-
|[[Grumman F-14 Tomcat]]
|-
|[[Fairchild A-10]]
|rowspan="4"|[[Boeing KC-135E|KC-135]]
|-
|[[F-117 Nighthawk]]
|-
|[[General Dynamics F-16]]
|-
|[[Northrop T-38]]
|}
 
When flying one of these aircraft in the default scenery area, one can locate the tanker aircraft using air-air [[TACAN]] and/or radar and then receive a full or partial load of fuel by flying in close formation behind the tanker. Refuelling is also possible between aircraft in a [[Howto: Multiplayer|multiplayer]] session.
 
It is not possible to control the boom/hose position yet; they are always operatable when the tankers are air-born.


== Necessary preparations ==
== Necessary preparations ==
Like the aircraft carriers, AAR is implemented as an "AI scenario". Selecting these normally requires editing the "preferences.xml" file in the flightgear data directory.
Like the [[aircraft carrier]]s, AAR is implemented as an AI scenario. Selecting these normally requires editing the "preferences.xml" file in the FlightGear data directory, or selecting the corresponding scenario from the [[FlightGear Launch Control|launcher/FGRun]].
 
There is a shortcut in this case though; simply selecting the Lightning, A4F or T38 should automatically load a scenario containing a tanker, assuming you haven't changed anything in your preferences.xml file.


Assuming this is the case, choose one of the aforementioned aircraft, make sure that "AI models" are enabled and start at [[KSFO]] (the default airport.)
There is a shortcut in this case though; simply selecting the Lightning, A4F or T38 should automatically load a scenario containing a tanker, assuming you haven't changed anything in your preferences.xml file. Assuming this is the case, choose one of the aforementioned aircraft, make sure that "AI models" are enabled and start at [[KSFO]] (the default airport.)


Depending on the scenario, you might see the tanker crossing overhead when the sim starts; if not, don't worry.
Depending on the scenario, you might see the tanker crossing overhead when the sim starts; if not, don't worry.
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=== Simulation vs. reality ===
=== Simulation vs. reality ===
 
[[Image:f16-air-air-refuel.jpg|thumb|270px|Approaching the tanker with a [[F-16]] - and receiving fuel already (FG 1.9.1)!]]
[[Image:f16-air-air-refuel.jpg|thumb|270px|Approaching the tanker with an F-16 - and receiving fuel already (v.1.9.1)!]]


There are a few things which are (presumably) easier in the simulation as compared with the real world, but there are also some that are harder. First, the envelope for refueling is actually quite generous - you start getting fuel in a position where in the real world this could not possibly work (see picture). The real refueling position of the F-16 feels a lot less comfortable! It is also mercifully short - usually holding the plane in the correct spot for about 30 seconds is all you need. There is also no turbulence or other change in the airstream induced by the tanker modelled.
There are a few things which are (presumably) easier in the simulation as compared with the real world, but there are also some that are harder. First, the envelope for refueling is actually quite generous - you start getting fuel in a position where in the real world this could not possibly work (see picture). The real refueling position of the F-16 feels a lot less comfortable! It is also mercifully short - usually holding the plane in the correct spot for about 30 seconds is all you need. There is also no turbulence or other change in the airstream induced by the tanker modelled.
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== More advanced topics ==
== More advanced topics ==
=== Multiplayer refuelling ===
Refuelling is possible within a multiplayer session given certain conditions. A basic flyable KC135 model is available - the pilot of this aircraft should use the callsign "MOBIL1", "MOBIL2" or "MOBIL3". Other numbers are acceptable, but only these three have A-A TACAN channels assigned. These are 060X, 061X and 062X respectively.


=== Multiplayer Refuelling ===
If the receiving aircraft uses a YASim FDM, there are no further complications. Should the receiving aircraft be JSBSim based, the user must make sure that there are no AI tankers in their configuration. This means disabling (commenting out) all refuelling "scenarios" in the relevant aircraft-set.xml and in preferences.xml.
 
Refuelling is possible within a MultiPlayer session given certain conditions.  A basic flyable KC135 model is available - the pilot of this aircraft should use the callsign "MOBIL1", "MOBIL2" or "MOBIL3".  Other numbers are acceptable, but only these three have A-A TACAN channels assigned.  These are 060X, 061X and 062X respectively.
 
If the receiving aircraft uses a YASim FDM, there are no further complications. Should the receiving aircraft be JSBSim based, the user must make sure that there are no AI tankers in their configuration. This means disabling (commenting out) all refuelling "scenarios" in the relevant aircraft-set.xml and in preferences.xml.


MP refuelling works in exactly the same way as AI refuelling and is a fun challenge. It is best to ensure that your network connection is as free from interruptions as possible; the MP code does a degree of prediction if there is a "blip" in the stream of packets and this can make close formation flight very difficult or even impossible.
MP refuelling works in exactly the same way as AI refuelling and is a fun challenge. It is best to ensure that your network connection is as free from interruptions as possible; the MP code does a degree of prediction if there is a "blip" in the stream of packets and this can make close formation flight very difficult or even impossible.


''See also [[Chat Menu]]''
''See also [[Chat Menu]]''


=== Selecting Different Scenarios ===
=== Selecting different scenarios ===
 
There are several AAR scenarios available in the AI directory. refueling_demo.xml has a KC135 circling near KSFO at 3000ft; refueling_demo_1.xml the KC135 on a North/South towline at 8000ft and refueling_demo_2.xml the KA6D on a similar N/S path but at 8500ft.
There are several AAR scenarios available in the AI directory. refueling_demo.xml has a KC135 circling near KSFO at 3000ft; refueling_demo_1.xml the KC135 on a North/South towline at 8000ft and refueling_demo_2.xml the KA6D on a similar N/S path but at 8500ft.


These can be selected by several methods; using the --ai-scenario [[Command Line Parameters|command line option]], or by editing preferences.xml.
These can be selected by several methods; using the --ai-scenario [[Command Line Parameters|command line option]], or by editing preferences.xml.


==== Command line method ====
==== Command line method ====
 
Add the --ai-scenario option to your usual FlightGear [[command line]]; eg.:
Add the --ai-scenario option to your usual flightgear [[command line]]; e.g. <code>fgfs --aircraft=lightning --ai-scenario=refueling_demo_2</code>
fgfs --aircraft=lightning --ai-scenario=refueling_demo_2


==== Preferences.xml method ====
==== Preferences.xml method ====
Use your operating system's search facility to locate this if you don't know where it is). Open preferences.xml in a text editor (e.g. notepad if on windows) and search for the <ai> </ai> tags. Place a line like <code><scenario>refueling_demo</scenario></code> somewhere within the <ai> tags; you should see other scenarios already there too, perhaps commented out : i.e. with <! --  -->
Use your operating system's search facility to locate this if you don't know where it is). Open preferences.xml in a text editor (e.g. notepad if on windows) and search for the <ai> </ai> tags. Place a line like <tt><scenario>refueling_demo</scenario></tt> somewhere within the <ai> tags; you should see other scenarios already there too, perhaps commented out: i.e. with <! --  -->
 
 
=== Version 1.9.1 ===


==For developers==
=== Implementing AAR capability in a receiver ===
In Flightgear Version 1.9.1, aircraft appear able to successfully be refueled by a KA6D if they have the lines
In Flightgear Version 1.9.1, aircraft appear able to successfully be refueled by a KA6D if they have the lines


<systems>
<systems>
<refuel>
  <refuel>
<type>probe</type>
  <type>probe</type>
<serviceable type="bool">true</serviceable>
  <serviceable type="bool">true</serviceable>
</refuel>
  </refuel>
</systems>
</systems>
 
somewhere in the aircraft description and can receive fuel from a KC135 if in the above 'probe' is replaced by 'boom'. At present, not every aircraft model which could be refueled in 0.9.10 has this (in particular the Lightning doesn't) which can lead to some frustration. Check if the lines appear before blaming your flight abilities, and if necessary add them to the file (aircraftname)-set.xml.


somewhere in the aircraft description (after the </sim> tag) and can receive fuel from a KC-135 if in the above 'probe' is replaced by 'boom'. At present, not every aircraft model which could be refueled in 0.9.10 has this (in particular the Lightning doesn't) which can lead to some frustration. Check if the lines appear before blaming your flight abilities, and if necessary add them to the file (aircraftname)-set.xml.


[[Category:Howto|Air-Air Refueling]]
[[Category:Howto|Air-Air Refueling]]
Retrieved from "https://wiki.flightgear.org/Special:MobileDiff/23588"

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