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Reverse thrust

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Reverse thrust

Postby bisutti » Wed Jun 04, 2008 1:58 am

Hi all

I have tried to put reverse thrust in my 737-400 without success.. I took the nasal file, and I did everything as the another planes.. what am I doing wrong?
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Re: Reverse thrust

Postby Golf Foxtrot Sierra » Wed Jun 04, 2008 5:31 am

I have never been able to get reverse thrust from JSBSim. To my knowledge, only models with YASim FDMs (like the 777, 787, and the Citations) have thrust reversers. You might have to convert your 737-400 to YASim in order to add the reverse thrust feature.
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Re: Reverse thrust

Postby AndersG » Wed Jun 04, 2008 8:38 am

Golf Foxtrot Sierra wrote:I have never been able to get reverse thrust from JSBSim. To my knowledge, only models with YASim FDMs (like the 777, 787, and the Citations) have thrust reversers. You might have to convert your 737-400 to YASim in order to add the reverse thrust feature.


Or you could "hack" one in JSBSim by messing with /fdm/jsbsim/propulsion/engine[x]/yaw-angle-rad ... That's what I do on the LZ-129. (It basically rotates the engine :)

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Re: Reverse thrust

Postby yurik_nsk » Wed Jun 04, 2008 10:23 am

Or you could "hack" one in JSBSim by messing with /fdm/jsbsim/propulsion/engine[x]/yaw-angle-rad


I use /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad for it, it's work fine.
but I don't know, it's a hack:) I think, it's "self-documented" property name :)
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Re: Reverse thrust

Postby Fahim Dalvi » Wed Jun 04, 2008 4:12 pm

yurik_nsk wrote:
Or you could "hack" one in JSBSim by messing with /fdm/jsbsim/propulsion/engine[x]/yaw-angle-rad


I use /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad for it, it's work fine.
but I don't know, it's a hack:) I think, it's "self-documented" property name :)


Hi,
Yup....ur right .....reverser-angle-rad works well too...
I had to do nasal for the reverse thrusters to work on a380.....
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Re: Reverse thrust

Postby AndersG » Wed Jun 04, 2008 4:21 pm

yurik_nsk wrote:I use /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad for it, it's work fine.
but I don't know, it's a hack:) I think, it's "self-documented" property name :)


Ah, nice didn't know that property existed for jet engines as it doesn't for piston engines. I guess variable pitch propellers are an other possibility for piston engines, but in my case I have fixed pitch propellers and reversing was done by running the engine backwards.. :)

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Re: Reverse thrust

Postby bisutti » Wed Jun 04, 2008 5:03 pm

Well I hadn´t success... maybe if I change this property?

Code: Select all
<flight-model>jsb</flight-model>
  <aero>737</aero>
 


to

Code: Select all
<flight-model>Yasim</flight-model>
  <aero>737</aero>
 
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Re: Reverse thrust

Postby YourDailyTsunami » Wed Jun 04, 2008 5:08 pm

So where do you put this property?
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Re: Reverse thrust

Postby bisutti » Wed Jun 04, 2008 5:09 pm

In 737-400-set.xml
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Re: Reverse thrust

Postby AndersG » Wed Jun 04, 2008 5:11 pm

bisutti wrote:Well I hadn´t success... maybe if I change this property?


No, then you have to redo the whole FDM from scratch. I would not recommend that, in particular as it seems JSBSim supports reversing.

Have you tried playing around with /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad ? Use the property browser to change it and see the effect.

/Anders
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Re: Reverse thrust

Postby bisutti » Wed Jun 04, 2008 5:26 pm

Have you tried playing around with /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad ? Use the property browser to change it and see the effect.

/Anders


Well, yes, i did it, without success... maybe because i haven´t animations in the reverse trhust :mrgreen: I just have this:

Code: Select all
<animation>
  <type>translate</type>
  <object-name>lreverserob</object-name>
  <property>/surface-positions/reverser-pos-norm</property>
  <factor>0.7</factor>
  <axis>
   <x>1.0</x>
   <y>0.0</y>
   <z>0</z>
  </axis>
 </animation>

<animation>
  <type>translate</type>
  <object-name>lreverserib</object-name>
  <property>/surface-positions/reverser-pos-norm</property>
  <factor>0.7</factor>
  <axis>
   <x>1.0</x>
   <y>0.0</y>
   <z>0</z>
  </axis>
 </animation>

<animation>
  <type>translate</type>
  <object-name>rreverserib</object-name>
  <property>/surface-positions/reverser-pos-norm</property>
  <factor>0.7</factor>
  <axis>
   <x>1.0</x>
   <y>0.0</y>
   <z>0</z>
  </axis>
 </animation>

<animation>
  <type>translate</type>
  <object-name>rreverserob</object-name>
  <property>/surface-positions/reverser-pos-norm</property>
  <factor>0.7</factor>
  <axis>
   <x>1.0</x>
   <y>0.0</y>
   <z>0</z>
  </axis>
 </animation>

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Re: Reverse thrust

Postby AndersG » Wed Jun 04, 2008 5:34 pm

bisutti wrote:
Well, yes, i did it, without success... maybe because i haven´t animations in the reverse trhust :mrgreen: I just have this:


Well, animations doesn't do anything except, well, animate 3d model stuff. I would start in the other end: find out how to brake the aircraft using thrust reversing.

A reasonable guess at what you might want to do to control reversing is to connect /surface-positions/reverser-pos-norm to /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad e.g. using some FCS components in the FDM config file or via Nasal.

/Anders
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Re: Reverse thrust

Postby bisutti » Wed Jun 04, 2008 5:39 pm

A reasonable guess at what you might want to do to control reversing is to connect /surface-positions/reverser-pos-norm to /fdm/jsbsim/propulsion/engine[x]/reverser-angle-rad e.g. using some FCS components in the FDM config file or via Nasal.


I use the reverse-thrust.nas from the 787
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Re: Reverse thrust

Postby AndersG » Wed Jun 04, 2008 5:45 pm

bisutti wrote:I use the reverse-thrust.nas from the 787


Well, it looks like the 787 is a YASim aircraft so it is unlikely that reverse-thrust.nas does the right thing for a JSBSim one.

/Anders
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Re: Reverse thrust

Postby bisutti » Wed Jun 04, 2008 5:51 pm

So... i have to use internal properties in 737-400-set.xml??
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