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CN_Lurker_1011

How to find the center of gravity

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How to find the center of gravity which relative to  the MountStation in RTD_Config.xml

not this one in the head of RTD_Config.xml, i try to use <CenterOfGravity x y z as a reference datum, got a wrong GroundContact

i try to use the postion of blue X showed in Object builder when editting Geometry LOD, also got a wrong MountStation, the real postion of center of gravity is always lower than the blue X, i didn't figure out how many meters it is

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On 10/8/2022 at 5:48 AM, CN_Lurker_1011 said:

How to find the center of gravity which relative to  the MountStation in RTD_Config.xml


MountStation doesn't refer to CoG but "rtd_center" instead. There's an error in the original RTD documentation in this regard, in my humble opinion. Still, this part of the documentation is worth reading carefully to understand how different parts of landing gear affect the position of contact points. 

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On 10/10/2022 at 7:16 PM, NightIntruder said:


MountStation doesn't refer to CoG but "rtd_center" instead. There's an error in the original RTD documentation in this regard, in my humble opinion. Still, this part of the documentation is worth reading carefully to understand how different parts of landing gear affect the position of contact points. 

how about the Position in <Rotor>   document said it relative to the vehicle body coordinate system, is it also relative to the rtd_center?

I use rtd_center as reference datum to locate MountStations of every GroundContacts, i found GroundContacts of wheels is a little higher than the center of wheels in resolution LOD, plus with radius in RTD_config , the edge of wheels can not contact the ground, but other GroundContact is looked fine (nose tip, tail etc), if plus with SuspensionLength too, the wheels' collision is almost correct but a little clip with ground.

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13 hours ago, CN_Lurker_1011 said:

how about the Position in <Rotor>   document said it relative to the vehicle body coordinate system, is it also relative to the rtd_center?

Yes. Just bear in mind, the vehicle coordinate system differs from the coordinate system used in OB2.

 

13 hours ago, CN_Lurker_1011 said:

i found GroundContacts of wheels is a little higher than the center of wheels in resolution LOD, plus with radius in RTD_config , the edge of wheels can not contact the ground, but other GroundContact is looked fine (nose tip, tail etc)

So, compare them and adjust them. Sometimes RTD strong damper characteristics can cause this issue. You should be aware that RTD config in XML is "invisible", it doesn't affect standard animations (except RTD-driven animations). Instead, animations react to what is happening with helo body "moved" by the invisible forces of AFM. In other words, AFM is like a skeleton of points to which aerodynamical and gravitational forces are applied. If those forces move the helo fuselage up, at some point dampers will lose contact with the ground and their animations will show that.

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