I added invisible skids to A-4.
And succeeded Belly landing.
thank you very much.
[skid1]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=-0.24,3.65,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0
Steerable=TRUE
MaxSteeringSpeed=41.15
Locking=FALSE
MaxSteeringAngle=35.0
InputName=YAW_CONTROL
[skid2]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=0.24,3.65,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0
Steerable=TRUE
MaxSteeringSpeed=41.15
Locking=FALSE
MaxSteeringAngle=35.0
InputName=YAW_CONTROL
[skid3]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=-0.64,-2.5,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0
[skid4]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=0.64,-2.5,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0
[skid5]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=-4.2,-2.5,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0
[skid6]
SystemType=LANDING_GEAR
Retractable=FALSE
IsSkid=TRUE
NoContactOnGround=true
HideGearNode=true
ModelNodeName=
ShockStroke=0.05
SpringFactor=0.2
DampingFactor=2.1
ContactPoint=4.2,-2.5,-0.85
RollingCoefficient=1.0
MaxLoadFactor=25.0