Re: [Jsbsim-devel] Prop aircraft yaws to the right on take-off.

[Bertrand C. <bco...@gm...>]

Hi Alan,

Le dim. 1 sept. 2019 à 23:30, Alan Teeder <ajt...@v-...> a écrit :

>
> I have made some progress by adding the following code to FGLGear
> bind(). (near line 798) I can now see these properties in Flightgear.
>
>    property_name = base_property_name + "/wheel-XForce-lbs";
>    PropertyManager->Tie(property_name.c_str(), &vFn(eX));
>    property_name = base_property_name + "/wheel-YForce-lbs";
>    PropertyManager->Tie(property_name.c_str(), &vFn(eY));
>    property_name = base_property_name + "/wheel-ZForce-lbs";
>    PropertyManager->Tie(property_name.c_str(), &vFn(eZ));
>
>    property_name = base_property_name + "/strutforce-lbs";
>    PropertyManager->Tie(property_name.c_str(), &StrutForce);
>
> The result of this is similar numbers in the property tree for
> wheel-ZForce-lbs and strutforce-lbs. With the throttle opened the
> numbers are larger for the left gear than the right gear, as expected.
> The value gets smaller as the aircraft accelerates on the runway.
>
> However  the properties wheel-XForce-lbs and wheel-YForce-lbs are zero.
> They stay this way  even with the brakes applied despite the aircraft
> coming to a halt.
>
> Is there any reason why vFn(eX) and vFn(eY) are zero?
>

Friction components are assessed at the global level i.e. when the sums of
all the forces and moments acting on the aircraft are available.
Therefore the computation of friction forces is taking place in
FGAccelerations::CalculateFrictionForces


>
> Regards
>
> Alan
>