Andy, > It's a misfeature in the gear modelling. YASim has pretty much the > same behavior. Both FDMs model gear force as a function of "skidding > velocity", which is fine for dynamic solutions. But a gear that is > planted on the ground is capable of "holding" an aircraft at zero > velocity, which doesn't work with the current FDMs -- zero velocity > produces zero force. It sounds as if we were to tell the weather system to model a significantly strong hurricane that we would see the parked aircraft swept away.
What I'm leading up to is that if this effect is happening whilst stationary, it's probably making the a/c more difficult to control on takeoff than it really is. That is if it still happens when the a/c is rolling. Just thinking about it... When the a/c is stationary the force on the wheels is the aircraft weight less the lift due to airflow over the lifting surfaces (a function of wind). As the a/c progresses on takeoff the above effect should change as the a/c gains speed. If it's having an effect straight away does it not need offsetting until a certain airspeed is reached (due to the weather system or a/c movement)? > What's needed is code that, at low speeds, uses a spring model for > gear force based on the distance in position from where the gear is > "stopped". Which sounds easy, but in practice is awfully hard. I've > gotten started on this several times, and never produced useful > code. So you're suggesting that the a/c mass, a friction coefficient dependent on weather condition and landing surface and tyre contact area are combined to provide a more realistic static case? If I've interpreted you correctly... what was the problem encountered? Chris. _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
