Re: [Flightgear-devel] about /velocities/mach, yasim& jsbsim match was: about velocities/u, v and wbody-fps, bug #202

[jean p. <jea...@wa...>]

> Message du 30/10/13 19:09
> De : "Eric van den Berg" 
> A : fli...@li...
> Copie à : 
> Objet : Re: [Flightgear-devel] about /velocities/mach, yasim& jsbsim match   was: about velocities/u, v and wbody-fps, bug #202
> 
> Hi Jano,
> 
> I just fully realised what you have done to fix the "airspeed" bug: 
> instead of fixing the problem in the pitot system where the root problem 
> lies, you changed the definition of the general Mach property. Just 
> because the pitot system by chance uses that property to calculate the 
> impact pressure.
> 
> As an alternative I would suggest the following until I come up with a 
> real solution.
> 1) Source /velocities/mach again from /fdm/jsbsim/velocities/mach for jsbsim
> 2) Make a change in yasim to source it from the total relative wind speed
> 3) Make an additional /velocities/machU property (from 
> /fdm/jsbsim/velocities/machU and the original Yasim "v[0]" parameter
> 4) change /systems/pitot to take /velocities/machU instead of Mach.
> Has the same effect as now, but is much cleaner. 4) I will then revert 
> when a real solution is in place.
> 
> Furthermore I had a close look at the airspeed indicator and all the 
> "safe guards" are in place, so we are safe there.
> 
> Also for reference I made a small spreadsheet with the meaning of some 
> of the airspeed properties and their sources in JSBsim. See attachment.
> 
> Cheers,
> 
> Eric
> 
>
that is my plan, and the yasim part is already  done, i let it like that for now to have working airspeed, and will do the other change once i'm sure alpha and beta (called side-slip) are sane.
you can have a look in a recently started wiki page, wich will list the fdm props, and th