On Samstag, 31. Januar 2004 16:41, Tony Peden wrote:
> I certainly do agree that selectable units would be nice to have, but it
> would double the property tree memory requirements (since each property
> would then have to have a units property associated with it. In
> addition, such a system would significantly increase the amount of code
> that would execute at each property access.
Yes, this would increase memory requirements. I don't know the property tree
code well enough to judge about how much this will increase the memory and
execution time usage.
Just for curiosity, how much memory usage does a single node in the property
tree have?
Or, do you know how much the usage of the property tree is compared to the
scene graph and the textures?
> > This will also simplify building aerodynamic coeficient lookup talbes
> > which are sometimes given in, say 'lift per degree elevator deflection'
> > or, for an other aircraft type in 'lift per rad elevator deflection'.
> > I know, this is simple scaling, but I think that simple things should be
> > left to a computer ...
> >
> > :)
>
> All coefficients must be in consistent units (generally those of force)
> after the multipliers are applied, so I see no advantage here. There
> is no formal requirement for this since JSBSim does not attempt to
> assure unit consistency but it's there nevertheless.
The advantage would be, in my example, that I have the angle of attack/surface
deflections available in rad but the tables I have found for an f-18, I am
currently modelling, contain tables for the coeficients in something per deg.
So I have to scale this tables by hand/matlab/octave.
For a more general case, if one has all those aerodynamic tables given in the
SI system (are there any aircraft models in the SI system?), one will be able
to take these tables and simply use the input values in the matching units.
I, for my stuff, can work around, but it would be neat to have.
May be it is not worth the effort ...
Greetings
Mathias
--
Mathias Fr�hlich, email: [EMAIL PROTECTED]
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