Hi Oliver Welcome to FG world.
I use vstab for lower wing on K5Y1 (Aka Tombo). You can see K5Y1.xml to find what should be done. The latest K5Y1 is available at CVS and: http://macflightgear.sourceforge.net/home/aircraft/k5y1 There're some points you need to know: - dihedral must be clearly specified, otherwise it will be set to 90 degree. - two vstab tags are needed (for left wing and right wing) since vstab will not be mirrored. - some attributes must be negative for the right wing (since dihedral > 90) I put incidence attribute to vstab, but I'm not that sure if it works properly. Does anyone know about this? If none knows, I'll take a look at Yasim code some time later (I have no time tonight...) Hope it helps. Tat On Jun 26, 2009, at 9:04 PM, Olivier Faivre wrote: > Interesting. Will try both possibilities. > if mstab is not use by the solver, What about biplane ? Not so clear anymore > in my mind... > > However, if i cannot set incidence to the mstab, my idea is dead... > > Olivier > > > 2009/6/26 leee <l...@spatial.plus.com> > On Thursday 25 Jun 2009, Maik Justus wrote: > > Hello Olivier, > > > > Olivier Faivre schrieb am 25.06.2009 20:52: > > > Hello guys, > > > ... > > > Actually, the wing is done with only one piece, 7° dihedral, no > > > twist. Can I use the "mstab" command to specify the outer wing > > > and the regular "wing" command for the inner one ? > > > > yes > > > > > In the readme file, I read this for mstab : these surfaces are > > > not involved with the solver computation these surfaces are not > > > involved with the solver computation... > > > > > > I'm not sure to well understand. > > > > if you define a yasim FDM you have to define two configurations > > with different airspeed, typ. cruise and approach. Yasim modifies > > lift and drag factors and the incidence of the wing to meet these > > configurations. Therefore the incidence of a wing will be > > modified by the yasim solver (only once - when the model is > > loaded) while the incidence of a mstab is unchanged. > > I just thought I'd point out that the YASim solver sets the > incidence for the <hstab> element, not the <wing> element. > > Thus, you can specify the incidence for the <wing>, but not for the > <hstab>. There is also an INCIDENCE control-axis in YASim, which > should allow the <wing> element incidence to be changed in flight > and I think the F-8E, which is shown on the FG aircraft download > web-page, may actually use this. However, when I've tried using > the INCIDENCE control-axis with <vstab> or <mstab> elements, to > simulate all-moving/slab tailfins/rudders (as in the BAC-TSR2) or > all-moving canards (as in the SU-37) it has had no aerodynamic > affect at all. > > YASim does indeed generate drag factors for <wing>, <vstab> and > <mstab> elements, but it is possible to modify the the AoA related > drag forces by including suitable <idrag> elements . This seems to > work well when you're trying to simulate all-moving tailplanes, for > example, if you specify a very low <idrag> factor for the <hstab> > element. > > I also experimented with using <mstabs> to more accurately model the > correct shape of wings when developing the Canberra-B(I)8 YASim > config but found that the solver does indeed ignore the <mstab> > elements when working out its stuff. While I could get it to > solve, the effect was that of just having the very short inner wing > panels. The <vstab> and <mstab> elements do have directional > effects however, and the control-surface sub-elements, such as > <flapn> and <spoiler> will also have an effect. > > For the main lifting surface then, using a full-span <wing> element > will give more accurate results than a combination of <wing> and > <mstab> elements because the <mstab> elements will be ignored. > Although this may seem less than ideal, it's possible to fine-tune > the single <wing> element to get very close to the real world > characteristics, and certainly closer than you could get with a > <wing> and <mstab> combination. > > LeeE > > ------------------------------------------------------------------------------ > _______________________________________________ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > > ------------------------------------------------------------------------------ > _______________________________________________ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel ------------------------------------------------------------------------------ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
