On Sunday 02 December 2007 14:48, Heiko Schulz wrote: > Hi, > > maybe this fit more to the flightmodel-list, but I'm > not sure about if this list is really be read;-) > > Trying to do a fdm with yasim for a Panavia Tornado > GR4 IDS I noticed that it seems to me not possible to > model a taileron (elevator and aileron in one control > surface at the tail)- I always get the error message: > "Insufficient elevator to trim for approach" > > I tried this also on the Lightning-yasim but the same > error... > > It is really not possible? > > On JSBsim I noticed that the thrust reverser are not > working ( as an example Fokker 70/100), but I remember > that it was working with 0.9.9 and 0.9.10 - something > changed or I'm too stupid? > > thanks > Regards > HHS
First of all, you _need_ to include an elevator-trim binding to the hstab for YASim to solve. Have a look at the BAC-TSR2 (combined elevator & aileron), YF-23 (combined elevator & rudder) or SU-37 (combined FCS pitch & roll). The SU-37 has a lot of additional control inputs that might be confusing but the BAC-TSR2 and YF-23 are fairly simple. YASim assumes a fixed elevator and determining it's incidence is fundamental to the way it works but it is possible to make a passable job of simulating elevons. Basically, you'll need four control inputs for the hstab element:- elevator, elevator-trim, aileron and aileron trim (remember to set the aileron and aileron-trim to split="true") YASim will then simply sum the inputs. The only thing to watch out for is that it can then output deflections of up to +-2.0 instead of limiting it to +-1.0 (it would be handy if such a limiter could be implemented). Another tip, one Andy R gave me a long time ago but one I've only recently understood the significance of, is to set the idrag for the elevators to a low value. With fixed tailplanes the drag will increase with AoA but with all-moving 'slab' tailplanes this isn't the case, so setting a low idrag value should help simulate this. So far I've only tried low idrag in the SU-37 (and I've just added it to the BAC-TSR2 that I'm currently revising) but it seems to work ok. LeeE ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel
