On 16 Oct 2002 07:58:22 -0700 Tony Peden <[EMAIL PROTECTED]> wrote: >On Wed, 2002-10-16 at 07:27, Curtis L. Olson wrote: >> Tony, I apologize, I should have been more clear in my original >> message. The JSBSim drives the ball in a reasonable way, as does this >> other FDM I'm playing with. However, the scaling is about an order of >> magnitude different between the two, even though they supposedly >> report the accels in the same units and are modeling the same >> aircraft. YASim seems to drive the ball yet another order of >> magnitude further. It's not so much the behavior, but the range of >> motion and scaling. > >Well, keep in mind that the accels driving the TC are calculated largely >from the aero and propulsion models, so differences of degree between >different models should not be surprising. Also, the FDM you are using >probably has better aero data driving the lateral-directional dynamics >(I'd guess it's based on Cessna flight test data). The lateral-directional terms in >the JSBSim c172 are based largely on >Roskam's estimates and pilot feedback, not actual data, so it doesn't >surprise me that they don't agree.
There is no way there should be an order of magnitude difference because of this. Off the top pf my head I'd suggest we all ought to be within 10% of each other as far as acceleration at the pilot eyepoint is concerned. If Curt's external FDM says there is a 0.2g side accel at the pilot eyepoint, there is no way we should be saying it is 1g or greater. Need to look at McFarland, and see if he has something we can use to get a sanity check on our stuff. Jon _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
