Jon S. Berndt wrote: > The JSBSim C172 FDM assumes the thrust line is the X axis. I'm not sure what > the angle of incidence of the wing is, but it seems that at rest on the > runway the pitch of the C172 should be 5 degrees, according to the picture > you attached. > > Jon > > But as others have pointed out, this attitude should be determined by the modeling of the main gear flex and nose strut compression. The 3D model should be such such that when the FDM calls for 0 degrees pitch, the 3D model does not need any pitch rotation. If the modeller tries to achieve the attitude that a taxiing AC would have (e.g. 5 degrees pitch) in blender or ac3d, then the AC will have that 5 degrees pitch when the FDM is calling for 0 degrees.
Dave P. > >> -----Original Message----- >> From: Heiko Schulz [mailto:[EMAIL PROTECTED] >> Sent: Monday, December 08, 2008 12:16 PM >> To: FlightGear developers discussions >> Subject: Re: [Flightgear-devel] c172p pitch at cruise question >> >> Hi, >> >> I had today a closer look into this issue. >> >> I got a drawing of the OM of a c172 which shows the the pitch angle >> with compressed nose gear. >> I tried to rotate the model but then I found something which shows me >> that the problem lies on the fdm: at cruise speed about 100kias I got a >> pitch about 0.3- 0.55 degres. >> Myself and some others in IRC-Chat noticed that the model is hardly to >> steer on the ground and lift of itself without touching the controls or >> the trim. I don't know, but could it be that the cg of the aircraft >> isn't right which makes all these? >> >> Attached the drawing from the OM. >> >> Cheers >> HHS >> >> >> >> >> >> > > > ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
