Re: [Flightgear-devel] JSBSim broken?
On Sunday 04 December 2005 11:27 am, Joacim Persson wrote: Reverser is also no functional. Can't tell if this is simply not implemented or if this ... The reverser method has changed. You set the reverser now by adjusting the /fdm/jsbsim/propulsion/engine[x]/reverser-angle property (where x is the engine number), which is the reverser angle in degrees. 90 degrees gives you zero thrust. A good value is about 120 degrees. You have to set this for all engines if you are using one throttle for all engines. The property /engines/engine[x]/Reverser doesn't work any more. Dave ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] JSBSim broken?
I couldn't help but notice that the JSB version of the 747 has a lift-ratio which would make a sailplane pilot envious. One can glide about with full flaps, gear out etc with AoA at 30--40° in 80 kias and keep it level. ;) When running it with --debug-level=debug I get some numbers on JSB's idea about drag, for instance: I appreciate the report. I wanted to let you know I got your email and your bug report is in the queue. I'll put this report in a JSBSim bug report (see www.jsbsim.org). I'd like to emphasize how important it is to get reports from users. THe very best way to let us know about bugs (for JSBSim) is to file a bug report at www.jsbsim.org. That way we are sure it won't get lost. We've got a lot going on right now, and I'll try to get to that ASAP. Maybe someone else can answer that sooner than I. Jon -- Project Coordinator JSBSim Flight Dynamics Model http://www.jsbsim.org ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] JSBSim broken?
I couldn't help but notice that the JSB version of the 747 has a lift-ratio which would make a sailplane pilot envious. One can glide about with full flaps, gear out etc with AoA at 30--40° in 80 kias and keep it level. ;) I've filed the bug as: http://sourceforge.net/tracker/?func=detailatid=119399aid=1372940group_id=19399 Thanks, Jon ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] JSBSim broken?
On Sunday 04 December 2005 11:27 am, Joacim Persson wrote: I couldn't help but notice that the JSB version of the 747 has a lift-ratio which would make a sailplane pilot envious. One can glide about with full flaps, gear out etc with AoA at 30--40° in 80 kias and keep it level. ;) ... The testbed being used here is a fresh cvs version. The first thing I would change is the idle thrust factor at 0 speed and 0 altitude. The value of 0.0836 was an old typo that got copied into several turbine config files. A value of 0.0317 looks better, and is what I'm using in the CFM-56 config. Also, there is no gear drag included. I would copy the gear drag coefficient out of the 737 config and paste it into the 747 config. Also, the newer turbine model allows one to knock off some thrust due to bleed/accessory/installation losses. I would knock off 4 percent. See the 737's CFM-56 config. As far as the drag values go, the CD0 looks good, and matches aeromatic well. The induced drag is calculated a different way than I do it, and I'd have to get the calculator out to compare results with the aeromatic method, which I hope to get to some time. I'm not a fan of the method used in the 747 config, even if the numbers turn out to be good. The flap drag looks good. Dave ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] JSBSim broken?
On Sun, 4 Dec 2005, Dave Culp wrote: As far as the drag values go, the CD0 looks good, and matches aeromatic well. ... The flap drag looks good. Then for some reason all those numbers are ignored. Either in jsbsim internally or in the fg--jsbsim interface. The plane glides virtually forever. Like overshooting the runway by 15nm (after which I got bored) with an attitude of 30° in 90kts at 180' AGL (=no ground effect). (It looks funny though. =) I've been testing other jsbsim models tonight apart from the 747-100: 737, c150, c182 and they all seem to have extremly low or zero drag. They won't stall. But since the jsbsim guys are busy preparing a new release which will affect the config files anyway(?) I think I'll just drop it for now.___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] JSBSim broken?
On Sunday 04 December 2005 05:55 pm, Joacim Persson wrote: Then for some reason all those numbers are ignored. Actually it seems that what's being ignored is my previous email. I'm not interested in helping you fix your problem if you aren't. Dave ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] JSBSim broken?
Log some output parameters. That can be done using the OUTPUT section of the config file. See the X-15 (?) or C-172x config file. I'll get around to it as soon as I can. I'm _sure_ there's a simple explanation for this. Jon -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Joacim Persson Sent: Sunday, December 04, 2005 5:55 PM To: FlightGear developers discussions Subject: Re: [Flightgear-devel] JSBSim broken? On Sun, 4 Dec 2005, Dave Culp wrote: As far as the drag values go, the CD0 looks good, and matches aeromatic well. ... The flap drag looks good. Then for some reason all those numbers are ignored. Either in jsbsim internally or in the fg--jsbsim interface. The plane glides virtually forever. Like overshooting the runway by 15nm (after which I got bored) with an attitude of 30° in 90kts at 180' AGL (=no ground effect). (It looks funny though. =) I've been testing other jsbsim models tonight apart from the 747-100: 737, c150, c182 and they all seem to have extremly low or zero drag. They won't stall. But since the jsbsim guys are busy preparing a new release which will affect the config files anyway(?) I think I'll just drop it for now. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] JSBSim broken?
I've been testing other jsbsim models tonight apart from the 747-100: 737, c150, c182 and they all seem to have extremly low or zero drag. They won't stall. Hmmm. I've not heard any complaints about the other aircraft. The 737 has been extensively tested by someone who knows how they fly. Also, if any of these aircraft had zero or artificially low drag, they thrust produced by the engine would propel them to unbelievably high speeds. Now, I haven't tested these models in a long time (yes, I am incredibly busy right now on many fronts), but if the C182 flew at 400 kts I think I'd hear about it. Jon ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
