Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. What way does Flightgear use? Static tables or real time calculations or something other? MfG, Oliver C. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
[EMAIL PROTECTED] wrote: Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. What way does Flightgear use? Static tables or real time calculations or something other? Both: YASim: runtime aircraft characteristics JSBSim/UIUC: static tables Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Erik Hofman wrote: [EMAIL PROTECTED] wrote: Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. What way does Flightgear use? Static tables or real time calculations or something other? Both: YASim: runtime aircraft characteristics JSBSim/UIUC: static tables Erik I know Falcon 4.0 is pretty poor when talking about phisics. It uses only primitive static tables, but these are very worked on though. FlightGear is way much better on this one! ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
[EMAIL PROTECTED] writes: In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. What way does Flightgear use? Static tables or real time calculations or something other? X-Plane's approach is interesting and novel, but far from perfect. You could think of it like a virtual, real-time wind tunnel. However, because of the computational complexity of flight, x-plane can only impliment an extremely crude and rudimentary wind tunnel. It has to fill in scads of approximations and assumptions to get everything to work. That said, it is still an interesting and useful approach for some situations and you can use it to build flight models that behave reasonably well for most type of aircraft. I don't mean to sound negative here, most of the time you only hear the hype, blade element theory, etc. etc. so I wanted to also present the other side as well. The downside to this approach is that in order to get your design to behave like the real thing, you have to go in and tweak a lot of non obvious parameters in non-obvious ways and deal with a lot of non-obvious interactions and side effects. Building an aircraft in X-plane that hits the real world numbers exactly is a little bit like voodoo. But if you are building some brand new design in your garage and want to know how it will fly (and don't have access to a real wind tunnel or super computer cluster) X-Plane will probably make a better guess at it than anything else available to an average person. It's like anything else ... x-plane has a particular approach to the problem of modeling flight. It shines in some areas, but has it's share of problems too. But like any approach, you can usually find ways to get around the weak spots to get something useful done. Regards, Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Citiescurt 'at' me.umn.edu curt 'at' flightgear.org Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Matevz Jekovec wrote: Erik Hofman wrote: YASim: runtime aircraft characteristics JSBSim/UIUC: static tables Erik I know Falcon 4.0 is pretty poor when talking about phisics. It uses only primitive static tables, but these are very worked on though. FlightGear is way much better on this one! We don't even use the complete list of tables available for the F-16 at this time (and haven't got the flight computer included at all) ... Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
At 7/24/03, Oliver C. wrote: Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. This statement in the context of the full article suggests that static tables (table lookup data) are the determining factor insofar as realism goes. I wish things were that black and white. The Devil is in the Details. Regards, Michael ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
David Megginson wrote: [EMAIL PROTECTED] writes: What way does Flightgear use? Static tables or real time calculations or something other? Both, sort-of. Unlike X-Plane, FlightGear does not limit you to a single type of physics engine. JSBSim works with static coefficients, and YASim works with geometry. I happened to come across the following article, and kept thinking about its application to flightgear. I wonder if this is the foundation beneath YASim? http://www.aa.washington.edu/faculty/eberhardt/lift.htm -Matt All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Matt Fienberg writes: David Megginson wrote: [EMAIL PROTECTED] writes: What way does Flightgear use? Static tables or real time calculations or something other? Both, sort-of. Unlike X-Plane, FlightGear does not limit you to a single type of physics engine. JSBSim works with static coefficients, and YASim works with geometry. I happened to come across the following article, and kept thinking about its application to flightgear. I wonder if this is the foundation beneath YASim? http://www.aa.washington.edu/faculty/eberhardt/lift.htm YASim airplanes start flying really crappy if you try to go inverted. If you don't believe me, just try taking the 747 on 100' AGL inverted pass over SFO. :-) Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Citiescurt 'at' me.umn.edu curt 'at' flightgear.org Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Curtis L. Olson writes: YASim airplanes start flying really crappy if you try to go inverted. If you don't believe me, just try taking the 747 on 100' AGL inverted pass over SFO. :-) Curt's joking, of course, but it's worth noting that any aircraft with positive dihedral is going to be brutally unstable in the roll axis when inverted -- that's why aerobatic planes don't tend to have dihedral. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Michael Selig [EMAIL PROTECTED] said: At 7/24/03, Oliver C. wrote: Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. This statement in the context of the full article suggests that static tables (table lookup data) are the determining factor insofar as realism goes. I wish things were that black and white. The Devil is in the Details. Reading the article it seemed that the author was just quoting Austin who talked about why his method was better, and other people that said how accurate X-Plane was, without actually knowing much about the topic he was writing on (typical popsci). So what you are saying isn't suprising. Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
On Thu, 2003-07-24 at 10:14, Michael Selig wrote: At 7/24/03, Oliver C. wrote: Am Donnerstag, 24. Juli 2003 10:19 schrieb Jon Stockill: Heads down guys - we just got another mention on slashdot :-) http://games.slashdot.org/article.pl?sid=03/07/23/1837201 In the article i read the following: In fact, flight characteristics are calculated in real time from aircraft design data, not static tables like MS Flight Simulator. This statement in the context of the full article suggests that static tables (table lookup data) are the determining factor insofar as realism goes. I wish things were that black and white. The Devil is in the Details. Yes, indeed. Regards, Michael ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel -- Tony Peden [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Curtis L. Olson [EMAIL PROTECTED] said: YASim airplanes start flying really crappy if you try to go inverted. If you don't believe me, just try taking the 747 on 100' AGL inverted pass over SFO. :-) You can lose your ticket for that! Actually that isn't really true. The A4 will fly all day long upside down. Some planes don't fly inverted well anyway, and I would guess the 747 is one of them. IIRC the tail incidence is different than the wing on some aircraft (like the P-51) and that causes a loss of lift when inverted. The camber would be an issue as well, I would think. Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
David Megginson [EMAIL PROTECTED] said: Curtis L. Olson writes: YASim airplanes start flying really crappy if you try to go inverted. If you don't believe me, just try taking the 747 on 100' AGL inverted pass over SFO. :-) Curt's joking, of course, but it's worth noting that any aircraft with positive dihedral is going to be brutally unstable in the roll axis when inverted -- that's why aerobatic planes don't tend to have dihedral. Ah yes. No dihedral on the A-4, either. Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
On Friday 25 July 2003 01:19, Jim Wilson wrote: David Megginson [EMAIL PROTECTED] said: Curtis L. Olson writes: YASim airplanes start flying really crappy if you try to go inverted. If you don't believe me, just try taking the 747 on 100' AGL inverted pass over SFO. :-) Curt's joking, of course, but it's worth noting that any aircraft with positive dihedral is going to be brutally unstable in the roll axis when inverted -- that's why aerobatic planes don't tend to have dihedral. Ah yes. No dihedral on the A-4, either. Best, Jim So the b-52, with anhedral, should fly better upside down? :) LeeE ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
Lee Elliott writes: So the b-52, with anhedral, should fly better upside down? So it would seem. I'd hate to see an engine flame out, though, and the flight crew end up having to make an approach and landing with only seven engines. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Incoming!!!!!!!!!!!!
On Thu, 2003-07-24 at 18:31, David Megginson wrote: Lee Elliott writes: So the b-52, with anhedral, should fly better upside down? So it would seem. I'd hate to see an engine flame out, though, and the flight crew end up having to make an approach and landing with only seven engines. Landing in a twin with one engine out is not terribly challenging, so I'd expect that on 7/8 it's not a big deal at all. All the best, David -- Tony Peden [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
