Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
On 26 Mar 2003, Tony Peden wrote: > Probably true, but credit (if it's due) is not terribly much to ask for. This is a recurring theme in the Windows world. Almost noone who develops train models for MSTS and Trainz wants to part with their 3d models, because of the abundance of unscrupulous folks who then market the stuff they got for free. One developer I know even went as far as changing locomotive shapes slightly to make rip-off models look really bad. I don't care that badly (but then again, I usually use the BSD license when I have the chance, so I'm a bit biased towards allowing the freedom of flattery-by-shameless copying; if you look at the number of devices that embed UCD-SNMP without credit you might be surprised, but I'm just flattered when I think that there are a couple of lines of my code in the commercial firewall where I first noticed it -- UCD-SNMP required credit as the only condition for use at the time). I haven't looked into it for lack of time, but a bunch of MSFS enthusiasts made landscapes for the Netherlands that might be converted into FlightGear format, and I hope that such positive sharing will really take off. With the formidable tasks that are behind simulator work, all the "content" that can be opened and shared is a win. Getting the credit is absolutely essential to keep folks motivated. Cheers, -- Bert -- Bert Driehuis -- [EMAIL PROTECTED] -- +31-20-3116119 If the only tool you've got is an axe, every problem looks like fun! ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
Bert Driehuis writes: > This is a recurring theme in the Windows world. Almost noone who > develops train models for MSTS and Trainz wants to part with their 3d > models, because of the abundance of unscrupulous folks who then market > the stuff they got for free. One developer I know even went as far as > changing locomotive shapes slightly to make rip-off models look really > bad. That's why I prefer public domain even to open source -- people spend way too long worrying about that kind of thing. 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] Re: [Jsbsim-devel] MSFS Aircrafts
Bert Driehuis wrote: I haven't looked into it for lack of time, but a bunch of MSFS enthusiasts made landscapes for the Netherlands that might be converted into FlightGear format, and I hope that such positive sharing will really take off. With the formidable tasks that are behind simulator work, all the "content" that can be opened and shared is a win. Getting the credit is absolutely essential to keep folks motivated. This is my biggest problem with this kind of action. The can use my data for whatever they want, *they just have to honour the GPL*. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
David Megginson wrote: Bert Driehuis writes: > This is a recurring theme in the Windows world. Almost noone who > develops train models for MSTS and Trainz wants to part with their 3d > models, because of the abundance of unscrupulous folks who then market > the stuff they got for free. One developer I know even went as far as > changing locomotive shapes slightly to make rip-off models look really > bad. That's why I prefer public domain even to open source -- people spend way too long worrying about that kind of thing. Now, I would be worried that getting data from other sources and putting it under the BSD license (which makes it possible to use it in closed source programs without permission from the original author) might be a problem for the original authour. Personally I think putting it under the GPL would be less of a problem to them. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
Erik Hofman writes: > > That's why I prefer public domain even to open source -- people spend > > way too long worrying about that kind of thing. > > Now, I would be worried that getting data from other sources and putting > it under the BSD license (which makes it possible to use it in closed > source programs without permission from the original author) might be a > problem for the original authour. Personally I think putting it under > the GPL would be less of a problem to them. That's pure speculation -- we have no way of knowing what the original publisher of the data might prefer. If the original publisher did maintain IP rights over the raw data, then we would have no right to put it under any license at all; if not, then the original publisher has no special rights in the case. Even the moral obligation of courtesy is a tricky one. James Clark used to stipulate that commercial users of his SGML software *not* mention his name without permission: he was worried that it would look like he was giving an endorsement. If a commercial 182 add-on for MSFS came out with this on the wrapper Now with NEW, ACCURATE flight data from JAN ROSKAM! Roskam might not be pleased either. 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] Re: [Jsbsim-devel] MSFS Aircrafts
> > A pilot familiar with that plane is almost certainly going to find it > > very unstable in the pitch axis, and complain that the nose bounces up > > and down too much. In the real plane, the dynamic pressure from the > > relative wind tends to hold the control surfaces in one spot, and it > > takes a bit of effort to move them from where they want to be (a *lot* > > of effort for a big deflection). A home-computer joystick or yoke > > might have a little spring in it, but in general, it's going to be far > > too easy for the computer user to create an elevator deflection, and > > the plane's going to feel unstable. Just an idea -- if someone were to build proper force-feedback yoke/pedals/etc., would FlightGear be able to drive them realistically? I.e., is force on the controls part of the FDM? > Fly! allowed one to change the exponential effect. Possibly it is > misnamed, x^n involves an exponent, perhaps it was 'n' that could be > varied. MSFS2K appears to have changed to some intrinsic non-linear > mapping compared to FS98. I don't know about Fly!, but "exponential" traditionally is a misnomer. A lot of RC transmitters allow you to set it, but that usually means that the response is proportional until you reach a certain deflection, then makes a kink and the control starts reacting with more authority, but still linearly. No such thing as an exponential function, which is probably because exponentiation is rather difficult to implement in analogue electronics. > Fly!, and MS FS/CFS allow one to change 'null zone' and > 'sensitivity' for the JS in the menu. Lower sensitivity adds more low Is the null zone there in a real aircraft (backlash), or just a feature of the sim to allow the pilot to go and grab a cup of coffee? > > -1.0 => -1.00 > > -0.5 => -0.25 > >0.0 => 0.00 > >0.5 => 0.25 > >1.0 => 1.00 This is a good response, but it also implies that at 0 deflection, the control is totally nonresponsive (gradient is zero). Shouldn't we simply add a linear term here? That would make the control linear around the centre and transition into a square response at higher deflections. Andras === Major Andras e-mail: [EMAIL PROTECTED] www:http://andras.webhop.org/ === ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
--- Major A <[EMAIL PROTECTED]> wrote: > > > > A pilot familiar with that plane is almost certainly going to > find it > > > very unstable in the pitch axis, and complain that the nose > bounces up > > > and down too much. In the real plane, the dynamic pressure from > the > > > relative wind tends to hold the control surfaces in one spot, and > it > > > takes a bit of effort to move them from where they want to be (a > *lot* > > > of effort for a big deflection). A home-computer joystick or > yoke > > > might have a little spring in it, but in general, it's going to > be far > > > too easy for the computer user to create an elevator deflection, > and > > > the plane's going to feel unstable. > > Just an idea -- if someone were to build proper force-feedback > yoke/pedals/etc., would FlightGear be able to drive them > realistically? I.e., is force on the controls part of the FDM? The flight control system in JSBSim will allow for it as it stands, but work would have to be done to get that info to FG. Also, none of our models currently calculate the forces. > > > Fly! allowed one to change the exponential effect. Possibly it > is > > misnamed, x^n involves an exponent, perhaps it was 'n' that could > be > > varied. MSFS2K appears to have changed to some intrinsic > non-linear > > mapping compared to FS98. > > I don't know about Fly!, but "exponential" traditionally is a > misnomer. A lot of RC transmitters allow you to set it, but that > usually means that the response is proportional until you reach a > certain deflection, then makes a kink and the control starts reacting > with more authority, but still linearly. No such thing as an > exponential function, which is probably because exponentiation is > rather difficult to implement in analogue electronics. > > > Fly!, and MS FS/CFS allow one to change 'null zone' and > > 'sensitivity' for the JS in the menu. Lower sensitivity adds more > low > > Is the null zone there in a real aircraft (backlash), or just a > feature of the sim to allow the pilot to go and grab a cup of coffee? > > > > -1.0 => -1.00 > > > -0.5 => -0.25 > > >0.0 => 0.00 > > >0.5 => 0.25 > > >1.0 => 1.00 > > This is a good response, but it also implies that at 0 deflection, > the > control is totally nonresponsive (gradient is zero). Shouldn't we > simply add a linear term here? That would make the control linear > around the centre and transition into a square response at higher > deflections. Umm, I think that he's trying to reduce the response around the center. > > Andras > > === > Major Andras > e-mail: [EMAIL PROTECTED] > www:http://andras.webhop.org/ > === > > ___ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > > __ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
Major A writes: > Is the null zone there in a real aircraft (backlash), or just a > feature of the sim to allow the pilot to go and grab a cup of coffee? I think it's a different attempt to compensate for the lack of control loading. > > > -1.0 => -1.00 > > > -0.5 => -0.25 > > >0.0 => 0.00 > > >0.5 => 0.25 > > >1.0 => 1.00 > > This is a good response, but it also implies that at 0 deflection, the > control is totally nonresponsive (gradient is zero). Shouldn't we > simply add a linear term here? That would make the control linear > around the centre and transition into a square response at higher > deflections. I'm not sure that I understand the problem. As soon as you move the control, it is no longer at zero and will get a gradually increasing response. 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] Re: [Jsbsim-devel] MSFS Aircrafts
> > This is a good response, but it also implies that at 0 deflection, the > > control is totally nonresponsive (gradient is zero). Shouldn't we > > simply add a linear term here? That would make the control linear > > around the centre and transition into a square response at higher > > deflections. > > I'm not sure that I understand the problem. As soon as you move the > control, it is no longer at zero and will get a gradually increasing > response. Yes, but wouldn't it be better to have at least a small amount of control around the centre? I think it would make things more natural. The best example I can think of now is aileron -- a linear term would make it easier to keep the aircraft level. Andras === Major Andras e-mail: [EMAIL PROTECTED] www:http://andras.webhop.org/ === ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Jsbsim-devel] MSFS Aircrafts
Major A writes: > Yes, but wouldn't it be better to have at least a small amount of > control around the centre? You do. Unlike a dead zone, this approach has no location where moving the joystick will not produce some kind of input. 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] Re: [Jsbsim-devel] MSFS Aircrafts
Major A writes: > Just an idea -- if someone were to build proper force-feedback > yoke/pedals/etc., would FlightGear be able to drive them > realistically? I.e., is force on the controls part of the FDM? You could build a software interface to your hardware that could read the appropriate control position, apply some sort of control algorithm, and drive your force feedback motor appropriately. Regards, Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Cities[EMAIL PROTECTED] [EMAIL PROTECTED] 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] Re: [Jsbsim-devel] MSFS Aircrafts
Ron, I must admid it, you have made my day. :-) Erik Very few MSFS AC have 'realistic' flight models. ;) Though AVSIM reviewers and a bunch of desktop pilots often think they are. FS2K+ can't use realistic values of Cm_q and Cn_r at Mach 0.7/30,000 ft or higher I've had to increase those two by 50% or more to get enough pitch and yaw stability so the crappy 'autopilot' in FS2K2 won't make an AC porpoise or even lose ALT control. In the jets, MS defaults and 99% of FS 2'nd party AC are set with dampings 4 to 20X realistic values. Assuming Cm_q = -20 is ealistic. -5.0 is more likely for the Fighters mentioned above. Further, I found a 30 lb AC isn't stable in FS2K2 with nominal SD's. Nor did scaling it to 80 lbs help. Lighter FS2K2 AC may jitter on the runway unless Roll MoI is increased above the real value. Ron ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
