[Flightgear-devel] Gas Turbine Modelling
Hi, I am new to this mailing list, so don't know the current state of things. Just wondering if someone has put their hand up for the Gas Turbine modelling goal. I do not use FGFS but am interested in modelling gas turbines and would like to do simple, general, thermodynamic models for turbo jet, turbo shaft / prop and fan jet engines. Please let me know if I can be of any use to the project :-) Cheers, Scott. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Is the world round or flat ?
Title: Message Hi guys, I just wanna find out how Simgear actually works. Does it generate the world as a sphere, or as a flat world ? Kind Regards Danie Heath ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Is the world round or flat ?
Danie Heath wrote: I just wanna find out how Simgear actually works. Does it generate the world as a sphere, or as a flat world ? An irregular WGS84 spheroid, I think, which is more accurate than either flat or spherical. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Is the world round or flat ?
On Saturday, 22 November 2003 14:20, Danie Heath wrote: Hi guys, I just wanna find out how Simgear actually works. Does it generate the world as a sphere, or as a flat world ? Kind Regards Danie Heath Neither! It generates the world as a WGS84 ellisoid which is accurate to about 100 meters in altitude and even better in the horizontal plane. You'll find the wgs84 routines under simgear/math/ Regards Paul ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Helicopters: wow!
I just tried flying the bo105 around Ottawa a bit: FlightGear has made an incredible amount of progress over the past few weeks. All of the jitters in the heli flight model are gone, the 3D interior looks great (though it needs a bit of instrumentation -- I'm using the HUD for now), and the sound really helps to set the mood. I'm still not good enough to land on top of one of the little white apartment buildings, though. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Is the world round or flat ?
Ah David beat me to it. Actually David is correct in calling it a WGS84 spheroid and not an ellipsoid since spheroids are only flattened on one minor-axis and not two or more minor-axis like a true ellipsoid. Paul On Saturday, 22 November 2003 15:01, Paul Surgeon wrote: On Saturday, 22 November 2003 14:20, Danie Heath wrote: Hi guys, I just wanna find out how Simgear actually works. Does it generate the world as a sphere, or as a flat world ? Kind Regards Danie Heath Neither! It generates the world as a WGS84 ellisoid which is accurate to about 100 meters in altitude and even better in the horizontal plane. You'll find the wgs84 routines under simgear/math/ Regards Paul ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] New timer code ported onto old
Russell Suter wrote: Andy Ross wrote: Instead, try this as a more verbose variant and see if it works. It adds an explicit cast to the type of the table, and uses a char* to get around the original error: h-table = (struct HashNode**)(((char*)h-nodes) + sz*sizeof(struct HashNode)); You could do this but using again what you said about pointer arithmetic it can be reduced to: h-table = (struct HashNode**) (h-nodes + sz); You must have the parens around the addition since the cast has a higher precedence. Both seem to work well (in which case I prefer the later solution). But then I get a problem with the test.nas script which runs fine from 0 to 93 and then seems to hang ... Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Re: Helicopters: wow!
* David Megginson -- Saturday 22 November 2003 14:24: the 3D interior looks great (though it needs a bit of instrumentation Thanks. But as of now it's only a smaller copy of the fuselage so that you would see some interior at all. I'll make a better interior once the fuselage is done. I'm still working out bumps and edges. Then I'll also weld the halves together and make the join seamless. The final interior will be done in higher resolution and I'll eventually turn the complete exterior off in pilot view (apart from the main rotor and the skids; you don't see anything else through the windows and open doors anyway :-). BTW: you can open the backdoor: /controls/backdoor (range 0 to 5.5; will normalize it later), the other doors come later. m. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Is the world round or flat ?
David Megginson wrote: Danie Heath wrote: I just wanna find out how Simgear actually works. Does it generate the world as a sphere, or as a flat world ? An irregular WGS84 spheroid, I think, which is more accurate than either flat or spherical. Speaking of which, After searching from some more information about the WGS84 model I came across a site that could calculate the local gravity based on the WGS84 model: http://solid_earth.ou.edu/notes/potential/igf.htm But after searching a bit more I found the following site with lots of information that might be of interest for us: http://www.mathworks.com/access/helpdesk/help/toolbox/aeroblks/aero_ref.shtml This site also had a reference to the World Magnetic Model 2000: http://www.ngdc.noaa.gov/seg/WMM/DoDWMM.shtml ftp://www.ngdc.noaa.gov/Solid_Earth/Mainfld_Mag/DoD_Model/C_Software/ Is this something we could use? Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Human conquers helicopter
Finally. On the roof, with the engine shut down, after taking off from a nearby airport: http://www.megginson.com/flightsim/roof.jpg Airspeed management is very different in a helicopter than in a plane -- I'm still trying to get a handle on it. By the way, I always have to put on the parking brake (!!) to stop the skids from acting like wheels. Is there an easy fix to the YASim model? All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
David Megginson [EMAIL PROTECTED] said: Finally. On the roof, with the engine shut down, after taking off from a nearby airport: http://www.megginson.com/flightsim/roof.jpg Wow! Now _that_ looks like fun! I was trying to do that with the downtown skyscrapers (knowing I couldn't actually land) when the bo105 first appeared without much luck. Another one that was quite challenging was trying to land in the football stadium. Airspeed management is very different in a helicopter than in a plane -- I'm still trying to get a handle on it. Pull back on the cyclic stick. Depending on what speed you are going dropping collective too. I like to swoop down to create some downward momentum and then pull back. I'm not sure if this is a legal move :-), but if you are going really fast and want to stop quickly, pull the stick way way back and raise the collective all the way up for a few seconds. Kind of like reverse thrust on a jet. Part of the problem is the ground effect isn't modeled. It is in FlyII and that helps quite a bit with hovering as for a landing. I've read that flight training in the real world usually involves hovering around the field at about 10-20 ft for quite some time (until it becomes second nature). By the way, I always have to put on the parking brake (!!) to stop the skids from acting like wheels. Is there an easy fix to the YASim model? We could force the breaks on...but it is also possible for a skid to skid...isn't it? Anyway, I'm off to find a roof. :-) Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
Jim Wilson wrote: Pull back on the cyclic stick. Depending on what speed you are going dropping collective too. I like to swoop down to create some downward momentum and then pull back. I'm not sure if this is a legal move :-), but if you are going really fast and want to stop quickly, pull the stick way way back and raise the collective all the way up for a few seconds. Kind of like reverse thrust on a jet. Thanks. I do understand that part, but I'm still trying to get a feel for the exact speed effects, especially through the transition from cruise to hover. Part of the problem is the ground effect isn't modeled. It is in FlyII and that helps quite a bit with hovering as for a landing. I've read that flight training in the real world usually involves hovering around the field at about 10-20 ft for quite some time (until it becomes second nature). It does, from what I've seen at airports: not just hovering, but hover-taxiing and (especially) gazillions of autorotations. To learn to control the bo105, I made up a little exercise for myself to climb to 5 ft, hover-taxi forward, land on the next runway stripe, and repeat to the numbers at the end of the runway. Anyway, I'm off to find a roof. :-) Try to make sure that you're down around 15 kt before you get too close to the roof. In the bo105, at least, if you have to raise to nose to lose speed, you can also lose sight of your landing spot. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
David Megginson [EMAIL PROTECTED] said: Pull back on the cyclic stick. Depending on what speed you are going dropping collective too. I like to swoop down to create some downward momentum and then pull back. I'm not sure if this is a legal move :-), but if you are going really fast and want to stop quickly, pull the stick way way back and raise the collective all the way up for a few seconds. Kind of like reverse thrust on a jet. Thanks. I do understand that part, but I'm still trying to get a feel for the exact speed effects, especially through the transition from cruise to hover. Yep, it is a feel, how much collective lift to add. The thing that usually screws me up is the tail rotor when hovering. In general the rudder control on my X45 sucks, partially because it is my left hand and I'm very right handed, but also because it is a rocker. How are the helos with the pedal controlers? Part of the problem is the ground effect isn't modeled. It is in FlyII and that helps quite a bit with hovering as for a landing. I've read that flight training in the real world usually involves hovering around the field at about 10-20 ft for quite some time (until it becomes second nature). It does, from what I've seen at airports: not just hovering, but hover-taxiing and (especially) gazillions of autorotations. To learn to control the bo105, I made up a little exercise for myself to climb to 5 ft, hover-taxi forward, land on the next runway stripe, and repeat to the numbers at the end of the runway. Autorotation is good practice for approaches, since that's pretty much what you do to land (the engine just happens to be running giving you a little more leeway for errors). Anyway, I'm off to find a roof. :-) Try to make sure that you're down around 15 kt before you get too close to the roof. In the bo105, at least, if you have to raise to nose to lose speed, you can also lose sight of your landing spot. Yeah...and hitting the ground with the tail is always a distinct possibility. That seemed to be a frequent occurance when I was doing this in Fly. I usually angle the view sharply downward (out the bottom windows) and use the heads up display to check on attitude. Approaches are with the nose high but not too high to see the target. I try to get the approach angle at about 30kts...so that it'll slow down steadily, which seems to work really well when I get it. Keep in mind that I'm not a pilot and don't _really_ know what I'm doing ;-) Here's a couple shots from downtown. I also tried it with a 20kt wind. Couldn't even get close to landing in that. http://www.spiderbark.com/fgfs/101california1.png http://www.spiderbark.com/fgfs/101california2.png Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
David Megginson wrote: By the way, I always have to put on the parking brake (!!) to stop the skids from acting like wheels. Is there an easy fix to the YASim model? First off, we should stop mapping a brakes property to something that doesn't have brakes. Put a value of 1 somewhere in the property tree using the -set.xml file, and map that to the brakes instead. :) With just a little code work, we could add a stump attribute (or whatever) to the gear tag that tells the wheel to ignore the rolling action. Andy ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] New timer code ported onto old
Erik Hofman wrote: Both seem to work well (in which case I prefer the later solution). But then I get a problem with the test.nas script which runs fine from 0 to 93 and then seems to hang ... Works for me, obviously. Stack trace? Andy ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
Andy Ross wrote: First off, we should stop mapping a brakes property to something that doesn't have brakes. Put a value of 1 somewhere in the property tree using the -set.xml file, and map that to the brakes instead. :) With just a little code work, we could add a stump attribute (or whatever) to the gear tag that tells the wheel to ignore the rolling action. Never mind. Someone already added a skid attribute to the parser (or maybe I did long ago and forgot). Just set skid=1 on the gear objects and remove the brake mappings from the property tree. Andy ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] compilation problems
FlightGear compiles successfully with the plib1.7c102 and plib1.7-dev Debian packages, but issues the warning: Plib PSL scripting: You will not be able to run scripts written in PSL and some advanced GUI and input features may not work. Download and install the latest CVS version of plib if you would like to enable PSL support. But when one actually grabs the CVS version of plib and tries compiling against it instead, gcc complains: /home/brandon/sg/lib/libsgsky.a(cloud.o)(.text+0x1eb3): In function `SGCloudLayer::draw()': /home/brandon/sg/src/SimGear/simgear/scene/sky/cloud.cxx:453: undefined reference to `ssgCullAndDraw(ssgRoot*)' /home/brandon/sg/lib/libsgsky.a(sky.o)(.text+0x915): In function `SGSky::preDraw(float, float)': /home/brandon/sg/src/SimGear/simgear/scene/sky/sky.cxx:175: undefined reference to `ssgCullAndDraw(ssgRoot*)' because plib appears to no longer provide the ssgCullAndDraw(ssgRoot*) but instead provides a similar function taking different arguments. Have the FlightGear developers ceased developing against the most recent CVS version of plib, and simply forgotten to update the advice given by the configure script, or are there other problems at work in my attempt to build and run FlightGear? -- Brandon Craig Rhodes [EMAIL PROTECTED] http://rhodesmill.org/brandon ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Re: compilation problems
Andy Ross [EMAIL PROTECTED] writes: You installed the libraries from the new plib, but you didn't recompile FlightGear against the new headers ... Interesting; it appears that not recompiling and reinstalling SimGear was my problem. It has no --with-plib configure option, so I wrongly assumed it did not depend upon plib. The lack of a --with-plib option also meant it could not find my homebuilt plib without a jury-rigged ./configure run that looked like: CFLAGS=-I$PLIB/include LDFLAGS=-L$PLIB/lib ./configure ... where for the two instances of $PLIB I actually typed the directory specified with plib's --prefix configure option. For the reference of others with this problem who might search this list, the error given when SimGear did not find plib in the standard directories was: texcoord.cxx: In function `point_list sgCalcTexCoords(const SGBucket, const point_list, const int_list, double)': texcoord.cxx:189: error: `SGD_DEGREES_TO_RADIANS' undeclared (first use this function) Thanks for the help, -- Brandon Craig Rhodes [EMAIL PROTECTED] http://rhodesmill.org/brandon ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Easy-XML
Jon Berndt [EMAIL PROTECTED] wrote: Well, I want to look at it because I sort of hope to migrate the JSBSim XML definition to a more robust and compliant format at some point in the future. Even now, it would be nice to make some changes here and there that allowed us to move towards an emerging standard for aircraft models (that JSBSim, incidentally, played a small part in inspiring): http://dcb.larc.nasa.gov/utils/fltsim/DAVE/intro.html BTW, as it appears to me they include a complete F-16 aero model in a link on their website. Right ? Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Use of FlightGear
Hello, I just came across this site after reading a posting on the autopilot-devel mailing list: http://www.u-dynamics.com/aerosim/ They suggest using FlightGear to be driven by their external FDM via network, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
Jim Wilson [EMAIL PROTECTED] wrote: David Megginson [EMAIL PROTECTED] said: Airspeed management is very different in a helicopter than in a plane -- I'm still trying to get a handle on it. Pull back on the cyclic stick. Depending on what speed you are going dropping collective too. I like to swoop down to create some downward momentum and then pull back. I'm not sure if this is a legal move :-), but if you are going really fast and want to stop quickly, pull the stick way way back and raise the collective all the way up for a few seconds. This actually _is_ called the quick-stop :-) Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
Jim Wilson wrote: Yep, it is a feel, how much collective lift to add. The thing that usually screws me up is the tail rotor when hovering. In general the rudder control on my X45 sucks, partially because it is my left hand and I'm very right handed, but also because it is a rocker. How are the helos with the pedal controlers? I haven't tried that recently -- it's such a pain to set up the yoke and rudder pedals that I rarely bother. I just use the two little sticks on my WingMan, or alternatively, drag the mouse left and right for the rudder. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] New timer code ported onto old
Andy Ross wrote: Erik Hofman wrote: Both seem to work well (in which case I prefer the later solution). But then I get a problem with the test.nas script which runs fine from 0 to 93 and then seems to hang ... Works for me, obviously. Stack trace? Not yet, I haven't looked into that part yet (at first I was under the impression that this was C(++) code until I discovered I was already running a script :-) I think it might be a big-/little endian problem. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Easy-XML
Martin Spott wrote: Jon Berndt [EMAIL PROTECTED] wrote: Well, I want to look at it because I sort of hope to migrate the JSBSim XML definition to a more robust and compliant format at some point in the future. Even now, it would be nice to make some changes here and there that allowed us to move towards an emerging standard for aircraft models (that JSBSim, incidentally, played a small part in inspiring): http://dcb.larc.nasa.gov/utils/fltsim/DAVE/intro.html BTW, as it appears to me they include a complete F-16 aero model in a link on their website. Right ? Yep, it's the exact same data we are using now. But I have extended data for the F-16, it's just not implemented (in the right way) yet. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Human conquers helicopter
Andy Ross wrote: Never mind. Someone already added a skid attribute to the parser (or maybe I did long ago and forgot). Just set skid=1 on the gear objects and remove the brake mappings from the property tree. Done. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Helicopters: wow!
Am Samstag, 22. November 2003 14:24 schrieb David Megginson: I just tried flying the bo105 around Ottawa a bit: FlightGear has made an incredible amount of progress over the past few weeks. All of the jitters in the heli flight model are gone, the 3D interior looks great (though it needs a bit of instrumentation -- I'm using the HUD for now), and the sound really helps to set the mood. I'm still not good enough to land on top of one of the little white apartment buildings, though. Hello, I allways wanted to fly the helicopter but i don't know how to start the engines. I pressed every key kombination but still no luck. I could need an advice how to start the engines. Best Regards, Oliver C. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Gas Turbine Modelling
Just wondering if someone has put their hand up for the Gas Turbine modelling goal. I do not use FGFS but am interested in modelling gas turbines and would like to do simple, general, thermodynamic models for turbo jet, turbo shaft / prop and fan jet engines. John Wojnaroski was working on one. I don't know if Jon Berndt is still interested in a physics/thermodynamics model of a turbine for JSBSim, but we saved a spot in the class structure for it (FGTurbine) when the non-physics model (FGSimTurbine) was introduced. I don't know if the physics/thermo model would be very practical, given the paucity of needed data to model a particular engine, but it is certainly interesting in it's own right. Dave -- David Culp davidculp2[at]comcast.net ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
