Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On Fri 6 July 2007 01:41, John Denker wrote: > On 07/05/2007 06:57 PM, gh.robin wrote: > > When i opened that topic , it was to know if we could hope any FG update > > to get an altitude instrument which can be able to indicate more than > > 61000 ft. > > > > We have had a lot of discussion on it , but nothing which could give the > > right answer. > > Do we have to stay with that limitation => 61000 ft ? > > No, we do not. > > Back on 06/19/2007 03:20 PM, I sent a message Gérard off list, including > a patch to fix this, extending the existing model to over 100,000 feet. > > Apparently the message got lost somehow. > > > Do we have to conclude that FG altitude instruments is unable to give the > > right value? > > As I explained on-list, there is nothing wrong with the altimeter. > I fixed the altimeter months ago. > > The problem is in the model of the atmosphere, in environment.cxx, > where it computes the ambient pressure. > > I will have more to say about this anon, but for now, here is > the patch again. It applies to today's CVS (offset one line). Thanks Jon, Yes the patch has vanished , probably in the vacuum space :) Because your patch is only a simple extension of the existing table it could be commit without any risk. Regards -- Gérard - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On Fri 6 July 2007 01:41, John Denker wrote: > On 07/05/2007 06:57 PM, gh.robin wrote: > > When i opened that topic , it was to know if we could hope any FG update > > to get an altitude instrument which can be able to indicate more than > > 61000 ft. > > > > We have had a lot of discussion on it , but nothing which could give the > > right answer. > > Do we have to stay with that limitation => 61000 ft ? > > No, we do not. > > Back on 06/19/2007 03:20 PM, I sent a message Gérard off list, including > a patch to fix this, extending the existing model to over 100,000 feet. > > Apparently the message got lost somehow. > > As I explained on-list, there is nothing wrong with the altimeter. > I fixed the altimeter months ago. > > The problem is in the model of the atmosphere, in environment.cxx, > where it computes the ambient pressure. > > I will have more to say about this anon, but for now, here is > the patch again. It applies to today's CVS (offset one line). Well your patch is right, i have tested it with Blackbird up to 9 ft does anybody who has access to CVS source could commit it , both branch ? here again is the John Denker Patch. Thanks -- Gérard --- src/Environment/environment.cxx 2007/06/19 18:58:22 1.1 +++ src/Environment/environment.cxx 2007/06/19 19:03:22 @@ -48,43 +48,50 @@ // Atmosphere model. -// Copied from YASim Atmosphere.cxx, with m converted to ft, degK -// converted to degC, Pa converted to inHG, and kg/m^3 converted to -// slug/ft^3; they were then converted to deltas from the sea-level -// defaults (approx. 15degC, 29.92inHG, and 0.00237slugs/ft^3). - -// Original comment from YASim: - -// Copied from McCormick, who got it from "The ARDC Model Atmosphere" -// Note that there's an error in the text in the first entry, -// McCormick lists 299.16/101325/1.22500, but those don't agree with -// R=287. I chose to correct the temperature to 288.20, since 79F is -// pretty hot for a "standard" atmosphere. +// Calculated based on the ISA standard day, as found at e.g. +// http://www.av8n.com/physics/altimetry.htm -// Elevation (ft), temperature factor (degK), pressure factor (inHG) +// Each line of data has 3 elements: +// Elevation (ft), +// temperature factor (dimensionless ratio of absolute temp), +// pressure factor (dimensionless ratio) static double atmosphere_data[][3] = { - { 0.00, 1.00, 1.000 }, - { 2952.76, 0.98, 0.898 }, - { 5905.51, 0.96, 0.804 }, - { 8858.27, 0.94, 0.719 }, - { 11811.02, 0.92, 0.641 }, - { 14763.78, 0.90, 0.570 }, - { 17716.54, 0.88, 0.506 }, - { 20669.29, 0.86, 0.447 }, - { 23622.05, 0.84, 0.394 }, - { 26574.80, 0.82, 0.347 }, - { 29527.56, 0.80, 0.304 }, - { 32480.31, 0.78, 0.266 }, - { 35433.07, 0.76, 0.231 }, - { 38385.83, 0.75, 0.201 }, - { 41338.58, 0.75, 0.174 }, - { 44291.34, 0.75, 0.151 }, - { 47244.09, 0.75, 0.131 }, - { 50196.85, 0.75, 0.114 }, - { 53149.61, 0.75, 0.099 }, - { 56102.36, 0.75, 0.086 }, - { 59055.12, 0.75, 0.075 }, - { 62007.87, 0.75, 0.065 }, + { -3000.00, 1.021, 1.1133 }, + { 0.00, 1.000, 1. }, + { 2952.76, 0.980, 0.8978 }, + { 5905.51, 0.959, 0.8042 }, + { 8858.27, 0.939, 0.7187 }, + { 11811.02, 0.919, 0.6407 }, + { 14763.78, 0.898, 0.5697 }, + { 17716.54, 0.878, 0.5052 }, + { 20669.29, 0.858, 0.4468 }, + { 23622.05, 0.838, 0.3940 }, + { 26574.80, 0.817, 0.3463 }, + { 29527.56, 0.797, 0.3034 }, + { 32480.31, 0.777, 0.2649 }, + { 35433.07, 0.756, 0.2305 }, + { 38385.83, 0.752, 0.2000 }, + { 41338.58, 0.752, 0.1736 }, + { 44291.34, 0.752, 0.1506 }, + { 47244.09, 0.752, 0.1307 }, + { 50196.85, 0.752, 0.1134 }, + { 53149.61, 0.752, 0.0984 }, + { 56102.36, 0.752, 0.0854 }, + { 59055.12, 0.752, 0.0741 }, + { 62007.87, 0.752, 0.0643 }, + { 65000.00, 0.752, 0.0557 }, + { 68000.00, 0.754, 0.0482 }, + { 71000.00, 0.758, 0.0418 }, + { 74000.00, 0.761, 0.0362 }, + { 77000.00, 0.764, 0.0314 }, + { 8.00, 0.767, 0.0273 }, + { 83000.00, 0.770, 0.0237 }, + { 86000.00, 0.773, 0.0206 }, + { 89000.00, 0.777, 0.0179 }, + { 92000.00, 0.780, 0.0156 }, + { 95000.00, 0.783, 0.0135 }, + { 98000.00, 0.786, 0.0118 }, + { 101000.00, 0.789, 0.0103 }, { -1, -1, -1 } }; - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On 07/05/2007 06:57 PM, gh.robin wrote: When i opened that topic , it was to know if we could hope any FG update to get an altitude instrument which can be able to indicate more than 61000 ft. We have had a lot of discussion on it , but nothing which could give the right answer. Do we have to stay with that limitation => 61000 ft ? No, we do not. Back on 06/19/2007 03:20 PM, I sent a message Gérard off list, including a patch to fix this, extending the existing model to over 100,000 feet. Apparently the message got lost somehow. Do we have to conclude that FG altitude instruments is unable to give the right value? As I explained on-list, there is nothing wrong with the altimeter. I fixed the altimeter months ago. The problem is in the model of the atmosphere, in environment.cxx, where it computes the ambient pressure. I will have more to say about this anon, but for now, here is the patch again. It applies to today's CVS (offset one line). --- src/Environment/environment.cxx 2007/06/19 18:58:22 1.1 +++ src/Environment/environment.cxx 2007/06/19 19:03:22 @@ -48,43 +48,50 @@ // Atmosphere model. -// Copied from YASim Atmosphere.cxx, with m converted to ft, degK -// converted to degC, Pa converted to inHG, and kg/m^3 converted to -// slug/ft^3; they were then converted to deltas from the sea-level -// defaults (approx. 15degC, 29.92inHG, and 0.00237slugs/ft^3). - -// Original comment from YASim: - -// Copied from McCormick, who got it from "The ARDC Model Atmosphere" -// Note that there's an error in the text in the first entry, -// McCormick lists 299.16/101325/1.22500, but those don't agree with -// R=287. I chose to correct the temperature to 288.20, since 79F is -// pretty hot for a "standard" atmosphere. +// Calculated based on the ISA standard day, as found at e.g. +// http://www.av8n.com/physics/altimetry.htm -// Elevation (ft), temperature factor (degK), pressure factor (inHG) +// Each line of data has 3 elements: +// Elevation (ft), +// temperature factor (dimensionless ratio of absolute temp), +// pressure factor (dimensionless ratio) static double atmosphere_data[][3] = { - { 0.00, 1.00, 1.000 }, - { 2952.76, 0.98, 0.898 }, - { 5905.51, 0.96, 0.804 }, - { 8858.27, 0.94, 0.719 }, - { 11811.02, 0.92, 0.641 }, - { 14763.78, 0.90, 0.570 }, - { 17716.54, 0.88, 0.506 }, - { 20669.29, 0.86, 0.447 }, - { 23622.05, 0.84, 0.394 }, - { 26574.80, 0.82, 0.347 }, - { 29527.56, 0.80, 0.304 }, - { 32480.31, 0.78, 0.266 }, - { 35433.07, 0.76, 0.231 }, - { 38385.83, 0.75, 0.201 }, - { 41338.58, 0.75, 0.174 }, - { 44291.34, 0.75, 0.151 }, - { 47244.09, 0.75, 0.131 }, - { 50196.85, 0.75, 0.114 }, - { 53149.61, 0.75, 0.099 }, - { 56102.36, 0.75, 0.086 }, - { 59055.12, 0.75, 0.075 }, - { 62007.87, 0.75, 0.065 }, + { -3000.00, 1.021, 1.1133 }, + { 0.00, 1.000, 1. }, + { 2952.76, 0.980, 0.8978 }, + { 5905.51, 0.959, 0.8042 }, + { 8858.27, 0.939, 0.7187 }, + { 11811.02, 0.919, 0.6407 }, + { 14763.78, 0.898, 0.5697 }, + { 17716.54, 0.878, 0.5052 }, + { 20669.29, 0.858, 0.4468 }, + { 23622.05, 0.838, 0.3940 }, + { 26574.80, 0.817, 0.3463 }, + { 29527.56, 0.797, 0.3034 }, + { 32480.31, 0.777, 0.2649 }, + { 35433.07, 0.756, 0.2305 }, + { 38385.83, 0.752, 0.2000 }, + { 41338.58, 0.752, 0.1736 }, + { 44291.34, 0.752, 0.1506 }, + { 47244.09, 0.752, 0.1307 }, + { 50196.85, 0.752, 0.1134 }, + { 53149.61, 0.752, 0.0984 }, + { 56102.36, 0.752, 0.0854 }, + { 59055.12, 0.752, 0.0741 }, + { 62007.87, 0.752, 0.0643 }, + { 65000.00, 0.752, 0.0557 }, + { 68000.00, 0.754, 0.0482 }, + { 71000.00, 0.758, 0.0418 }, + { 74000.00, 0.761, 0.0362 }, + { 77000.00, 0.764, 0.0314 }, + { 8.00, 0.767, 0.0273 }, + { 83000.00, 0.770, 0.0237 }, + { 86000.00, 0.773, 0.0206 }, + { 89000.00, 0.777, 0.0179 }, + { 92000.00, 0.780, 0.0156 }, + { 95000.00, 0.783, 0.0135 }, + { 98000.00, 0.786, 0.0118 }, + { 101000.00, 0.789, 0.0103 }, { -1, -1, -1 } }; - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On Mon 18 June 2007 10:06, Stefan Seifert wrote: > John Denker wrote: > > If you want to know exactly why FGFS poops out at approximately > > 62,000 feet, look at line 88 of Environment/environment.cxx > > > >You can contrast that with the ISA table that goes up to 278,000 > >feet as found e.g. at the top of > > http://www.av8n.com/physics/altimetry.htm > > Just for my understanding: this table is only used for instrumentation, > isn't it? > Both JSBSim and YASim have their own atmosphere models including such > tables where JSBSim goes up to 259186ft and YASim to 18900m (62008ft). > > Reminds me that I should test again, if it's still possible to reach > Earth orbit and do interstellar travel with an F-16 ;) Maybe this got > better in newer JSBSim versions. But it's pretty strange, since JSBSim > should be the FDM to do this right with the table up to 260Kft... > > Nine > > Hello everybody, Tell me if i am wrong, When i opened that topic , it was to know if we could hope any FG update to get an altitude instrument which can be able to indicate more than 61000 ft. We have had a lot of discussion on it , but nothing which could give the right answer. Do we have to stay with that limitation => 61000 ft ? Do we have to conclude that FG altitude instruments is unable to give the right value? Or is it only a bug which could be solved ? Thanks for the answer -- Gérard - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
John Denker wrote: > That's an interesting question. > > So there's not a clean division between "instrumentation" and > "other". > > 2) But wait, there's more. The FDM's model of the atmosphere > model is blissfully ignorant of the properties of the actual > air mass. If you change the local barometric pressure, the > MAP that you observe (with the engine off) should track the > barometric pressure, but it doesn't. > > You can easily verify this while sitting on a runway with > the engine turned off. Changing the barometric pressure > affects the altimeter but not the MAP. > > 3) Tangential remark: the c182r engine continues to run at > 100,000 feet. In fact with the throttle at idle, the engine > spins up to thousands of RPM. It's quite comical. Please make bug reports here for JSBSim: http://sourceforge.net/tracker/?atid=119399&group_id=19399&func=browse At least they can be tracked there, although some of the ones listed need toe cleaned up. > 5) I'm not even going to ask why a single copy of FGFS has at > least three different atmosphere-models (one in the Environment > directory, one for JSBSim, and one for YASim). There's more than that: JSBSim has two Earth atmosphere models. Some of the simulators we use in my day job also have several selectable atmosphere and wind models. JSBSim needs its own atmosphere model because it maintains the ability to be run on its own in a batch mode, and also because it tries to be a drop-in FDM for other general purpose simulators (see the JSBSim list this morning for another example of that). It appears that we need to do some work here, though. Thanks for pointing these things out, and please do report these at the above link. It really helps our development process. Jon -- Jon S. Berndt Development Coordinator JSBSim Project www.JSBSim.org - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
John > Sent: 18 June 2007 10:41 > To: FlightGear developers discussions > Subject: Re: [Flightgear-devel] Instrument-altimeter unable > to indicate altitude above 61831 feet > > > On 06/18/2007 04:06 AM, Stefan Seifert wrote: > snip > > 4) By the way, did you ever wonder what "osi" means, in the > context of the mp-osi property? The only documentation I can > find on the subject is here: > > http://baron.flightgear.org/pipermail/flightgear-devel/2003-Ma y/017373.html The only problem is that it is 100% false. Hmm - I always thought that it was a typo that no one got around to fixing. I tried once, but it crept back in. Vivian - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
John Denker a écrit : > 4) By the way, did you ever wonder what "osi" means, in the context > of the mp-osi property? The only documentation I can find on the > subject is here: > http://baron.flightgear.org/pipermail/flightgear-devel/2003-May/017373.html > The only problem is that it is 100% false. Sorry, that's not clear, what is false, the acronysm definition or the use made of ounces by square inch ? Alexis - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On Mon 18 June 2007 10:06, Stefan Seifert wrote: > John Denker wrote: > > If you want to know exactly why FGFS poops out at approximately > > 62,000 feet, look at line 88 of Environment/environment.cxx > > > >You can contrast that with the ISA table that goes up to 278,000 > >feet as found e.g. at the top of > > http://www.av8n.com/physics/altimetry.htm > > Just for my understanding: this table is only used for instrumentation, > isn't it? > Both JSBSim and YASim have their own atmosphere models including such > tables where JSBSim goes up to 259186ft and YASim to 18900m (62008ft). > > Reminds me that I should test again, if it's still possible to reach > Earth orbit and do interstellar travel with an F-16 ;) Maybe this got I discovered the problem with the recent BlackBird which goes up to 8 ft > better in newer JSBSim versions. But it's pretty strange, since JSBSim > should be the FDM to do this right with the table up to 260Kft... > > Nine > Regards -- Gérard - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On 06/18/2007 04:06 AM, Stefan Seifert wrote: >> If you want to know exactly why FGFS poops out at approximately >> 62,000 feet, look at line 88 of Environment/environment.cxx > Just for my understanding: this table is only used for instrumentation, > isn't it? > Both JSBSim and YASim have their own atmosphere models including such > tables where JSBSim goes up to 259186ft and YASim to 18900m (62008ft). That's an interesting question. I said there was a mess, but I barely hinted at how big a mess it is. Here are a few more hints: 1) Do you consider the MAP (manifold absolute pressure) instrument to be "instrumentation"? In the c182r, the MAP instrument looks at the mp-osi property, as it should. The mp-osi property is driven by the FDM (i.e. JSBSim). At 100,000 feet, I observe that map-osi property reads 0.32 with the engine turned off, which is a sensible value, vastly more sensible than the "environment" and "static" pressures. So there's not a clean division between "instrumentation" and "other". 2) But wait, there's more. The FDM's model of the atmosphere model is blissfully ignorant of the properties of the actual air mass. If you change the local barometric pressure, the MAP that you observe (with the engine off) should track the barometric pressure, but it doesn't. You can easily verify this while sitting on a runway with the engine turned off. Changing the barometric pressure affects the altimeter but not the MAP. 3) Tangential remark: the c182r engine continues to run at 100,000 feet. In fact with the throttle at idle, the engine spins up to thousands of RPM. It's quite comical. 4) By the way, did you ever wonder what "osi" means, in the context of the mp-osi property? The only documentation I can find on the subject is here: http://baron.flightgear.org/pipermail/flightgear-devel/2003-May/017373.html The only problem is that it is 100% false. 5) I'm not even going to ask why a single copy of FGFS has at least three different atmosphere-models (one in the Environment directory, one for JSBSim, and one for YASim). *) Note that it is /not/ a cause for concern that the altimeter has its own model. The altimeter necessarily models an ideal atmosphere, whereas the Environment (and the FDMs) should be modeling the real atmosphere. They have some things in common, but they are not the same thing. A pilot who thinks that pressure altitude is equal to true altitude is asking for trouble, possibly fatal trouble. - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 John Denker wrote: > If you want to know exactly why FGFS poops out at approximately > 62,000 feet, look at line 88 of Environment/environment.cxx > >You can contrast that with the ISA table that goes up to 278,000 >feet as found e.g. at the top of > http://www.av8n.com/physics/altimetry.htm Just for my understanding: this table is only used for instrumentation, isn't it? Both JSBSim and YASim have their own atmosphere models including such tables where JSBSim goes up to 259186ft and YASim to 18900m (62008ft). Reminds me that I should test again, if it's still possible to reach Earth orbit and do interstellar travel with an F-16 ;) Maybe this got better in newer JSBSim versions. But it's pretty strange, since JSBSim should be the FDM to do this right with the table up to 260Kft... Nine -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFGdjzu1QuEJQQMVrgRCNXkAJ9LEGSovz4FKalzRa799fJomGk/KwCfaKlw TCFgXFccBK+QAU5NjCFXxS0= =2izZ -END PGP SIGNATURE- - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
On 06/16/2007 09:12 PM, gh.robin wrote: > I notice a some strange behaviours with the Instrument Altimeter > The Instrument Altimeter is unable to indicate more than 61831 feet > > Here the snapshot of property: >instrument/altimeter/indicated-altitude-ft==> 61831 >position/altitude-ft ==> 75793 I agree this is strange and deplorable ... but it is /not/ a problem with the altimeter instrument! Let's look more closely at the properties: Let's fly up to 100,000 feet and see what happens: /position/altitude-ft = 10 # so far so good /environment/pressure-inhg= 1.94# trouble in the environment /systems/static/pressure-inhg = 1.94# static system dutifully follows the environment /instrumentation/altimeter/indicated-altitude-ft = 61800 # altimeter dutifully follows the static pressure FYI, under ISA conditions, according to my calculations: 61,800 feet of pressure_altitude ==> pressure is 1.94 inHg. 100,000 feet of pressure_altitude ==> pressure is 0.32 inHg; If you want to know exactly why FGFS poops out at approximately 62,000 feet, look at line 88 of Environment/environment.cxx You can contrast that with the ISA table that goes up to 278,000 feet as found e.g. at the top of http://www.av8n.com/physics/altimetry.htm More generally, the code that calculates the /environment/pressure-inhg is a mess from end to end, to put it politely. For example: *) In the front-end gui, the Weather Conditions popup allows the user to specify, layer by layer, the altitude AND the temperature AND the altimeter setting. Almost all ways of filling in the gui form will be inconsistent with the basic laws of nature. *) In the back-end c++ code, there is quite a bit of code that has never been tested. Indeed some of it has never been executed AFAICT. *) The back-end c++ code performs calculations that bear no discernible relationship to the equation of state of the atmosphere. This is particularly noticeable under nonstandard-day conditions. *) Don't get me started about the documentation or lack thereof. The atmosphere-modeling features need to be properly thought through, and then re-implemented from end to end. For example, in my private copy of FGFS, in the Weather Conditions popup, all the numbers in the rightmost column (altimeter settings) have been replaced by a single number representing the QNH of the air mass. Alas this is only 1% of what's involved if you want to do the job right. - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Instrument-altimeter unable to indicate altitude above 61831 feet
Hello, I notice a some strange behaviours with the Instrument Altimeter The Instrument Altimeter is unable to indicate more than 61831 feet Here the snapshot of property: instrument/altimeter/indicated-altitude-ft==> 61831 position/altitude-ft ==> 75793 http://perso.orange.fr/GRTux/Instrument_altimeter.jpg Regards -- Gérard - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel