[Flightgear-devel] Re: property control question
* Ampere K. Hardraade -- Thursday 07 April 2005 06:00: On April 6, 2005 05:18 am, Melchior FRANZ wrote: This isn't a big problem and works, too. It's just a waste of CPU cycles and then, you may want to use the gear functions for other effects, where it could be a problem. Something along these lines may be able to free up those CPU cycles: binding commandnasal/command script # Command flaps' movement. /script /binding Huh? WHAT?!?! Do you even know what you are talking about? m. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Re: Glut problem
Asking for how to fix the compilation problems would have been a little smarter, wouldn't it? Probably you don't have the glut headers installed. No, they are installed in /usr/include/GL and also into the X11 includes. Infact I have the problem only with that file. Bytheway, you didn't answer to my question: which exact version of GLUT I need to compile FG? thanks darko ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Re: Glut problem
darko wrote: No, they are installed in /usr/include/GL and also into the X11 includes. Infact I have the problem only with that file. Bytheway, you didn't answer to my question: which exact version of GLUT I need to compile FG? You will need the very latest (at least 3.7.x) Erik ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Re: Glut problem
* darko -- Thursday 07 April 2005 10:26: Asking for how to fix the compilation problems would have been a little smarter, wouldn't it? Probably you don't have the glut headers installed. No, they are installed in /usr/include/GL and also into the X11 includes. Infact I have the problem only with that file. Bytheway, you didn't answer to my question: which exact version of GLUT I need to compile FG? Yes. Did you read somewhere that I would answer all questions? If so, this was a lie and you should complain to the author. :-P Anyway: I would use freeglut from here: http://freeglut.sf.net/ This is (almost fully) compatible with glut. (The auto-key-repeat default seems to differ, but that's no problem for fgfs, now that the Spitfire changed the ignition code.) I expect that your next posting contains some real error messages. Otherwise I suggest to continue this thread on flightgear-users. m. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Simgear related problem
Hi there, I get errors running FG under Windows in debug mode : assertion failed in ctype.h in isspace cause a character was not in the range 0..255. Running in debug mode I saw that the problem happened during airports loading because of the copyright character. I modified simgear/misc/strutils.cxx so that in split_whitespace method isspace(str[i]) is replaced by isspace((unsigned char)str[i]). Then it works. I see isspace call in do_strip method too. I have not modified as below and this method was never called during my little test. Does my modification make sense ? Is this a simgear bug ? Maybe each isspace call should be cast as I did... David ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Simgear related problem
Quoting BONNEVILLE David: Hi there, I get errors running FG under Windows in debug mode : assertion failed in ctype.h in isspace cause a character was not in the range 0..255. Running in debug mode I saw that the problem happened during airports loading because of the copyright character. I modified simgear/misc/strutils.cxx so that in split_whitespace method isspace(str[i]) is replaced by isspace((unsigned char)str[i]). Then it works. I see isspace call in do_strip method too. I have not modified as below and this method was never called during my little test. Does my modification make sense ? Is this a simgear bug ? Maybe each isspace call should be cast as I did... This is how I locally circumvent the problem. It seems strange that MSVC's issomething accept an int in the interface but assert that the value is in the [0..255] range. When you give it a char that is not ASCII ( value = 128 ), it is signed extended, becomes negative and trigger the assertion. So casting to unsigned char to block the sign extension seems to be the good solution. -Fred ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Re: Glut problem
Melchior FRANZ wrote: Yes. Did you read somewhere that I would answer all questions? If so, this was a lie and you should complain to the author. :-P don't worry, I'm a developer too, brother ;-) Anyway: I would use freeglut from here: http://freeglut.sf.net/ This is (almost fully) compatible with glut. (The auto-key-repeat default seems to differ, but that's no problem for fgfs, now that the Spitfire changed the ignition code.) I expect that your next posting contains some real error messages. Otherwise I suggest to continue this thread on flightgear-users. ok, I don't have an error but I've found something. Into the includes of the package glut-3.5 there's no reference to glutSpecialUpFunc glutKeyboardUpFunc glutGameModeString glutEnterGameMode glutLeaveGameMode glutGameModeGet functions, while is present into freeglut-2.2.0 package. bye darko ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Re: Glut problem
* darko -- Thursday 07 April 2005 11:43: don't worry, I'm a developer too, brother ;-) Sometimes I miss the obvious. :-) m. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
On Wed, 2005-04-06 at 18:13, Josh Babcock wrote: Arnt Karlsen wrote: On Tue, 05 Apr 2005 22:22:48 -0400, Josh wrote in message Be warned, racy but authentic nose art... ..cute. We need more of these, to remain authentic. ;o) Yeah, this is an excellent opportunity to spread some historical information... Interactive history is certainly far better than dry facts in books, but we'd have to be careful how we spread historical information. FlightGear might well be a great means of keeping the historical flying experience alive. The trouble is, AFAIK *no* airplane currently modelled in FlightGear has ever been verified against the original machine. I'm *not* knocking what Josh has done here - nor of course anyone else's efforts. FlightGear is great for all those people who (like me) cannot afford to pilot real aircraft, or who just don't want to. However, we can't ignore the fact that, good though it may be, FlightGear is basically a video game. [ I take it, Josh, that I'm right in assuming that you've not flown a real B29? Nor even put an accurate model of a B29 in a wind tunnel to check how well the FDM is doing its stuff? :-) ] That's not to be taken as a complaint, but if we don't make people aware of this, then in 100 years time they'll be trying to re-enact battles of WWII using your B29 model on FlightGear 29.2.1 for HoloDeck and wondering why the bomber jocks of WWII claimed certain feats which they can't duplicate in 2105. So they'll rewrite history books to reflect what the HoloDeck simulation showed (the historical accounts obviously being exaggerated!), and they'll be wrong. Just as we can tell that the ancient Egyptians had help from aliens in building the pyramids, 'cos they obviously couldn't have done it by themselves. :-) Steve ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Re: b-29 alpha
* Steve Hosgood -- Thursday 07 April 2005 13:58: FlightGear is basically a video game. BS! No matter how much you detest it, it's still a simulator. Yes, it has shortcomings, and yes, in some areas we lack reliable data. But this doesn't make it a game. (Where is the gameplay. How do you enter the next level? How do you get scores and all that?) I don't really care what people will play on holodecks in the future. But given that you post this on the developers list: what are you going to contribute to improve the situation? m. -- Opinion/Contribution Floating point exception (core dumped) ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Steve Hosgood probed: However, we can't ignore the fact that, good though it may be, FlightGear is basically a video game. Don't feed the trolls, folks. Andy ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: Re : Re: [Flightgear-devel] compiling with .NET
BONNEVILLE David wrote: I think I see what you mean, but my intention is to make a .NET project that is coherent with the GNU makefiles so that I could fully use all the wonderful .NET functionnalities is it too much ? Don't feed the trolls, folks. :) (OK, that probably wasn't an intentional troll. But I couldn't resist.) Andy ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Steve Hosgood wrote: Interactive history is certainly far better than dry facts in books, but we'd have to be careful how we spread historical information. FlightGear might well be a great means of keeping the historical flying experience alive. The trouble is, AFAIK *no* airplane currently modelled in FlightGear has ever been verified against the original machine. I'm *not* knocking what Josh has done here - nor of course anyone else's efforts. FlightGear is great for all those people who (like me) cannot afford to pilot real aircraft, or who just don't want to. However, we can't ignore the fact that, good though it may be, FlightGear is basically a video game. I'm not disagreeing, but I would like to point out that FlightGear has a lot of stuff built in for those that want to move beyond a simple video game. There are hooks and facilities to connect FlightGear up to realistic cockpit controls, switches, etc., and connect up to lights, gauges, etc. A cockpit mockup with the displays and controls in the correct locations goes a long ways torwards turning FlightGear into a legitimate training tool. We have the ability to syncronize multiple display channels, which allows people to design advanced visual systems with wrap around screens. FlightGear can drive projectors or monitors which gives you a lot of flexibilty to create a display system appropriate for your particular needs and budget. As shipped you are right, but there are a lot of hooks built in which allow you to use FlightGear in much more serious and professional settings. [ I take it, Josh, that I'm right in assuming that you've not flown a real B29? Nor even put an accurate model of a B29 in a wind tunnel to check how well the FDM is doing its stuff? :-) ] To be fair to Josh, this is big reason why big full motion simulators for a specific aircraft cost millions of dollars. The flight dynamics data (and the work to get it and validate it) alone can easily exceed a million dollars. We are all doing the best we can. In the case of the B29, I'm sure the hope is to simply get as close as reasonably possible. Unless someone with a few million dollars laying around wants a perfect simulation of a B-29. In that case I can hook you up with some contacts. :-) That's not to be taken as a complaint, but if we don't make people aware of this, then in 100 years time they'll be trying to re-enact battles of WWII using your B29 model on FlightGear 29.2.1 for HoloDeck and wondering why the bomber jocks of WWII claimed certain feats which they can't duplicate in 2105. So they'll rewrite history books to reflect what the HoloDeck simulation showed (the historical accounts obviously being exaggerated!), and they'll be wrong. What happens in 2105 I'm sure will depend on how the future historical writers want to slant the past, and what point they want to make. Oh and don't forget that stupid is hereditary. :-) I'm sure it will exist in 2105 with very similar proportions to today. :-) There was an aviation accident where people were hurt. This led to the inevitable lawsuits. The plaintif's lawyers found a simulator of the same type of aircraft and flew into the flight regime in question and made some observations about the aircraft's behavior in that regime. In this lawsuit, the defense brought in their own expert to testify about how the real aircraft would behave, which was different from the results in the sim. The plaintif's lawyers pressed said expert witness on the point, at which time he revealed that he was the one who developed the flight dynamics for said simulator, and the regime the plaintif was exploring was outside of the realm where data was taken and validated for this sim, and thus the results were completely invalid. So you are right, people will probably try to derive useful conclusions from simulators in 2105 and there's a good chance they will be wrong. :-) Just as we can tell that the ancient Egyptians had help from aliens in building the pyramids, 'cos they obviously couldn't have done it by themselves. :-) Unless someone comes up with a 3000 year old pyramid building simulator that clearly shows they had help from aliens, I still am going to believe that the aliens built the pyramids entirely themselves before returning to Kobol and Caprica to work on their new fancy robot project that just got funding. Curt. -- Curtis Olsonhttp://www.flightgear.org/~curt HumanFIRST Program http://www.humanfirst.umn.edu/ FlightGear Project http://www.flightgear.org Unique text:2f585eeea02e2c79d7b1d8c4963bae2d ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
On Thu, 2005-04-07 at 15:45, Curtis L. Olson wrote: AFAIK *no* airplane currently modelled in FlightGear has ever been verified against the original machine. I'm not disagreeing, but I would like to point out that FlightGear has a lot of stuff built in for those that want to move beyond a simple video game. Yeah, and I'm not knocking FlightGear and all the great work that's been put into it. As you say, the ability to connect it to dedicated cockpit simulators (even on a motion-platform?) moves it well away from just a game. Some of the folk on this list are private pilots from what I see being discussed. How well do those pilots reckon the simulated aircraft in FlightGear mimic the real ones, given that the FDMs are (apparently) empirically created from the aircraft's basic layout and physical properties? There are hooks and facilities to connect FlightGear up to realistic cockpit controls, switches, etc., and connect up to lights, gauges, etc. A cockpit mockup with the displays and controls in the correct locations goes a long ways torwards turning FlightGear into a legitimate training tool. We have the ability to syncronize multiple display channels, which allows people to design advanced visual systems with wrap around screens. FlightGear can drive projectors or monitors which gives you a lot of flexibilty to create a display system appropriate for your particular needs and budget. Is there actually a way to connect a motion platform? I recall hearing about a motion chair connected to one of the old (0.5.6 ish) versions of FG, but I'm not sure if that's the same thing. Similarly, what about force-feedback to control-columns? To be fair to Josh, this is big reason why big full motion simulators for a specific aircraft cost millions of dollars. The flight dynamics data (and the work to get it and validate it) alone can easily exceed a million dollars. Josh has done some good work. Keep it up, Josh. Especially the nose art :-) Steve ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Re: b-29 alpha
On Thu, 2005-04-07 at 13:24, Melchior FRANZ wrote: * Steve Hosgood -- Thursday 07 April 2005 13:58: FlightGear is basically a video game. BS! No matter how much you detest it, it's still a simulator. I *knew* I'd get flamed by Melchior! I don't detest FG, it's a fine bit of work. True, the word game was a bit too harsh. But given that you post this on the developers list: what are you going to contribute ... Anyone want an RPM packaging (for Fedora Core 2) for 0.9.8? I noticed that the previous attempt at RPMing hadn't been updated since 0.9.4. So I did my own. Also I packaged up scenery for Great Britain Ireland, The Faroe Islands and France as separate entities. The idea is to get the RPMs put on a YUM archive (or APT) so that newbies can just say yum install FlightGear-Terrain-FR and they'd get all that they needed for flying (in this case in France). The scenery RPMs would load the basic FlightGear program and base-files automatically if you didn't already have them (RPMs can auto-require other ones). I was planning on doing Benelux and Spain next, but if other people wanted to join in, they're welcome to my SRPMs to use as a basis for their own lands. It may not be much, but I do *try* to contribute! Steve. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Re: b-29 alpha
* Steve Hosgood -- Thursday 07 April 2005 17:48: I *knew* I'd get flamed by Melchior! Hey, you can count on me! (And I was only flaming back.) m. ;-) ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Steve Hosgood wrote: Some of the folk on this list are private pilots from what I see being discussed. How well do those pilots reckon the simulated aircraft in FlightGear mimic the real ones, given that the FDMs are (apparently) empirically created from the aircraft's basic layout and physical properties? To my knowledge there _are_ aircraft in FlightGear that are build upon real data. Right ? To my experience what makes the most significant difference between FlightGear and a real aircraft is the limited view angle in FlightGear - as long as you don't have a a simulator with multiple screens. But for the price tag of a couple of large TFT displays you can afford your own PPL Compared to that the difference in the flight 'behaviour' of a real C172 (or PA-28) and the one in FlightGear is neglectible. At least these two get really close to reality - pretty much close enough to use FlightGear for trainig final approaches for example, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Martin Spott wrote: To my knowledge there _are_ aircraft in FlightGear that are build upon real data. Right ? I think this is always the case. Take the B-29 for instance. Josh has obviously done a ton of research to get the dimensions and proportions down exactly right ... that's a key component of dynamics modeling. Along with that you want to figure out the mass of the aircraft and refine the mass distribution throughout the airframe (engines, fuel, pilots, cargo, balance, etc.) Then of course you need flight data, but even with limited flight data, you can start to craft a very plausible model based on aircraft mass, dimensions, power plants, etc. I don't think anyone sits down and makes up an entire aircraft from scratch based on ficticious number and pure guessing. We use guesses just do that to fill in the gaps for things we don't know. But often the guesses are educated and at least in the right ball park. In the end, the quality of the model depends greatly on the quality and amount of data the aircraft designer can find. For Level 3 FTD certification, the FAA has a long lists of flight tests you need to run to validate against real aircraft performance. It is very difficult/expensive to get all the data required for the FAA certification, and no FlightGear model has gone to those extremes that I'm aware of. However, someone with the resources, time, and data could certainly go through the process. There's nothing in our code or infrastructure that would prevent or limit us from being able to do this. To my experience what makes the most significant difference between FlightGear and a real aircraft is the limited view angle in FlightGear - as long as you don't have a a simulator with multiple screens. But for the price tag of a couple of large TFT displays you can afford your own PPL Compared to that the difference in the flight 'behaviour' of a real C172 (or PA-28) and the one in FlightGear is neglectible. At least these two get really close to reality - pretty much close enough to use FlightGear for trainig final approaches for example, Yes to get to a good level of realism you need: 1. A cockpit mockup with all the gauges, switch, lights, controls etc. in approximately the right place. 2. A reasonable field of view on your visual system (often accomplished with multiple projectors, or large screens.) 3. Refined/validated flight dynamics. 4. Motion isn't required at the lower levels of FAA certification, but it is a really nice thing to have when done right. The problem is that it is hard to do right, and there is a cascading effect on other elements of the simulator. It's actually a lot of fun to play around at this next level up, but it's also a lot of work, and there's enough issues and problems that it's difficult for a single person to do everything well themselves. It often becomes less of a hobby and more of a sickness (or business.) :-) Curt. -- Curtis Olsonhttp://www.flightgear.org/~curt HumanFIRST Program http://www.humanfirst.umn.edu/ FlightGear Project http://www.flightgear.org Unique text:2f585eeea02e2c79d7b1d8c4963bae2d ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Steve Hogood wrote: Some of the folk on this list are private pilots from what I see being discussed. How well do those pilots reckon the simulated aircraft in FlightGear mimic the real ones, given that the FDMs are (apparently) empirically created from the aircraft's basic layout and physical properties? That's true of YASim, but not JSBSim which can take real, measured data if you have it. The problem with real data, of course, is that in general it lies (or doesn't make sense in isolation -- same deal), and at best isn't available in all regimes, or at all. The kind of fidelity you are asking for is a straw man. No simulator is going to provide it. You could just as easily point at a 40 million dollar military sim and say it doesn't do this, this and this, so it's a toy!. If simulators could be perfect, pilots wouldn't train in real aircraft. If you have complaints, make them. If you want features, ask. Trolling like this (yes, this is trolling, even if you don't realize it) isn't helping anyone or anything. Basically, grow up. :) Andy ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Martin Spott wrote: To my knowledge there _are_ aircraft in FlightGear that are build upon real data. Right ? Yes, the C172p. At least and the F-104, F-15 and F-16 are based on windtunnel data. The T-37 is partially based on flight test data. And Both the Fokker 70/100 and Fokker 50 use available data where possible. None of them are extensively validated though (although I do thrust the windtunnel and test-flight data). Erik ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] Help with B-29
Andy Ross wrote: I wrote: Jim Wilson wrote: 4) Fixed rpm/power numbers under the prop tags. They need to be scaled back according to the gear ratio. Someone with a better understanding of mech engineering might be able to explain why the BHP on the prop shaft is reduced by a factor of 0.35 when that's the gear ratio, or maybe that is wrong and there is something going on in the YASim calcs. Yeah, that's a bug. Power is power. If the prop wants to sync X horsepower at Y RPM, then the engine ought to be defined as producing the same X hp at Y/gear-ratio RPM. Let me take a look. Indeed, there was yet another spot I missed when adding the gear-ratio stuff. The torque conversion from propeller side to engine side worked correctly during solution, but not at runtime. This is fixed now, so you should be able to use real numbers in your propeller tags. FWIW, I also took the opportunity to re-visit the P-51D configuration that I promised (long ago) to hack at. Attached is a version that should perform more realistically. The biggest change is that I reduced the cruise speed (360-310) to represent what a typical aircraft should be able to achieve with 50% fuel. The resulting aircraft is a *lot* less slick (it produces almost three times as much parasite drag), and should perform more realistically at low altitudes. You should still be able to hit the textbook numbers with a stripped aircraft and empty tanks. Also, there is a syntax fix: the piston-engine tag should be a subtag of the propeller tag. Putting it immediately after the propeller definition works only due to a lucky interaction with the way the parser stores its current object pointer. It doesn't clear the value when it sees /propeller, so you can get away with putting the engine at any point in the file before the next tag that sets a current object. I haven't flown this enough to say whether it's worth checking in. Let me know if anyone tries it and likes it. I'm currently developing the YASim config for the Hawker Hurricane model. I took the P51d config and plugged in some authoritative numbers for the Merlin XX. Mirabile dictu, it worked right out of the box. The model takes off and flies well (very well, I think), with the performance closely matching the published figures. It can't quite reach the service ceiling, but perhaps the standard atmosphere ain't quite what it was in 1941, or perhaps I need to pump up the supercharger a bit :-). The wastegate opens and closes when it should, and the 2 speed supercharger works correctly. Good work, Andy. However (and there's always a however), I can't land the thing. Closing the throttle and pulling back the propeller pitch control doesn't reduce the power enough. I reasoned that there was too much boost with the throttle closed, (currently set at 10%, AFAICS). 10% of the supercharger output at sea level before the wastegate is a big number - I set it 3% (based on nothing more than a WAG) and it works well. Perhaps we can make this parameter settable with a default value of 10%? One other 'however': the property mp-inhg seems to be bound to the supercharger output before the wastegate is applied. Useful for development, but not for the input to the manifold pressure gauge. Locally, I've added a parameter for manifold pressure after the wastegate. If no one objects, I can send Erik the required changes in the next week or so. Regards Vivian ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Help with B-29
Vivian Meazza wrote: However (and there's always a however), I can't land the thing. Closing the throttle and pulling back the propeller pitch control doesn't reduce the power enough. I reasoned that there was too much boost with the throttle closed, (currently set at 10%, AFAICS). 10% of the supercharger output at sea level before the wastegate is a big number Yeah, that's a good point. The idle tuning of the engine was done before turbocharging was added, and doesn't really map well to the new regime. As a near-term workaround, you can always pull the mixture way back to reduce power to near-zero. I'm wary of adding a magic number to the configuration files for this, though. I wonder if there's a saner way of calculating an appropriate idle power dynamically from the input values... A related issue that stands to be fixed is that the current code doesn't really model a gear-driven supercharger properly. With a centrifugal compressor like this, the output pressure gain is a direct funcition of RPM. The existing code tries to model an exhaust-driven turbo charger by simply multiplying the input MP by the turbo-mul factor, which isn't the same thing. The behavior will match at maximum power output, but be off in the middle and at the low end. One other 'however': the property mp-inhg seems to be bound to the supercharger output before the wastegate is applied. Really? PistonEngine.cpp:112 looks like it is setting the current MP based on the turbo output. Maybe there's a different bug somewhere (units conversion, maybe?) Andy ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Andy Ross wrote: Steve Hosgood probed: However, we can't ignore the fact that, good though it may be, FlightGear is basically a video game. Don't feed the trolls, folks. Andy ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d But they're so cute when the beg for food! ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
Steve Hosgood wrote: On Wed, 2005-04-06 at 18:13, Josh Babcock wrote: Arnt Karlsen wrote: On Tue, 05 Apr 2005 22:22:48 -0400, Josh wrote in message Be warned, racy but authentic nose art... ..cute. We need more of these, to remain authentic. ;o) Yeah, this is an excellent opportunity to spread some historical information... Well, I wasn't planning on claiming any great accuracy of the flight model, though I will try and make the appearance and systems as close as I can. It's actually not that complex of a plane, except for a few features like the gun targeting computer (yup, i said targeting computer) that won't be modeled anyway. And no, I haven't had the pleasure of flying a B-29 :) There are however those who still fly one (soon to be two), and at some point I will invite them to try this one out and give some input. I don't really expect to get any though. I was thinking more along the lines of providing a brief written synopsis of the history of the plane and the firebombing of Japan, which I think is a very underreported part of WWII history. Few people realize that Hiroshima was just barely the most deadly raid, and not even the most destructive. Nagasaki didn't even come in second in either category. In fact, it was Tokyo that lost the largest number of lives throuought the whole campiagn. It kind of puts all the fuss about displaying the 'Enola Gay' at the Smithsonian in perspective. There are some great histories out there and I have read several doing research for this project. I'd like to share some of what I have learned. Josh ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] Help with B-29
Andy Ross wrote Vivian Meazza wrote: However (and there's always a however), I can't land the thing. Closing the throttle and pulling back the propeller pitch control doesn't reduce the power enough. I reasoned that there was too much boost with the throttle closed, (currently set at 10%, AFAICS). 10% of the supercharger output at sea level before the wastegate is a big number Yeah, that's a good point. The idle tuning of the engine was done before turbocharging was added, and doesn't really map well to the new regime. As a near-term workaround, you can always pull the mixture way back to reduce power to near-zero. Unfortunately, the Hurricane had/has automatic mixture control! I'm wary of adding a magic number to the configuration files for this, though. I wonder if there's a saner way of calculating an appropriate idle power dynamically from the input values... That would be good ... if we knew or could deduce the HP. Meanwhile, it's quite easy to tune the minimum output using the so called 'magic number' A related issue that stands to be fixed is that the current code doesn't really model a gear-driven supercharger properly. With a centrifugal compressor like this, the output pressure gain is a direct funcition of RPM. The existing code tries to model an exhaust-driven turbo charger by simply multiplying the input MP by the turbo-mul factor, which isn't the same thing. The behavior will match at maximum power output, but be off in the middle and at the low end. Working on it right now. BTW the Merlin had a Roots type displacement compressor. I'm looking at some representative pressure ratio curves wrt rpm. I'm testing out a supercharger which varies output with engine rpm, modified by throttle. One other 'however': the property mp-inhg seems to be bound to the supercharger output before the wastegate is applied. Really? PistonEngine.cpp:112 looks like it is setting the current MP based on the turbo output. Maybe there's a different bug somewhere (units conversion, maybe?) The property is bound to the variable _mp, while the wastegate is applied to the variable mp. If the property is bound to mp, it gives the right output. The problem is entirely in the binding - the turbo code works correctly. Regards, Vivian ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Help with B-29
On Thu, 7 Apr 2005 19:16:08 +0100, Vivian wrote in message [EMAIL PROTECTED]: Andy Ross wrote Vivian Meazza wrote: However (and there's always a however), I can't land the thing. Closing the throttle and pulling back the propeller pitch control doesn't reduce the power enough. I reasoned that there was too much boost with the throttle closed, (currently set at 10%, AFAICS). 10% of the supercharger output at sea level before the wastegate is a big number Yeah, that's a good point. The idle tuning of the engine was done before turbocharging was added, and doesn't really map well to the new regime. As a near-term workaround, you can always pull the mixture way back to reduce power to near-zero. ..how about solving for idle static thrust? Unfortunately, the Hurricane had/has automatic mixture control! ..??? The only ones I'm aware of had such fancy gear, is the Axis side, look for kommandogerat, was used in all frontline piston powered WWII Luftwaffe fighters. I'm wary of adding a magic number to the configuration files for this, though. I wonder if there's a saner way of calculating an appropriate idle power dynamically from the input values... That would be good ... if we knew or could deduce the HP. Meanwhile, it's quite easy to tune the minimum output using the so called 'magic number' A related issue that stands to be fixed is that the current code doesn't really model a gear-driven supercharger properly. With a centrifugal compressor like this, the output pressure gain is a direct funcition of RPM. The existing code tries to model an exhaust-driven turbo charger by simply multiplying the input MP by the turbo-mul factor, which isn't the same thing. The behavior will match at maximum power output, but be off in the middle and at the low end. Working on it right now. BTW the Merlin had a Roots type displacement compressor. ..this is the big ass clutch-housing-and-gearbox like thing down the rear end of the Merlins? ..ahem; http://www.enginehistory.org/merlin_xx.htm , specificly http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2i.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2j.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2k.jpg ..looks centrifugal, no? ;o) I'm looking at some representative pressure ratio curves wrt rpm. I'm testing out a supercharger which varies output with engine rpm, modified by throttle. One other 'however': the property mp-inhg seems to be bound to the supercharger output before the wastegate is applied. Really? PistonEngine.cpp:112 looks like it is setting the current MP based on the turbo output. Maybe there's a different bug somewhere (units conversion, maybe?) The property is bound to the variable _mp, while the wastegate is applied to the variable mp. If the property is bound to mp, it gives the right output. The problem is entirely in the binding - the turbo code works correctly. -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Help with B-29
On Thu, 7 Apr 2005 21:37:31 +0200, Arnt wrote in message [EMAIL PROTECTED]: On Thu, 7 Apr 2005 19:16:08 +0100, Vivian wrote in message [EMAIL PROTECTED]: Andy Ross wrote Working on it right now. BTW the Merlin had a Roots type displacement compressor. ..apologies all, I hit the wrong button as I was gonna wipe out... : ..this is the big ass clutch-housing-and-gearbox like thing down the rear end of the Merlins? ...before putting this right under Vivian's compressor line, and found the end result in message[EMAIL PROTECTED] a fair bit embarrasing. ;o) ..ahem; http://www.enginehistory.org/merlin_xx.htm , specificly http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2i.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2j.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2k.jpg ..looks centrifugal, no? ;o) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Re: property control question
On April 7, 2005 03:09 am, Melchior FRANZ wrote: Your standard Nasal key binding skeleton with one commented out line would do (literally) nothing to solve this problem. But maybe I just didn't understand your performance enhancement!? Are you suggesting that we replace all nasal key bindings by NOOPs to save CPU cycles? :-] m. It was merely a pseudo code. Forgive me if I interpeted the problem incorrectly. ;-) Ampere ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] Help with B-29
Arnt Karlsen wrote Andy Ross wrote Vivian Meazza wrote: However (and there's always a however), I can't land the thing. Closing the throttle and pulling back the propeller pitch control doesn't reduce the power enough. I reasoned that there was too much boost with the throttle closed, (currently set at 10%, AFAICS). 10% of the supercharger output at sea level before the wastegate is a big number Yeah, that's a good point. The idle tuning of the engine was done before turbocharging was added, and doesn't really map well to the new regime. As a near-term workaround, you can always pull the mixture way back to reduce power to near-zero. ..how about solving for idle static thrust? If we knew the static idle thrust that would be a good way to go. I was considering solving for idle rpm, which we do know. If I can't, Andy will come up with a way, I'm sure. Unfortunately, the Hurricane had/has automatic mixture control! ..??? The only ones I'm aware of had such fancy gear, is the Axis side, look for kommandogerat, was used in all frontline piston powered WWII Luftwaffe fighters. Surprised me too. Seems unlikely: the Spitfire had a manual mixture lever. I'm going by the Pilot's Notes para 19: Throttle. The throttle lever works is a slot in the decking shelf on the left-hand side of the cockpit. The take-off position is gated. There is a friction adjuster on the inboard end of the lever spindle. The mixture control is fully automatic and there is no pilot's control lever. I can't identify a lever in any of the contemporary photos that I have access to, but I can't be absolutely certain - they are pretty blurred. Wishful thinking by the author of the Notes? Possibly, but I'm going to stick with the reference, unless anyone can come up with an amended version. I'm wary of adding a magic number to the configuration files for this, though. I wonder if there's a saner way of calculating an appropriate idle power dynamically from the input values... That would be good ... if we knew or could deduce the HP. Meanwhile, it's quite easy to tune the minimum output using the so called 'magic number' A related issue that stands to be fixed is that the current code doesn't really model a gear-driven supercharger properly. With a centrifugal compressor like this, the output pressure gain is a direct funcition of RPM. The existing code tries to model an exhaust-driven turbo charger by simply multiplying the input MP by the turbo-mul factor, which isn't the same thing. The behavior will match at maximum power output, but be off in the middle and at the low end. Working on it right now. BTW the Merlin had a Roots type displacement compressor. ..this is the big ass clutch-housing-and-gearbox like thing down the rear end of the Merlins? Yes ..ahem; http://www.enginehistory.org/merlin_xx.htm , specificly http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2i.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2j.jpg http://www.enginehistory.org/ModelEngines/Hares/Merlin XX/2k.jpg ..looks centrifugal, no? ;o) Yes - bit of brain fade there - I interpreted one of my references incorrectly, but on closer reading I was quite wrong. I read 2 impellors and assumed that meant Roots type, which has 2, but of course they are on the same shaft and centrifugal, giving 2 compressor stages. (And 2 speed, but that's another story) Thank you for pointing it out. Regards, Vivian ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] can flightgear give distances from aircraft toa nearby ob
Both. To be more accurate, anything in the vicinity of the aircraft's flightpath. From: Mathias Fröhlich [EMAIL PROTECTED] Reply-To: FlightGear developers discussions flightgear-devel@flightgear.org To: FlightGear developers discussions flightgear-devel@flightgear.org Subject: Re: [Flightgear-devel] can flightgear give distances from aircraft toa nearby object? Date: Thu, 7 Apr 2005 07:23:46 +0200 On Donnerstag 07 April 2005 06:16, Michael Matkovic wrote: Could anyone point me to a website, docs or other info which would show me how to get distances to nearest objects of the aircraft I'm flying in Flightgear? Is this available in Flightgear? You are talking about the nearest triangle of the scenery? Or the nearest AI aircraft/whatever? Greetings Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] b-29 alpha
From: Steve Hosgood FlightGear might well be a great means of keeping the historical flying experience alive. The trouble is, AFAIK That is right. You don't know. *no* airplane currently modelled in FlightGear has ever been verified against the original machine. I'm *not* knocking what Josh has done here - nor of course anyone else's efforts. FlightGear is great for all those people who (like me) cannot afford to pilot real aircraft, or who just don't want to. However, we can't ignore the fact that, good though it may be, FlightGear is basically a video game. I think this guy is a troll. [ I take it, Josh, that I'm right in assuming that you've not flown a real B29? Nor even put an accurate model of a B29 in a wind tunnel to check how well the FDM is doing its stuff? ] That's not to be taken as a complaint, but if we don't make people aware of this, then in 100 years time they'll be trying to re-enact battles of WWII using your B29 model on FlightGear 29.2.1 for HoloDeck and wondering why the bomber jocks of WWII claimed certain feats which they can't duplicate in 2105. So they'll rewrite history books to reflect what the HoloDeck simulation showed (the historical accounts obviously being exaggerated!), and they'll be wrong. Just as we can tell that the ancient Egyptians had help from aliens in building the pyramids, 'cos they obviously couldn't have done it by themselves. And this proves it. Or maybe just a moron. What a useful contribution. How long did it take you to write that Steve? Best regards, Jim ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
