Re: [Flightgear-devel] Bug 772 (Yasim on ground)
Hello, I have re-opened today this issue again, after I played with some better developed YASim aircrafts like MD 81 to find out what is the issue behind the bad crosswind behavior of my Dornier 328TP- project, and a lot of other aircraft. (couldn't test all of course) Especially I tested the MD81 by Gary Neely after I read his very good YASim tutorials. Gary Neely MD81, gross weight 157503 lb Location: Edwards base KEDW, RWY 15 Weather: 08025KT 12SM 20/08 Q1013 NOSIG Takeoff behavior: as soon I reach 110-120ktn the aircraft will drift into the wind. Landing behavior: I noticed that even this aircraft will drift away as soon the nose gear will touch down with wind speeds about more than 20ktn and wind from left Crosswind limitation for the real thing is 30ktn on dry runways. (http://www.hilmerby.com/md80/md_basic.html) No problems with wind from right, even with much higher wind speeds- and that's exactly what makes we wonder. now the 777-200ER, gross weight: 574595 lb Location: Edwards base KEDW, RWY 15 Weather: 08025KT 12SM 20/08 Q1013 NOSIG Takeoff behavior: Flaps 15: as soon I reach 110-120ktn the aircraft will drift into the wind as well. (Vr: 130ktn) Flaps 5: as soon I reach 110-120ktn the aircraft will drift into the wind as well. (Vr: 130ktn) Landing behavior: I noticed that even this aircraft will drift away as soon the nose gear will touch down with wind speeds about more than 20ktn and wind from left as well Crosswind limitation for the real thing is about 40ktn on dry runways. (http://www.pprune.org/archive/index.php/t-285471.html) So, I'm sure the problem isn't solved. No idea where the cause of this problem could be- I'm not sure if it is really the aircraft configuration... Kind regards HHS-- See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831iu=/4140/ostg.clktrk___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Bug 772 (Yasim on ground)
Hi all, Hyde has submitted a work-around for issue 772, which you can see here: https://gitorious.org/fg/flightgear/merge_requests/1572 He'd like this merged before the freeze (actually it's a fix so it can be merged afterwards, but still), I'd like to hear any opinions on if this is a bad idea or good idea. Personally I'm not so affected by issue 772, but if many people are, the work-around seems just-about-acceptable to me. (Obviously it would be nicer to fix Yasim for real, but let's skip that just for a moment) Does anybody feel strongly that either: - the bug is very bad, so that the workaround is definitely needed (keeping in mind it's a long-standing bug) - the work-around is very bad, for some scenario I didn't imagine myself? (Helicopters on the ground? But they likely benefit more from the fix?) I'm happy to merge the change above to get some feedback, with the understanding that if people raise 'problems which are worse than the original issue' before 2.12 is final, we could revert it. James -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
James Sent: 11 June 2013 13:09 To: FlightGear developers discussions Subject: [Flightgear-devel] Bug 772 (Yasim on ground) Hi all, Hyde has submitted a work-around for issue 772, which you can see here: https://gitorious.org/fg/flightgear/merge_requests/1572 He'd like this merged before the freeze (actually it's a fix so it can be merged afterwards, but still), I'd like to hear any opinions on if this is a bad idea or good idea. Personally I'm not so affected by issue 772, but if many people are, the work-around seems just-about-acceptable to me. (Obviously it would be nicer to fix Yasim for real, but let's skip that just for a moment) Does anybody feel strongly that either: - the bug is very bad, so that the workaround is definitely needed (keeping in mind it's a long-standing bug) - the work-around is very bad, for some scenario I didn't imagine myself? (Helicopters on the ground? But they likely benefit more from the fix?) I'm happy to merge the change above to get some feedback, with the understanding that if people raise 'problems which are worse than the original issue' before 2.12 is final, we could revert it. I haven't noticed any particular issue with crosswinds myself, but the fix seems to be illogical. I can't imagine what disabling wind on the ground is going to do for take-offs. How would the transition work? Has anyone shown that there is anything wrong with Andy's math? I'd like to hear what Andy has to say about this one. In the meantime I would object to this fix. Vivian -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
On Tue, 11 Jun 2013 14:09:27 +0200, James wrote in message 068d459e-8a17-4403-89b1-92606456d...@mac.com: Hi all, Hyde has submitted a work-around for issue 772, which you can see here: https://gitorious.org/fg/flightgear/merge_requests/1572 ..does this test for _both_ speed and altitude? ..I see no test for friction (maybe elsewhere in the code?), on e.g. wet ice, wind _should_ push you around, but a wee 3kts breeze shouldn't move an airliner, a say 30kts gust probably should rock it a wee bit, and say a 60kts gale should have it skating away. Maybe test friction forces against (cross)wind forces? He'd like this merged before the freeze (actually it's a fix so it can be merged afterwards, but still), I'd like to hear any opinions on if this is a bad idea or good idea. Personally I'm not so affected by issue 772, but if many people are, the work-around seems just-about-acceptable to me. (Obviously it would be nicer to fix Yasim for real, but let's skip that just for a moment) Does anybody feel strongly that either: - the bug is very bad, so that the workaround is definitely needed (keeping in mind it's a long-standing bug) - the work-around is very bad, for some scenario I didn't imagine myself? (Helicopters on the ground? But they likely benefit more from the fix?) ..one problem with good work-arounnds, is they have a way of becoming permanent fixes despite their often fundamentally flawed assumptions, because they work well enough. I'm happy to merge the change above to get some feedback, with the understanding that if people raise 'problems which are worse than the original issue' before 2.12 is final, we could revert it. James -- ..med vennlig hilsen = with Kind Regards from Arnt Karlsen ...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. -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
With respect, I'd prefer to hold off on this fix until we have more test data and additional input by experienced Flightgear users. Which planes exhibit this tendency under what exact conditions? What version of Flightgear is being used? Under what OS? Did this effect begin to occur after a specific Flightgear release? Currently I've not experienced anything as severe as what some of the bug posters describe, at least not with aircraft having well-designed and tuned YASim FDMs. Admittedly I fly only a handful of planes, usually my own efforts. I do know that YASim friction effects are not what they could be, and this can be aggravated by poor friction settings or settings that have been compromised to offset some other characteristic. Many YASim planes don't have adequate weight-and-balance settings and commonly aren't tested against pilot handbook crosswind limitations. Because of this they often handle terribly under those conditions, with even modest crosswinds. I know this because I've adjusted the balance and flight surface effects of a number of YASim planes to allow them to handle crosswinds up to the handbook's limits. I'm not suggesting this is necessarily related to the bug problem, only that the bug needs to be tested against aircraft with YASim FDMs that have been designed to reflect the aircraft's limitations. -Gary aka Buckaroo -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
Gary I agree with all of this. I have just tested the 777-200 in a moderate crosswind. First time I ever used it. There is a tendency to fly up into wind once the main wheels are on the deck, but nothing which can't be handled with a bootfull of rudder. Perhaps a little more rudder authority would be nice. I would leave well alone unless and until Andy advises otherwise. Vivian From: Gary Neely [mailto:grne...@gmail.com] Sent: 11 June 2013 18:33 To: FlightGear developers discussions Subject: Re: [Flightgear-devel] Bug 772 (Yasim on ground) With respect, I'd prefer to hold off on this fix until we have more test data and additional input by experienced Flightgear users. Which planes exhibit this tendency under what exact conditions? What version of Flightgear is being used? Under what OS? Did this effect begin to occur after a specific Flightgear release? Currently I've not experienced anything as severe as what some of the bug posters describe, at least not with aircraft having well-designed and tuned YASim FDMs. Admittedly I fly only a handful of planes, usually my own efforts. I do know that YASim friction effects are not what they could be, and this can be aggravated by poor friction settings or settings that have been compromised to offset some other characteristic. Many YASim planes don't have adequate weight-and-balance settings and commonly aren't tested against pilot handbook crosswind limitations. Because of this they often handle terribly under those conditions, with even modest crosswinds. I know this because I've adjusted the balance and flight surface effects of a number of YASim planes to allow them to handle crosswinds up to the handbook's limits. I'm not suggesting this is necessarily related to the bug problem, only that the bug needs to be tested against aircraft with YASim FDMs that have been designed to reflect the aircraft's limitations. -Gary aka Buckaroo -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
Hi, I'm a guy who submit that fix. I tested today without my fix, I noticed it's been fixed!! There still be the pulling power but it's controllable by steering now. I'm sorry to bother all of you but I didn't know it was fixed. I gladly withdraw my request. I will report what change fixed the issue later. Best, Hyde -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
On 11 Jun 2013, at 22:01, Hyde Yamakawa h...@hyde-tech.com wrote: Hi, I'm a guy who submit that fix. I tested today without my fix, I noticed it's been fixed!! There still be the pulling power but it's controllable by steering now. I'm sorry to bother all of you but I didn't know it was fixed. I gladly withdraw my request. I will report what change fixed the issue later. Okay, thanks to everyone for looking at this, if someone could update the issue as WontFix or Invalid for now it's probably wise, it can always be re-opened if someone disagrees. Regards, James -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Bug 772 (Yasim on ground)
James, Done Vivian From: James Turner [mailto:zakal...@mac.com] Sent: 11 June 2013 22:43 To: FlightGear developers discussions Subject: Re: [Flightgear-devel] Bug 772 (Yasim on ground) On 11 Jun 2013, at 22:01, Hyde Yamakawa h...@hyde-tech.com wrote: Hi, I'm a guy who submit that fix. I tested today without my fix, I noticed it's been fixed!! There still be the pulling power but it's controllable by steering now. I'm sorry to bother all of you but I didn't know it was fixed. I gladly withdraw my request. I will report what change fixed the issue later. Okay, thanks to everyone for looking at this, if someone could update the issue as WontFix or Invalid for now it's probably wise, it can always be re-opened if someone disagrees. Regards, James -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
