Re: [Flightgear-devel] Retractable Gear
On Sunday 02 December 2001 12:00 pm, you wrote: Tony Peden writes: I put some kludge code in to JSBSim.cxx to force the gear down before doing a ground trim. Wow! I'm going to grab the latest JSBSim CVS and try this out. Looks like we'll need to add gear indicators to the panel sooner rather than later. It looks like what ever controls the default value of FGControls::get_gear_down() (which may well be FGControls itself) defaults it to gear up which is a problem for the c310. The default value needs to be set in preferences.xml. Also, for any model which uses retractable gear, some thought needs to be given to fuselage/wing/nacelle/prop etc. contact points if the gear are up. (They need to be added to the config file) I will add those to the C310 from the 3-view. It was necessary to change the config files again, so make sure you update *all* the config files in your base tree, not just the c310. There are ways to design config files so that they are both forwards-and-backwards compatible (with quality degrading gracefully both ways). When we're through this round of technical changes, let's see if we can make the JSBSim formats a little less brittle. Yes, I mentioned the same to Jon privately. My thought is to begin moving towards fully well-formed XML. This would make it much easier to a) flag a missing required parameter and b) have optional parameters e.g. if I could have added something like: RETRACTABLETRUE/RETRACTABLE its presence or lack thereof in the config file would be easy to detect and, in this case, default the gear unit to fixed. This also brings up the recurring question regarding the use of a third-party XML parser. For once, I'll have to side with keeping our own, since that would allow us to change the config file over in phases rather that all at once. All the best, David -- Tony Peden [EMAIL PROTECTED] We all know Linux is great ... it does infinite loops in 5 seconds. -- attributed to Linus Torvalds ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Retractable Gear
On Mon, 3 Dec 2001 11:04, you wrote: On Sunday 02 December 2001 02:07 pm, you wrote: On Mon, 3 Dec 2001 03:22, you wrote: OK, JSBSim now supports retractable gear. I have built flightgear with it and it works. Note that if the gear are not fully down, they essentially don't exist as far as JSBSim is concerned. This could be a problem. IIRC aircraft like the DC-3 never fully retract their gear. The gear in the DC3 only goes half way into the engine. Can JSBSim handle this? Well sort of, you could define two contact points for each gear one up, and one down and that would cover the fully retracted case. Yeah but I'm talking about the drag situation. The wheels create drag even when retracted in this aircraft. Can you have some drag that gets created even when retracted? David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Retractable Gear
David Findlay writes: Yeah but I'm talking about the drag situation. The wheels create drag even when retracted in this aircraft. Can you have some drag that gets created even when retracted? That drag would already be built into the coefficients, I'd expect. All the best, David -- David Megginson [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Retractable Gear
David M. is correct. That drag would already be built into the coefficients, I'd expect. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Retractable Gear
On Sunday 02 December 2001 05:25 pm, you wrote: On Mon, 3 Dec 2001 11:04, you wrote: On Sunday 02 December 2001 02:07 pm, you wrote: On Mon, 3 Dec 2001 03:22, you wrote: OK, JSBSim now supports retractable gear. I have built flightgear with it and it works. Note that if the gear are not fully down, they essentially don't exist as far as JSBSim is concerned. This could be a problem. IIRC aircraft like the DC-3 never fully retract their gear. The gear in the DC3 only goes half way into the engine. Can JSBSim handle this? Well sort of, you could define two contact points for each gear one up, and one down and that would cover the fully retracted case. Yeah but I'm talking about the drag situation. The wheels create drag even when retracted in this aircraft. Can you have some drag that gets created even when retracted? All you need is an increment for gear down. The gear up drag, if there is any, is in the basic drag for the airplane. David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel -- Tony Peden [EMAIL PROTECTED] We all know Linux is great ... it does infinite loops in 5 seconds. -- attributed to Linus Torvalds ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Retractable Gear
On Sunday 02 December 2001 9:15 pm, you wrote: John Check writes: A lot of stuff needs that. Which reminds me.. does preferences.xml handle logic? I was thinking it might be nice to include a section of defaults that get set when --aircraft=$multi_engine. If not, will setting prefs (ie /controls/mixture[1]) mess up anything? The best way to accomplish that for now is with overlays. FlightGear reads preferences.xml first, then it reads user-supplied config files, so you can overwrite any of the default values. All the best, David Okay so a --config is sufficient... ok ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
