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737 Decent flying

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737 Decent flying

Postby avt416 » Sun Jan 12, 2020 12:04 pm

Help
Looking for the most decent and developed 737 on fg
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Re: 737 Decent flying

Postby Ysop » Sun Jan 12, 2020 1:20 pm

there are two to mention:
737-800
https://github.com/YV3399/737-800YV

737-300
the one you find in the normal FGAddon in flightgear.

both have a highly developed fdm. don't expect the flying to be easy.
you need to use the route manager, as the fms is not fully programmed.
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Re: 737 Decent flying

Postby tdammers » Mon Jan 13, 2020 11:37 am

I don't think the 737-800YV is particularly difficult to fly, really. It's an airliner, so things are more complex than in a Cessna, and you probably want to use the automation a lot, but as far as hand-flying goes, I don't find it particularly difficult to handle.
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Re: 737 Decent flying

Postby Ysop » Mon Jan 13, 2020 12:44 pm

Oh, I didn't want to say, that it is difficult.

It is just, that I am always way off, when I grab my cup of tea or so. Things are happening fast

Amazing details in the FDM.
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Re: 737 Decent flying

Postby asr » Tue Jan 14, 2020 12:00 am

The 737-800YV linked above is much more realistic and rewarding than it seems at first glance. I'm surprised there's so few people flying it. Completely underrated. I wish the author(s) and excellent aircraft modelers we have around here could find some time to polish some details and make it perfect.

I've been flying this aircraft almost exclusively for the last year. I have a bunch of (small) patches and fixes here and there. You might want to give my fork a try too: https://github.com/adriansr/737-800YV

I still have to find what causes it's sluggish performance (low frame rate). I've made some decent improvements (not commited yet), but there's something that causes the simulation performance to decay with time. It pauses every second for ~0.1s after 2-3h of flight, and about 0.2s after 5-6h which is annoying.
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Re: 737 Decent flying

Postby tdammers » Tue Jan 14, 2020 12:04 pm

Sounds like a resource leak, either a memory leak, or, more likely, a concurrency leak (long-running asynchronous tasks being forked off and never terminating).

Anyway, yes, it's a lovely aircraft; only reason I don't fly it much is because my computer can't currently handle it (intel graphics on a fairly old mobile i5); I have new hardware incoming though, so I expect to fly it more. It seems that if you can get consistently flyable frame rates, it'll be easier to fly than my go-to aircraft, the CRJ700/900/1000 (and also comes with proper autothrottle, autoland, FLCH mode, etc.).
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Re: 737 Decent flying

Postby asr » Wed Jan 15, 2020 5:27 pm

tdammers wrote in Tue Jan 14, 2020 12:04 pm:Sounds like a resource leak, either a memory leak, or, more likely, a concurrency leak (long-running asynchronous tasks being forked off and never terminating).

Anyway, yes, it's a lovely aircraft; only reason I don't fly it much is because my computer can't currently handle it (intel graphics on a fairly old mobile i5); I have new hardware incoming though, so I expect to fly it more. It seems that if you can get consistently flyable frame rates, it'll be easier to fly than my go-to aircraft, the CRJ700/900/1000 (and also comes with proper autothrottle, autoland, FLCH mode, etc.).


Yes, it feels like a Nasal/timers issue, I'm still investigating. If I manage to fix it I will publish the fix and contribute it upstream. FYI, my system is a 2013 Macbook retina, also an i5 with intel graphics. I get 20-30 fps at first and it decays to 10-15 fps after a few hours.

Also, by any chance have you tried the IDG-MD-11? It's systems are more complete, looks nicer and flies good too. Also it has much better performance. I don't fly it much because I keep having issues with the autopilot, maybe I don't understand its logic completely. Too bad development has been discontinued.
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Re: 737 Decent flying

Postby tdammers » Thu Jan 16, 2020 11:44 am

Haven't tried the MD-11, but my new computer is now complete, so I'm going to give a bunch of beefier aircraft a spin now. This machine should be able to handle quit a bit.
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Re: 737 Decent flying

Postby V12 » Thu Jan 16, 2020 4:04 pm

FPS decay is problem of the many models in the sim. Some months ago i forgot running fg with UFO hovering over LOWI circa 16 hours, after that time FG was almost unresponsive with 1 fps, 16GB memory full, additional 32 GB swap almost full too. If I'm remember correctly, it was FG 2018.3.something.
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Re: 737 Decent flying

Postby Thorsten » Thu Jan 16, 2020 7:58 pm

FPS decay is problem of the many models in the sim.


Funny - the simple ufo kills you off after 16 hours and people manage to do missions of a few days with the waaay more complex Shuttle? Fancy that.
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Re: 737 Decent flying

Postby abassign » Fri Jan 17, 2020 1:31 pm

V12 wrote in Thu Jan 16, 2020 4:04 pm:FPS decay is problem of the many models in the sim.


I would be curious to know which os you are using, memory and if you use swap space. An important thing that I notice with the G91R1B: if you have a google browser open, in Linux, I observe an immediate slowdown of the frame rate by 30-50% depending on the number of panels open in the browser. Current browsers are real memory, CPU and GPU killers. Check if you close the browser the frame rate increases.
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Re: 737 Decent flying

Postby V12 » Fri Jan 17, 2020 6:23 pm

It was on Lubuntu 18.04, FG2018.3.something. Dual boot with Win7.
GPU 2GB GTX750 Ti, CPU i5 2550K on stock frequency, 16 GB 1333 MHZ RAM, 500 GB SATA mechanical drive (not SDD). ALS render, all shaders except clouds (i really dislike cartoon rendered clouds)on max. LOD 10,20,270. AW active with all functions ON, max. visibility limit 250 km. No OSM features, only autogen tweaked with random building density 10, vegetation density high without shadows (on my LUbuntu shadows doesn't work, on Win 10 yes).
I hope, it is all about cfg, my last serious flight in FG2019.1.2 was 2 months ago, in FG2018.3.X 7 or 8 months ago.

I never observed fps drop with FireFox.
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Re: 737 Decent flying

Postby Thorsten » Fri Jan 17, 2020 6:37 pm

i really dislike cartoon rendered clouds


And I really dislike people who do nothing but complain all the time - still not happy enough with FSX, are you?
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Re: 737 Decent flying

Postby asr » Sun Jan 19, 2020 10:28 am

Thorsten wrote in Thu Jan 16, 2020 7:58 pm:
FPS decay is problem of the many models in the sim.


Funny - the simple ufo kills you off after 16 hours and people manage to do missions of a few days with the waaay more complex Shuttle? Fancy that.


Maybe you can help a little with the problem I'm trying to resolve.

The issue is that the sim works fine the first hour or so, as (sim) time passes there is one frame every two seconds that takes longer and longer. I monitor "max-frame-latency" and it starts at 30/60ms (depending on plane) and keeps rising to 150-200ms and more, which is not such a big deal when flying on the A/P but makes really annoying to fly a manual approach after a long flight because the sim "sticks" for this fraction of a second every 2 secs.

Originally I though it was a 737-800YV problem (is nasal-heavy and the code is pretty convoluted in some areas, also a WIP). But then I tested two more planes, the 707 which I had flown for hours many times in the past, and the aero-commander (Yasim).

The commander doesn't seem to exhibit this problem, not at least at a noticeable rate (I used time-compression and refill tanks to keep in the air for 8h.

The 707 does show the same problem but at a slower rate (it takes longer for this latency to increase to a noticeable rate). It's a less nasal-heavy aircraft and better optimised.

I have the feeling that it's related to some leak in nasal, I have gone through all the diagnostics here and in the wiki to no avail. I have reviewed the nasal code plenty of times but didn't find anything that could account for a leak. All timers and listeners are created in the global scope, I didn't find a function that could be spawning more timers or listeners by mistake.

Also in the 737 I tried to selectively disable nasal scripts. With a minimal subset of them, the problem doesn't appear or is not noticeable after 5h (also the avg fps is much better). But then as I slowly re-add the disabled nasal scripts, the problem appears and there is no individual script that could be blamed.

Now I want to build fgfs with some added debug info, mainly # of listeners installed and # of timers, but this is going to take a while.

Also the perf monitor shows plenty of hits for the events subsys, and it was running coupled with model-hz(120). I altered some listeners so that now it acts just once a frame but that didn't make the problem disappear. One thing to note is that the std.dev. column shows a high deviation value for events, 30ms or so, while others are sub-millisecond.
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Re: 737 Decent flying

Postby wkitty42 » Sun Jan 19, 2020 6:14 pm

what version of FG, please? full version including year, please...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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