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JSBSim: searching air-to-fuel-ratio property

Postby benih » Sat Sep 08, 2018 4:41 pm

Hello, i'm in search for a property hat reports the current air-to-fuel-ratio but couldn't find one.

Had somebody found something like that? If no, how can i calculate this correctly?
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Re: JSBSim: searching air-to-fuel-ratio property

Postby Megaf » Sat Sep 08, 2018 11:42 pm

Hi mate, hows things?
Why don't you join us in our Discord server? https://discord.gg/gQuFDRP

A guy there actually asked me to invite you, you can go to channel #aircraft_dev there and talk to other aircraft devs.
Though it'd be very nice if his question was answered here as well!
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Re: JSBSim: searching air-to-fuel-ratio property

Postby benih » Sun Sep 09, 2018 8:35 am

Isn't the official project forum better for documenting?
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Re: JSBSim: searching air-to-fuel-ratio property

Postby wkitty42 » Sun Sep 09, 2018 9:10 am

no, not really... neither is discord because those posts disappear over time... the wiki is really the place for documenting things... there may even be a JSBSim section already...
"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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Re: JSBSim: searching air-to-fuel-ratio property

Postby Thorsten » Sun Sep 09, 2018 10:23 am

The general notion is right though - discussing in small private groups tends to hide knowledge away - whereas it is best spread where as many eyes as possible can see it.

So the fragmentation of discussions isn't a good thing as such.

In the event, the reason you don't see answers is likely that the JSBSim developers rarely visit here at all... they know the engine model best.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby Alant » Sun Sep 09, 2018 3:51 pm

The JSBSim piston engine model is described here http://jsbsim.sourceforge.net/JSBSim/cl ... iston.html.
It uses equivalence ratio instead of Air fuel ratio (AFR) . See this for an explanation of equivalence ratio https://x-engineer.org/automotive-engin ... rformance/

The code is well commented src/FDM/JSBSim/models/propulsion/FGPiston.cpp and FGPiston.h.

If you ask on the JSBSim email list you may be able to persuade one of the developers to expose AFR to the property tree. I could do this on your behalf should you wish. If so, please let me know why you need it.

FGPiston.cpp does have code to calculate AFR, but this is commented out. It looks as if it was only used foe debugging purposes when the module was written.

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Re: JSBSim: searching air-to-fuel-ratio property

Postby benih » Sun Sep 09, 2018 8:10 pm

I would want to use the property to show exhaust smoke when there is incomplete combustion due too rich mixture.
It would be nice if you could ask, since i think this property could be useful otherwise too.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby Alant » Sun Sep 09, 2018 8:49 pm

I have sent them this, and will keep you informed:-

Is it possible to expose air-fuel ratio to the property tree?
A user on the FG forum (viewtopic.php?f=66&t=34762&p=336225#p336225) wants this so that he can trigger exhaust smoke with an over-rich mixture.
Thanks

Alan
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Re: JSBSim: searching air-to-fuel-ratio property

Postby swampthing » Sun Sep 09, 2018 11:48 pm

Nothing is hidden when anyone can join. We also have separate servers for FDM, 3D etc so things don't get so lost up the line in chatter of the bigger server so serious people wanting to learn to develop and people who are developing can ask questions to very experienced developers. I agree the wiki pages are good but if you have a question about something on the wiki page that confuses you it doesn't talk back but the wiki pages are sighted for some questions. The thing about searching on your own as a new user in the wiki pages, it can be hard for new users to find and navigate. If you have people that know just which link to send them it can be sent by people that know off of the top of their head then as they get more familiar with how the FG world works they can take off on their own. Why reinvent the wheel? If they have further question they can ask. We can drag and drop files back and forth so its a pretty good environment to work in. The general FG server is more for people just wanting to fly, create events (that IMO should be also posted on the forum) and talk about the planes planes. Once we hit a certain number of users we realised we needed to make separate servers regarding different aspects of development that can then be broken down into channels. Its not a competition between the forum and Discord, its just a matter of how you like to work. Why not ask on both and see which answer suites you best? There may be someone who can answer the question on the forum that we don't have a good answer for on discord or there maybe be someone who can answer the question that doesn't get answered on the forum. Its really not a big deal.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby Thorsten » Mon Sep 10, 2018 5:17 am

Nothing is hidden when anyone can join.


It may not be hidden in theory and intention, but in practice people will not visit two dozen different places to get information (the discord thing, issue discussions on devel repositoris on GitHub, SourceForge, the FG and JSBSim mailing lists, this forum, things like the FGUK forum, other national FG forums,,...) to follow discussions even if these two dozen places are openly accessible, so in practice what you do will tend to hide away knowledge.

This actually happens awfully often for my taste - like when I learn here about some long standing bug I could have fixed in two minutes if someone had just told me here, rather than debate the issue elsewhere and find workarounds.

Or vice versa when we send out a note to aircraft developers about a need to take action due to core changes on two or three different channels and then got complaints back that we didn't reach out over channel 12, 13 or 14 as well.

Why reinvent the wheel?


I dunno - you tell me!

Its really not a big deal.


Personally I believe it is for the reasons outlined above. Personally I also believe the separation between mailing list and forum is really bad.

But despite common claims to my 'omnipotence', people rarely do what I believe to be best :D
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Re: JSBSim: searching air-to-fuel-ratio property

Postby benih » Mon Sep 10, 2018 6:29 am

Thank you very much for your support, Alan!

Alant wrote in Sun Sep 09, 2018 8:49 pm:I have sent them this, and will keep you informed:-

Is it possible to expose air-fuel ratio to the property tree?
A user on the FG forum (viewtopic.php?f=66&t=34762&p=336225#p336225) wants this so that he can trigger exhaust smoke with an over-rich mixture.
Thanks

Alan
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Re: JSBSim: searching air-to-fuel-ratio property

Postby swampthing » Mon Sep 10, 2018 6:34 am

Thorsten we really aren't going to go here again are we? The quotes and all? This could possibly the be the reason people move to a different place to talk. Nothing I said should have gotten your panties in a wad so take a breath and chill. The problem is here it seems people can't even talk. I thought it was getting better but maybe not. I also don't remember talking about 2 dozen places but if you think they won't visit the places I've mentioned its funny that they are. If you think that nothing Flightgear related should be talked about other than 2 places your quite full of yourself. Get over it man. Could it be that the constant argumentative nature is what runs people off? Never mind, we've beat this dead horse before. No point in even trying.
Last edited by swampthing on Mon Sep 10, 2018 6:40 am, edited 1 time in total.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby Thorsten » Mon Sep 10, 2018 6:39 am

Look, I tell people of an issue I believe to be relevant - dividing up discussion into a dozen place tends to hide information.

You can look into my past forum posts that I have said the same thing about forum and mailing list over and over for years. If you opt to take this personally and 'go here again' or if you believe we can't talk because my opinion differs from yours, you have to 'go here' alone - I'm not interested. If you're really only interested in talking to people who share your opinion, I fear you need a place elsewhere, sorry.

There's no disrespect or unfriendliness intended from my side - I see an actual problem here (which is not specific to you). Is that so different to accept for you when I say that?

Ideally, some problems are best dealt by the people who wrote the relevant code. The fact of the matter is that all too often they never learn of this and hence never deal with it - so we keep accumulating workarounds, patch-ups etc. Not a good thing.
Last edited by Thorsten on Mon Sep 10, 2018 6:42 am, edited 1 time in total.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby swampthing » Mon Sep 10, 2018 6:41 am

I thought I made a reasoble friendly post. you took it to a whole other level as usual.
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Re: JSBSim: searching air-to-fuel-ratio property

Postby swampthing » Mon Sep 10, 2018 6:43 am

You say things and you don't even know who your disrespecting at the same time. I'm not going to drop names but please stop.
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