A tool for JSBsim Airfoil Modelling

[bomber]

oh blimey...I'll have a look at it.

Does your fuel system work... it seems a very complex system.

Been watching xfoil tutorials....got sucked into watching xflr5 vids as well..

[IAHM-COL]

oh blimey...I'll have a look at it.

Good.
If ran in trouble, post here

Baseline you will need python 3 with modules matplotlib numpy and scipy

https://www.python.org/downloads/
https://matplotlib.org/users/installing.html
https://numpy.org/install/
https://www.scipy.org/install.html

And then our code

BTW, if you use the pip installs it is usually painless

[IAHM-COL]

Does your fuel system work... it seems a very complex system.

I'm testing, so far so good

It's a very complex way of doing a very simple thing I guess.

The plane has 2 wing tanks that feed two collector tanks, one per engine.
But also, for gained range (up to 4600 nm -- which is mind blowing for a plane her size) it carries extra auxiliary tanks.

The plane carries two pumps one for each wing tank feeding the collectors, from where fuel is injected to the engines.

In normal operation, the plane cross feeds the wing tanks from the auxiliary tanks. I have it emptying these at a given order; trying to keep balance throughout. Crossfeeding also implies that both wings feed the injectors. There's a knob in the plane that cancels the Xfeed of wing or right tank when there is a unilateral fuel imbalance you can use that.

in case of a AC electrical reduction the plane automatically switches tot eh AC Pumps 1 and 2. This cancels all crosfeeding. Now the fuel goes from left wing to left collector to injector, and Right likewise (unless the knobs for AC are in OFF).

Finally, there is a DC pump. This one works if there no AC electrical power. ie, it feed the APU from the right wing only, or it feeds both left and right collectors from right wing only. If you get here on midflight, your life is already stressful on other levels, not only fuel.

The xfeed and pumps are what's currently simulated in that code.
Electrical is very rudimentary still on the plane, so I need to learn howto make these systems before thinking electrical.

Other things on fuel systems still to be made: ie, the fuel does not have temperature yet. Trying to figure out how to calculate that. I was thinking it might be related to external temp, and oil temperature. But oil does not have temperature yet either. so that's that. Stuck duck.

Other things on the fuel systems still to be made relates to rework the eicas announcements data.

[123apple]

> ie, the fuel does not have temperature yet. Trying to figure out how to calculate that. I was thinking it might be related to external temp, and oil temperature.

JSBSIm has its own temperature simulation based on the area of the tank and true air temperature.

It is output to /consumables/fuel/tank[i]/temperature_degC

[IAHM-COL]

/consumables/fuel/tank[i]/temperature_degC

I dont have those

[bomber]

[Edit]
Another question comes to mind, also; how is this method comparing to the current bechmark (aka autocad?)
[/Edit]

To answer this I've produced this spreadsheet... the Copy sheets are the previous results...

https://docs.google.com/spreadsheets/d/ ... sp=sharing

If you scroll down on a sheet and scroll down on the corresponding sheet, you can flick between the two and get an idea of the differences
I wasn't expecting a lot of differences, but there are some and how this effects the flight performance is any mans guess.

regards

Simon

[IAHM-COL]

What I see is that in some more advanced stations there is some lift deprivation with the new airfoil shapes that are more pronounced than with autocads, but no a great effect on drag.

[ie at station3]


Would some of these differences raise an immediate flag for you, or is more like test on perfomance and see?

[bomber]

Most of the differences seem to be post stall... at this point in time things are happening very fast, you're passing through these AoA on the way to either greater AoA's and a deeper stall or the opposite and recovering... So it's not like you're 'flying' in these AoA.

I don't have any problems with the results, in fact they may add more spice to the stall regime and any resulting spin.

Simon

[123apple]

I think you need to init it in tank definition like so:


<temperature>50</temperature>

[IAHM-COL]

what value is that 50 about?
and if JSbsim calculates it, why does it need additional initializing?
I'll will try that, thou.