A tool for JSBsim Airfoil Modelling

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IAHM-COL
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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 11:01 am

@Bomber

Sweet.
That's encouraging.

I'm surprised to see that the smoothing by itself had such nice effect on the polars!

Had you tried out the spanwise projectors (like 2_2.csv, or 5_5.csv) to check if/how the shape transformation is making sense too?
In shape and in polars obtained.

Best,
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 11:09 am

does something come to mind about why in the resulting polars, for lift given drag, in the green plot, there is no lift coefficients calculated for drag coefficients about 0.175?
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

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Re: A tool for JSBsim Flight Modelling

Postby bomber » Thu Jun 18, 2020 2:28 pm

IAHM-COL wrote:@Bomber

Had you tried out the spanwise projectors (like 2_2.csv, or 5_5.csv) to check if/how the shape transformation is making sense too?
In shape and in polars obtained.

Best,


If you could redo but for 8 sections only... I'd have a like for like comparison.... but as yours is in split into 10, it makes it a bit different.

regards

Simon
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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Re: A tool for JSBsim Flight Modelling

Postby bomber » Thu Jun 18, 2020 2:30 pm

IAHM-COL wrote:does something come to mind about why in the resulting polars, for lift given drag, in the green plot, there is no lift coefficients calculated for drag coefficients about 0.175?


I'm not sure I understand as I'm not seeing this in the graph

Ah I see what you're saying.... those are plots per AoA
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 3:23 pm

bomber wrote:
If you could redo but for 8 sections only... I'd have a like for like comparison.... but as yours is in split into 10, it makes it a bit different.

regards

Simon


Yes. I can do.
Do you mean every 0.125 evenly?
like

[0,0.125,0.25, .... 1] ?
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

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If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 3:55 pm

bomber wrote:
IAHM-COL wrote:does something come to mind about why in the resulting polars, for lift given drag, in the green plot, there is no lift coefficients calculated for drag coefficients about 0.175?


I'm not sure I understand as I'm not seeing this in the graph

Ah I see what you're saying.... those are plots per AoA


an image is worth 1000+ words
an image with words is worth 1000+words words

Image
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

bomber
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Re: A tool for JSBsim Flight Modelling

Postby bomber » Thu Jun 18, 2020 3:57 pm

I think it's 1/7 for an 8 wing split

0 = root
0.1428571428571429‬
0.2857142857142857
0.4285714285714286‬
0.5714285714285714‬
0.7142857142857143‬
0.8571428571428571‬
1‬ = tip
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 4:06 pm

https://github.com/IAHM-COL/py-JSBsim-g ... src/output

I think this is what we want
the wing is split in even 8 segments
0 = chord
7 = tip
1-6 = internal segments going from low (chord wise) to high (tip wise)

Used this segments proprortions:

Code: Select all

array([0.        , 0.14285714, 0.28571429, 0.42857143, 0.57142857,
       0.71428571, 0.85714286, 1.        ])
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

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Re: A tool for JSBsim Flight Modelling

Postby IAHM-COL » Thu Jun 18, 2020 4:07 pm

bomber wrote:I think it's 1/7 for an 8 wing split



You are exactly right.
I didnt introduce the numbers myself, so even my brain fooled me, the software said, no no,.

It seems we are good now.

See post above
I did not update images or video, as it is not fully necessary for this test.
but csv files are up to date
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

R.M.S.
If we gave everybody in the World free software today, but we failed to teach them about the four freedoms, five years from now, would they still have it?

bomber
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Joined: Mon Nov 30, 2015 3:40 pm

Re: A tool for JSBsim Flight Modelling

Postby bomber » Thu Jun 18, 2020 4:09 pm

and image of the wing within the Autocad file..

the white dims show the dimensions for the centre of each wing section

https://drive.google.com/file/d/11edKmP ... sp=sharing
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell


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