Best practice: fuselage + wing

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soaring
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Re: Best practice: fuselage + wing

Postby soaring » Wed Jan 02, 2019 2:26 pm

heu...can someone help me, i have a dummy question...

1) i watched the microelly test video of gordon surface : https://www.youtube.com/watch?v=GVai3IXQxc0
2) i understand design conception through this video (not freecad) : https://www.youtube.com/watch?v=BQo34zlWx5I

But, bassicaly...i dont know howto create de surface structure in the first video :-( i know how to design sketch on plan (XY) but i dont know how to link sketchs which are not on the same plan. in this videos, it seems there are several bsplines lined linked each other on different plans, i don't know how...could explain me ?

Thank you for your support !
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hammax
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Re: Best practice: fuselage + wing

Postby hammax » Wed Jan 02, 2019 4:12 pm

… we have cold and ugly weather here - best place in front of a PC.
My minimalistic quick and dirty trial to model a streamlined body.
Most pity is, that there is still no possibility to set visible and parametric points in sketcher for snapping.
Also knot points in BSpline are unconstrainable and therefore useless ( I delete them if possible).
Coincidences of frames to stringers are mostly "aimed" visually. Gordon is rather tolerant.
Only the outer edges must be exactly joined.

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soaring
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Re: Best practice: fuselage + wing

Postby soaring » Wed Jan 02, 2019 9:49 pm

Sincerly, thank you, i've got a lot too learn, but i've just done my first Gordon successfully !!! :-) So HAPPY !!!!!
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hammax
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Re: Best practice: fuselage + wing

Postby hammax » Mon Jan 07, 2019 12:11 pm

… recently I lamented, that there are no visible and parametric snap points in the SketcherWB.
But there is a possible workaround when using the tool to convert lines into splines.
Out of them you can compose multiple constrained and closed frames with great variability.

Periodic BSpline has a flaw with the "disoriented" Seedpoint.
A BSpline "closed by constraints" has only one visible seedpoint.
But a composed chain of BSplines has as much points as you like.
It's more complex, but worth experimenting with it.

Edit: Gordon does not like the composed BSpline frame. It must be converted to Approximation_Curve (SmoothingAlgo) .
But with loft it works good and has a lot of seedpoint lines.
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hammax
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Re: Best practice: fuselage + wing

Postby hammax » Tue Jan 15, 2019 6:25 am

… concerning CurvesWB: https://forum.freecadweb.org/viewtopic. ... 30#p280130
Not only aeroplane designers are happy about Gordon Surface, there are other "flying vehicles".
Lately I saw a picture of snow kiters and their "sails". The kite surfers do it also on water (fluid).
They have special kites with inflated tubes as leading edge and ribs,
stabilizing the airfoil and preventing sinking.
To model such kind of paraglider gordon surface works well.
The shape is done by combined_projection_curves and some rib sketches.
The leading edge needs a splitting or a new construction to get 4 outer gordon edges.
Its done either by Split_Curve or by Discretize_Edge and reconstruction via Interpolation_Curve.
The basic master model is small, but when gordon and sweeps are included it gets over 1 MB.
https://forum.freecadweb.org/viewtopic.php?f=24&t=13497
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soaring
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Re: Best practice: fuselage + wing

Postby soaring » Fri Jan 18, 2019 10:21 am

Sure ! thank you for reference, i will update the index. I'm feeling some WB (air wing desig / paraglider can share some approach).
seems also glider workbench is still active, need to take time to see features deeply :-)

Split_Curve, Discretize_Edge and reconstruction via Interpolation_Curve => are they python functions wrapped around OCC functions ?
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hammax
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Re: Best practice: fuselage + wing

Postby hammax » Wed Feb 13, 2019 6:10 am

… here is a brilliant example for the usage of CurvesWB and Combined_Projection_Curves:
https://forum.freecadweb.org/viewtopic. ... 10#p284596
soaring
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Re: Best practice: fuselage + wing

Postby soaring » Thu Feb 14, 2019 1:46 pm

Thank you hammax, i've just posted an "hello" on their thread and offer to work together in the learning curve, very closed.

i miss some time currently but will continue my tests / forum thread / documation, asap.

Thank you again !

i will add the link to the index
soaring
Posts: 38
Joined: Sat Dec 31, 2016 10:27 pm

Re: Best practice: fuselage + wing

Postby soaring » Thu Feb 21, 2019 3:30 pm

work in progress in the curvesWB thread, new tool that can help us a lot : "The editable interpolation curve tool" : https://forum.freecadweb.org/viewtopic. ... &start=310

i'm gonna try to play with it...