Unwrapping a conic loft airfoil section...

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LVAeronautics
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Re: Unwrapping a conic loft airfoil section...

Post by LVAeronautics »

edwilliams16 wrote: Fri Dec 02, 2022 4:40 pm We cant follow your procedure without the dat file. Please upload or paste it between code tags.
Did you try my python?

Code: Select all

 2D Upper
 1.0000000     0.0000499
 0.9889011     0.0007737
 0.9692493     0.0025317
 0.9472183     0.0051842
 0.9237276     0.0086856
 0.8992380     0.0128973
 0.8739591     0.0176007
 0.8482614     0.0225868
 0.8223521     0.0277711
 0.7962421     0.0330979
 0.7700260     0.0384812
 0.7438704     0.0438239
 0.7178489     0.0490538
 0.6919526     0.0541288
 0.6661887     0.0590081
 0.6405620     0.0636455
 0.6150537     0.0680008
 0.5896590     0.0720417
 0.5644285     0.0757211
 0.5393918     0.0789737
 0.5145263     0.0817448
 0.4897933     0.0839896
 0.4651169     0.0856810
 0.4404324     0.0868147
 0.4156889     0.0873940
 0.3908392     0.0874370
 0.3658379     0.0869730
 0.3406982     0.0860496
 0.3155138     0.0846971
 0.2903578     0.0829215
 0.2652820     0.0807180
 0.2403108     0.0780718
 0.2154435     0.0749763
 0.1907819     0.0714412
 0.1664829     0.0674364
 0.1425823     0.0628996
 0.1191378     0.0578379
 0.0967390     0.0523932
 0.0762947     0.0466640
 0.0584915     0.0407860
 0.0437645     0.0351875
 0.0322803     0.0302786
 0.0235843     0.0260842
 0.0169405     0.0224068
 0.0117680     0.0190584
 0.0077300     0.0158571
 0.0046926     0.0126226
 0.0025868     0.0093087
 0.0012164     0.0060394
 0.0003284     0.0029366
-0.0000000     0.0000000
[code]
"Testing leads to Failure, and Failure leads to Understanding" -Burt Rutan
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LVAeronautics
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Re: Unwrapping a conic loft airfoil section...

Post by LVAeronautics »

Here is the second airfoil:

Code: Select all

3D Upper
 1.0000000     0.0000499
 0.9889995     0.0007404
 0.9693932     0.0024287
 0.9473703     0.0049834
 0.9239067     0.0083568
 0.8994827     0.0124114
 0.8743041     0.0169357
 0.8487331     0.0217286
 0.8229687     0.0267119
 0.7970129     0.0318344
 0.7709456     0.0370162
 0.7449276     0.0421646
 0.7190371     0.0472093
 0.6932648     0.0521100
 0.6676166     0.0568283
 0.6420980     0.0613203
 0.6166916     0.0655473
 0.5913890     0.0694785
 0.5662351     0.0730712
 0.5412614     0.0762646
 0.5164502     0.0790057
 0.4917702     0.0812504
 0.4671515     0.0829700
 0.4425370     0.0841592
 0.4178946     0.0848162
 0.3931822     0.0849474
 0.3683252     0.0845748
 0.3433110     0.0837504
 0.3182431     0.0825107
 0.2932002     0.0808602
 0.2682274     0.0787945
 0.2433501     0.0763003
 0.2185655     0.0733703
 0.1939563     0.0700121
 0.1696732     0.0662027
 0.1457645     0.0618816
 0.1222525     0.0570373
 0.0996253     0.0517826
 0.0787429     0.0462043
 0.0603394     0.0404098
 0.0450748     0.0348463
 0.0332084     0.0299686
 0.0242379     0.0257987
 0.0174041     0.0221464
 0.0121054     0.0188310
 0.0079789     0.0156709
 0.0048686     0.0124828
 0.0026903     0.0092167
 0.0012559     0.0059884
 0.0003347     0.0029147
-0.0000000     0.0000000
[code]
"Testing leads to Failure, and Failure leads to Understanding" -Burt Rutan
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LVAeronautics
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Re: Unwrapping a conic loft airfoil section...

Post by LVAeronautics »

@edwilliams16 I am going to try the Python code you sent me...but want to learn some basics before I give it a go. In short, I separated the airfoil coordinates between the upper and lower surfaces. Then, once converted from a wire to a sketch file, I removed the line connecting leading to trailing edge, converted back to a wire, then wire to b-spline.

We are doing a validation test right now, making a sample wing section out of the plotted unwrap and airfoils and assembling them. All the measurements match up; we're about to assemble it.
"Testing leads to Failure, and Failure leads to Understanding" -Burt Rutan
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Re: Unwrapping a conic loft airfoil section...

Post by LVAeronautics »

I think we got it, gents!
Centerbody Lower.jpg
Centerbody Lower.jpg (41.96 KiB) Viewed 640 times
Ended up creating my first macro to help speed up the initial scaling process, but bottom line is that I can now loft & unwrap each individual section without complications...and if fate would have it, I have that leading edge split line! What you see in the screen grab took about 20 minutes to do.

The light finally clicked on! Thanks @hammax and @edwilliams16 for your assistance!!
"Testing leads to Failure, and Failure leads to Understanding" -Burt Rutan
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Re: Unwrapping a conic loft airfoil section...

Post by hammax »

... some further experiments with a redrawn Sketcher-BSpline profile. Length 100
Trying to reproduce the mean camber line.
When scaling I noted for the first time, that the "weight circles" are dimensionless.

FlyWing_4.png
FlyWing_4.png (25.41 KiB) Viewed 576 times
Attachments
NACA653218_H_0.FCStd
FC.20.1
(26.45 KiB) Downloaded 10 times
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Re: Unwrapping a conic loft airfoil section...

Post by edwilliams16 »

@hammax

In your NACA653218_H file how did you get Sketch_up from BSpline_up? Did you fit by eyeball, or did you use tools? The resulting BSpline has many fewer knots.
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Re: Unwrapping a conic loft airfoil section...

Post by hammax »

... fitting by eyeball (overlay).
Creating a knotless BSpline from a straight line by converting it to BSpline and inserting control points.
Position control_points (LE and TE) and pull and manipulate their weight_circles.
Fixing it all by constraints and dimensioning.
The gag is how the dimensionless diameter of weight_circles controls curvature => playing with it.
Result is a clonable => 2axes scalable and smooth profile.
Angle of Attack by placement.
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Re: Unwrapping a conic loft airfoil section...

Post by edwilliams16 »

Took me some fiddling, but it works well.
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Re: Unwrapping a conic loft airfoil section...

Post by LVAeronautics »

Great stuff, all. Thank you once again for the input!!
"Testing leads to Failure, and Failure leads to Understanding" -Burt Rutan
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