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rkirk77
06-24-2020, 05:37 AM
I've gone ahead and made my airfoil ( NACA 23012 ) but don't know how to bring it to proper scale.

cwilliamrose
06-24-2020, 06:40 AM
I'm not sure I understand. Did you use the published ordinates for the 23012? Using those you need to multiply by the chord of the wing. The chord (X in the tables below) in the published ordinates is expressed as a percentage 0-100%. The thickness (Y in the tables below) is also expressed as a percentage of the chord. I often use a spreadsheet to do the calcs and make tweaks;

8494

cwilliamrose
06-24-2020, 06:55 AM
If your airfoil was plotted using the straight ordinates you have created an airfoil with a chord of 100(units). If the units are inches and you want a 60" chord you would scale the model to 60%. This can be done using the Insert|Features|Scale.... function in the menus. There are options for that function so make sure you understand it so you get what you need.

vondeliusc
06-25-2020, 11:15 AM
8496

rkirk77-
Very simple: Use Excel and arrange the X coords along Z in SW and the Y coords along Y and set 0 for all the X coords.
You can find most airfoils in this DB: https://m-selig.ae.illinois.edu/ads/coord_database.html


The file format must be a three-column, tab, or space-delimited list of only X, Y, and Z coordinates. Do not include any column headings, such as X, Y, and Z or other extraneous data.
Save it as a .txt or .sldcrv file type.

Use 0 to 1 or 0 to 100 so it should look like this-ish:
0 0 0
0 .25 -.1
0 .375 -.2
0 .4 -.3
...
0 .2 -.9
0 .1 -.95
0 0 -1
This will give you a nice airfoil on the right plane with the nose fwd in the +Z direction
Your actual data from the above site:
NACA 23012 12%
1.00003 0.00126
0.99730 0.00170
0.98914 0.00302
0.97563 0.00518
0.95693 0.00812
0.93324 0.01176
0.90482 0.01602
0.87197 0.02079
0.83506 0.02597
0.79449 0.03145
0.75070 0.03712
0.70417 0.04285
0.65541 0.04854
0.60496 0.05405
0.55335 0.05924
0.50117 0.06397
0.44897 0.06811
0.39733 0.07150
0.34681 0.07402
0.29796 0.07554
0.25131 0.07597
0.20738 0.07524
0.16604 0.07320
0.12732 0.06915
0.09230 0.06265
0.06203 0.05382
0.03730 0.04324
0.01865 0.03176
0.00628 0.02030
0.00015 0.00956
0.00000 0.00000
0.00533 -0.00792
0.01557 -0.01401
0.03029 -0.01870
0.04915 -0.02248
0.07195 -0.02586
0.09868 -0.02922
0.12954 -0.03282
0.16483 -0.03660
0.20483 -0.04016
0.24869 -0.04283
0.29531 -0.04446
0.34418 -0.04510
0.39476 -0.04482
0.44650 -0.04371
0.49883 -0.04188
0.55117 -0.03945
0.60296 -0.03655
0.65360 -0.03327
0.70257 -0.02975
0.74930 -0.02607
0.79330 -0.02235
0.83407 -0.01866
0.87118 -0.01512
0.90420 -0.01180
0.93279 -0.00880
0.95661 -0.00621
0.97543 -0.00410
0.98901 -0.00254
0.99722 -0.00158
0.99997 -0.00126
Which I copy/pasted to notepad and saved.
Then imported to Excel and with a little wizardry becomes:


x0
y
z(x)


0
0.00126
-1.00003


0
0.0017
-0.9973


0
0.00302
-0.98914


0
0.00518
-0.97563


0
0.00812
-0.95693


0
0.01176
-0.93324


0
0.01602
-0.90482


0
0.02079
-0.87197


0
0.02597
-0.83506


0
0.03145
-0.79449


0
0.03712
-0.7507


0
0.04285
-0.70417


0
0.04854
-0.65541


0
0.05405
-0.60496


0
0.05924
-0.55335


0
0.06397
-0.50117


0
0.06811
-0.44897


0
0.0715
-0.39733


0
0.07402
-0.34681


0
0.07554
-0.29796


0
0.07597
-0.25131


0
0.07524
-0.20738


0
0.0732
-0.16604


0
0.06915
-0.12732


0
0.06265
-0.0923


0
0.05382
-0.06203


0
0.04324
-0.0373


0
0.03176
-0.01865


0
0.0203
-0.00628


0
0.00956
-0.00015


0
0
0


0
-0.00792
-0.00533


0
-0.01401
-0.01557


0
-0.0187
-0.03029


0
-0.02248
-0.04915


0
-0.02586
-0.07195


0
-0.02922
-0.09868


0
-0.03282
-0.12954


0
-0.0366
-0.16483


0
-0.04016
-0.20483


0
-0.04283
-0.24869


0
-0.04446
-0.29531


0
-0.0451
-0.34418


0
-0.04482
-0.39476


0
-0.04371
-0.4465


0
-0.04188
-0.49883


0
-0.03945
-0.55117


0
-0.03655
-0.60296


0
-0.03327
-0.6536


0
-0.02975
-0.70257


0
-0.02607
-0.7493


0
-0.02235
-0.7933


0
-0.01866
-0.83407


0
-0.01512
-0.87118


0
-0.0118
-0.9042


0
-0.0088
-0.93279


0
-0.00621
-0.95661


0
-0.0041
-0.97543


0
-0.00254
-0.98901


0
-0.00158
-0.99722


0
-0.00126
-0.99997


Copy paste into notepad and lose the header.
Use the 'Curve through XYZ Points' tool.
Browse for your NACA 23012.sldcrv file you saved from notepad.
Import and you get a nice spline.
Insert a sketch on the R plane and project the imported spline.
Cap with a nice line at the tail.
Now it is 1" long; either scale the sketch or extrude it .1" to a solid,
and then scale the solid.
You can do a root version chord length and a tip version chord length, and
even introduce washout (twist) and then loft for a complex wing including sweep.
Easy peasy.
'-)
-Christian

8496
8497
8498


Part and data files:
8499

vondeliusc
06-25-2020, 11:49 AM
Here is half the 30' span wing with 15 degree sweep, 3 degrees dihedral, and 1.5 degrees washout, 66" root & 22.25" tip.
If you study the assembly, you will see how I did it; tip: study the skeleton: you can change parameters and the model will update.
https://drive.google.com/file/d/19_CI-MX5jCCVtk-4QP3E0fth5ONHqj7A/view?usp=sharing
Pack N'Go Assy ^^
-Christian

FlyingRon
06-25-2020, 12:09 PM
You do understand about Reynolds numbers?

North_roll
06-25-2020, 07:07 PM
I would like to enter into solidworks a rib shape using the XYZ curve tool...ive included the rib shape with dimensions....does the above information apply to this also...Ive tried to enter the dimensions into solidworks manually but I get modern art and not a rib shape...so I~m doing something wrong...is there a good write up on this xyz tool to understand it better. I`m a little baffled how the xyz numbers relate..

Thanks

vondeliusc
06-26-2020, 06:15 AM
North_roll(real name would be nice)-
Normally airfoil data is in terms of 0 to 1 from nose to tail, with the Yu(pper) and Yl(ower) either given as shown,
or with Y +/-.
SolidWorks' convention in general is that [+X is left], [+Y is up], and [+Z if fwd].
So if you look normal to the right plane from the left, the origin is zero, with -Z going right, and +Y is above the Z axis
and -Y is below.
If you specify the nose of the airfoil at Z=0, the TE will be at Z=-1
The Curve through XYZ are cartesian coords with the above SW convention.

Using the tool to draw an airfoil, you specify the Upper TE coord, progressing along the upper camber forward.
In other words: (set X to zero for all coords and disregard)
For the airfoil coordinate pairs: Z starts at -1 and and the corresponding Y values increase from near zero to max upper camber and then Y values decrease to 0 as Z approaches 0 at the nose,
where normally Z and Y=0.
Continuing on around below the nose, Z again moves back toward the tail increasing(?-decreasing) to -1 again,
while Y increases in the negative with a maximum value a maximum lower camber until it approaches near 0 again.
A careful reading (many times?) of the above description and you should understand.

So converting the numbers from the ZA plans, the SW coords are as follows:
(You could imagine those numbers as X,Y on a standard graph from the parentheses),
but they have to be in the order they are below for the Curve thru XYZ to lay on the R Plane.
Also, since your AF is not '1' long, you will start at Z=0 for the front rib rear and end at Z=499 for the front.
In the case of your numbers, assume 499 = '1' for Z

Your Fwd rib becomes:
X Y(vert) Z(horz)


0
-90
0


0
-89.5
100


0
-86
200


0
-77
300


0
-71
350


0
-61.8
400


0
-56
425


0
-49
450


0
0
499


0
49
475


0
71.5
450


0
87.7
425


0
100
400


0
119
350


0
131.2
300


0
144
200


0
147
100


0
148.5
0



Study how the numbers are translated from the plans chart.
After the curve is generated, you must 'project' it on a sketch on the R plane.
For the rear rib:
X= all zero
Plans X=SW Z
Plans Y=SW Y, with upper = positive
and lower = negative
It takes about 1 minute to enter into Excel, but since it is not continuous, you MUST do a separate sldcrv for each curve.
(Don't forget to use a metric template in SW)
So:


Normal X,Y
Y
X

Y
X


SW Y,Z
Y
Z

Y
Z


0
148.5
0
0
-90
0


0
145
-100
0
-89.3
-100


0
137.5
-200
0
-84
-200


0
127
-300
0
-74
-300


0
114
-400
0
-30
-622


0
96.5
-500





0
77
-600





0
72
-622





The section specified as straight appears negligible to me compared to the SW spline.
The SW file is available for study here: https://drive.google.com/file/d/1BG3xljeFubox1Ov_XS0PrlqxM97Hxpdy/view?usp=sharing
You must pay attention to the operation of whether the numbers are positive or negative.
-Christian

North_roll
06-26-2020, 07:32 AM
Thank you for taking the time to explain this ...really demystified it for me....

I'll start playing with numbers using the information you gave me and in the post above you did for the other member..


Thanks
Michael

rkirk77
08-16-2020, 04:24 PM
I think I am having some difficulty with getting the airfoil to scale down so the airfoil has a 63" chord (..or 63% from what i am reading here).

I am trying to make it so I can make a layout for making new ribs for my project and want to be able to mark out where the spars and stringers will be positioned.
I am new to Solidworks, so it's sometimes hard to understand what to do.

rkirk77
08-16-2020, 04:49 PM
8640

vondeliusc
08-17-2020, 12:36 PM
8642
8640
rkirk:
If you review the my post from 06/25, using an 'x' scale of 1 for LE to TE will generate an airfoil 1" long; then you scale it up by a factor of 63 which will make it 63" long LE to TE.
It is unclear where you are lost. Please review my detailed previous posts in this thread and try to duplicate them. There is even a 'pack n'go' of the files to download to step through
the procedure.
-Christian

rkirk77
08-17-2020, 05:18 PM
Hi Christian,

I have reviewed this / your previous post and have read them carefully, and know this is a VERY easy operation to someone like you but I am a blithering idiot when it comes to SW.

How do you use an "x" scale and increase it to 63"?
How do I project the splines?

I am lost and I am sorry if this seems like common sense to you.. but it's CLEARLY NOT for me.

rkirk77
08-17-2020, 05:39 PM
8643UPDATE : I think I've got it.

I am trying to make this so I can print it out and layout my ribs.. any suggestions?

rkirk77
08-17-2020, 05:54 PM
..and this.

86448644

vondeliusc
08-18-2020, 03:33 PM
To print it full scale, create a drawing with the view of the part normal to the rib.
Under 'Sheet Properties' make sure the scale is 1:1
Un-tick Display Sheet Format, and tick Custom Sheet Size: I went 65 x 10.
In the normal view, create a horz line and some vert lines at each segment of some
equal segments; I did 10"; This will give you something to align to and to select for printing.
Save. I also left the 'spar' sketch visible in the part. (My 'spar' rectangles are random for demonstration)
Then select print, under Page Setup, set to 100%.
For Print Range select 'Selection'; a rectangle will pop up and move it to the portion of the airfoil to print.
You will have to do this seven times.
Each sheet will come out perfectly at 100%. Align the sheets with the horz/vert marks and tape together.
See the .jpg; hope that helps. You should sign with your actual name.
-Christian
8645

bigdog
08-20-2020, 07:15 PM
I see you posted an O-57 drawing. If your project is an O-57 or L-2 and you have the drawing CD set, you have enough info to plot the airfoil full size without scaling from the theoretical ordinates. The actual profile may be slightly modified from the NACA profile. The 23000 series typically is modified to remove the cusp. I made a jig for wood ribs from those drawings and it didn't take that long. As you can see, I plotted it directly on the MDF. The shipset of ribs was done in about 6 weeks including creating the jig and all the routing templates for plywood parts.

If you really want to get it in SolidWorks either as an exercise or for further use, consider using the dimensions from the drawings to draw it full size in SW.

86568657

rkirk77
08-21-2020, 05:03 PM
I am still learning the basics of SW and eventually (.. within the next week) I am hoping to have it complete to print out.

PS, my plane is an experimental BC-12 that will have a few more features than the original.