Sketching a curve through use of a function 2

[u6s5l]

I would like to sketch a NACA wing profile into NX. The easiest way would be to create a script that uses a function to sketch the curve for me, altering the thickness over a specified length.

ie.

For x=0:0.01:1
y=(0.2969sqrt(x)-0.126x-0.3516x^2 +0.2843x^3-0.1015x^4)
end

I am using NX 7.5.

Thanks for any help or tips,

Matt

 

[cowski]

Have a look at law curves in the help file. They can be a bit tricky to set up, so feel free to post specific questions.

Also there are a few recent threads with models posted using law curves perhaps those will help you get started.

one or more of the models in:
thread561-291246

the compression spring posted by mmauldin in:
thread561-234523
this particular model uses another curve rather than a function to drive the law curve, not directly applicable to your question but a good technique to keep in mind.

 

[JohnRBaker]

Attached is an NX 7.5 part file containing a Law Curve representing an involute sprial. Editing the value of 'r' will control the size (radius) of the involute while 'Turns' will control the number of 'loops' in the spiral.

While this is not an 'airfoil', it is another example which might help you with using Law Curves.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[potrero]

@ u6s5l
If you do make an NX part implementing the NACA 4-digit curve, it'd be a big contribution to post it in this thread.
Thanks in advance.

 

[FrankSwinks]

I have created a journal/program (VB) which creates a studio spline. At this stage it simply creates it at the origin in modeling. If it is suitable I can place it in a sketch. It is also possible to place it at any predefined position and orientation.

Frank Swinkels

 

[u6s5l]

In the help menu it says the "Law Curve is found in
Insert?Curve?Law Curve

However my only Options are:

Insert?Curve?Line
?Arc/Circle
?Lines and Arcs ?
?Helix
?Studio Spline

The examples here show a Helix being made but I don't think this process is comparable to the wing shape I actually need to produce.

Frank

I went into the Journal to edit it the formula is only good from 0-1, so I have to put a multiplier outside the brackets of the formula to achieve my scaling, in this instance it is "120". I'll try and learn more about the programming the journal, and running it, as I think I can see where all the changes need to be made. I need to plot this curve, and it's inverse to get the profile.

I'm curious if the Law curve is standalone in older versions of NX, or is it embedded somewhere else that I can't find. (I'm using NX 7.5)

Thanks,

Matt

 

[u6s5l]

Never mind Frank, I was zoomed out too far, and couldn't see the sketch produced. The program worked perfect!! I just changed the resolution, and put a multiplier to put it to the scale I needed.



(I had missed your division I just saw integer, and the scale of 1 to 100 and commented without understanding the program, I apologize)



Thanks!!
Matt

 

[u6s5l]

NX cannot offset this profile, so is there a way in journal to put a multiplier to scale it up by 120??

 

[u6s5l]

I got it.. I know matlab... so just tried to figure it out from there...

Again thanks for all your help!

 

[FrankSwinks]

Matt

If you want to contact me directly at fsw13678@bigpond.net.au I would be happy to modify the journal to your requirements.

Frank Swinkels

 

[cowski]

The current 'role' you are using will govern what menu choices you see. Try changing to one of the roles with 'full menus' to get the law curve option.

 

[u6s5l]

Cowski,
Yeah, I didn't realize I was on a reduced menu. The option appeared.

FrankSwinks,
I managed to modify your program to work to produce the wing I required also. Thanks a lot!!

Thanks everyone for the input!