Airfoil in cylindrical coordinates 1

[insideman]

I am using Acad 2006. I need to plot airfoils in cylindrical coordinates so several sectons at different radii can be combined into a fan blade. All insights gratefully accepted!

 

[chicopee]

This is going to be tough. Assuming that you have your X,Y and Z values for each section, I would line up these section on a common axis parallel to the Z axis,then use the surface 3D mesh command. I never used the 3D mesh command but from reading the help section, it seems to be the way to go. I am quiet certain that you can not invoke the solid draw commands w/ ACAD 2006 to do what you want. Now just to give an idea what I did w/ACAD 2000 a few years back, I combined it w/Mechanical desktop to draw a solid spiral bevel gear.

 

[insideman]

Thanks Chicopee. I have r, theta, z, not x,y,z. Will try it!

 

[insideman]

Sorry-No joy. 3d mesh seemingly won't work. And niether will anything else. HELP!

 

[CarlB]

I would write a formula in Excel to give you x,y coordinates (relative to 0,0). You can paste these x,y coordiantes in to AutoCAD command prompt for polyline coordinates. This would give you the different outlines. I assume you have sections at intervals. After they're in AutoCAD assign a z value to the polylines to represent separation of the sections. Or you could assign the z in Excel, then draw 3dpolylines in AutoCAD.

After sections are drawn, use something like "ruled surface" to create a mesh of entire airfoil.

 

[insideman]

Hi CarlB: I'm not sure why you suggest xyz coordinates rather than r theta z. Please clarify.

 

[CarlB]

You can enter cylindrical coordinates directly into AutoCAD, but would be tedious and error-prone. Entering it in Excel is a much easier interface and allows checking. From AutoCAD help for cylindrical coordinates:
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To enter cylindrical coordinates

At a prompt for a point, enter the coordinate values using the following format:

x<[angle from X axis],z

X represents the distance from the UCS origin (0,0,0)
Angle from X axis represents the angle from the X axis in the XY plane.
Z represents the distance from the origin (0,0,0) along the Z axis.
For example, 4<60,2 represents a location that is 4 units along the X axis from the UCS origin measured at 60 degrees from the positive X axis and at 2 units in the positive Z direction.
-----------------------------------------------------

To omit the x-y conversion formula-writing step you could enter data in Excel and get it into the AutoCAD cylindrical format. Start the 3d polylines in AutoCAD, then paste in the Excel data.

If in Excel you have columns of radius, angle, and z in columns A -- C, then formula to create AutoCAD ready input would be"

=A1&"<"&B1&","&C1