Re: [CAD_CAM_EDM_DRO] Modeling a twisted blade on autocad?? PLease help!

>I was wondering if somebody teach me how to design a twisted blade
>such as a fan blade. I know how to make a straight blade with
>polylines but I cant twist it and make the contours i want.
>
>Could someone teach me?
>
>Thanks.
>
>
>

Jepps

Here is the method that I came up with for twisting a blade. Bear in
mind that it will produce a wireframe and not a solid as ACAD 2000 does
not have a feature to give volume to a edge surf mesh.

Step one.

Draw your root airfoil. in poly line.

Step two.

draw your tip airfoil the proper distance from the root airfoil

step three

rotate your tip airfoil the needed degrees

step four

break your airfoils midchord, do not break at the leading or trailing
edge as the surface mesh will do some interesting things. The end
result needs to be both tip and root airfoils are split at the chordline
and edges joined back together.

step five
create a second layer
put the back half of the root and tip on the second layer
turn the second layer off

step five
type in "surftab1" (this is the command that wiill allows you to tell
the surface patch the number of facets to create in one axis)
follow the promts
ditto for "surftab2"

Step six


make the visable layer current
using lines connect the front halfs of the root and tip airfoils
together.
from the draw menu select edgesurf
follow the promts.

if done correctly you should now have the front half of a twisted blade.

step seven

turn the visible layer off and turn layer 2 on
make the visible layer current

connect the root and tip airfoils
repeat edgesurf
turn layer one back on


at this point you should now have a twisted blade.

all the best
Sean Trost