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

> blades out of CARBON FIBER with titanium spar inserts. This is much like

the

> Pratt & Whitney designs i've seen. Carbon Fiber blades are supposed to be
> much moe capable than metal blades.

A little OT, but in some past reading on turbine blades, there was a
reference to the DeHavilland 'Comet''s engines not working properly until
its' carbon fiber blades were replaced with metallic ones. Of course, that
was '50s carbon fiber technology. Turns out engines were the least of its'
worries :)

> I have the root and tip cross sections needed for the blade. The problem
> with autocad is that I cant get them to "connect" and "twist" to make a
> complete blade. The only type of so called blade I can make is a staight
> one. When I do this I just draw the airfoil section and then add thickness
> to it. At this point it looks like a straight blade but its not a solid ,
> its just a polyline with the top and bottom open. This is on Autocad.

A polyline isn't a surface, and as far as I know can't be made one (or a
solid) automatically. What you need to work with are surfaces/solids (You
knew this, probably). You can create surfaces via the sections you have; but
you'll still need to make sure everything 'seals' to get a solid out of your
surfaces. A CAD 'solid' = a set of surfaces whose edges are bounded
completely by other members of the set.

My guess as to your best bet to get from your profile to surface is to
'explode' your polylines, match entity counts between root and tip, rotate
to a viewpoint so you can see both, and surface them. Create a flat surface
at the root and tip; and combine top, bottom, and sides into a solid. ACAD
v13 is where I left the AutoCAD ship - I'm not aware of a solid conversion
function at that revision level... Maybe with the newer versions?

Try searching AutoCAD help files for Solid + conversion + merge + surface +
tutorial

An AutoCAD forum might be better place to get more AutoCAD specific answers
along these lines.

- Keith

----- Original Message -----
From: "Bobby Rastifard" <bobby808@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, July 16, 2002 1:44 PM
Subject: Re: [CAD_CAM_EDM_DRO] Modeling a twisted blade on autocad?? PLease
help!