http://i160.photobucket.com/albums/t190/webchameleon/12-16-20091-50-14PM.png

–I can’t find any clear information on how this rotating ring works. I think I might have a pretty good idea, but haven’t written my equation yet. I think all I have to do is take my measurement of the angle the blades use and determine the appropriate arc length of the pivot slides.
–I can’t find any information at all on how the leaves mesh together in the middle w/o one of them being completely on top of the others. My blades are just flat.

I drew the blades in AutoCAD and used some high-precision measurements. After some experimentation I determined that I could make it close completely if I had “an equation to get an angle THETA such that the second circle, when rotated around the point P(0,13.5), intersects the point P(0,0). The radii of the two circles are identical, but not r. r=13.5 and is the distance of the axis of rotation from the origin. The radii of the circles are both 10m.”
…
Confused yet? See here: http://i160.photobucket.com/albums/t190/webchameleon/problem_example.gif

That second circle represents the inner side of a diaphragm leaf. Turned out I was right, but couldn’t prove it. I thank CarlB over at CADforums for assistance in developing an equation (something I usually do myself). He came up with this:

“Look at the triangle formed by the 2 13.50 long sides, the base of that triangle has a length of R. Divide that triangle in half to form 2 right triangles. For that right angle:

sin (a/2)=(R/2)/13.5
a/2=arcsin (R/27)”

If I’d just divided that triangle I drew to make two right triangles, this would have been obvious. Thanks, Carl.

My question to you, Madox, if you don’t mind my asking, is how do these things mesh in the center?

Here’s a crude, optimized 3dsMAX model from the drawing:

http://i160.photobucket.com/albums/t190/webchameleon/12-16-20091-48-37PM.png

Awesome job, big Stargate fan so viewed with great interest.

Design has inspired me to develop a new device for my business, actually would you be interested in doing some design work for us? Your skill set leaves mine for dust on 3D modeling, along with teh rapid prototyping using Shapeways we could get a prototype model going in next to no time. Investors would go nuts!!

Drop me an email if interested.

AJW