RE: Classic pattern for .20 cu.in
 

I have the Tweedy Bird, if that's what you're referring to. PM me your email address and I'll send you a full-size copy.

David

RE: Classic pattern for .20 cu.in
 

The Tweedy Bird seems to be exact downscaled copy of DB, isn´t it?

RE: Classic pattern for .20 cu.in
 

Rainedave. I am amazed at your collection of plans. I bet you find it hard to choose which plane to start next after you finish one.

I recently started to redraw my plans in CAD. I was wondering what you use to draw your plans and do you use any addins for tracing them? I've been using Autocad 2006 with an addin called Cadraster. Cadraster is similer to the new Autodesk Raster Design but works with older versions of Acad. Really cool as it allows you to import tif files directly in to autocad.

RE: Classic pattern for .20 cu.in
 

Roguedog, I bounce back and forth between Autocad R14 and Deltacad. Both let you import raster images like jpg's.

I trace the imported raster images on a new layer and I almost always make changes to the internal structures to simplify and lighten the models. Some of the older designs - especially from the '60s - are ridiculously over-complicated inside.

You'll notice that the Tweedy Bird - being a set of kit plans - doesn't include the ribs. I traced the root in cad, exported the dwg into a dat file, and imported that into Profili. It sounds complicated, but only took about fifteen minutes. I now have a set of rib templates for the plans.

David

RE: Classic pattern for .20 cu.in
 

Way cool. I've been collecting MK plans and just about every one only has the wing root and Rib W-4. No other rib or former templates. Bummer.

I've been creating ribs by using the Fuse's side view of the wing root as well , then subtracting 3/32 for the skin. The tough part is gettin the the right height of the rib at the wing tip. Since I don't have Profili I copy the root and scale it down to the length of the tip rib than loft the two together to get a 3D version of one side of the wing. At this point I add 3/32" 3d rectangles thru the wing then use the interfere comand to get the ribs. I guess it's the long way around, but I get a 3d verison of the ribs then use the Explode command to get a 2d for laser cutting.

RE: Classic pattern for .20 cu.in
 

Wow!! That is very nice work Roguedog. It's Classic in the New Age!


DM

RE: Classic pattern for .20 cu.in
 

Yep, not having the tip rib is tough. So many designs used thinner airfoils at the tip.

Like Aurora_60 said, that is definitely the traditional way done digitally. I don't miss lofting airfoils by hand on drafting paper.

The biggest problem with Profili are the dxf files it generates. They always have several hundred points (it seems) along the ribs' surfaces. This is way to expensive to send to my laser cutter, not to mention the wood gets burned a lot more. So, I use a three-point-arc tool to re-trace Profili ribs to make cut files. I can get them down to around twenty or so points per surface using that tool.

Here's a screenshot showing a rib I traced with the 3-point arc tool on top and a Profili rib under it. Since laser cutters typically charge for the time the laser is turned on, you can see how much more expensive the bottom rib would be to cut.

David

RE: Classic pattern for .20 cu.in
 

Boy I wish I still had my original tweety bird....

OS 25FSR.... just a nice combination.

I had another kit for the longest time, and wanted to put retracts in it. Languished until I could find the very rare IM .20 size retracts. I never did.

I guess I should have just built it. I sold is about 2 house-moves ago.

Ironically some good .20 size retracts exist today.

RE: Classic pattern for .20 cu.in
 

Maybe we will get lucky and someone will kit it again for us. Maybe...


Ed Cregger

RE: Classic pattern for .20 cu.in
 

Well, if there is enough interest. There are actually very few parts to laser cut. What would run the price up would be one-piece fuse sides. They are about 37 1/2" long, so 40" or 48" balsa would have to be used. That jacks up the laser cutting cost and the shipping cost, too. If people don't mind splicing together a two-piece side, or, simply cutting their own sides out of their own stock, a short kit could be made pretty cheap.

David

RE: Classic pattern for .20 cu.in
 

Hi David... I forgot to tell you thanks!!

RE: Classic pattern for .20 cu.in
 

I was talking with Roguedog yesterday about your cad work Dave. It is really something to have you in this forum sharing your talents. Thanks also! :D


DM