CAD files and other interesting items from the Old Yahoo Group

[Jflyer]

There has been a number of discussions on other threads about CAD files (DXF, DWG, etc.) for the ribs, plates and just about anything that can be produced with CNC machines.

Some of the discussions have referred to the 'Old Yahoo Group' having files listed for all things Bearhawk. I have a CNC router that I've used the Yahoo Group DXF files to test cut the center section and nose ribs, which worked fine. I am also building a larger CNC machine to handle 4 X 12 sheets of aircraft aluminum (and smaller) in order to make all the parts for my Bearhawk build as well as any other homebuilt aircraft that friends are building.

Interestingly enough, all those files are still posted at the 'Old Yahoo Group' and can be downloaded and saved. Not only the CAD files, but everything that had been posted over the years. I've downloaded just about everything from that group to my PC for future use.

The really cool (aviation term) and interesting files are the DXF files for the ribs and the spars, which include the spar plates, strut attach bar and more. They tell a lot and answer a lot of questions. I don't know who originally produced them, but the accuracy seems to be dead on. Any use of these files should be with caution and the builder obviously is responsible to verify the accuracy.

You'll need to sign in with your Yahoo Group particulars, and on the front page under the emotional inspiring photo of Pat Fagan's campsite, click the word 'Files'
Or just use this after you sign in.

https://groups.yahoo.com/neo/groups/Bearhawk/files

All you'll need to view and manipulate these DXF files is a 2-D CAD Software. There is a great free software which is a fully functional 2-D CAD program that is amazingly close to AutoCAD.
It's 'DraftSight' by Dessault Systems. I've had the DraftSight for over two years and works great. Many of the same symbols and functions as AutoCAD. No time limit on it's use

http://www.3ds.com/products-services/draftsight/

[Jflyer]

I have the Yahoo User Group Files in Zipped format. The entire list is too large to post. I should be able to email it as it's 10MB.

The CAD files are attached here.
And to be clear, these are the DXF and DWG files for the 4-Place Bearhawk



YahhooFilesCAD.zip

[Chewie]

How does this software compare to Nanocad?

[X'N]

Others may have experience with Nanocad. I can tell you one thing for sure being draftsight is made by the same company that produces solidworks its a good product but being its free your not going to get all the features that a paid cad program would give you. Personally I use a different CAD/CAM software that i use for my router that was $700, I have on occasion imported my stuff into draftsight because I couldn't accomplish what I wanted to do in my software.

[Chewie]

Is there a way to add vertices to an existing spline?

[Mark Moyle]

Not sure if those are the DXF I generated? If they are....all the parts to be bent have the bend radius calculated for the exact thickness of the plate. I found it easier to cut the parts to be bent wider/longer than required. After bending then shape to the finished specs...also drill the holes after bending. Mark M. Sent from my iPad using Tapatalk HD

[Jflyer]

If you're needing to draw and manipulate 2D Drawings such as the Bearhawk DXF files, the free free version of DraftSight will work great.

[Chewie]

With a week of splicing and dicing, I finally have a rib template DXF. I had to scan the profile in sections and used Gimp to stitch them together, then export to .tif which Draftsight can import. Amazing what you can do with free software! I attached the result. Since this is my master template, I traced to the inside of the profile line - is that what I was supposed to do? The length of that chord line is 64.95 inches.

I've used Autocad for a few years so I found the CAD portion was the easiest part of the process. It's a nice program!

[Jflyer]

That's correct!. I forgot all about that angle and I've used it before as well. You can import/underlay a tif into most cad programs. Then Trace over that tif with your vectors. One trick I use is to zoom in really-really close and place two crossed lines over the tif lines. They look like a plus sign but they're really two intersecting lines. Then use the 'spline' tool and snap to the "intersection". When you zoom out, your airfoil in CAD will be more accurate than is needed using routers to cut it out.

[Deftone]

I know I am digging this subject up from the distant past, but has anyone used the .dxf files to CNC any items? I was talking to someone about CNC today and thought I might get them to knock up a CNC'd MDF form block to compare to my own and possibly use as a beater block.

[Jflyer]

I've CNC'd some rib forms with MDF and test cut the nose rib to a Patrol in aluminum. Everything came out great.