CNC files

[Jflyer]

http://mit.imt.si/Revija/izvodi/mit125/benisa.pdf

Here's a great article describing the rubber forming process including some trial and error experiments making aircrafts parts including wing ribs.

[DRLPatrol]

Thanks for posting that. It would take an engineer to understand it all but I am going to give it a try anyway.
Doug

[Jflyer]

Doug,

Yes, all we need are engineers to chime in and help translate.

The Reader's Digest version of me, after looking at all the pretty pictures, is that we should be able to form the complete rib section including the lightening hole flanges and side flanges in one process, as the sample rib photo displays in the article.

I am planning to build a shop press with either a 40 ton or 50 ton hydraulic bottle jack. I think that should provide enough power. If not, there are 100 ton bottle jacks available as well. This may sound like overkill, but I can build/weld the press for far less than buying one and also build it to the dimensions needed. I already have available to me the 'I' Beam and channel stock needed to complete the press, I will also have plenty of uses for the tool after the ribs.

Other than the rubber form system being way up there on the 'Really Cool' meter, my reasoning for wanting to use it is the ease of use and speed of duplication. This process coupled with the CNC machines should allow me to duplicate the ribs, spars and other items quickly. So 'when' I make a mistake during construction, I'm not spending weeks and months reproducing the damaged items.

[Craig Benbow]

No problem opening the wing spar files. I couldn't get the NACA file to open.

I did a similar air box for hold down. Yes, top board was surfaced (2" planning bit) on both side. Vacuum sucks down through the mdf, just pourous enough to hold a larger sheet in place.

When I went to cut a smaller inspection ring, as you can imagine it did slip.

Don't worry about the NACA file as it is just a plot of the 4412 airfoil scaled to the bearhawk dimensions. Its only there so people can compare the bearhawk airfoil against it and see where Bob "modified" it
Interesting what you guys are doing. Keep it up!