Source: 1995 Beartracks, Bob Barrows
Here are a few tips to help you build ribs. I would strongly recommend that you purchase all three (Note there are four Bingelis books now) of Tony Bingelis’ books to help you through the construction of your BEARHAWK. You can order his books from the EAA (or via this link). The EAA also offers VCR tapes and other books that you may find helpful during construction.

BOOKS BY TONY BINGELIS…

• THE SPORTPLANE BUILDER
  
• FIREWALL FORWARD
  
• SPORTPLANE CONSTRUCTION TECHNIQUES
  
• TONY BINGELIS ON ENGINES
  

MARKING TOOL – – –

One of the more useful tools I have is the marking tool guide. The guide is nothing more than a plastic circle of 1/4″ thick material with a 1/4″ hole in the center to fit a marker in. The tool rolls along the edge of the form block as you mark out the proper sized flange. You will need to make two of these guides, one for a 9/16″ flange and one for a 1/2″ flange.

After marking the rib remove it from the form block. Cut out rib blank with large Duck Bill tin snips. Polish all edges smooth.

Hold the above assembly in a large vice and ‘C’ clamp as needed to keep the two blocks together. Lightly tap down flange over rib form block being sure the radius is set. The flange will be wavy. Take your time and work your way around the rib.








After you are finished forming the flange, remove the rib from the form block and set it on a large flat surface. Using your mallet lightly tap the flange over to a 90° angle. Again, take your time and work around the rib.

Flanging Lightening Holes

After forming the rib it is time to cut in the lightening holes and flange them. Using a fly cutter and a drill press cut the proper sized holes in the ribs. You will now use the flanging tool to put a 30° finish angle on the lightening holes. Pull up on the tool and slide around hole 2 – 3 turns until approximately a 30° angle is formed. Wax aluminum as needed for smooth operation of the flanging tool. After forming flange the rib will be slightly warped. To correct this set the rib on two wood blocks with the flange pointing down. Using the butt end of the flanging tool apply pressure to the flange and slide it around to straighten out the rib.