Bearhawk 4 Place Plans #1582

Entry: Fri May 22 2020

It's getting real!

Took a personal day from work today to extend the long weekend. First order of business was finishing up the wing form block by routing out the remaining releaf areas to allow clearance for the lightning hole flanges. Once that was complete I needed a backup block to support the rib while hammering out the edge flanges. I was able to use the second 3/4" oak board which had the tear out earlier to make this part. It's an exact copy of the wing master template that is then relieved by 1/8" so that you have some clearance to set the edge while hammering. With these two parts done it was off to the races flanging.

I'm not sure if i've mentioned it previously but I'm really following the process another builder Chris Owens shared over at the Bearhawk forums. He is building an sized Bearhawk 4-place he is calling the Expedition. You can find more details at the links below.

I was able to get flanges on half my nose ribs today, but I did have one that developed a tear at the edge of one of the flutes where I didn't do a good enough job cleaning up a nick in the edge. Good news is that I do have a spare blank that i'll trim to length and flange tomorrow. The process i'm using to form the edge flange is pretty simple.

  1. clamp the blank between the flanging form and the backing block using the jig pen holes to line every thing up
  2. With a dead blow hammer the edge over ~20 degrees then focus hammer blows at the edge to "set the edge" I was able to monitor progress by looking at how the edge would reflect light.
  3. The edge wouldn't fully set due to the curvature so I'd use the edge of a screwdriver to set the flutes into the routed notches in the form block.
  4. Then I'd hammer it some more to get it layed over and flat as possible.
  5. Flip the form and repeat for the other edge.

The ribs are turning out very nice but will need a little work to get them to lie flat and true up the flange to 90 degrees.

Today feels a little bit like a milestone since these are near final products. Up next, severaDDl hours of hammering out flanges.

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This post is from Bearhawk 4 Place Plans #1582