I'd like to share work completed on various scratch built ribs. I made the three samples shown in the photo, and I like each sample for different reasons.
The rib in the bottom of the photo represents a "one-piece-sheet metal rib". The rib blank was sandwiched between two wood shapes,
then the flanges hammered using a plastic mallet. I then used fluting pliers to shrink the flanges where needed. The lightening holes
would be punched and flared using a "Mittner Punch". I only have access to a 4" diameter Mittner punch, so the lightening holes would be a little small.
Stiffening beads can be added using a bead tool, however the bead on the rib was made by hand. The rib material is 0.020" 6061T6 aluminum.
11.04 ounce (3/4 rib) before holes are punched.
The rib in the center of the photo is a "three-piece-stamped rib". Here, I made forms (nose, center, long tip, short tip) to router out the rib blanks, then form the
rib using a hydraulic press (hydroforming) using similar dies. I made all the forms and dies by hand. The rib shown requires the ribs to attach on the web of the spar,
however, the ribs can be attached to the top and bottom flanges of the spars, with similar forms and dies. The rib material is 0.020" 6061T6 aluminum. 11.62 ounce (full rib).
The trussed rib at the top of the photo is made of Carlson cap strips, and 0.020" 6061T6 aluminum. I have since made another using 0.016" aluminum (I like it). I included stiffening beads,
and later I added lightening holes all over. 12.32 ounce (full rib). Very, very strong rib. I've seen similar rib come in lighter than this one. I also bent up a piece of 6063T52 aluminum angle,
1/16" thick, 1/2" x 1/2", and like it as well. I like the trussed rib a lot simply due to being able to use very simple tools to make it. A person can almost make these in their living room.
I made two forms for the trussed rib, one form to pre-bend the cap strip, and a second form to maintain final shape during assembly.
My build partner Charlie was able to buy some beat up stock Piper ribs, and one of the FULL ribs I weighed came in under 7 ounces! I checked my scale calibration,
and feel confident that that is a good weigh. The Piper cap strip is so light and flimsy, that I feel any of the ribs I made are "over built".
More to come as I learn.
john