RE: Pfalz DIII resources -- Photos, Drawings, Plans, etc.
Hi Erich,
Yes you are quite right, there's structure under the anchors! I glued a plywood block to the rib and spars, and keyed it to lock between the spars too. Each block is flush with the top of the rib, and drilled for bolts (one hole for the anchor, another for the strut). On the underside, I framed-out a little balsa well around the block, flush with the bottom of the rib to form a pocket, framed the bottom of that with 1/64 ply for the covering to attach to. Fake backing plates cover the wells. The well hides the nut holding the rigging anchor bolt, and the head of the bolt going up into the strut.
The struts are laminated light ply with a core of 5-ply near the attachment points, spruce strips on the LE and TE, and 1/2 oz glass. The A nyloc nut is embedded in the core plywood with a bolt hole lined with brass tube epoxied into it. A brass U-shaped "tang" is silver soldered to the brass tube, and the tangs are glassed to the outsides of the strut. An aluminum ball is drilled and glued to the tube, and a cup made of brass is glued to the tube and the ball. Final glueing of the ball-cup is done on the plane to get the angles right. The fake bracket is a combo of plastic sheet on the flats areas, and epoxy filler on the rounds. I made 3D metal and fibergalss brackets for the cabane struts, and decided I wasn't going to try that again!
I don't know if this makes sense!! I can sketch it if anyone's interested.
The black material visible in the well is carbon laminate on the spars. The bottom of the pockets looks uneven because (1) they are, to match the angle of the bolts, and (2) the ply glue lines create funny perspective.
I think this placement relative to the ribs is not quite scale, since the original had these fittings on a spreader-bar connecting the spars, between ribs. But I'm trying to keep this fun!!
Wings have not been painted yet so they're a bit shiny.