D4 Delta2p Evolution (2020 John Middendorf portaledge design)
D4 portaledge Design
D4 Delta2p—the first “foot-out” portaledge design, 2020
Working out issues with this “foot-out” portaledge concept took some time and a marriage of various new technological developments like CAD/CAM, and this post will also provide tips for other innovators. In the meantime, see https://www.bigwalls.net/the-d4-story.html
As of October, 2021, 32 D4 Delta2p’s have been produced in Tasmania by John Middendorf, Anna-Véronique L'hoest, Hanna Vasilades, Carl Hanson, Simon Bischoff, Danny and many others. Eight Delta2p’s went to expert product testers. Open Source design notes and plans on bigwalls.net
Manual for the Delta2p, with climber review: https://www.bigwalls.net/download/delta2p-manual-v2.pdf
Main D4 Delta2p page: https://www.bigwalls.net/d4-delta2p.html
The Evolution continues:
The original conception of the design
Original Concept for the “foot-out” portaledge dates back to 1999, after I lost my design role at a major outdoor gear company, I did a bit of consulting, but it was difficult to get the shop space and time to pursue the design for the next couple decades (while initially working half the year on the rivers of the southwest).
The original 1999/2000 design was a hinged design; however, hinges in portaledges tend to result in a wobbly frame, and it had flaws, namely that the wobble would cause the ledge to creep up the wall (also the suspension points were not optimised):
I was also working on this design at the time:
Related to the above design, Jeff Lowe had submitted this sketch to A5 in the 1980’s (prototypes were too floppy):
