RE: please help identify this plane
Brian-David-Frank,
I happen to have a GreatPlanes/Bridi Glass Dirty Birdy sitting in a mold so I can make a couple more. I also have the plans for the RCM Dirty Birdy as well and they, the glass plan and built up are exacly the same. I purchase the RCM DB plan 2008 and when I got the Glass DB a year later that was the first question I asked myself. How much did they differ? To my amazement they were the same. I had the plans scanned and overlayed them both and the outlines are exacly the same.
If the built up ones you have seen are square then they were that way due too a lazy or scared builder who didn't sand the sides all the way to achieve the symmetry as the built up plan shows. A rounder one could be achieved by more sanding but I think that would weaken the fuse considerably at the corners without beefing them up.
Also someone had to make a plug for the original glass Dirty Birdy and I bet he just followed the RCM plan and sanded the fuse to achieve the correct symmetry as indicated on the plan.
Bryan