The following link provides access to the updated specification plan for the Bird of Prey 18. The change is the type of material used for the joiner, which is now Teflon PTFE with a 1/32 in. ID and a 1/16 in. OD. On the plans, I included the McMaster-Carr part number. I also added a stop below the joiner, which is noted on the plans.https://drive.google.com/file/d/0Bwj9y_lTaMmFWkp0dFpzUEJMVTQ/view?usp=sharing
I removed the older version of the Bird of Prey 18 plan from my Google Drive. I switched to this tubing after construction of the initial four versions of the Bird of Prey 18 (two for me, one for Phil, and one for Tom), because it was a tight fit to insert the wing spars into the old joiner made from the wire insulation. Also, the new material is stiffer than the wire insulation, so it hold the dihedral angle better over time. The four initial versions of the Bird of Prey 18 were upgraded and there was no change in performance. The tubing is the same type of material that I use on the Bird of Prey 36 and 48. Very happy it is made in this very small diameter.
Yours in kiting,