Fri Sep 03 2021

Installing popup tipup mechanism

With the F-704 bellcrank in place as well as the NACA vent and some SCAT tube, I used a piece of tubing to determine what path the forward pushrod will need to take. This will allow me to cut the ends of the torsion tube to their final length and get the popup tipup mechanism installed. Once that is installed, I can measure what length pushrod needs to go here and fabricate it.

In order to install the popup tipup mechanisms between the ribs, I needed to drill starter holes in the bellcranks. I recently bought this drilling guide to permit me to accurately drill on center. Worked great. Sorry for the blurry picture.

After drilling both bellcranks, I cut the AN3-41A bolt heads off, then threaded the ends so there was 1" full thread at each end. These will replace the mild steel pushrods I had previously made.

With the mechanisms temporarily installed in the ribs and rotated to the "up" position (which, BTW, pulls the canopy *down* tightly), I clamped the bellcrank tubes to the torsion tubes and match drilled. At this point, I had already cut the torsion tube down quite a bit. I left an inch or two at each end for final trimming in a bit.

Torsion tube match drilled to both bellcranks.

Here's a view from below. Don't get too excited about the long bolt through the tube...all these bolts are just temporary while I'm fitting this up.