On Sunday, March 8, 2015 at 4:07:53 AM UTC-7, wrote:

UH,
I beg to differ: the bolt holds the stabilizer from moving forward. In the assembly there are a couple of (horizontal) pins which engage with the sockets in the vertical stabilizer's spar. (A drawing is on the Yahoo ASW20 group. Look for a file called "200_38-37_S1_BL1.pfd"). Those pins are the ones which take the vertical loads....

Well, sort of. Those pins do react the a lot of the lift loads, but don't help much with loads that try to lift the stabilizer's leading edge. In the absence of the tape, a lifting force that raises the leading edge could easily have bent the plate that anchors the spar pins and allowed the stabilizer to fly free. In most high-performance sailplanes, the tailplane does indeed lift upward when flying at low speed at anywhere but the most forward part of the CG envelope.

For the HP-24 sailplane, I chose to adopt (or "leverage," in Silicon Valley speak) the thumbwheel system used for attaching the stabilizer in Wolf Lemke's LS-series sailplanes. In that system, if the stabilizer is not secured enough to go flying, it will be so loose on the fin top that it will be clearly insecure and unsafe.

Thanks, Bob K.