Turbo Timber SWS ARF – Part 3: Another Tail reinforcement

Recently, I did as the instructions directed regarding the studs that hold the vertical fin in place and “…checked periodically to make sure they remain tight”

I had done this after the first couple dozen flights and found that they were a bit loose so I tightened them up a bit…. and again a couple dozen more flights later… and again they seemed to be loose. On a third check I again tightened them and then noticed that the aft most “stud” had started to protrude from the bottom of the airplane.  This was unexpected, as each time they seemed to tighten up fine and I never tightened them using excessive force, or so I thought.

Not suprisingly, removal of the fin revealed that the rear stud in particular had begun to pull out. This is a bit disappointing as well as concerning as these two studs/bolts are all that hold the fixed portions of the tail in place. 

I noodled on this for a while and almost decided to do a more traditional epoxy/permanent installation of the tail surfaces but I still wanted to preserve the ability to disassemble this part of the airplane… so I decided to try to better secure the stud.  To this end, I added a bit of glue and pushed the stud back in to what seems like its original position.  I then soldered some washers onto the stud against the bottom wood of the vertical fin and then epoxied over the entirety of that bottom surface and the washers and let it dry completely before reassembly.

I’m hopeful this will now remain tight and stable. If you fly this airplane, I’d recommend keeping a close eye on this.  I know I’ll be checking it again in the future.

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