AlexPeterson
Well Known Member
I'm doing the annual inspection on the plane, the 21st such time! Somewhere after a few hundred hours, I noticed a universal head rivet on the spinner backing plate assembly had lost its head. I drilled out the stump, re-riveted it and moved on. A few years later, the same thing happened in the same position. Again, I drilled and re-riveted it. Many years and probably 1200 additional hours went by with no more trouble. A year ago, I had the prop overhauled, and have flown around 50 hours in the past year.
Now I have, for the 3rd time, lost that same rivet. I did a very close inspection of the entire backing plate for any signs of cracks, damage, etc. None found. All four rivets in the symmetrical positions had smoking, not observed before. They are the rivets closest to the large bolts which attach it to the hub.
It must be related to exactly how the prop hub bolts are torqued. This prop has always been very smooth with no vibrations. I will likely get it dynamically balanced again, but I expect there won't be much change to the weights.
I may, symmetrically, add a few more rivets in the areas of interest. Fortunately, my squeezer reaches this area, so it's not a big deal.
Thoughts?
Now I have, for the 3rd time, lost that same rivet. I did a very close inspection of the entire backing plate for any signs of cracks, damage, etc. None found. All four rivets in the symmetrical positions had smoking, not observed before. They are the rivets closest to the large bolts which attach it to the hub.
It must be related to exactly how the prop hub bolts are torqued. This prop has always been very smooth with no vibrations. I will likely get it dynamically balanced again, but I expect there won't be much change to the weights.
I may, symmetrically, add a few more rivets in the areas of interest. Fortunately, my squeezer reaches this area, so it's not a big deal.
Thoughts?