The only problem I'm struggling with is. The props natural coning is away from the winglet also you are moving away from the prop when it fails. So, I would agree that maybe the prop failed and before it actually fully departed it was struck by the opposing blade doing its best barry bonds into your winglet...
Well, let me see if I can re-calibrate your intuition with some first hand experience (and some hand-waving physics).
A few years ago I had a small piece of music wire fall out of the back of the cowl, in flight. It was "U" shaped, with a total length of approximately 6 inches and a diameter of 1/8 inch. It fell more or less straight down for several feet before it was blown back approximately two inches to come into contact with the leading edge of my 62 in. diameter, B&T prop, hitting it ~5 inches from the tip. The wire cut a nice notch in the urethane leading edge material almost exactly to full depth, and only slightly crushed a small amount of wood directly behind the urethane LE at the impact point. The wire then ran roughly straight across the face of prop, leaving several significant gouges but nothing close to serious structural damage in it's wake.
The outer 6 inches of Urethane leading edge, since it had been disconnected from its inboard self, decided to come off. (Note that the leading edge on a B&T prop curves around the tip of the prop to the cord line, which is why 5 inches from the tip yields a 6 inch piece of LE; and that the LE urethane had a depth of about 1/4 to 3/8 inch where the wire hit.) As luck would have it, the LE piece impacted the left winglet almost exactly in its center. It made a goodly bang! There is absolutely no doubt that it was the leading edge that did the damage and NOT the music wire, because the LE left a perfect 'dusty "J" fingerprint' where it hit; and it was obvious that the LE piece hit the winglet almost flat. Think flyswatter hitting a table at ~800 fps and you'll have the picture. Despite wrapping around and cutting into the leading edge, the music wire was not much interested in flying outward after the hit, judging by its tracks on the prop face.
So what happened? The impact spalled the paint, primer and filler off of the winglet glass slick-as-a-whistle in a circle about 8 inches in diameter leaving a perfect, virgin glass surface that looked exactly like the day the glass was laid up. Zero damage to the glass, and zero damage to the finish outside the spall area. A little investigation, however, showed that the foam under the glass had been permanently crushed in about 1/8 of an inch in the vicinity of the impact point and (obviously) was debonded from the glass. An injection of flox slurry and local refinish fixed the damage.
So, that's ACTUAL experience, and now comes the hand waving (with sincere apologies to Joe Person with whom I agree on the undesirability of speculation).
Centrifugal forces acting on the propeller are huge (a significant fraction of the tensile strength of wood) in comparison to the trivial thrust loads (on the order of 100 lbf spread over the whole surface of the prop), which means that a piece of prop only wants to go straight out in the arc of the prop, not cone. (Think David's slingshot.) The most useful frame of reference moves with the plane, which places the winglet "in the line of fire", with a ~140 kt breeze blowing on the prop fragment, perpendicular to its motion, as it flies out toward the winglet. But the time available for this "breeze" to divert the flying piece of prop is practically nothing - (roughly 15 milliseconds at my guestimated 800 fps tip speed for the prop for a ~12 ft trip out to the winglet).
So here's my mental picture. In my case I had a fairly low-speed rifle bullet being fired in a 140 kt cross wind at a target a dozen feet away. I got lucky and the long, skinny "bullet" hit side-on, slapped the winglet and spalled off the finish. Yup, there was some wind drift, but not a lot. In Eddie's case he had a light-duty, cannon ball fired at the winglet. The result was about what you'd expect. Personally, I'm convinced that Eddie's "cannon ball" was a direct chunk of prop, and no chance that what hit the winglet was a either a "Barry Bonds bird" or "Barry Bonds prop chunk" (i.e., a secondary fragment). I'm inclined to agree with the idea that 'no sign of bird' suggests... no bird. But now I really am speculating, so I'll stop here!
Best,
