Who wants to speculate on what happened to THIS prop?

**Scream And Fly** · 07-19-2021, 03:20 AM

I don't think this one can be repaired.

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**WaterZebra** · 07-19-2021, 04:36 AM

I would like to say that its a crystaline failure in the blade root but the blade in the 7 o clock position is heeled over. The fracture line in all the blades is nearly identical. Did you hit something? No.

**rock** · 07-19-2021, 05:49 AM

I have destroyed many props over the years but very few done that well. Congratulations for a job well done.

Rock

**powerabout** · 07-19-2021, 06:19 AM

how could it fail first time out..must be warranty...

**TooStroked** · 07-19-2021, 06:25 AM

Interesting that the skeg and gearcase look untouched. Also appears to be a two engine installation. Hmmmm.

**Euroski** · 07-19-2021, 06:43 AM

Lab work... reduce diameter to get engine in RPM range!

**H2OPERF** · 07-19-2021, 07:22 AM

Blades are bent at the leading edge opposite of rotation so it was in reverse or the r/h prop is also destroyed

**XstreamVking** · 07-19-2021, 07:23 AM

When the prop meets the road......

**sharpeye Mike** · 07-19-2021, 07:29 AM

Jaws is still alive and well.

**Whaaaaat** · 07-19-2021, 08:21 AM

Originally Posted by sharpeye Mike

Jaws is still alive and well.

Definitely sharks!

**engineermike** · 07-19-2021, 09:31 AM

Man that’s an interesting failure. I actually don’t think it was caused by impact with an immovable object. Looks to me like a fatigue failure. The crack initiated at point A in the attached pic. B shows beech marks where it propagated and C is the final failure. One interesting point is that the blades we can see appear to have failed in a very consistent manner. The final failure is roughly half the original cross-sectional area, indicating they are normally run at about 50% of their strength. It is true that the final failure is in the reverse direction but this could just be coincidence as that was the load state at the time when stress > strength. It was going to fail soon whether in forward or reverse.

My best guess is that all blades had fatigued for some time due to extended surfacing and/or material deficiencies and/or stress riser due to machining. A hardness check could rule out one of those and a microscope could rule out another.

**rock** · 07-19-2021, 09:43 AM

Originally Posted by Whaaaaat

Definitely sharks!

You guys been watching Discovery channel. It's shark week.

Rock

**H2OPERF** · 07-19-2021, 10:05 AM

Also looks like they cut the hub maybe they nicked the blades all in the same area with the lathe... def started in the smooth almost cut looking areas at the trailing edge.