Crack in propeller spinner on '61 B model

[David Cabot]

Our 1961 B model has a crack on the propeller spinner that has me a little worried.  It has been drilled 3 times and shows no evidence of cracking past the last drill hole.  My partner is not worried about it, and says he has spoken to 2 mechanics who said to just keep an eye and make sure the crack doesn't continue.  The crack is on the 'trailing edge' of the flange and so is not exposed to the relative wind the prop when rotating.  Am I needlessly worrying for nothing?

[Bartman]

Looks like the crack goes through the hole for the fastener. If it were my spinner I would get that repaired if weld can fix it, or replaced. Mine has fiber washers under the fasteners. 

[Aaviationist]

Needs to be replaced in my opinion. 

Edited August 23 by Aaviationist

[cliffy]

Do you have any idea how strong the centrifugal force is at 2700 RPM on that broken corner? 

Once it lets go the added diameter to the spinner now is a weight throwing the balance out on the entire assembly 

Can you spell VIBRATION ?

To be honest I wouldn't pass it on a 100 hr inspection 

Get a new spinner and use plastic or fiber or nylon washers under the screw heads 

That is probably why it cracked in the first place

Welding won't work (at least I've never seen on welded that worked)

Its probably made from 2024 O condition aluminum and can't be welded. 

Learned that 50 years ago on Navajo spinners We couldn't keep them from cracking until we used plastic washers.

[47U]

7 hours ago, cliffy said:

We couldn't keep them from cracking until we used plastic washers.

Which the plastic washers help to prevent the tendency to over-torque the screws.  Tighten the screws to ‘snug’ (a technical term).  And that’s it.