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  #1  
Old 06-04-2022, 07:42 PM
mike3715 mike3715 is offline
 
Join Date: Jun 2017
Location: LA Area
Posts: 24
Default Cracked Backplates on propeller hub assembly

After investigating some play in my spinner, I discovered two of the four steel plates used to hold together my spinner hub cracked. The crack is near the large stud nuts.

Has anyone seen this issue before? Should there be washers at the base of the stud nuts?

Click image for larger version

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Last edited by mike3715 : 06-04-2022 at 07:48 PM.
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  #2  
Old 06-04-2022, 08:17 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 2,369
Default

Itís hard to tell from your picture what model of RV, what prop type, or where the cracks are.
Have you had a dynamic prop balance? It looks like in your picture that the bolt heads are in the aft side of the connection to the backplate bulkhead. Standard practice would have the bolt head on the forward side with a washer, since itís in fiberglass, but the manufacturers instructions may be different, due to interference issues, etc.
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RV6/2001 built 2000/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
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RV4/bought 2019/sold2021
RV6/August 2022 build - Phase 1
Cincinnati, OH/KHAO
JAN2022
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  #3  
Old 06-04-2022, 08:21 PM
mike3715 mike3715 is offline
 
Join Date: Jun 2017
Location: LA Area
Posts: 24
Default

It's an RV-7 with a whirlwind propeller. The cracks are indeed tough to see in the photo...they basically follow the an extended line from the nut side that is roughly up/down in the photo.

And yes the prop was dynamically balanced after last install.

Thanks!

Last edited by mike3715 : 06-04-2022 at 10:27 PM.
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  #4  
Old 06-05-2022, 01:59 PM
mike3715 mike3715 is offline
 
Join Date: Jun 2017
Location: LA Area
Posts: 24
Default Updated Photos and Info

I've attached some better photos. One highlights the crack, one shows things partially disassembled, and the other shows the prop hub info clearly. Note the MacAuley hub used by Whirlwind earlier models.

So I think the mystery is solved. Whirlwind did an overhaul in 2018 and replaced the spinner mounting plate, which is what I believe the cracked part to be. Before they did so, there were washers (you can see in earlier photo). In cracked photo, no washers. While the mounting plate is magnetic/steel, it seems pretty odd to leave off the washers. Looks like I'll be giving them a call tomorrow....
Attached Thumbnails
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Last edited by mike3715 : 06-05-2022 at 02:17 PM.
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