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Spinner vs Overhauled Propellers

Chachi7565

Chachi7565

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Two of us at SQL just got our Hartzell propellers back from overhaul. After reinstalling the propeller, we noticed that the holes on the spinner no longer align with the nut plates on the S603 front spinner bulkhead. I’m not sure how to sort this out. The holes are too close to simply redrill the spinner bulkhead’s mounting holes. It looks like if I order a new spinner bulkhead, all of the holes are already pre-drilled for mounting and would have the same issues. Have any of you had this issue? I could order a new spinner and drill that to match but damn, I’ll need to align, drill, finish, paint match…not really what I want to do right now. Pics for reference. Sharpie circles on the bulkhead show the degree of misalignment on mine; the other one is even greater.
 

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BTW can anyone confirm if a new spinner bulkhead is already pre-drilled? And if so, is it just the center four mounting holes, the perimeter holes to mount the spinner, or are the nut plates already installed? Part S-603 here.IMG_2884.jpeg
 
Buy a new spinner forward bulkhead and mount. Use the existing spinner as a drill jig to drill the spinner to forward buikhead holes. Disassemble and install nut plates for these holes.

Carl
 
Carl Froehlich said:
Buy a new spinner forward bulkhead and mount. Use the existing spinner as a drill jig to drill the spinner to forward buikhead holes. Disassemble and install nut plates for these holes.

Carl
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By your reply, do you mean that the spinner forward bulkhead is not already pre-drilled for the nut plates? That would be great! From this picture in the Van’s store, they looked pre-drilled.
 

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TParker said:
Slot the four holes on the forward bulkhead (S-603) where the forward is being attached to the hydraulic cylinder of the propeller.
Click to expand...
That’s a good idea. I’m wondering though, would the torque on that bulkhead cause an issue where it might shift? I don’t know the answer, what do you think?
 
Chachi7565 said:
Two of us at SQL just got our Hartzell propellers back from overhaul. After reinstalling the propeller, we noticed that the holes on the spinner no longer align with the nut plates on the S603 front spinner bulkhead. I’m not sure how to sort this out. The holes are too close to simply redrill the spinner bulkhead’s mounting holes. It looks like if I order a new spinner bulkhead, all of the holes are already pre-drilled for mounting and would have the same issues. Have any of you had this issue? I could order a new spinner and drill that to match but damn, I’ll need to align, drill, finish, paint match…not really what I want to do right now. Pics for reference. Sharpie circles on the bulkhead show the degree of misalignment on mine; the other one is even greater.
Click to expand...
I just went though this last month and what I did is detailed here.

All that said, there is undoubtedly a much easier way to do it.
 
Chachi7565 said:
That’s a good idea. I’m wondering though, would the torque on that bulkhead cause an issue where it might shift? I don’t know the answer, what do you think?
Click to expand...
I doubt it would cause an issue. The spinner as an assembly will still be restrained by the four aft bulkhead mounting bolts, and the friction from the bolts in the forward. If you're concerned, you could sharpie some alignment marks on the bolts and forward and check the alignment after flight/over time.

Slotting the holes in the forward is a pretty common modification after prop overhaul or replacement; those holes in the hydraulic cylinder aren't designed to be in a consistent location, they're just there for installation and removal of the cylinder.
 
Chachi7565 said:
Two of us at SQL just got our Hartzell propellers back from overhaul. After reinstalling the propeller, we noticed that the holes on the spinner no longer align with the nut plates on the S603 front spinner bulkhead. I’m not sure how to sort this out. The holes are too close to simply redrill the spinner bulkhead’s mounting holes. It looks like if I order a new spinner bulkhead, all of the holes are already pre-drilled for mounting and would have the same issues. Have any of you had this issue? I could order a new spinner and drill that to match but damn, I’ll need to align, drill, finish, paint match…not really what I want to do right now. Pics for reference. Sharpie circles on the bulkhead show the degree of misalignment on mine; the other one is even greater.
Click to expand...

Here's what I did. My prop came back with the hub holes rotated about 45 degrees from where they originally were. (No, I didn't actually measure it. Just used the mark 1 eyeball. And, there's nothing magic about the number....its just where the hub ended up when the prop shop reassembled it.) Not wanting to mess with the four bolt holes in the center of the spinner front bulkhead.....I opted to drill new nutplate holes on the spinner bulkhead flange. IE: match drill new holes to the spinner. Problem solved.

Next time might require a new bulkhead.....but that's down the road a bit.
 
They were not in the past. Call to find out. If they are now pre-drilled see if they have any that are not. This is is a "happens every time" for prop overhaul.

Carl
 
The way I’m understanding this is the prop went to Harrell for overhaul. Prop came back and now the spinner screw holes no longer line up with the nut plates. I’m curious if anyone a link to a prior explanation for how the bulkhead nut plates aren’t in the same positions they were before the overhaul. I can think of several absurd explanations, but am curious as to the real reason.
Thank you!
 
thodgdon said:
The way I’m understanding this is the prop went to Harrell for overhaul. Prop came back and now the spinner screw holes no longer line up with the nut plates. I’m curious if anyone a link to a prior explanation for how the bulkhead nut plates aren’t in the same positions they were before the overhaul. I can think of several absurd explanations, but am curious as to the real reason.
Thank you!
Click to expand...
The cylinder (see drawing below) is not oriented to any particular rotational position during prop assembly. The cylinder ends up where it ends up...every time it assembled. So, the 4x bolt holes used tor the front spinner baffle end up where they end up too.

compact hub.jpg

Image from Kitplanes article: https://www.kitplanes.com/firewall-forward-choosing-a-prop-for-your-project/
 
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Stevea said:
The cylinder (see drawing below) is not oriented to any particular rotational position during prop assembly. The cylinder ends up where it ends up...every time it assembled. So, the 4x bolt holes used tor the front spinner baffle end up where they end up too.
Click to expand...

FANTASTIC!! Thank you that’s exactly what I was looking for👍🏻
 
Stevea said:
Here's what I did. My prop came back with the hub holes rotated about 45 degrees from where they originally were. (No, I didn't actually measure it. Just used the mark 1 eyeball. And, there's nothing magic about the number....its just where the hub ended up when the prop shop reassembled it.) Not wanting to mess with the four bolt holes in the center of the spinner front bulkhead.....I opted to drill new nutplate holes on the spinner bulkhead flange. IE: match drill new holes to the spinner. Problem solved.

Next time might require a new bulkhead.....but that's down the road a bit.
Click to expand...
Thanks, I wish I had that option, but mine is only about 10 degrees out of whack - so I don't have the ability to do that, since the new holes would overlap the old nutplate holes.
 
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