M20 Spinner Bulkhead Needed

[Patrick M]

Looking for spinner rear bulkhead part number 680031-027 or 680031-017 and doublers 680031-029 or 680031-025.   I have had a stress crack failure a few times now on my M20F due to excessive wobble of the nose cone.  This bulkhead and doublers enable conversion to the M20J cowl by adding the eyebrow cut-out.  No surprise the stress crack starts from the bottom which is the weakest point (see pictures).  These parts are becoming scarce. Thanks, Patrick

[carusoam]

Welcome aboard, Patrick...

See if you can add some lower(?) detail for us to get in the ball park with...

What plane, and prop, did this come from?

M20F, with a two blade, Hartzell?

We have a few suppliers of the pre-owned parts around here...

@Alan Fox

@acpartswhse

@SheryLoewen

The actual part numbers will be important.  But the lesser detailed info will get some owners to look at what they have in the hangar...

Best regards,

-a-

[KSMooniac]

Patrick, if this bulkhead fits a 2 blade McCauley and J cowl I'd be interested in buying your cracked part...hopefully for the cost of shipping or scrap value. I'm collecting non-airworthy parts for mock up use.

Sent from my LG-US996 using Tapatalk

[Patrick M]

Alan - Hartzell HC-C2YK-1B / 7666-A2  Two blade with the "Q-Tip" spinner (see picture). 1967 Mooney M20F 200 HP IO-360-A1A with the M20J Cowl.   I am also looking to upgrade to a non AD prop hub.   Thanks!

Scott - these are from a Hartzell assembly.  I need to hold on to this one for now but if I find a replacement/upgrade then I could sell you the cracked one.  Thanks!

[mike_elliott]

What causes the back plate and dog ears to crack is the interference fit on the ring inside the spinner is too sloppy with the hub. It also helps to snug the ears to the back plate and spinner prior to tightening so as to not induce a slight misalignment load.

Yea, I bought a new back plate and a couple of ears (they always break at the narrow part) until I figured out the cause. It also doesnt hurt to take a little emery paper and knock the sharp edge off the dog ears to help mitigate the development of a crack.

 

[N201MKTurbo]

I traded one of them, which I mistakenly bought on eBay to LASER a few years ago. You might give them a call and see if they still have it.

[Guest]

It might be time to ask TCB Composites if they can do Mooney spinners in carbon fibre.

https://tcbcomposite.com/custom-orders/

Clarence

[Patrick M]

Mike - agree on the root cause:  wobble of the spinner due to gap between the forward bulkhead ring to prop hub dome. Shown on image:  Red and Blue.  Tape is used to make a snug fit.  I have attached two related service bulletins.  

M201MKTurbo - good idea.  I will give Laser a call.  

Clarence - carbon fiber or custom are an option I would consider if I can't find good used parts.  Probably too expensive. I will study.  

Russell - original kit was installed in 1984.  They were called Lasar Kits 100 and 117. No longer available.  I saw a kit by ARI  680031-517:one recently sold on ebay which was also cracked. 

All - thanks for your ideas!  

M20-201 Bulkhead Spinner.pdf M20-219 Bulkhead Spinner.pdf

[tankertoad]

Patrick - What did you end up doing on your bulkhead? I'm running in to the same problem on mine (75F, Mod Works Trophy 2 blade spinner - Mooney part#680031-515) and looking for a replacement or to get mine welded. 

- TT

[Mark89114]

I think i saw some type of spinner/backplate combo on mooney pilots on facebook.  Mighr be worth a look.

[Patrick M]

Tankertoad: 

My solution was to repair back to the original specifications.  I found a good used bulkhead (680031-027) and repaired the cracked doublers (680031-029) as they are no longer available. Even the bulkheads are hard to find now.  Only 20 hrs. ago so time will tell.

The fatigue crack originating in the narrowest area is due to the stress of the vibration from the spinner.  The doublers are so thin they provide little structure. I believe the key to minimizing this vibration is to carefully follow the shim-taping procedure (Hartzell Alert Service Bulletin HC-ASB-61-332) between the prop hub and front bulkhead which minimizes spinner wobble.   In my application the tape was worn mostly off and hence the fit was loose.  The tape is high-temp and specified in the bulletin.

 

Another option is to upgrade. Dan at Lasar was very helpful and offered a new spinner/bulkhead conversion which works with the M20J cowl: Hartzell A2295-5P / A2476-19. It comes with the spinner, bulkhead, doublers and fasteners. It relocates the rear bulkhead from the flywheel/ring gear to the prop hub.  The design is much better.  Un-fortunately this kit would not fit my cowl which is 1” longer than the M20J.

 

 

[carusoam]

Great details, Patrick...

We have seen the proper tape discussion come up before... 

People finding cracks don’t see any tracks of the missing tape... not sure how long the tape lasts...

PP thoughts only, not a mechanic...

Best regards,

-a-

[OR75]

How much would the bulkhead and doubler cost ? 

[Patrick M]

The Hartzell A2295-5 Spinner Assembly and A2476-19 Mounting Kit (fasteners) is about $2200 at Lasar.

[FloridaMan]

Call Dan at LASAR and get the Hartzell spinner. As someone who ended up AOG and then twice more with getting used replacement bulkheads that lasted a few hundred hours each, trying to save money cost me lots of frustration and thousands more than just buying the damn replacement spinner that Hartzell sells that bolts to the hub. I did seem to lose a little bit of cooling as I think the new spinner allows air out through the front of the cowling. LASAR had the best prices. 
 

Seriously, don’t do what I did and try to replace the part with design flaws with another flawed part. Get the one from Hartzell and be done with it. 

[tankertoad]

On 4/29/2020 at 4:53 PM, Patrick M said:

Tankertoad: 

My solution was to repair back to the original specifications.  I found a good used bulkhead (680031-027) and repaired the cracked doublers (680031-029) as they are no longer available. Even the bulkheads are hard to find now.  Only 20 hrs. ago so time will tell.

The fatigue crack originating in the narrowest area is due to the stress of the vibration from the spinner.  The doublers are so thin they provide little structure. I believe the key to minimizing this vibration is to carefully follow the shim-taping procedure (Hartzell Alert Service Bulletin HC-ASB-61-332) between the prop hub and front bulkhead which minimizes spinner wobble.   In my application the tape was worn mostly off and hence the fit was loose.  The tape is high-temp and specified in the bulletin.

 

Another option is to upgrade. Dan at Lasar was very helpful and offered a new spinner/bulkhead conversion which works with the M20J cowl: Hartzell A2295-5P / A2476-19. It comes with the spinner, bulkhead, doublers and fasteners. It relocates the rear bulkhead from the flywheel/ring gear to the prop hub.  The design is much better.  Un-fortunately this kit would not fit my cowl which is 1” longer than the M20J.

 

 

Which cowl do you have?

 

[Patrick M]

My cowl looks like an M20J but is about an inch longer at the nose.  It may have been part of a Lasar kit from the 1980s but I cannot verify. The 2295 kit is certainly for an M20J cowl.

[carusoam]

Got a pic of your cowl Patrick?

being off by an inch is possible, but  isn’t very likely...

The next cowl length covers an extra pair of cylinders... M20K/Missile...
 

But when it comes time to putting a proper cowl on... there is a small change from the older Mooneys to the newer M20Js...

There is probably a different prop spacer that makes a difference...

Best regards,

-a-

[Patrick M]

I measured an M20J and found my cowl was 1" longer.  Ideas appreciated. 

[carusoam]

Got a pic from the front?

It seems to have a modded front end...

Probably not unique, Just not standard M20F either...

If the front was modded, the logs should show what it is...

The extra inch is pointed out with blue...

See if there is an obvious prop spacer to match the extended cowl...

The original F cowling was all aluminum, and is aptly named the ‘guppy mouth’.

The M20J is mostly a modification of the M20F... Fiberglass farings everywhere...

Your cowl has the same side access panels normal for an M20F...

 

PP thoughts only... not a mechanic.
 

Best regards,

-a-

[FloridaMan]

I think that length might be that the rear of the upper cowl extends further back. The rear of my upper LoPresti cowl is flush with the lower. 

[carusoam]

16 hours ago, FloridaMan said:

I think that length might be that the rear of the upper cowl extends further back. The rear of my upper LoPresti cowl is flush with the lower. 

I see that as well...

But, the lower cheek Cowl seems to be all original...

This would set the length from front to back, same as the original cowl....

And what seem to make up an extra inch is that part between where the guppy mouth ended...

This cowl seems to have extended guppy lips...  

Looks like a Kcowl might be being employed for some reason?

The Kcowl is longer because it has to house a pair of extra cylinders...

Lots of extra work was used to put this cowl in place... the logs hold the info...

PP guesses only,

-a-

[Patrick M]

Interesting.  Log books from 1984 indicate the Cowl was a Lasar 117 kit but that part number could not be found by Lasar.  

[Andy95W]

IIRC, @RLCarter has a SWTA modified cowling.

[RLCarter]

1 hour ago, Andy95W said:

IIRC, @RLCarter has a SWTA modified cowling.

Nope, stock cowling on mine