+20 year old donuts (1966 M20E)

[N201MKTurbo]

1 hour ago, outermarker said:

@ Turbo...I hope you loaned them to someone based at your airport. Thanks for the offer too.

No, I loaned it to someone in Sierra Vista AZ, who then moved to El Paso TX with my tool. He was in the Army and was deployed over seas, but if he had time to move it to another state, he could have shipped it back. About a year ago, he flew it here in his Mooney.

[NotarPilot]

Did anyone ever end up using the OPPs from South Africa produced by @Gert?

[carusoam]

5 hours ago, NotarPilot said:

Did anyone ever end up using the OPPs from South Africa produced by @Gert?

I believe there may have been at least one taker…

The ability to call it an OPP was challenging… or less clear.

To make sense of a trial fitting… you need to be a mechanic… in case you decide to go back to the old donuts…

A lot of dough in donuts and install time make this a tough project to move forwards… 
 

Best regards,

-a-

[NotarPilot]

4 hours ago, carusoam said:

I believe there may have been at least one taker…

The ability to call it an OPP was challenging… or less clear.

To make sense of a trial fitting… you need to be a mechanic… in case you decide to go back to the old donuts…

A lot of dough in donuts and install time make this a tough project to move forwards… 
 

Best regards,

-a-

Based on the (ehem “little”) I know about owner produced parts, the interpretation is quite liberal. I remember reading an article by Mike Busch concerning this very subject. I only regret not participating in this lively debate last year and the year before in this thread. Here is a quote from part of the Mike Busch article concerning owner produced parts.

“The meaning of “owner-produced parts” was rather murky until April 5, 1993, when Donald P. Byrne, the FAA’s assistant chief counsel for regulations, issued a memorandum defining the term “owner (or operator) produced part” as used in FAR 21.303(b)(2). Byrne’s memo clarifies the FAA’s interpretation of the owner-pro- duced parts exception, and as you’ll see, that interpretation is surprisingly generous and liberal.
...AND WHAT THEY MEAN
Byrne explained that it is not necessary for the owner to actually manufacture the part himself for the part to be considered an “owner-produced part.” The owner may contract with a mechanic, a repair station, or even a non-certificated individ- ual or firm (e.g., a machine shop) to manufacture the part for him, provided that the owner “participated in controlling the design, manufacture or quality of the part.” The FAA deems the part to be owner-produced if the owner does any of the following things:
• Provides the manufacturer with design or performance data from which to manufacture the part—this test would be met if the owner provides the manu- facturer with the old part and asks that it be duplicated; or
• Provides materials to make the part; or
• Provides fabrication processes or assembly methods to be used in making the part; or
• Provides quality control procedures to be used in making the part; or
• Supervises the manufacture of the part.
In short, a part whose manufacture is contracted by the aircraft owner will qual- ify as “owner-produced” if the owner participates in the production of the part in any meaningful way at all.”

- Mike Busch, Sport Aviation August 2011

I believe @Gert’s manufactured shock discs would qualify if the owner was minimally involved in the process as described above. I don’t think the legality is so much in the question as is the question of, who wants to take the plunge?

In calculating the risk assessment the question ultimately comes down to, “What’s the worst that can happen?” What if one donut failed? What if two or three failed? What if they all failed at once? What would happen? What are the ramifications and what else might it affect? 
 

Can the risk be mitigated through frequent inspections of the donuts before and after each flight? 
 

What would be an acceptable failure rate or MTBFs?

I’m currently in need of a new set of donuts for my plane. Mine are 18 years old. I knew they were coming due, based on age, but they seemed fine until my A&P said, “Times up.” The prices have jumped significantly. I remember they were $110 each not long ago and now they best price I’ve found is $150+. 

I might be tempted to try the OPP donuts but I don’t want to wait and @Gert seems to have left this site nearly a year ago. 
 

Reference: https://resources.savvyaviation.com/wp-content/uploads/articles_eaa/EAA_2011-08_owner-produced-parts.pdf

Edit: I’d like to add that I just checked @Gert’s website www.avunlimited.co and he shows the Mooney Shock Disks on his site for $50 but they currently show “Out of stock”

Someone must be buying them.

[Fly Boomer]

9 hours ago, NotarPilot said:

he shows the Mooney Shock Disks on his site for $50 but they currently show “Out of stock”

Earlier in this thread, he said he runs off 400 at a time.

[NotarPilot]

32 minutes ago, Fly Boomer said:

Earlier in this thread, he said he runs off 400 at a time.

Yes, I saw that as well and if he’s sold out of 400 that would mean more than 30 planes should have them installed. I contacted Gert by email and he responded quickly advising that he was still running trials on Mooneys and expected the data in July 2022. Hopefully he returns with good news. Unfortunately, I cannot wait and will be forced to spend about $1700 on a new set.

[Fly Boomer]

3 hours ago, NotarPilot said:

forced to spend about $1700 on a new set

Ouch.  Does that include installation?

[Shadrach]

4 hours ago, NotarPilot said:

Yes, I saw that as well and if he’s sold out of 400 that would mean more than 30 planes should have them installed. I contacted Gert by email and he responded quickly advising that he was still running trials on Mooneys and expected the data in July 2022. Hopefully he returns with good news. Unfortunately, I cannot wait and will be forced to spend about $1700 on a new set.

Call Herber Aircraft in El Segundo, CA 310.322.9575, ask for Dwayne.

Part number is J-11968-14

I believe I paid right around $100 a piece for them last fall.

Edited April 20, 2022 by Shadrach

[carusoam]

@NotarPilot,

+1 for the definition of OPP…

The concern is/was eligibility…

At first OPP was a method of getting parts made when no parts were commercially available…

Which is the case for the Mooney Mite donuts…

 

Can we use the OPP route when Lord is still making expensive donuts for Modern Mooneys?

+1 for gert and the other guy…

Best regards,

-a-

From another current thread regarding OPP and eligibility…

@EricJ gave us this…

AC 23-27 just says that substitution via OPP can apply "where the parts or materials are either difficult or impossible to obtain".    My understanding from the old salt instructors at A&P school was that OPP was originally developed for the airlines so that they could fab their own parts when possible rather than suffer down time due to long lead times or other part inventory issues.    So even if a part is "available", OPP can apply if it is diffcult to obtain.    AC 23-27 also says this helps owners obtain "newer and usually better parts". 

I think most people were going to McFarlane (et al) for cables because there weren't other practical sources.    You could order one from an MSC with a TBD delivery that might be measured in years.   A reasonable person might conclude that constitutes "difficult to obtain".     I don't think they were necessarily cheaper from McFarlane, either.   I ordered two from McFarlane under OPP and one with a Mooney part number once they started accepting that, and the prices weren't any different, and as far as I could tell not much different than what the MSCs would charge when they had them.

[NotarPilot]

9 hours ago, Shadrach said:

Call Herber Aircraft in El Segundo, CA 310.322.9575, ask for Dwayne.

Part number is J-11968-14

I believe I paid right around $100 a piece for them last fall.

Thank you for that. I’ll call them today. 
 

@carusoam I remember Mike Busch mentioning that the airlines are the biggest adopters of the OPP regulations and often fabricate their own parts. I found that pretty interesting being that most airliners in use are often still in production or, one would think, still supported by the OEMs. The 757 and A340 have been out of production for years but I would imagine are still fairly well supported by Boeing and Airboos.

[outermarker]

Where can I find the manufactured date on the disc? I see the part number. I'm curious as to just how old my discs are. This has been a very good thread!

[Hank]

2 minutes ago, outermarker said:

Where can I find the manufactured date on the disc? I see the part number. I'm curious as to just how old my discs are. This has been a very good thread!

It's molded into the outside edge. Should be numbers--mine were "06-1969" but they were upside down and I thought it was "09-1996" before I replaced them in 2012.

[outermarker]

Thanks Hank....I now have a project for this weekend!

[RobertGary1]

45 minutes ago, outermarker said:

Thanks Hank....I now have a project for this weekend!

Note that date is not a good way to determine donuts need replacement. The FSM describes how to measure them. 

 

-Robert

[outermarker]

Thanks Robert. I know mine are old and long in tooth. I'm simply curious at this point. The discs will be replaced this year. 

[RobertGary1]

On 4/22/2022 at 12:33 PM, outermarker said:

Thanks Robert. I know mine are old and long in tooth. I'm simply curious at this point. The discs will be replaced this year. 

Have you measured them?

[NotarPilot]

On 4/20/2022 at 2:38 PM, Fly Boomer said:

Ouch.  Does that include installation?

No

[corn_flake]

For our collective knowledge.  I just got off the call with Herber.  The cost at 2025 is $192 per donuts.  It look like AircraftSpruce has the lowest price today at $177.  

Herber says price goes down to around $150 if we order 100 donuts or more.  Are there 10 Mooney out there that need their donuts replaced?   Check your date, they should be replace every 12 years for short body.  Heavier long body will require replacement sooner.  

[Hank]

41 minutes ago, corn_flake said:

Are there 10 Mooney out there that need their donuts replaced?   Check your date, they should be replace every 12 years for short body.  Heavier long body will require replacement sooner.  

Where did you get this? All I've ever seen is the gap test immediately after jacking the main wheels off the ground.

[corn_flake]

I got the 12 years number on Lasar web site.   It's not a requirement, but simply a recommendation.   My main donuts has date stamp of 1999. 25 year is beyond overdue.  

 

https://lasar.com/mooney-shock-disc-replacement-and-nose-gear-wear-and-tear

[cliffy]

Rubber also hardens with age.  Causing fuel tank leaks????

Naw- because we all land smooooth!   :-)

[MikeOH]

1 hour ago, cliffy said:

Rubber also hardens with age.  Causing fuel tank leaks????

Naw- because we all land smooooth!   :-)

Just soak 'em in G100UL for a bit, they'll soften right up

[corn_flake]

It's amazing that Mooney used these puck because they were off the shelf parts.  If I remember correctly, they were engine mount on International Harvester.  After several decade, Harvester stop using the same parts, and we are now stuck with ridiculous over priced rubber donuts....  

[cliffy]

Only the first M!0 Mooney Mite used truck engine mounts

[47U]

1 hour ago, MikeOH said:

Just soak 'em in G100UL for a bit, they'll soften right up

W100 might work, too.  But will probably take a lot longer.  Cliffy’s ‘truck engine mounts’ comment reminded me of this bit of neglected mx, committed by me.  This is the lower left isolator, hidden behind the battery box on my ‘63C.