Replacement Elevator Weights - Can't Find

[BenP]

Hello all! Here's the short version: I recently purchased a 1967 M20F with composite elevator weights. Those weights are cracked and the plane is grounded per the AD that came out in February. I am considering buying a whole new elevator to expedite getting the plane back in the air. Is that a dumb idea or does it make sense? 

Long version: I purchased the aircraft back in May. I am based in Iowa and the plane was purchased from a gentleman in Florida. There was a pre-buy inspection completed in April and the inspector flagged the elevator weights, but I was not aware of the AD on that component. The aircraft also needed a new engine (cracked case + old case unable to be overhauled again), so it has remained in Florida for engine replacement from June through early October (the engine shop was backed up). The engine is done, but the airplane is now undergoing annual since the previous annual lapsed during the engine shenanigans. The previous owner ate most of the cost of the engine replacement, so I didn't get burned on the whole deal. However, through no one's fault the elevator weight AD went unnoticed by everyone (other than the inspector) until now. 

I need to get the plane in service ASAP, as I will be tied up at work for almost all of November and December. I am unwilling to have someone else ferry the plane if it gets done after my availability closes up, although the previous owner has graciously agreed to do so for only travel expenses.

Some quick research on my part showed that the non-AD all-lead elevator weights in circulation dried up quickly after the AD came out in February. 

I am considering simply buying a whole elevator to hopefully get the aircraft in service before my availability closes up. A new elevator set would be $2k-ish plus labor and a set of weights would be $500 plus labor if I could even find them, which is a big "if". I already struck out with the nearest MSC and my A&P IA hasn't heard back from LASAR yet. 

Am I foolish or would a new elevator make sense under the circumstances? Or is there an alternative solution that I am not seeing?

(I can post pictures upon request)

[Fritz1]

call Paul Loewen Mooney salvage 707 272 8638, he is somewhat retired but had lot of stuff, if he is really retired he will know where his inventory went

[KSMooniac]

Loewens sold their salvage hoard to BAS, I believe.  

I would also call Maxwell Aviation and see if they have a line on any right now.  I saw a pile of bad ones on a table when I was there in July, so they've been changing them.

[Kelpro999]

I have an extra weight from a damaged elevator I purchased for other reasons. I added some weight so it’s very close to 3.2 lbs. Originally it was closer to 2.5 lbs.  but I think the AD replacement one is 3.2 lbs.

  I’m done with surface balancing issues I had so won’t be needing it. 
Would need to ship from San Diego 

 Kevin 

Edited October 26, 2023 by Kelpro999
Photo

[Utah20Gflyer]

Why not make a mold of the old part, then melt some lead and pour it into the mold?  I think this is the route I would take if I was an unfortunate individual with a composite elevator weight.  

[M20F]

4 hours ago, KSMooniac said:

 

I would also call Maxwell Aviation and see if they have a line on any right now.  I saw a pile of bad ones on a table when I was there in July, so they've been changing them.

Maxwell did my annual and I waited a couple of months to get them from the factory.  No real short cuts to this problem if your serial # is in the AD that I am aware of. 

[BenP]

I apologize for not updating this sooner: The A&P doing the annual, by some miracle, managed to find a set of elevator weights. The plane should be done in about a week. I will post again at that time with where he found them and how much they cost, just in case there's any other bad elevator weights floating around in the fleet.

Hopefully I'm one of the last ones to run into this issue. If I read correctly, only about 180 Mooneys were made with the composite elevator weights. I'm sure most of the rest have already been repaired or are no longer in service.

[Echo]

Glad you found a solution and your bird will be coming north.   Scott

[hoot777]

Texas Air Salvage , Lasar, and I believe BAS in Colorado are possible sources

[MikeOH]

On 10/25/2023 at 4:05 PM, Utah20Gflyer said:

Why not make a mold of the old part, then melt some lead and pour it into the mold?  I think this is the route I would take if I was an unfortunate individual with a composite elevator weight.  

I'm no A&P/expert but I'm not sure that would work.  The overall density of the old composite part will NOT be the same as an all lead one made to the shape of the original.

[Kelpro999]

1 hour ago, MikeOH said:

old composite part will NOT be the same as an all lead one made to the shape of the original.

Doesn’t have to be since the new part is one pound heavier than the hybrid. Balance at new specification listed in A.D. 

 

[MikeOH]

17 minutes ago, Kelpro999 said:

Doesn’t have to be since the new part is one pound heavier than the hybrid. Balance at new specification listed in A.D. 

 

Are you saying that if you mold to the OLD outline with all lead the weight will be the SAME as the new part?  I was under the impression that the new part was of a different outline/mold shape than the original.

[Kelpro999]

15 hours ago, MikeOH said:

Are you saying that if you mold to the OLD outline with all lead the weight will be the SAME as the new part?  I was under the impression that the new part was of a different outline/mold shape than the original.

 Yes, you could mold exactly to shape of hybrid, New is same as non- hybrids , they have to fit into the horns just like all of them, given smooth skin internal rib elevators. I would venture to say that one could cut off the steel tube end and lead braise a complete new end, file to shape and run it. It’s only lead

Edited December 4, 2023 by Kelpro999
Asleep while responding

[cliffy]

Just curious about the legality of making your own without any applicable drawings of how it was made originally?

We are just "assuming" its poured pure lead. There are many alloys of lead and strength varies with each one.

Which alloy do we need to use? Without the original drawing we have no idea. 

And that is part of the OPP route. 

We're talking about maybe the most critical part on the airplane as far as flutter mitigation goes and we want to guess

at what we are doing?

Weight is only one component of the part, strength is the other and without the correct alloy we have 

no idea what the strength required is. 

Now chemical analysis and a DER sign off would  be the correct way to go OPP in this case I do believe. 

Thoughts?

[Kelpro999]

7 hours ago, cliffy said:

Just curious about the legality of making your own without any applicable drawings of how it was made originally?

I’m also curious since there’s no published method for adding weight for balancing purposes after refinishing. I’ve used Antimonial lead of unknown percentage for balancing. Basically mixed wheel weight lead. It produced approximately the same hardness but who knows what’s supposed to be used. I do know I have perfectly balanced surfaces and for that I’m happy 

[Hank]

10 hours ago, Kelpro999 said:

I’m also curious since there’s no published method for adding weight for balancing purposes after refinishing. I’ve used Antimonial lead of unknown percentage for balancing. Basically mixed wheel weight lead. It produced approximately the same hardness but who knows what’s supposed to be used. I do know I have perfectly balanced surfaces and for that I’m happy 

Wheel weights are (or at least used to be, when they were crimped in) much harder than pure lead.

[Pinecone]

Lead clip on wheel weights still are but are getting harder to find.  If you get some and want to melt them down, make sure you don't use any that seem light for their size.  Some are made of zinc, and you don't want to melt that into your mix.  If you use JUST enough temp to melt the lead ones, the zinc ones will float on time.  But a bit more heat and they also melt.

The stick-on ones are almost pure lead.

[N201MKTurbo]

A quick web search taught me a lot about lead alloys.

You could get pretty close to the correct alloy by testing the hardness of the factory weights, than making test alloys until you matched the hardness. Add tin to 5%, then add antimony up to 2%.

You can get the hardness tester and casting equipment from reloading suppliers.

The harder the alloy, the harder it is to cast. The harder alloys will freeze in the mold and not flow well.

[Kelpro999]

6 hours ago, Hank said:

Wheel weights are (or at least used to be, when they were crimped in) much harder than pure lead.

After making 400lb of lead bars from wheel weights and removing dross at same time it seemed hardness was nearly equal to the balance weights using only a drop peen test.

[Hank]

Just now, Kelpro999 said:

After making 400lb of lead bars from wheel weights and removing dross at same time it seemed hardness was nearly equal to the balance weights using only a drop peen test.

I've molded bullets from lead, and a friend used wheel weights. We shot NRA Hunting targets, made of 1/4" steel plate. His wheel-weight bullets left circular dents, mine left lead splashes . . . .

[Kelpro999]

11 minutes ago, Hank said:

I've molded bullets from lead, and a friend used wheel weights. We shot NRA Hunting targets, made of 1/4" steel plate. His wheel-weight bullets left circular dents, mine left lead splashes . . . .

That’s right so the strength concerns I had evaporated when thinking about the bending moment required for failure of 1”x2” bar shoved into the horn. Also soft enough HCF & LCF are presumably beyond anything our elevators could transfer. Although maybe not legal, options exist for future needs in the event of no factory or PMA availability. I’m no legal expert, just a guy with a toolbox 

[cliffy]

On 12/4/2023 at 6:22 PM, Kelpro999 said:

I’m also curious since there’s no published method for adding weight for balancing purposes after refinishing. I’ve used Antimonial lead of unknown percentage for balancing. Basically mixed wheel weight lead. It produced approximately the same hardness but who knows what’s supposed to be used. I do know I have perfectly balanced surfaces and for that I’m happy 

By "perfectly balanced " you do mean the correct trailing edge heavy weight required- correct? 

I think to be correct we would need to see what was called for on the Mooney drawings- lead, linotype lead, babbitt lead. etc. 

Strength is only one of the design requirements that would be called out on the required reference material. 

There is an FAA webinar on the 20th dealing with the currently approved ways to keep our vintage aircraft supplied with parts.

I intend to listen in 

"Pro Tips for Maintenance Vintage Aircraft Replacement and Modification Article VARMA"
Topic: Do you fly or maintain Vintage aircraft? This webinar can help with how you maintain the aircraft along with part substitution.
On Wednesday, December 20, 2023 at 19:00 Central Standard Time (17:00 PST; 18:00 MST; 20:00 EST; 15:00 HST; 16:00 AKST; 18:00 Arizona; Thursday, December 21, 2023 01:00 GMT)
 

[Kelpro999]

10 hours ago, cliffy said:

By "perfectly balanced " you do mean the correct trailing edge heavy weight required- correct? 

 Yes, balanced within grams of midpoint specifications for each surface and total mass within ozs. Left v right. I know overkill but since I was there anyway..

  I wasn’t too concerned about the lead chemical properties because it’s just an overlay on the existing weights. Flow out and mixing with the original parts was excellent and corrosion resistance is proven by the add materials track record. 
 Thank you for the information link, it should provide very useful information.