20 or 40

[Jakes Simmons]

     Airplane is in annual now, original 20:1 gears are worn well past limits, including worm gear. I searched the site for discussions on previous folks’ needs but did not see any resolutions. We know Mooney won’t make new ones, LASAR is looking for any serviceable ones for me. Any vintage owners out there could point me in a direction for either the 40:1 kit or serviceable 20:1 ? Appreciate the help. 

[Matthew P]

7 hours ago, Jakes Simmons said:

     Airplane is in annual now, original 20:1 gears are worn well past limits, including worm gear. I searched the site for discussions on previous folks’ needs but did not see any resolutions. We know Mooney won’t make new ones, LASAR is looking for any serviceable ones for me. Any vintage owners out there could point me in a direction for either the 40:1 kit or serviceable 20:1 ? Appreciate the help. 

Jake, will you please send me the old gear set so I can have them sent to a metalurgist for destructive testing to determine the type of steel and hardening process?  I have the 3D CAD drawings of the gear set but not the metal specs...I'll contact Mr. Pollack tomorrow to see where we are on getting a batch made up, probably no closer than 3 months ago but I'll try...looking to go the OPP route and once I get the metalurgy report done, my plan is to share the info on mooneyspace...unfortunately it won't help you currently...please let me know if you are willing to send me the worn gear set.  V/r

 

Matt

[67 m20F chump]

Would it be better (faster) to get the parts for a Johnson bar?  I don’t know if the conversion is possible but I would think parts would be available.

[A64Pilot]

On an aircraft that was originally manual there are I believe Mooney drawings at least that allow conversion to electric, converting back in my opinion is allowed because your taking it back to its TC. Opinions of course do vary.

On an aircraft that came from the factory electric if it did, installing manual gear is in my opinion a Major alteration and I think would require a field approval. There may be no differences, but its TC is electric gear.

Before starting down this road I think you should have your IA contact the local FSDO to see if they would support it.

Of course your IA’s opinion may differ from mine and he may decide it’s a minor, but either way I think you should see if it’s possible before buying parts.

Edited September 17 by A64Pilot

[M20F-1968]

3 hours ago, bluehighwayflyer said:

The conversion is definitely possible, in either direction.  We are the second owner of our ‘65 C.   Its original owner had Charlie Dugosh convert it to electric when it was practically brand new, and we converted it back to manual in the mid 80s.  We called Charlie, who was still running the business, and he sent us all of the parts we would need.  We mailed what we took off back to him in exchange.  He said he converted a few in each direction every year back then.  It was only a couple push rods, up and down lock blocks, and the Johnson bar assembly itself, if I remember correctly.  And since ours had originally been manual, all the mounting holes we needed were already there.  I’m surprised more people aren’t doing exactly this, to be honest.  

Eventually, in old age, my dad developed shoulder problems that made operation of the Johnson bar difficult for him, but in the absence of that it really is a remarkably simple and easy-to-use-and-maintain system.  

Even with shoulder problems, the Johnson bar should be very easy to operate.  I can operate my with two fingers on the bar.  It took some time to understand how to rig it properly however.  At the time, Mooney had two fuselage lengths, but made three different push rod lengths that hold the main grear springs.  I guess there was sufficient variation that they needed to use the push rod lengths that worked the best for each plane.  Also, the 1968 Johnson bar is different from the other years.  That may also contribute some reasons why there were three push rods made.  The 1968 Johnson bar is only in the 1968 plane.

John Breda

[EricJ]

20 minutes ago, M20F-1968 said:

Even with shoulder problems, the Johnson bar should be very easy to operate.  I can operate my with two fingers on the bar. 

With shoulder issues sometimes it's not the force that's the problem it's the range of motion.   

[MB65E]

Please post a picture of your actuator gear itself.

I believe many are scrapping gears prematurely for scalloping. I believe the new gears have the scalloping. 
As long as the backlash is not over 1/2 tooth, the gear should still be good. 

Mine was scalloped with ZERO ware. 
 

[Matthew P]

3 hours ago, A64Pilot said:

On an aircraft that was originally manual there are I believe Mooney drawings at least that allow conversion to electric, converting back in my opinion is allowed because your taking it back to its TC. Opinions of course do vary.

On an aircraft that came from the factory electric if it did, installing manual gear is in my opinion a Major alteration and I think would require a field approval. There may be no differences, but its TC is electric gear.

Before starting down this road I think you should have your IA contact the local FSDO to see if they would support it.

Of course your IA’s opinion may differ from mine and he may decide it’s a minor, but either way I think you should see if it’s possible before buying parts.

So, you missed the part where it came from the factory with a J-bar and then upgraded to electric

[MikeOH]

1 hour ago, MB65E said:

Please post a picture of your actuator gear itself.

I believe many are scrapping gears prematurely for scalloping. I believe the new gears have the scalloping. 
As long as the backlash is not over 1/2 tooth, the gear should still be good. 

Mine was scalloped with ZERO ware. 
 

Thanks for the photos.  I'm no ME, but I believe the scalloping is by design for a 90 degree worm gear.  I'd hate to think some A&Ps are condemning gear sets over that!  As you said, it's the backlash that is critical.

[Jakes Simmons]

15 hours ago, Matthew P said:

Jake, will you please send me the old gear set so I can have them sent to a metalurgist for destructive testing to determine the type of steel and hardening process?  I have the 3D CAD drawings of the gear set but not the metal specs...I'll contact Mr. Pollack tomorrow to see where we are on getting a batch made up, probably no closer than 3 months ago but I'll try...looking to go the OPP route and once I get the metalurgy report done, my plan is to share the info on mooneyspace...unfortunately it won't help you currently...please let me know if you are willing to send me the worn gear set.  V/r

 

Matt

I’ll send them to you once I gain a solution. Gears are not scalloped but teeth are worn down, worm gear ridge is worn razor thin in the middle. 

[PT20J]

2 hours ago, MikeOH said:

Thanks for the photos.  I'm no ME, but I believe the scalloping is by design for a 90 degree worm gear.  I'd hate to think some A&Ps are condemning gear sets over that!  As you said, it's the backlash that is critical.

That would be the norm for a worm and wheel gear set.

[MB65E]

Thanks, Worm gear 101 if you ask me. 
I didn’t see anyone post pictures of the gear themself and wanted to provide a data point. 
-Matt

[Matthew P]

3 hours ago, Jakes Simmons said:

I’ll send them to you once I gain a solution. Gears are not scalloped but teeth are worn down, worm gear ridge is worn razor thin in the middle. 

Thanks, I appreciate it, there should still be enough for the metalurgist to determine, through destructive testing, the material used as well as the heat treatment, then I have the info for the manufactures to get quotes to fabricate and their report should satisfy the "as good as or better than OEM" for OPP

[Nico1]

Wasn't there a process through the FAA to get the technical data released if they were not manufacturing the part? Might be another option if no luck with getting some produced. (or destructive testing I guess would accomplish that too)

[A64Pilot]

17 hours ago, Matthew P said:

So, you missed the part where it came from the factory with a J-bar and then upgraded to electric

I did, but my post was more for everyone than this particular aircraft, we all sometimes think well Joe did it so I should be able to also.

With the FAA that’s not always the case, for Field Approvals it often helps quite a bit if you can get a copy of the 337  of a previously approved modification if your doing exactly the same thing, but today even that’s not the slam dunk it used to be, and of course that’s for a field approval which an IA may want.

But even in this case I think that he needs to ask his IA or shop around to find one that agrees as many modifications are considered permeant as in you can’t go back.

The bottom line is I promise you, you can’t always use what you consider to be obvious or logical when dealing with the FAA. Best before you start spending money to ask first.

[A64Pilot]

11 hours ago, Nico1 said:

Wasn't there a process through the FAA to get the technical data released if they were not manufacturing the part? Might be another option if no luck with getting some produced. (or destructive testing I guess would accomplish that too)

Believe it or not but the FAA often doesn’t have a copy of all the drawings, the amount of drawings are enormous and of course they change often, so the man power and just plain storage space for an FAA MIDO to have a copy of all drawings would be pretty much impossible, and of course drawings changed often so someone would have to post every change for every drawing. Can you imagine for instance the FAA having all the drawings for every Gulfstream ever built and then to keep them current?

Gulfstream is of course only one manufacturer that ATL MIDO manages. I assume it would fall under the MIDO, but it could be the ACO?

Thrush was the only source of their drawings, if the FAA had a question about a part then of course Thrush would send them a copy of the drawings. Back two owners ago they got into a bad habit, if they wanted to change something they simply changed the drawings and didn’t seek FAA approval, how could they get caught?

Well later on the Thrush QC head went to work at the FAA MIDO in Atl, and now the FAA keeps a copy of all current production aircraft for Thursh.

I would hope that mooney if they had no interest in manufacturing the part would give a copy of the parts drawings. I know I used to. We tired to support all of our old aircraft but it just wasn’t possible for every part, in many cases the tooling for parts that hadn’t been built in 40 years didn’t exist and no one was still around who know how to build the thing, drawings often don’t tell you how to build the thing and there is a heck of a lot of what I call Tribal knowledge in building an airplane.

Edited September 18 by A64Pilot

[Matthew P]

11 hours ago, Nico1 said:

Wasn't there a process through the FAA to get the technical data released if they were not manufacturing the part? Might be another option if no luck with getting some produced. (or destructive testing I guess would accomplish that too)

Good Morning, yes and I'm working on that but having spoken with the certification branch it seems as though it's a protracted process, which I'm willing to try, just trying to expedite things if there's another way...

[A64Pilot]

Determining heat that level and material type if steel or aluminum isn’t difficult. We determined heat treat level by its Rockwell hardness and if aluminum by believe it ir not but it’s electrical conductivity. I don’t remember what we did for steel to be honest, but none of the tests were destructive, the part was unharmed, the Rockwell hardness tester leaves a small pit type of mark of course.

But are these gears steel? 

[Pinecone]

The problem is you need a sample for analysis for what alloy the part is.

Yes, if you know the alloy, you can determine hardness by Rockwell number for steel.

[A64Pilot]

12 minutes ago, Pinecone said:

The problem is you need a sample for analysis for what alloy the part is.

Yes, if you know the alloy, you can determine hardness by Rockwell number for steel.

We had something that for example could tell the difference between 4340 steel and 4130 for example, and those steels are pretty near identical, but 4340 heat treats “better” on thicker parts, better as in more evenly where 4130 was more difficult to get the same heat treat through the whole part.  We used both types of steel of course and had to be able to ensure there wasn’t a mix up in the machine shop for example, and the part had to be unharmed.

Point I’m trying to make is it’s not difficult or expensive to have done, they don’t need a scanning microscope or whatever. We had to determine the type and heat treat level of critical parts like wing spars for example when we “bought” in parts.

I don’t remember what it was we had though, but it wasn’t exotic. But it satisfied the FAA. 

Of course you need the part.

My bet is this will involve a DER to get done, but maybe not

Edited September 18 by A64Pilot

[N201MKTurbo]

I toured a testing facility a month ago. They mostly did construction stuff, but they had all the tools to figure it out. They would section and polish a sample, then image it in a SEM, then do a spectral XRF analysis of the material and finally do a Rockwell hardness test at many points on the sample. The lady who did this could tell you exactly what the material was had how it was heat treated. She mostly inspected welds, but could do anything. She really knew her stuff.

https://pnltest.com/

 

[Pinecone]

2 hours ago, A64Pilot said:

We had something that for example could tell the difference between 4340 steel and 4130 for example, and those steels are pretty near identical, but 4340 heat treats “better” on thicker parts, better as in more evenly where 4130 was more difficult to get the same heat treat through the whole part.  We used both types of steel of course and had to be able to ensure there wasn’t a mix up in the machine shop for example, and the part had to be unharmed.

Point I’m trying to make is it’s not difficult or expensive to have done, they don’t need a scanning microscope or whatever. We had to determine the type and heat treat level of critical parts like wing spars for example when we “bought” in parts.

I don’t remember what it was we had though, but it wasn’t exotic. But it satisfied the FAA. 

Of course you need the part.

My bet is this will involve a DER to get done, but maybe not

How do you know that the part is either 4130 or 4340????  The issue is, it is not this or that, it is SOME alloy.  It could be 4140, used in a lot of gears.  

It could be one of the stainless steels (303, 304 or 316 or even 440C).  Or a tool steel such as 1020 or 1045.

[N201MKTurbo]

21 minutes ago, Pinecone said:

How do you know that the part is either 4130 or 4340????  The issue is, it is not this or that, it is SOME alloy.  It could be 4140, used in a lot of gears.  

It could be one of the stainless steels (303, 304 or 316 or even 440C).  Or a tool steel such as 1020 or 1045.

X-ray fluorescence is the method most often used to determine what the alloy is. I was just reading the users manual for one of these. They will just read out on the display what it is. They will also tell if there are multiple alloys in the sample.

It seems they are used a lot by metal recyclers. For 20 AMUs you can have one in your tool box too.

 

https://www.olympus-ims.com/en/xrf-analyzers/handheld/vanta/?creative=675403255164&keyword=xrf gun&matchtype=e&network=g&device=c&campaignid=20260938134&adgroupid=152889751569&gad_source=1&gclid=EAIaIQobChMIqMfE3fnMiAMVUA6tBh2wMjUlEAAYAyAAEgJ4kfD_BwE

 

[Hank]

26 minutes ago, Pinecone said:

How do you know that the part is either 4130 or 4340????  The issue is, it is not this or that, it is SOME alloy.  It could be 4140, used in a lot of gears.  

It could be one of the stainless steels (303, 304 or 316 or even 440C).  Or a tool steel such as 1020 or 1045.

It's easy to tell 300-series stainless from 400-series--the 300s are iron-free, therefore not magnetic, and cannot be heat treated. 

[MikeOH]

3 hours ago, Hank said:

It's easy to tell 300-series stainless from 400-series--the 300s are iron-free, therefore not magnetic, and cannot be heat treated. 

All stainless steels are primarily iron based.  The magnetic properties are based on grain structure and highly influenced by nickel content.

https://www.pencomsf.com/wp-content/uploads/technical-reference-files/magnetism_other_stainless_steel_properties.pdf