20 or 40

[Grant_Waite]

9 minutes ago, Matthew P said:

$4-6k for just the gears?

Oh no, for the whole actuator, I have no idea what the gears are worth. 

[Echo]

11 hours ago, Matthew P said:

Good morning, still working the issue but feel that it's now become stonewalling. From what I understand, 60 years ago Mooney contracted to have the actuators made but using their engineered gear set which is manufactured by a 3rd party, so the drawings and specs are Mooney proprietary and Mooney will not release them nor say who they used to manufacture them, I have asked the CEO if they refuse to have them produced than why not license them to  i.e. Lasar so that 1, Mooney can make a little money and 2 we can get the frigging parts....all I got back thus far is a, I'll call you this afternoon, well, that was a week ago.  If anyone can send me an old set so I can get a metallurgy (destructive testing) report done, that would help as I already had a new set loaned to me and had them scanned and I have the CAD drawings for, I've also petitioned the FAA, Certification Branch, under the OPP guidelines, for a copy of the drawings and technical specifications since there is still an active SB and Mooney refuses to have the parts produces, so that's where we are at..wish I had better news and was closer that we were 4 months ago.

Thank you for your work on this Mathew.  Endevor to persevere...Mooney.  WTF!  Stand up and fly right!  Shame.

[Pinecone]

7 hours ago, MikeOH said:

@Pinecone

I don't agree.

1) Tcal indicates that wear was why they were taken out of service; consistent with excessive backlash.

2) My research on worm gear design on this site (https://khkgears2.net/catalog5/ has many drawings, photos, and descriptions that do NOT show any such tooth width variation.  They do discuss backlash and the tooth dimensions that cause it.  Again, the variation in tooth width, wide at the ends and narrow in the middle, is evidence of wear.

I'm willing to reconsider if you can cite some design information supporting your contention.

https://www.grainger.com/product/793AJ9?gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231&gad_source=1&gclid=EAIaIQobChMIsaKag97ciAMV22lHAR1oXynEEAQYByABEgK0sfD_BwE&gclsrc=aw.ds

 

[Vance Harral]

7 hours ago, MikeOH said:

My guess (and it's only a guess) is that the gears that wear out were not regularly inspected and regreased properly.  Maybe the 40:1 will take that kind of abuse?

Every time you post this hypothesis that only poorly-maintained 20:1 gears wear out, I'm going to counter with my anecdotal story that our 20:1 gears wore to the point of failing the SB M20-190B inspection, despite regular maintenance and proper regreasing per the associated SB/AD, over many years of ownership.  We knew this was coming, as the backlash in the gear set got progressively worse over a period of multiple inspections.

Wear is obviously a function of gear cycles, and we put more on our airplane than most.  So I'm not surprised there are airframes with the original 20:1 gears, and lots more hours than ours.  I'm sure it's also true that poorly maintained gears wear faster.  But the 20:1 gears absolutely do wear out, even when maintained properly.

[MikeOH]

1 hour ago, Pinecone said:

https://www.grainger.com/product/793AJ9?gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231&gad_source=1&gclid=EAIaIQobChMIsaKag97ciAMV22lHAR1oXynEEAQYByABEgK0sfD_BwE&gclsrc=aw.ds

 

@Pinecone

Ah, I see the issue.  I'm NOT referring to the vertical 'scalloping' which is absolutely part of the design.  I'm talking about the actual width of the teeth; your link shows teeth that are of constant width, while in the photo from Tcal it is clear that the teeth are worn in the middle.

[MikeOH]

5 minutes ago, Vance Harral said:

Every time you post this hypothesis that only poorly-maintained 20:1 gears wear out, I'm going to counter with my anecdotal story that our 20:1 gears wore to the point of failing the SB M20-190B inspection, despite regular maintenance and proper regreasing per the associated SB/AD, over many years of ownership.  We knew this was coming, as the backlash in the gear set got progressively worse over a period of multiple inspections.

Wear is obviously a function of gear cycles, and we put more on our airplane than most.  So I'm not surprised there are airframes with the original 20:1 gears, and lots more hours than ours.  I'm sure it's also true that poorly maintained gears wear faster.  But the 20:1 gears absolutely do wear out, even when maintained properly.

@Vance Harral

You are overstating my claim.  I'm stating that lack of maintenance may explain the premature wear.  I am NOT trying to claim they won't wear out at all!  Certainly, the 20:1 gears are under more load than 40:1 so it makes sense the 40:1 will last longer.

Of course backlash is going to increase with use whether 20:1 or 40:1.  My opinion is that there is nothing really wrong with 20:1 gears when properly inspected and maintained.  Mine have certainly soldiered on but will obviously need replacing sometime.  IOW, merely going to 40:1 gears doesn't 'solve' the issue; my understanding is that inspection and maintenance is still required even with 40:1 gears.  Will 40:1 last longer than 20:1?  No doubt, but is that 100 years instead of only 50?

[Nico1]

13 hours ago, Matthew P said:

Good morning, still working the issue but feel that it's now become stonewalling. From what I understand, 60 years ago Mooney contracted to have the actuators made but using their engineered gear set which is manufactured by a 3rd party, so the drawings and specs are Mooney proprietary and Mooney will not release them nor say who they used to manufacture them, I have asked the CEO if they refuse to have them produced than why not license them to  i.e. Lasar so that 1, Mooney can make a little money and 2 we can get the frigging parts....all I got back thus far is a, I'll call you this afternoon, well, that was a week ago.  If anyone can send me an old set so I can get a metallurgy (destructive testing) report done, that would help as I already had a new set loaned to me and had them scanned and I have the CAD drawings for, I've also petitioned the FAA, Certification Branch, under the OPP guidelines, for a copy of the drawings and technical specifications since there is still an active SB and Mooney refuses to have the parts produces, so that's where we are at..wish I had better news and was closer that we were 4 months ago.

Thanks for your perseverance! Huge public service. It makes zero sense for them to sit on this or make it difficult...

[Matthew P]

26 minutes ago, MikeOH said:

@Vance Harral

You are overstating my claim.  I'm stating that lack of maintenance may explain the premature wear.  I am NOT trying to claim they won't wear out at all!  Certainly, the 20:1 gears are under more load than 40:1 so it makes sense the 40:1 will last longer.

Of course backlash is going to increase with use whether 20:1 or 40:1.  My opinion is that there is nothing really wrong with 20:1 gears when properly inspected and maintained.  Mine have certainly soldiered on but will obviously need replacing sometime.  IOW, merely going to 40:1 gears doesn't 'solve' the issue; my understanding is that inspection and maintenance is still required even with 40:1 gears.  Will 40:1 last longer than 20:1?  No doubt, but is that 100 years instead of only 50?

Problem is, you can't get either the 20:1 or 40:1 

[MikeOH]

3 minutes ago, Matthew P said:

Problem is, you can't get either the 20:1 or 40:1 

100% aware of that!

It's why I'm meticulous about the 100/200 hour service interval...I need to make mine last until you solve this

[N201MKTurbo]

I bought my 40:1 gears in 05 they were about $250. I bet they will be way more than that if you can ever get them.

[Vance Harral]

34 minutes ago, MikeOH said:

My opinion is that there is nothing really wrong with 20:1 gears when properly inspected and maintained.

On that we agree.  We know they wear, but not at a rate of concern provided they're inspected and maintained.  I do think the speculation on how many years they might last is pointless, as it's not calendar time that causes them to wear.

36 minutes ago, MikeOH said:

Of course backlash is going to increase with use whether 20:1 or 40:1.

Are you certain of that?  Some closed, lubricated systems effectively form a constant thin film between the meshing surfaces, such that the surfaces never actually touch.  I'm mostly ignorant in such matters, and not claiming the 40:1 gears last "forever".  But I could believe it's possible to design a set of gears with a high enough ratio that the force between gear teeth is never sufficient to entirely displace the lubricant.

[Ragsf15e]

1 hour ago, MikeOH said:

@Pinecone

Ah, I see the issue.  I'm NOT referring to the vertical 'scalloping' which is absolutely part of the design.  I'm talking about the actual width of the teeth; your link shows teeth that are of constant width, while in the photo from Tcal it is clear that the teeth are worn in the middle.

My 20:1 gears were replaced ~5500 hours ttaf.  Im not sure about the maintenance prior because it wasn’t mine yet.  They eventually wear out but do appear robust.

[MikeOH]

9 minutes ago, Vance Harral said:

On that we agree.  We know they wear, but not at a rate of concern provided they're inspected and maintained.  I do think the speculation on how many years they might last is pointless, as it's not calendar time that causes them to wear.

Are you certain of that?  Some closed, lubricated systems effectively form a constant thin film between the meshing surfaces, such that the surfaces never actually touch.  I'm mostly ignorant in such matters, and not claiming the 40:1 gears last "forever".  But I could believe it's possible to design a set of gears with a high enough ratio that the force between gear teeth is never sufficient to entirely displace the lubricant.

I find it interesting that you find it pointless how long the gears last (we can quibble over whether years or hours is a better measure), but then suggest upping the ratio to a point where there is no wear so they would last 'forever'!

I'm sure dealing with replacing the gears that wore out was expensive and a hassle but if I had to replace my 20:1 gears tomorrow I'd be perfectly satisfied to put in another set of 20:1 gears should they last the same time!  IOW, I wouldn't trade more life for slower operation; I'm perfectly happy with the life of 20:1 gears.

The issue is there are NONE available at any gear ratio!!

[Shiroyuki]

On 9/24/2024 at 9:36 AM, Matthew P said:

From what I understand, Mooney Engineers designed the gearing to be used in the actuators and therefore the gears (drawings) are Mooney proprietary that are produced by a 3rd party vendor, which is still in business and CAN fabricate the gears but Mooney REFUSES to take/place an order for us. Johnny is just as frustrated as we are as he's very customer focused, he's asked about alternatives, on behalf of some customers, but he's ignored by the engineers that he poses the questions to.

 

On 9/24/2024 at 9:45 AM, N201MKTurbo said:

Don’t you think Dukes designed the gears? It is possible that Mooney may not have the drawings for the gears. They may belong to their vendor.

https://lasar.com/actuators/gear-actuator-102000-1-sn-1245

Is this the part I'm talking about? When I first searched it up I was shocked by it's price. So if someday my 77 J's gear acturator decide to quit, then I'm doomed? Because there is no part avalible?

It the electric motor in this assembly replacement on it's own? My mechanic keeps talking about I should send the gear motor to LASAR to get inspected or overhauled, since it hasn't been done for over ten years, but I'm not too sure what is he talking about.

Can someone design an STC and manufacture a different gear acturator to replace it? 

In Canada we have something called limited STC, usually used to design a repair or a modification. It is much easier to get issued then a reguler STC. I wonder if one day my gear acturator quit, would I be able to hire a Transport Canada Design Approve Representative and design a new gear acturator?

[MikeOH]

@Shiroyuki

That part is NOT the one WE are talking about.  That is the actuator for later models that suffer from the no-back spring.  I know those are hard to find, too.

The Dukes actuator we are discussing has a worm gear set that wears to a condition that it has to be replaced.  There is a service bulletin that describes the inspection procedures: one every 100 hours (not to invasive) and another every 200 hours (requires removal and disassembly).

Problem is, if the these gears are bad there are NO replacements available.  Basically, you are forced to buy a used actuator.  Or, supposedly, you can spend a bunch to convert the plane to manual gear (after you find all of those parts somewhere!)

[1980Mooney]

1 hour ago, Shiroyuki said:

 

https://lasar.com/actuators/gear-actuator-102000-1-sn-1245

Is this the part I'm talking about? When I first searched it up I was shocked by it's price. So if someday my 77 J's gear acturator decide to quit, then I'm doomed? Because there is no part avalible?

It the electric motor in this assembly replacement on it's own? My mechanic keeps talking about I should send the gear motor to LASAR to get inspected or overhauled, since it hasn't been done for over ten years, but I'm not too sure what is he talking about.

Can someone design an STC and manufacture a different gear acturator to replace it? 

In Canada we have something called limited STC, usually used to design a repair or a modification. It is much easier to get issued then a reguler STC. I wonder if one day my gear acturator quit, would I be able to hire a Transport Canada Design Approve Representative and design a new gear acturator?

@Shiroyuki

Take a look at this post.  It has pictures of the Dukes actuator which was also manufactured by ITT (interchangable).  There is an exploded diagram of the worm gear and gear set.  

There is also a picture of the Eaton actuator used in 1978 and on for comparison.  The Eaton was also manufactured under the names of Eaton and also Avionics Products Company, CONDEC, Vickers (all the same actuator - just predecessor companies acquired by Eaton).  This is the actuator with the "no-back spring".

There was also an actuator shown made by Plessey which was interchangeable with the Eaton.  Plessey is no longer supported and should be avoided. .

 

 

Edited December 27, 2024 by 1980Mooney

[Shiroyuki]

57 minutes ago, MikeOH said:

@Shiroyuki

That part is NOT the one WE are talking about.  That is the actuator for later models that suffer from the no-back spring.  I know those are hard to find, too.

The Dukes actuator we are discussing has a worm gear set that wears to a condition that it has to be replaced.  There is a service bulletin that describes the inspection procedures: one every 100 hours (not to invasive) and another every 200 hours (requires removal and disassembly).

Problem is, if the these gears are bad there are NO replacements available.  Basically, you are forced to buy a used actuator.  Or, supposedly, you can spend a bunch to convert the plane to manual gear (after you find all of those parts somewhere!)

 

39 minutes ago, 1980Mooney said:

@Shiroyuki

Take a look at this post.  It has pictures of the Dukes actuator which was also manufactured by ITT (interchangable).  There is an exploded diagram of the worm gear and gear set.  

There is also a picture of the Eaton actuator used in 1978 and on for comparison.  The Eaton was also manufactured under the names of Eaton and also Avionics Products Company, CONDEC, Vickers (all the same actuator - just predecessor companies acquired by Eaton).  This is the actuator with the "no-back spring".

There was also an actuator shown made by Plessey which was interchangeable with the Eaton.  Plessey is no longer supported and should be avoided. .

 

 

Thanks for the explaining. This is new knowledge for me today. I have read both SB 112 and 190 and wasn’t sure how big of a deal they are. For my 77J, according to serial number I probably have a duke actuator.

I have timed my gear retraction before and it took 5 seconds, so I suppose it has the 40:1 gear.

How long do these worm gear actually fail? I suppose I can reduce the wear and tear on the actuator by getting the gear up asap so it put less strain on the mechanism… and lower them at a slower airspeed too. I hope that will prolong their life.

so now the worm gear set is no longer available, how difficult is it to find a used actuator? Are they widely available, show up for sell from time to time, or are they rarely available as well?

[N201MKTurbo]

4 hours ago, Shiroyuki said:

 

Thanks for the explaining. This is new knowledge for me today. I have read both SB 112 and 190 and wasn’t sure how big of a deal they are. For my 77J, according to serial number I probably have a duke actuator.

I have timed my gear retraction before and it took 5 seconds, so I suppose it has the 40:1 gear.

How long do these worm gear actually fail? I suppose I can reduce the wear and tear on the actuator by getting the gear up asap so it put less strain on the mechanism… and lower them at a slower airspeed too. I hope that will prolong their life.

so now the worm gear set is no longer available, how difficult is it to find a used actuator? Are they widely available, show up for sell from time to time, or are they rarely available as well?

If they are serviced properly, they last a very long time.

[Matthew P]

5 hours ago, Shiroyuki said:

 

Thanks for the explaining. This is new knowledge for me today. I have read both SB 112 and 190 and wasn’t sure how big of a deal they are. For my 77J, according to serial number I probably have a duke actuator.

I have timed my gear retraction before and it took 5 seconds, so I suppose it has the 40:1 gear.

How long do these worm gear actually fail? I suppose I can reduce the wear and tear on the actuator by getting the gear up asap so it put less strain on the mechanism… and lower them at a slower airspeed too. I hope that will prolong their life.

so now the worm gear set is no longer available, how difficult is it to find a used actuator? Are they widely available, show up for sell from time to time, or are they rarely available as well?

Problem is, you find a used actuator and have no idea as to the condition of the gears...

[Shiroyuki]

3 hours ago, N201MKTurbo said:

If they are serviced properly, they last a very long time.

I suppose it also depends on the gear cycles…

Why is the SB based on hours not cycles? Obviously 200 hour flying circuits is different from 200 hours long cross country. One might have 1000 gear cycle, the other maybe 100…..

[N201MKTurbo]

1 minute ago, Shiroyuki said:

I suppose it also depends on the gear cycles…

Why is the SB based on hours not cycles? Obviously 200 hour flying circuits is different from 200 hours long cross country. One might have 1000 gear cycle, the other maybe 100…..

I have wondered the same thing. 
 

Gears wear by cycles, grease dries out by time. Choose your poison.

[Shiroyuki]

3 minutes ago, N201MKTurbo said:

I have wondered the same thing. 
 

Gears wear by cycles, grease dries out by time. Choose your poison.

Greasing the actuator gear box is on the annual inspection guide. If someone is concerned about grease drying out over time then it should be a calendar item, also not based on hours…

I’m curious as how they come up with this 200 hour number…

[N201MKTurbo]

8 minutes ago, Shiroyuki said:

Greasing the actuator gear box is on the annual inspection guide. If someone is concerned about grease drying out over time then it should be a calendar item, also not based on hours…

I’m curious as how they come up with this 200 hour number…

No clue.

When I do the 200 hour, I take actuator out of the plane. I remove the gear cover and remove the ring gear. Then I wash out all the old grease so it is nice and clean plus I can inspect the gears. Then I replace the ring gear, pack the gearbox with the moly grease and replace the cover. Then I will give it a couple of pumps of grease through the zerk, till it comes out of the screw hole. Then I put it back in the plane.

[Shiroyuki]

2 minutes ago, N201MKTurbo said:

No clue.

When I do the 200 hour, I take actuator out of the plane. I remove the gear cover and remove the ring gear. Then I wash out all the old grease so it is nice and clean plus I can inspect the gears. Then I replace the ring gear, pack the gearbox with the moly grease and replace the cover. Then I will give it a couple of pumps of grease through the zerk, till it comes out of the screw hole. Then I put it back in the plane.

https://mooney.com/wp-content/uploads/2020/12/100-HOURANNUAL-Inspection-Guide.pdf

Page 5 under electric gear retraction system.. it says lubricate actuator gear box for duke and itt…

[N201MKTurbo]

17 minutes ago, Shiroyuki said:

https://mooney.com/wp-content/uploads/2020/12/100-HOURANNUAL-Inspection-Guide.pdf

Page 5 under electric gear retraction system.. it says lubricate actuator gear box for duke and itt…

Yes, for the annual, you give it a few pumps of grease till it comes out the screw hole. This is done in the plane.