the infamous gear actuators

[j3gq]

18 hours ago, Yetti said:

You are going to cycle this say 150 times per year.   The unanswered question was how many cycles the Engineer designed them for.   Should we say 10,000.    So there is your math.   Can you replace the gears, have a brass disc machined?  Yep. 

You know, you are doing a good job while stubbornly insisting in your point. I am coming around and see it too ... your way. And had you not insisted and replied multiple times, I may have just missed that point. So what am I gonna do ? I think I have to sleep over it. Good job !

[larrynimmo]

When I bought my Mooney I was told there is one company that specializes in landing gear gear box....TopGun aviation in California...they did my spring replacement...which was expensive, but they may be another source to buy one....

[Guest]

1 hour ago, EricJ said:

I like how Figure 2 shows putting Loctite in the bearing. 

That converts it back to a D model!

Clarence

[carusoam]

I sense a lot of activity picking on the fixed gear sites 2-night...

Congrats to all y’all speed and efficiency demons...

poor guy was looking for a reason to stay with fixed gear, and you handed it to him...! 

 

Add some realism for a moment...

My gear is in transit for about five seconds... let’s say 10 to make things... interesting..?

I use the plane once per week... call it twice... just to be interesting...?

10 seconds for up, 10 seconds for down, twice each week... 40 seconds per week...

How many seconds in an hour? How many hours per year...  Alexa says... 35 minutes every year...

 

Without taking the math much further... you find quite quickly you chance of wearing these devices out is pretty slim...

As far as finding a way to break them goes.. that gets a bit more common...

There are folks that appreciate all the manual options that the older Mooneys have to offer...

nothing more classic than an all manual Mooney...

• manual gear
• hydraulic flaps
• vac or crank step
• crank speed brakes

Don’t feel alone because your friends all want electric gear and flaps...

You can go all manual and still get WAAS approaches...

if there is still concern regarding the manufacture of the no back spring clutch... spring... itself...  issue...

Find the thread replete with pics by Andrew... he did a great job of documenting things...

One thing to remember... a big challenge is the mistake of clashing the automated system with the manual system... that can end badly...  if j3 is a mechanical engineer, he will realize how poor a choice brass actually is when a harder material is really required... brass, bronze, aluminum... whatever...

I don’t recall that happening in years...

more likely to fly into a mountain, or have diesel fuel put in your gas tank...

The opportunities for pilot mistakes are giant.  They are significant. But, they don’t happen with any regularity...

So.... let’s continue to fight the issues that cause bad outcomes...

Which one was I looking for?

who makes the 20:1 gears, who has the 40:1 gears?

I think somebody was trying to convince the IP to buy a brand new plane...

I think j3 is smarter than that...

Sure, it would be nice... but, pre-owned Mooneys are pretty nice too...

Everyone holds out for the particulars they want...

Write a list of must haves, want to haves, and don’t care...  see where the plessy or ITT lands on your list compared to the 40:1 number...

PP thoughts only, I really loved my manual M20C... 

Best regards,

-a-

 

[PT20J]

Here's an interesting NTSB report from an accident last June. Late model M20J with a Plessey actuator. No back spring tang failed 427 hours and about 5 years after replacement. Mooney told NTSB Plessey actuators and no back springs are unavailable. Normally gear ups don't turn into accidents, but this one ground down part of the tubular structure causing "substantial damage." Had this been an air carrier accident, I'm sure NTSB would have looked deeper into the cause of the spring failure and traced it back to the point of manufacture. 

I wonder which is more failure prone: Eaton or Plessey?

Skip

Investigative Photographs_6 Pages-Rel.pdf

Report_ERA22LA319_105499_12_17_2022 4_50_16 AM.pdf

[PT20J]

Looking at the Mooney service bulletins, apparently Plessey calls this part a torsion spring and Eaton calls it a no back spring. I assume that they work similarly given the design of the actuators. Jack screws with acme threads, like the Mooney trim actuator, are self locking. However, the Plessey and Eaton landing gear actuators use a ball screw which has lower friction but can be back driven and requires some sort of brake. The spring acts as a wrap spring clutch allowing the motor to drive the gear to the down position, but preventing the gear from moving down from the retracted position on its own. The Dukes actuator has a pinion and wheel gear drive, like the flap actuator, which provides the locking function.

Eaton's Grand Rapids MI repair facility lists Mooney actuators among the products that it repairs. I wonder if they replace springs and at what cost?

https://www.eaton.com/us/en-us/services/aerospace-repair-centers/grand-rapids.html

Skip

[GeeBee]

1 hour ago, PT20J said:

Looking at the Mooney service bulletins, apparently Plessey calls this part a torsion spring and Eaton calls it a no back spring. I assume that they work similarly given the design of the actuators. Jack screws, like the Mooney trim actuator, with acme threads tend to be self locking. However, the Plessey and Eaton landing gear actuators use a ball screw which has lower friction but can be back driven and requires some sort of brake. The spring acts as a wrap spring clutch allowing the motor to drive the gear to the down position, but preventing the gear from moving down from the retracted position on its own. The Dukes actuator has a pinion and wheel gear drive, like the flap actuator, which provides the locking function.

Eaton's Grand Rapids MI repair facility lists Mooney actuators among the products that it repairs. I wonder if they replace springs and at what cost?

https://www.eaton.com/us/en-us/services/aerospace-repair-centers/grand-rapids.html

Skip

That is interesting. I sometimes am in GRR, maybe I can stop by and find something out.

[0TreeLemur]

So, there is this tiny spring in the electric gear actuator as a single point of failure so that if it's "tang" fails, you have a Bad Day ?   I'm starting to miss my Johnson Bar already...

[toto]

20 minutes ago, 0TreeLemur said:

So, there is this tiny spring in the electric gear actuator as a single point of failure so that if it's "tang" fails, you have a Bad Day ?   I'm starting to miss my Johnson Bar already...

Yeah - there’s a SB for it (attached). Discussed ad nauseum here on MS, but basically …. This spring fails every once in a while, and when it fails, it takes out both the primary actuator and the manual extension. Yay. The documented failures are mostly associated with a bad batch of springs, but who knows whether the replacements are any better. There isn’t enough history to evaluate the risk, and the springs aren’t currently available anyway, so we just kind of fly the plane and worry about other things. Jonny said this is one of the items they’re prioritizing, but who knows when they’ll next be in stock. 
 

 

SBM20-282A.pdf

[EricJ]

4 hours ago, 0TreeLemur said:

So, there is this tiny spring in the electric gear actuator as a single point of failure so that if it's "tang" fails, you have a Bad Day ?   I'm starting to miss my Johnson Bar already...

The earlier electric actuators don't have this issue, only the later ones with the no-back spring.    My 77 J model doesn't have this problem.

[0TreeLemur]

51 minutes ago, EricJ said:

The earlier electric actuators don't have this issue, only the later ones with the no-back spring.    My 77 J model doesn't have this problem.

Anyone know when the no-back spring appeared?

[toto]

33 minutes ago, 0TreeLemur said:

Anyone know when the no-back spring appeared?

I think it’s basically any aircraft with an Eaton/Vickers actuator. The SB even includes the C model, though I doubt there are many C’s affected. 

If you have a Plessy actuator, I think you’re good. If you have an Eaton, then you have a NBS and the SB would apply. 

[1980Mooney]

6 hours ago, toto said:

Yeah - there’s a SB for it (attached). Discussed ad nauseum here on MS, but basically …. This spring fails every once in a while, and when it fails, it takes out both the primary actuator and the manual extension. Yay. The documented failures are mostly associated with a bad batch of springs, but who knows whether the replacements are any better. There isn’t enough history to evaluate the risk, and the springs aren’t currently available anyway, so we just kind of fly the plane and worry about other things. Jonny said this is one of the items they’re prioritizing, but who knows when they’ll next be in stock. 

Do you mean the commitment made to prioritize this back in November 2020...?   Maybe they are in stock - I haven't had the need to look.

 

[1980Mooney]

1 hour ago, toto said:

I think it’s basically any aircraft with an Eaton/Vickers actuator. The SB even includes the C model, though I doubt there are many C’s affected. 

If you have a Plessy actuator, I think you’re good. If you have an Eaton, then you have a NBS and the SB would apply. 

"If you have a Plessey actuator you're good"....as long as you never need it repaired.  There are no parts and no support for Plessey. 

[toto]

Just now, 1980Mooney said:

"If you have a Plessey actuator you're good"....as long as you never need it repaired.  There are no parts and no support for Plessey. 

You’re good wrt the no-back spring. No idea about Plessy actuators otherwise. 

[1980Mooney]

4 minutes ago, toto said:

You’re good wrt the no-back spring. No idea about Plessy actuators otherwise. 

Plessey/GEC actuators had their own problems wrt the "torsion spring"  There was a 1992 Service Bulletin M20-92.  It highlighted 2 gear failures.

C:sb-si-slSISi-92.PDF (mooney.com)

[toto]

33 minutes ago, 1980Mooney said:

Plessey/GEC actuators had their own problems wrt the "torsion spring"  There was a 1992 Service Bulletin M20-92.  It highlighted 2 gear failures.

C:sb-si-slSISi-92.PDF (mooney.com)

I retract what I said about Plessy being good

 

[Raymond J1]

There is a STC to install a johnson bar on an M20 R ? 

[Pinecone]

Someone on MS has a PMA and was looking at making no back springs.  Whatever happened to that effort?

[0TreeLemur]

5 hours ago, Raymond J1 said:

There is a STC to install a johnson bar on an M20 R ? 

Reminder that Jbar's have their own unique set of drawbacks.  Yesterday after raising the gear I struggled to engage the Jbar in the gear-up position because a the co-pilot's seat belt strap was in the way.   Solved that.  Engaged the Jbar in the retainer on the floor solidly, or so I thought, and a few seconds later it decided to become un-engaged and whack me in the arm.  Probably the fourth or fifth time that's happened to me in over 500 hours...

[Fly Boomer]

18 hours ago, PT20J said:

Eaton's Grand Rapids MI repair facility lists Mooney actuators among the products that it repairs. I wonder if they replace springs and at what cost?

The list on their web showing the ones they work on looks promising, but I don't know if those "customer part numbers" make any sense:

Eaton      Customer
Part       Part

102000-2   N/A          Actuator, Landing Gear      Mooney M20

102000-3   560254-503   Actuator, Landing Gear      Mooney M20

102000-4   560254-505   Actuator, Landing Gear      Mooney M20

102000-7   560254-507   Actuator, Landing Gear      Mooney M20

102000-9   N/A          Linear Actuator             N/A

102000-10  N/A          Actuator Assembly, Linear   Mooney M20

102000-12  N/A          Actuator Assembly, MLG      N/A

102000-13  N/A          Actuator, Landing Gear      Mooney

 

[A64Pilot]

On 10/20/2019 at 12:16 PM, larrynimmo said:

When I bought my Mooney I was told there is one company that specializes in landing gear gear box....TopGun aviation in California...they did my spring replacement...which was expensive, but they may be another source to buy one....

6 months ago I paid them $1,000 to order me a NBS, they told me in a few months, a few months later they said expect Dec.

Not saying anything against them they don’t have anything to do with the spring, I did wonder about having to pay for it first though.

What I am saying is if you expect to ever have to replace this thing better get one on order and save it when it comes in. I’m afraid the supply may already have dried up.

My Actuator works fine smooth and no noise, but it’s got 40 yr old grease in it, it  at least needs cleaning and re greasing.

I’ve tried several times to get in touch with Lasar, left a phone message or two and an email or two, no answer, Top Gun at least answered the phone. When the spring comes in I plan on sending them the actuator. I’m an IA and can legally do it, but never having done so and I guess zero parts availability I think it best to have them do it.

[toto]

1 hour ago, A64Pilot said:

What I am saying is if you expect to ever have to replace this thing better get one on order and save it when it comes in. I’m afraid the supply may already have dried up.

@Alan Foxhad a couple of brand-new NBSs that he posted on MS a while back. I was too slow to get one at the time, but he might have a source?

[A64Pilot]

15 minutes ago, toto said:

@Alan Foxhad a couple of brand-new NBSs that he posted on MS a while back. I was too slow to get one at the time, but he might have a source?

I wasn’t aware of that or I would have bought one. I’m hoping Mooney has done an order and I’ll get one soon.

Surely at $1,000 ea they have to be a high profit item so I would expect ready availability, but there is obviously something I don’t know.

[Will.iam]

As discussed before mooney has no spare cash for inventory. Can only sell what they order and one off’s or 2 or three more expensive so when they get about 10 orders or so pre paid they get an oder put through. I think last order they had arrive were already spoken for.