Gear Rigging

[RLCarter]

I used a small "C" clamp to hold the tool in place, I had to remove some of the powder coating from the tool so it would fit over the arm. I agree that a 1/2" drive that is clocked 45* is a poor design, i ended up buying an adapter from Sears (craftsman) that is clocked 45*.  All my settings were at the high side, a little harder to lower or raise but I didn't want the gear to fold up on landing

[Andy95W]

9 hours ago, DaV8or said:

First, I'd like to say that I am sadly disappointed in the "special tool" to check the preload. It's kinda crappy. 

This brings up the second stupid thing about this tool. It has nothing to secure it at the pivot point. It can easily slip off

 I realize that not all Mooneys may not be the same 

my mains are set at around 310 inch-pounds. They were last set by LASAR and are very close left to right. The manual calls for 240-280 inch-pounds. Should I mess with them, or is a little extra a good idea these days?? Should I trust my readings? The whole thing seems kind of imprecise and loose to interpretation.

First, I can commiserate with you about the main gear tool, but I will say that the more you do it, the better you'll get at it.  It's really not that bad, just kind of unwieldy until you get the hang of it.  And actually, all Mooney landing gear are the same.  They beefed-up some of the attach points in the 80/90's to get a weight increase, but the retract and over-center mechanism for them stayed the same after SB M20-155.  

As far as your 310 in-lbs: that depends on two things.

1.) How is your nose gear rigging?  Is it between 100-130 in-lbs (or within limits for bungee spring compression if you have electric gear)?  If it is outside of the limits, I would adjust all 4 adjustment points- 2 for the nose gear, 1 for each main.  If your nose gear is exactly right, I would probably leave the mains where they are, depending on #2, below.

2.) I would verify that you are taking your measurement at exactly the right moment as the over center link begins to move.  I suggest taking a beer can and cutting a few strips of metal about 3" long and 3/8" wide to use as a feeler gauge.  Pinch that metal strip in the over center link and start your test pulling very gently on the strip.  When it just begins to slip out, take your reading.

Changing the pre-loads is almost as much art as science.  If you change one rod end, it will affect the other three adjustment points.  Officially, of course, I would say this is something that should be done by an A&P.

[DaV8or]

2 hours ago, RLCarter said:

I used a small "C" clamp to hold the tool in place, I had to remove some of the powder coating from the tool so it would fit over the arm. I agree that a 1/2" drive that is clocked 45* is a poor design, i ended up buying an adapter from Sears (craftsman) that is clocked 45*.  All my settings were at the high side, a little harder to lower or raise but I didn't want the gear to fold up on landing

Yes, stiffer is better to prevent gear collapse, but in my case, I have electric gear. So I believe that having the gear rigged on the high side puts more load and therefore more wear on the actuator. Throw in the mix that I have the original 20:1 gears and I have some concern. On the other hand, it seems to work just fine as is.

[DaV8or]

58 minutes ago, N1395W said:

1.) How is your nose gear rigging?  Is it between 100-130 in-lbs (or within limits for bungee spring compression if you have electric gear)?  If it is outside of the limits, I would adjust all 4 adjustment points- 2 for the nose gear, 1 for each main.  If your nose gear is exactly right, I would probably leave the mains where they are, depending on #2, below.

2.) I would verify that you are taking your measurement at exactly the right moment as the over center link begins to move.  I suggest taking a beer can and cutting a few strips of metal about 3" long and 3/8" wide to use as a feeler gauge.  Pinch that metal strip in the over center link and start your test pulling very gently on the strip.  When it just begins to slip out, take your reading.

Changing the pre-loads is almost as much art as science.  If you change one rod end, it will affect the other three adjustment points.  Officially, of course, I would say this is something that should be done by an A&P.

I have not checked the nose gear yet. I have electric, so I have to use the measurement with caliper method. It is next on the list when I get back to the hangar. I think to do your beer can method I would need three hands. One to move the wrench, one to pull on the beer can strips and one to hold the gear tool from slipping.

[carusoam]

I recall somebody discussing buying a 45° Socket extension from a good tool supplier. Around here somewhere....

Best regards,

-a-

[Andy95W]

You kind of hold the metal strip with your index and middle finger, and stabilize the tool with your thumb, if necessary.  You're just feeling for the first instant of movement of the feeler gauge.  Keep at it, it gets easier.  After a few minutes of moving the tool on the gear you'll be able to get it to stay on without holding it, after which it will pop off the linkage, but hopefully you've gotten a good torque reading by then.

No, it really isn't a precision measurement, but after doing it a few times you will get a feel for what's right and what isn't.

[DaV8or]

1 hour ago, carusoam said:

I recall somebody discussing buying a 45° Socket extension from a good tool supplier. Around here somewhere....

Best regards,

-a-

An extension makes the problem much worse. With an adapter, the force is no longer being applied along the axis of the gear actuation rods. This makes the tool want to slip off even more.

[Guitarmaster]

Since you can't get at it with an adapter, 280 inch pounds is 23 foot pounds. Just sayin

Sent from my XT1254 using Tapatalk

[47U]

Rather than struggle with a 3/8" to 1/2" adapter, I scrounged up a scrap length of 1/2" OD square tube, which conveniently has a 3/8" ID.  Cut off 1/2" or so length and dress up the edges with a file.  It slides right over the 3/8" drive of the torque wrench and fits nicely inside the 1/2" square hole in the gear tool.  Red paint is optional.  It really does help with stability of the torque wrench. 

[DaV8or]

52 minutes ago, 47U said:

Rather than struggle with a 3/8" to 1/2" adapter, I scrounged up a scrap length of 1/2" OD square tube, which conveniently has a 3/8" ID.  Cut off 1/2" or so length and dress up the edges with a file.  It slides right over the 3/8" drive of the torque wrench and fits nicely inside the 1/2" square hole in the gear tool.  Red paint is optional.  It really does help with stability of the torque wrench. 

If you read my posts above, that's exactly what I did. It really helped. There is a little more to it. There was a lot of filing required on the inside of the tubing, but not difficult work. I used 1/2" square cold rolled .062 wall tubing.

Also for those that don't want to be a CB, you can also buy this-

It is a sleeve that slips over the 3/8" drive and has magnets to hold in place on the socket. $10 on Amazon. I had the tubing already and it got me closer on axis then this would.

Edited October 7, 2016 by DaV8or

[carusoam]

Dav8 has got some skills!

Best regards,

-a-

[Shiny moose]

So I used one an electronic torque adapter to rig my new to me  m20f gear. It worked really well and consistent readings, anyone else used one of these or think that it's a bad idea this is not the one I have but you get the idea .https://www.denniskirk.com/283927.sku?utm_source=google&utm_medium=cse&gclid

 I just had a hard time with the .005-.010 movement at X as  stated in the MM.  Now that's a calibrated finger. I would like to hear more on the measurement . I did Use a cut down feeler gauge for the movement at the link edge but I could feel movement way before this feelergauge had clearance.  the MM shows movement location away from the edge of the link not at the edge. I would like to hear from experienced people on the best way to measure this. My gear seems way to tight at the Johnson bar, with a new downlock block from laser

 

[Yetti]

This is a great read: A guy complains about the subjectivity of gear rigging and someone suggest cutting up a beer can.... presumably empty...

Which of course reminds me of that saying "here hold my beer and watch this"

Please return to your regular programming

[carusoam]

Torque wrenches get periodically tested/calibrated over time.  You could have the electronic device tested the same way if you were going to use it on something that is expensive/important to fix.

Ask a mechanic how often the shop's important tools get calibrated?

PP thoughts only, not a mechanic...

Best regards,

-a-

[Shiny moose]

I understand torque wrench calibration and gear rigging very well, we're it got a bit weird was where to measure the movement according to the maintenance manual it's not measured at the end of the link where a feeler gauge could be used, or I'm just reading to much into this. If I was home I would copy the paragraph. Anybody??

[RobertGary1]

16 hours ago, carusoam said:

Ask a mechanic how often the shop's important tools get calibrated?

 

-a-

AC43.13 says every year but every 6 months is more common. 

- Robert

[RLCarter]

paragraph "g" is confusing 

Edited January 3, 2017 by RLCarter

[N201MKTurbo]

23 minutes ago, RLCarter said:

paragraph "g" is confusing 

What is confusing about it?

 

[salty]

4 hours ago, RLCarter said:

paragraph "g" is confusing 

Yeah it is confusing. It sounded contradictory to me. My A&p Explained that one set of retraction tubes is referring to the nose, and the other is the mains, but I don't recall which is which now. It was relatively easy to figure out once he explained that to me. 

[Sabremech]

23 hours ago, RobertGary1 said:

AC43.13 says every year but every 6 months is more common. 

- Robert

Once every 12 months is more common. Typically only less if dropped or suspected to be out of cal. 

Edited January 3, 2017 by Sabremech

[N201MKTurbo]

1 hour ago, salty said:

Yeah it is confusing. It sounded contradictory to me. My A&p Explained that one set of retraction tubes is referring to the nose, and the other is the mains, but I don't recall which is which now. It was relatively easy to figure out once he explained that to me. 

The nose gear rods push to extend the gear, the mains pull to extend. So after you get the no preload lengths, 2 1/2 turns longer on the nose rods and 2 1/2 turns shorter on the main rods should get you the correct preload.

[RLCarter]

12 hours ago, N201MKTurbo said:

The nose gear rods push to extend the gear, the mains pull to extend. So after you get the no preload lengths, 2 1/2 turns longer on the nose rods and 2 1/2 turns shorter on the main rods should get you the correct preload.

As the J-Bar is rotated from the floor to the "Gear Down" lock under the panel, wouldn't the the retraction tubes be pulling on the nose and pushing on the mains? And again step "G" does not say which tubes to shorten and which to lengthen

 

[N201MKTurbo]

6 hours ago, RLCarter said:

As the J-Bar is rotated from the floor to the "Gear Down" lock under the panel, wouldn't the the retraction tubes be pulling on the nose and pushing on the mains? And again step "G" does not say which tubes to shorten and which to lengthen

 

You are correct, I have gear dislexia. The point is some are pushing and some are pulling. It is obvious when you are looking at it.

[thinwing]

Actually the beer can method is closest on my Mooney Bravo shop manual.Basically calls for a feeler strip and torque measurement is taken at point strip falls out on its own

[RLCarter]

I have an original Mooney Maintenance Manual (Hard Cover) that came with the plane when I purchased it. While out at the hangar today I looked to see what it had to say about "Gear Rigging", it reads word for word as the current manual except the older copy has the part#'s for the items they are talking about. I keep referencing step "g" from above as the confusing part, with the part#'s in place you can reference the drawing which also has the part#'s and it becomes very clear that the front retraction tubes get shortened and the mains get lengthened. I'm currently double checking the rigging  and the entire landing gear system, all over center torque values are in spec but I play hell getting the j-bar handle to release from under the panel to retract the gear and then the fight is on again to lock the handle back up when lowering the gear. I have ordered a new latch socket from LASAR as mine is worn, not sure if it will make a difference or not.