Gear Rigging

[Sabremech]

9 hours ago, RLCarter said:

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.

I had a similar experience with my J bar after installing a new down lock. I found my J bar handle was bent. I had it straightened and it works great now. 

[RLCarter]

1 hour ago, Sabremech said:

I had a similar experience with my J bar after installing a new down lock. I found my J bar handle was bent. I had it straightened and it works great now. 

I remember reading that and looking at mine at the time, hopefully this corrects the issue.

[Sabremech]

2 hours ago, RLCarter said:

I remember reading that and looking at mine at the time, hopefully this corrects the issue.

If you haven't already done this, put a straight edge on your j bar handle and see if it's flat. It gets bent by being accidentally kicked out of the up lock  and slamming into the down lock block in flight. 

[Shiny moose]

So Please explain how you determined it was bent , where exactly was the bend , and  explain how it was straightened.

using this information for my own benefit 

[Sabremech]

2 hours ago, Shiny moose said:

So Please explain how you determined it was bent , where exactly was the bend , and  explain how it was straightened.

using this information for my own benefit 

It was bent aft from the top to the bottom. A straight edge the length of 12 inches placed on the aft side of the bar form the lowest point on the floor on up will show light between the ruler and bar. I couldn't see the bend by just looking at it but it was quite obvious once the straight edge ruler was used. 

I removed the j bar assembly from the aircraft and had it straightened at a local machine shop. 

[Shiny moose]

Thanks for the information. Do you think the bend happened due to something getting stuck under the j bar during retraction (i.e. A seatbelt) and I wonder how many of these j bars are bent and we don't even know it, the preload is just considered our at annual and adjusted until the gear is just to hard to unlock or lock for an average person ( excluding Arnold or Hulk)  

[carusoam]

ShinyM,

if the jbar gets released at cruise speed, it comes swinging down to the floor in a memorable way.

You don't want to experiment releasing the bar above certain logical speeds...Vle

Something I learned with my M20C before the days of the Internet....

If it can bend a JBar, it can snap a bone...

At ordinary gear extension speeds your hand is in complete control of the Jbar.  Unless you are Arnold, bending that tube would take great strength.

there is a speed that makes the gear down process take very little effort.  It is a combination of gravity, g load and or velocity...  the gear doors work like a sail.

Best regards,

-a-

[Sabremech]

3 hours ago, Shiny moose said:

Thanks for the information. Do you think the bend happened due to something getting stuck under the j bar during retraction (i.e. A seatbelt) and I wonder how many of these j bars are bent and we don't even know it, the preload is just considered our at annual and adjusted until the gear is just to hard to unlock or lock for an average person ( excluding Arnold or Hulk)  

I don't think it can get bent during retraction from a seatbelt getting stuck. When I found mine bent, I talked with Dmax and he said it happens from someone sitting in the backseat accidentally kicking the gear handle in cruise and the gear slamming down into the down lock block. 

David

[Shiny moose]

I guess bent is bent! I checked mine ( new to me M20F) today, in the first 12 inches with a straight edge I've got more than an 1/8 inch bend! That could be a 1/4 inch over the length of the tube.  I will be removing it to have it straightened next week. 

Thanks for the input 

 

[Sabremech]

I suspect there's more airplanes flying out there with the J bar bent and worn down lock blocks. Mine really came to light when I changed my down lock block and then had trouble getting the handle to lock. I found I was pushing the handle assembly into the fuel line under the floor from the right tank over to the fuel selector valve. This is what lead me to check the bar for straightness. 

 David

[RLCarter]

27 minutes ago, Sabremech said:

I suspect there's more airplanes flying out there with the J bar bent and worn down lock blocks. Mine really came to light when I changed my down lock block and then had trouble getting the handle to lock. I found I was pushing the handle assembly into the fuel line under the floor from the right tank over to the fuel selector valve. This is what lead me to check the bar for straightness. 

 David

The new lock block will be in Monday, once installed and with the (4) retraction tubes set at "Zero" I would think getting the handle locked and unlocked from the block should be almost effortless. 

[RLCarter]

Installed the LASAR gear down lock this afternoon, the gear was left in the "Zero" preload from the other day. With the new block in place the J-bar handle still required some effort to engage it in the block, but not near as much as before. I double checked the J-bar for straightness at three locations and all was good. Looking at the old block it seems the handle is off to the left side according to wear. Will set the preload back to zero tomorrow and remove the handle from the J-bar and check the last few inches to make sure it's not bent there....

as you can see from photo it was well past time to replace the lock block

[carusoam]

That photo shows the nice step that wears in.  The chrome coated steel handle is harder than the aluminum.  This causes the slow erosion of the aluminum.  There is probably no wear of the Jbar...

The track indicates that the bar seems to head straight up the center before landing in the off-center egg shaped hole.

Best regards,

-a-

[Guitarmaster]

I like my electric gear!! Nevermind that it won't come down in cold weather....

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[RLCarter]

I have a reconditioned handle from LASAR (re-chromed), taking my digital inclinometer out in the morning to see if I can find something out of alignment. Electric gear not coming down in the cold could be an issue, 20 minutes and I'm rested enough to swing the gear.....lol

[Marauder]

I like my electric gear!! Nevermind that it won't come down in cold weather....

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You still having a problem? I thought by now you would have resolved it.


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[Guitarmaster]

You still having a problem? I thought by now you would have resolved it.


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Just bought a relay and am installing it on the 24th.

$26.00. Talk about CB!! Lol!

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[Marauder]

Just bought a relay and am installing it on the 24th.

$26.00. Talk about CB!! Lol!

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Please do a write-up on the cause. Could help another one of us in the future.


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[RLCarter]

Spent the last few days looking over the manual gear system trying to find the cause for the excessive amount of force it takes to release and lock the j-bar handle from the gear down lock. To eliminate as much as possible all gear doors have been disconnected, the new LASAR lock block helped some but it was still just shy of a two handed operation when rigged. Two things that got my attention are as follows:

(1)  With all 4 retraction links disconnected at the J-bar, the bar does not go the last 3/8” to 1/2” forward so the handle will slide into the “Gear Down” lock with out a little forward pressure. This was not noticed before due to the fact that the 2 Bungee assemblies are still attached to the J-bar forcing it towards the floor. The bungees relax allowing the J-bar to become very easy the last inch or so before getting to the gear down lock. By pushing with one finger on the J-bar just below the handle and holding the release button with my other hand the handle snaps in place fully, the J-bar is hitting the plastic around the nose wheel well. Most of the older Moonies I have seen have carpet around the nose wheel well which is thicker than the plastic. So how much clearance should there be?

(2) The rigging procedure calls for getting “Zero” Pre-load, then shortening the 2 retraction tubes going to the nose wheel. When set at “Zero” both bolts move freely in the rod-end bearings, when the tubes are shortened equally 2 turns the last of the 2 tube is difficult to install the bolt. I have checked and both rod-end bearings have the same thread pitch. The other (forward) ends of the nose wheel retraction tube have the eccentric bushings, could these cause the retraction tubes to not line up if the bushing are not set the same?

[N201MKTurbo]

Don't try to install the bolts with the gear down. Unlatch the j bar and make sure the over center links are not over center. The bolts will go right in.

 

[RLCarter]

Just now, N201MKTurbo said:

Don't try to install the bolts with the gear down. Unlatch the j bar and make sure the over center links are not over center. The bolts will go right in.

 

Mine wont, if the left side is installed 1st the right is too short, right side 1st left is too long ( talking Nose Wheel)

[N201MKTurbo]

Just now, RLCarter said:

Mine wont, if the left side is installed 1st the right is too short, right side 1st left is too long ( talking Nose Wheel)

Huh, they were even before you put the two turns on and now they are not? If it is just a tiny amount you might try moving the nose wheel up and down with your hand to compress the bungee on the one that is already connected.

[RLCarter]

Just now, N201MKTurbo said:

Huh, they were even before you put the two turns on and now they are not? If it is just a tiny amount you might try moving the nose wheel up and down with your hand to compress the bungee on the one that is already connected.

No bungees on the nose retraction tubes, not sure what's going on, I can get the 2nd bolt in, it just takes more force to do so

[salty]

I'm not a mechanic, and I have a lousy memory, but I think mine needed an extra half turn on one side of the nose wheel. The two turns are what "should" put them where you want, but, as I understand it, that is meant to be a starting point to get you close. I think you should adjust the length so that the bolt fits. My understanding is that is the whole point of the exercise.

[carusoam]

When my 65C got a new carpet... the Jbar ran into some restriction as the gear went up/bar went down...

The original coating on the nose wheel house was a thin piece of fabric. Mine got replaced with a thin piece of carpet.

Just Another thing to consider from the old guys with fuzzy memory committee.... 

Best regards,

-a-