M20F Trim system missing

[davesly]

I purchased a 1969 Mooney airframe (sans motor, prop and autopilot).  The elevator trim shaft (going to tail) is not connected to anything on the cockpit end.  I assume there was a trim motor and gear system that was removed when they took out the Stec autopilot.  Does this entire mechanism come with a new autopilot system, or is the trim system an individual component.  If it is individual, where can I purchase a new or used trim motor+gears so that I can hook up my elevator trim again?

If I can't find electric trim, then perhaps I'll need to find the missing parts to connect the tube from the tail to the tube from the trim wheel.  Anyone have a picture of that?

[N201MKTurbo]

look in the IPC. I think there is a support block and a little U joint. A salvage yard is your friend.

[EricJ]

28 minutes ago, davesly said:

I purchased a 1969 Mooney airframe (sans motor, prop and autopilot).  The elevator trim shaft (going to tail) is not connected to anything on the cockpit end.  I assume there was a trim motor and gear system that was removed when they took out the Stec autopilot.  Does this entire mechanism come with a new autopilot system, or is the trim system an individual component.  If it is individual, where can I purchase a new or used trim motor+gears so that I can hook up my elevator trim again?

If I can't find electric trim, then perhaps I'll need to find the missing parts to connect the tube from the tail to the tube from the trim wheel.  Anyone have a picture of that?

You need the Illustrated Parts Catalog for your airplane, which will show all of the parts and the relevant part numbers.   I think the one for your airplane is Mooney MANUAL p/n 205.   If you search around on the internet you can probably find it to download, it might be on here, too.

[KSMooniac]

Are you missing that hand trim wheel and mechanism that goes thru the floor? That drives a torque tube to crank the trim actuator at the back. Electric trim piggy -backs on that system.

Sent from my LM-V600 using Tapatalk

[Fly Boomer]

3 hours ago, davesly said:

If I can't find electric trim, then perhaps I'll need to find the missing parts to connect the tube from the tail to the tube from the trim wheel.  Anyone have a picture of that?

https://mooneyspace.com/files/file/193-m20j-ipc-man226/

 

[PT20J]

The manual trim wheel needs to be there even if there is electric trim so that you can trim it manually if the trim servo fails. It sounds like someone removed that part of the airplane before you bought it. Hopefully you won't find too many other missing parts.

[davesly]

3 hours ago, Fly Boomer said:

https://mooneyspace.com/files/file/193-m20j-ipc-man226/

 

Thanks!  This M20J manual image is better than the parts manual I have for the 1969 M20F.

On PDF page 376, image J27-4001, I appear to be missing the swivel u-joint called 10-A which joins the back shaft to the front shaft.

[davesly]

1 hour ago, PT20J said:

The manual trim wheel needs to be there even if there is electric trim so that you can trim it manually if the trim servo fails. It sounds like someone removed that part of the airplane before you bought it. Hopefully you won't find too many other missing parts.

I have the trim wheel and the shafts back past the battery, but the the rear shaft starting around the battery to the back square slip joint was just sitting in the tail and was not connected to the front shaft.  It appears that I might only be missing the swivel U-Joint which connects the two.  Perhaps the electric trim gear sits in place of this swivel?  I'll get some pictures next time I get to the hangar.

[davesly]

6 hours ago, N201MKTurbo said:

look in the IPC. I think there is a support block and a little U joint. A salvage yard is your friend.

Yep - no u-joint connecting front and rear shaft.  Anyone have one?

[N201MKTurbo]

9 minutes ago, davesly said:

Yep - no u-joint connecting front and rear shaft.  Anyone have one?

I have like 4 of them, but if I gave you one I’d be in the same shape as you.

[davesly]

I found out that the swivel is part number MS20270-B8 (also shown as -8B).  This is a standard Apex Mil Spec U-joint still available commercially from the Apex Tool Group for around $200.  I also found that he pin holding the swivel to the shaft is an AN392-19 which is available on ebay for around $5.

The shaft in the tail section from the back cabin wall swivel (behind battery on F models) all the way to the tail gear assembly (square slider tube) is part number 915026-021 and is used on all models (C, E, F, G).

This shaft passes through a hole in the frame that originally had a plastic cover over the sharp edges.  On my plane the plastic cover was missing and the shaft was wearing against this brace.  Someone had applied grease to the brace to lubricate any interference but the brace still cut a groove into the tube.  I am looking for a new tube (915206-021) and plan to install a Panduit slotted sheet metal edge guard for future protection.

I will include pictures of all this when I get back to the plane (#GEE99F-C)

[PT20J]

2 hours ago, davesly said:

I found out that the swivel is part number MS20270-B8 (also shown as -8B).  This is a standard Apex Mil Spec U-joint still available commercially from the Apex Tool Group for around $200.  I also found that he pin holding the swivel to the shaft is an AN392-19 which is available on ebay for around $5.

The shaft in the tail section from the back cabin wall swivel (behind battery on F models) all the way to the tail gear assembly (square slider tube) is part number 915026-021 and is used on all models (C, E, F, G).

This shaft passes through a hole in the frame that originally had a plastic cover over the sharp edges.  On my plane the plastic cover was missing and the shaft was wearing against this brace.  Someone had applied grease to the brace to lubricate any interference but the brace still cut a groove into the tube.  I am looking for a new tube (915206-021) and plan to install a Panduit slotted sheet metal edge guard for future protection.

I will include pictures of all this when I get back to the plane (#GEE99F-C)

Good work! The AN392-19 is a clevis pin and common hardware. The AN numbers have been mostly replaced with MS numbers. I believe the current part number is MS20392-1C19 and should be readily available for less than $1.

You are right to replace the tube as there is a spec on how deeply it can be scored. I don’t remember the number, but it’s not much.

At some point, Mooney started using a 1” diameter nylon grommet for the holes. NAS557-16B. Mooney also installed a piece of heat shrink tubing over the tube at each point where there is a bushing. Even with the nylon bushing and the shrink, it should still be lubricated with a small amount of grease per my M20J service manual.

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