Spar piece part #

[MikeB]

Hey everybody, I'm a new guy, I have a 1965 M20C that I'm trying to resurrect. It has one dime size corrosion spot that goes down 28 percent through it's thickness, Intergranular. I can't find the part in an exploded diagram to get the part #.

Does anybody have a way to get the part number before I call Mooney?

It's the piece that sits in the center directly at the base of the main spar.

I can get to both sides of this piece easily and have full access to the rivets, is it as straight forward as it looks? Drill out the rivets remove corroded piece put on the new piece and rivet it back up? Is there any problems with that idea?

see picture

[MB65E]

Good for you! I just looked thru the IPC. There is not a great view of that build up that I can see. All the P/N are probably there but can't see exactly what it's called. Send Dan at Lasar that same picture and I'm sure he'll have one for you quickly. 

Keep us updated on your progress. It will keep us all from going insane. (See there is another guy just like me...I'm not crazy)

www.lasar.com

Best,

-Matt

[MB65E]

And welcome!!

-Matt

[MikeB]

Thanks! I just sent them an email with the picture. Here's a picture of what I'm working on. It's been sitting for 3 years. Corrosion in the cylinders and on the cam, not a lot though, they should be able to be overhauled. I work under the guidance of my A&P so I get to do all the dirty work. It also needs a new panel. I'm crazy but it's in good shape otherwise.

 

 

[MikeB]

[MB65E]

Looks neat!

Before you dive into that spar repair, double check the steel tubes, aft carry thru spar, spar caps, and wheels wells for corrosion. The search function works really well here too.

enjoy!

-Matt

[Piloto]

Try lifting the back of the fuselage to relief the tension on the spar splice before removing it. The center bottom splice together with the top one are assembled at the factory on a jig under no load.

Moisture trapped on the carpet is the cause of corrosion in this area. Before reinstalling the carpet cover the entire cap with aluminum tape to keep moisture out. On the older Mooneys water gets in through the panels in front of the windshield when it rains. The water droplets fall into the carpet and propagates toward the back (spar cap). You can tell if you have a leak problem by just touching the carpet at the back seats after it rains. 

José

Edited July 21, 2016 by Piloto

[MikeB]

MB65E, I have the entire interior and every inspection plate off from head to tail. The airframe is perfect, aside from that one piece

Edited July 21, 2016 by MikeB

[MikeB]

MB65E you are a champion and a scholar, Lasar already got back to me, the part is in stock at Mooney and they can drop ship it for $383! Yes!

[carusoam]

Kids have a tendency to spill all kinds of acid beverages/fluids on that piece.

it is amazing how quickly the corrosion deepens after it gets started.  The light dusty surface hides the depth of the activity.

Note: get the old pieces coated /painted to match the new ones.

Welcome aboard and best regards,

-a-

 

[MikeB]

Pstone, that is an excellent question! I shall ask them, thanks!

[MikeB]

Carusoam I was really suprised with his deep it was too. Craziness. It looks like everything is painted with yellow zincromate.

[Piloto]

11 minutes ago, pstone said:

Hi Mike,

Is the new part pre-drilled or undrilled?  A predrilled part may or may not match your rivnuts. I went down this road many years ago.

 

 

Pat

That is why you have to relief the tensile stress on the wing before removing and reinstalling it. This is a tight fit part to insure no added stress on the other parts of the splice.

José

[MikeB]

Just got an email back from Lasar, Dan said it should be a prescribed part. I'll have to read up on the proper way to relieve the tensile stress.

[N601RX]

Is the part held together with rivets or Hi-locks?

[Piloto]

8 minutes ago, N601RX said:

Is the part held together with rivets or Hi-locks?

Both

[Piloto]

30 minutes ago, MikeB said:

Just got an email back from Lasar, Dan said it should be a prescribed part. I'll have to read up on the proper way to relieve the tensile stress.

One way to relief tensile stress on the wing is by putting a strap around the backside of the fuselage (just behind the wing) and lifting it until the mains tires are just barely touching the ground. The effect on the clearance is minimal but enough to allow the Hi-locks to be removed.

José 

[N201MKTurbo]

Just now, Piloto said:

One way to relief tensile stress on the wing is by putting a strap around the backside of the fuselage (just behind the wing) and lifting it until the mains tires are just barely touching the ground. The effect on the clearance is minimal but enough to allow the Hi-locks to be removed.

José 

I've never done this, but wouldn't just putting it up on jacks do the trick?

[PTK]

I have no experience with this but I sure hope whoever does the repair has done it before!

Quoting Don Maxwell on spar damage and repairs...

"...incorrectly repairing spar is a quick way to turn the airplane into a worthless pile of metal!"

[MikeB]

yep, I'm thinking a strap is a great idea

[Marcopolo]

No, putting it on jacks would only move the related stress outward a few inches, the idea is to not have any portion of the airframe's weight supported by the wings.

 

Ron

[MikeB]

PTK, that's true, Not a lot of room for error here

[N201MKTurbo]

35 minutes ago, Marcopolo said:

No, putting it on jacks would only move the related stress outward a few inches, the idea is to not have any portion of the airframe's weight supported by the wings.

 

Ron

Ah, I was backwards.

[Mark89114]

You are a brave man.

 

[MikeB]

Metal and rivets, not rocket science. Of course proceed with caution be informed and have knowledgable people watch assist and inspect. 

However as far as the airplane goes, no great loss if I screw it up, it was on it's way to being scrapped anyways.