SB M20-345

[cliffy]

PLEASE BE AWARE THAT YOU MAY BE MISSING A BIG POIUNT IN "BALACING" THE ELEVATOR!

The elevator is NOT "balanced" around its hinge line. It does NOT sit level when "balanced" according to the book.

It is trailing edge heavy by the amount shown in the limits section of the MM. The CG of the surface is behind the hinge line for stability.

Can't just use any weight that fits, Part numbers are called out in the parts manual. They vary by model and maybe S/N

The round piece is probably heavy metal used for balancing where solid lead won't give enough weight for the size of the volume. 

I'm sure Mooney never figured on 50 years of life for corrosion when they made the part.  

 

[EricJ]

I've noticed others like mine, where it is clearly screws on one elevator, and something else (rivets?) on the other.   My left elevator has philips-head screws top and bottom, and the right one has some sort of rivet or something both top and bottom.

 

[PT20J]

1 hour ago, DCarlton said:

I'll take a pic of mine.  Don't remember them being bolt or screw like at all.  

Believe they are attached with flathead iron rivets. Later Js changed to machine screws with threaded inserts. 

[mooniac15u]

1 hour ago, jamesm said:

am I reading the SB correctly .... If you have the hybrid center plug type elevator counter weights with any crack formation on them you are grounded.  so this SB only identifies the problem but has no solution/resolution ?

Thanks in advance,

James '67C

That's right.  It only identifies the problem but offers no current solution.

Based on Note 2 in the SB you are grounded if you have that type of weight regardless of whether it is currently cracked.

"NOTE 2:
If elevator balance weights are the original 430018-1 style, DO NOT FLY, the balance weights will need to
be replaced with new weights developed by Mooney in a later revision of this Service Bulletin."

[mooniac15u]

14 minutes ago, EricJ said:

I've noticed others like mine, where it is clearly screws on one elevator, and something else (rivets?) on the other.   My left elevator has philips-head screws top and bottom, and the right one has some sort of rivet or something both top and bottom.

 

Did it come from the factory with two different attachment methods or has one of your elevators been repaired/replaced?

[EricJ]

21 minutes ago, mooniac15u said:

Did it come from the factory with two different attachment methods or has one of your elevators been repaired/replaced?

I haven't noticed anything in the logbooks to indicate they've been changed.   The airplane was painted once about twenty-five years ago.

I've seen other airplanes with this same arrangement, though, so I'm curious what's up.

[PT20J]

7 minutes ago, EricJ said:

I haven't noticed anything in the logbooks to indicate they've been changed.   The airplane was painted once about twenty-five years ago.

I've seen other airplanes with this same arrangement, though, so I'm curious what's up.

Looks like you have one original and one that has been replaced. Maybe one needed adjusting for balance after painting.

[carusoam]

It kind of looks like there was adjustability with installation…

As there is a varying gap where the plug can be slid in or out from/to the full in position…

PP thoughts only…

Best regards,

-a-

[Pinecone]

On 10/9/2022 at 8:02 AM, 67 m20F chump said:

It would be working with lead.  I’m not interested in doing that.  I think I will wait on Mooney to make the part.  I think they have a contractor in mind.  The guy I talked with at Mooney said they thought it would be 100 or so planes that had the problem weight.  Maybe I will call them Monday and see if they have a wag on how long they think it will be.

You are melting the lead, not boiling it.

[Pinecone]

15 hours ago, carusoam said:

How many MSers have melted lead?

1) Where did you get the Pb?

2) How did you melt it?

 

I have been casting lead alloy for many years.

I get it from scrap metal dealers.  Or friends who get it from various sources and sell it in reasonable portions (they buy by the ton).

Or order it from someone like Rotometals.
 

I have a lead casting pot.  But I have also used a cast iron pan or pot and normal stove.  Just don't EVER use that pan or pot for cooking.

[N201MKTurbo]

I have an old farm scale in the back yard. I bought some new (to me) counterweights and the seller had bead blasted them. He blasted out the calibration weights (lead). I just went to the Walmart and bought 1 OZ fishing weights. Cheapest lead I could find. I just used the acetylene torch held about 6 inches away. It melted in about 20 seconds.

For the scale geeks out there, the weights had three calibration holes for lead in the cast iron weights. I had an existing 200Lb counterbalance weight, so I piled on 2 bags of salt, a bag of cement and a few cinder blocks until it was about 220 Lbs. I then changed to the new counterbalance weight hanging upside down so the holes were pointing up. I used a pair of dikes to cut chips of lead into the hole until the scale balanced. Then I took it back to the garage and melted the chips into the hole with the torch. The two weights are within 1 line width, about 1/10 Lb. It is a 100/1 scale so the counterbalance weights are within 1/1000 of a pound.

[N201MKTurbo]

If you want lead, there is a guy on EBAY selling 10 Lbs of lead egg sinkers for $27 with free shipping. Cheaper then the guys selling bulk lead.

[N201MKTurbo]

1 hour ago, Pinecone said:

I have been casting lead alloy for many years.

I get it from scrap metal dealers.  Or friends who get it from various sources and sell it in reasonable portions (they buy by the ton).

Or order it from someone like Rotometals.
 

I have a lead casting pot.  But I have also used a cast iron pan or pot and normal stove.  Just don't EVER use that pan or pot for cooking.

Are you casting bullets?

[DCarlton]

3 hours ago, PT20J said:

Believe they are attached with flathead iron rivets. Later Js changed to machine screws with threaded inserts. 

Yep.  That's what they look like; iron rivets.  Pics below are from my '67F.  I couldn't readily find the fasteners in my parts manual.  Looks like the iron causes a little corrosion.  I'm going to touch mine up with some primer and paint.  

[67 m20F chump]

The Weights are held on with (P/N 224497 - Iron Rivet (.187” x 1.375”) – use AN960-10L washers between head of rivet and skin

 

 

[Pinecone]

14 hours ago, N201MKTurbo said:

Are you casting bullets?

Yeap.  Started casting in college to save money.

And when I was a kid, somehow we ended up with some molds for cast lead military miniatures.  And lead fishing weights.  So did some casting of those, and played with the toys.   I have to see if my Dad still has those molds.

 

[67 m20F chump]

Making bullets in the peoples republic of Maryland?  Living on the edge!  You ever get your blood tested for lead?  Some of the guys working the government range I used to use had elevated lead levels and ever since I found religion about it.  I know we are getting off the point of the thread but lead poisoning is why Mooney doesn’t make the weights now.

[Igor_U]

23 hours ago, DCarlton said:

Yep.  That's what they look like; iron rivets.  Pics below are from my '67F.  I couldn't readily find the fasteners in my parts manual.  Looks like the iron causes a little corrosion.  I'm going to touch mine up with some primer and paint.  

 

Correct, iron rivets. Clean the corrosion prime and paint. It would be a pain to install those. 

So, question is do you have hybrid weights or not? What is that pinhole on the side view? It's hard to say but it seems like a small gap covered with paint.

[Aerodon]

Here is a picture of a spare set of M20K weights, about 3.425 lbs each, with threaded metal inserts for mounting.  

And I'd like to re-iterate what was mentioned above, balancing does not mean the elevator is balanced on the hinge line.  Aircraft control surface balancing is the process of ensuring that the control surface 'imbalance' is between the fore and aft limits.

 

 

 

 

[DCarlton]

2 hours ago, Igor_U said:

 

Correct, iron rivets. Clean the corrosion prime and paint. It would be a pain to install those. 

So, question is do you have hybrid weights or not? What is that pinhole on the side view? It's hard to say but it seems like a small gap covered with paint.

No. I reported not having them with my serial number in a couple of areas.  My mechanic and I examined all three on my plane including the rudder.  And my serial number is reportedly past when they were used.  I believe there are two different threads going on MS for this same issue unfortunately.  

 

[PT20J]

3 hours ago, Aerodon said:

And I'd like to re-iterate what was mentioned above, balancing does not mean the elevator is balanced on the hinge line.  Aircraft control surface balancing is the process of ensuring that the control surface 'imbalance' is between the fore and aft limits.

Interestingly, the Mooney surfaces are balanced trailing edge heavy, which is unusual. Usually, control surfaces are balanced leading edge heavy for flutter prevention. Evidentially, the Mooney control system is stiff enough that flutter is not an issue and the balance is set for other reasons -- likely control response.

[Aerodon]

1 hour ago, PT20J said:

Interestingly, the Mooney surfaces are balanced trailing edge heavy, which is unusual. Usually, control surfaces are balanced leading edge heavy for flutter prevention. Evidentially, the Mooney control system is stiff enough that flutter is not an issue and the balance is set for other reasons -- likely control response.

I checked both my Seneca and C172 handbooks - both require trailing edge heavy.  Some surfaces from 0 to 'training edge heavy'.  Piper and Cessna use different signs for under and over balanced, but the instructions are clear enough.

Seneca ailerons have a wide range from leading edge heavy to trailing edge heavy.

 

Aerodon

[JimB]

Just out of curiosity, how many Mooneys are out there that have the smooth skin elevators? Mine is beaded and when I google pictures the vast majority look like they are beaded. 

[Shadrach]

28 minutes ago, JimB said:

Just out of curiosity, how many Mooneys are out there that have the smooth skin elevators? Mine is beaded and when I google pictures the vast majority look like they are beaded. 

I believe that beaded control surfaces started in 1969. 

[Pinecone]

23 hours ago, 67 m20F chump said:

Making bullets in the peoples republic of Maryland?  Living on the edge!  You ever get your blood tested for lead?  Some of the guys working the government range I used to use had elevated lead levels and ever since I found religion about it.  I know we are getting off the point of the thread but lead poisoning is why Mooney doesn’t make the weights now.

The elevated lead levels from shooting tend to come from the lead styphnate in the primers not the bullets.

Yes, I have been tested.

And my profession is occupational health and safety.