Mooney Elevator AD

[67 m20F chump]

I think it’s about $750 but I can’t say for sure.

[Gary0747]

On 3/13/2023 at 2:45 PM, Dmax said:

New Style Counter Weights for AD 2023-02-04 are now available from any Mooney Service Center. Kit Pn.# M20-345-001

I must say Mooney did a nice job making these.

[Kelpro999]

47 minutes ago, Gary0747 said:

I must say Mooney did a nice job making these.

Could you weigh one? Kind of curious 

[Gary0747]

11 hours ago, Kelpro999 said:

Could you weigh one? Kind of curious 

3.18 pounds. Both the same. 

[Kelpro999]

35 minutes ago, Gary0747 said:

3.18 pounds. Both the same. 

Now compare to the removed ones. Not sure why I had to add 6 oz. to get there with original “good” weights 

[hammdo]

Overall, they responded fairly fast and look nice! Give Mooney props when deserved.

-Don

[Igor_U]

1 hour ago, Kelpro999 said:

Now compare to the removed ones. Not sure why I had to add 6 oz. to get there with original “good” weights 

Can you explain? my removed weight (-1) was 2.10 lb while a solid lead (-17) weight came up 3.28 (with installation holes). It makes sense as lead is heavier then steel rod, plus removed (-1) weight had an .75" diameter hole in the base of it.

[Kelpro999]

58 minutes ago, Igor_U said:

Can you explain? my removed weight (-1) was 2.10 lb while a solid lead (-17) weight came up 3.28 (with installation holes). It makes sense as lead is heavier then steel rod, plus removed (-1) weight had an .75" diameter hole in the base of it.

I can’t explain why mine came up lighter than required. The only reason I have issues is because I checked balance after painting, otherwise I would still be poor dumb and happy. Even after removing new paint it barely met under-balance specs for my S/N (4 rib elevators).

 The weight of your new vs old doesn’t make sense either unless you “filed” one pound off the new ones or your elevators were grossly under balance.

 Now I’m poor confused and concerned 

[Igor_U]

2 minutes ago, Kelpro999 said:

I can’t explain why mine came up lighter than required. The only reason I have issues is because I checked balance after painting, otherwise I would still be poor dumb and happy. Even after removing new paint it barely met under-balance specs for my S/N (4 rib elevators).

 The weight of your new vs old doesn’t make sense either unless you “filed” one pound off the new ones or your elevators were grossly under balance.

 Now I’m poor confused and concerned 

What is the value of your underbalance?

If you read the SB carefully you will noticed that with old (-1) weight manual calls for 1.57-1.75 lb underbalance and replacement weight (-17) calls for 1.09-1.3 lb underbalance. All I had to do is replace the weights and the solid weight (-17) being heavier came up within spec. No filing or adding lead. 

[Kelpro999]

5 minutes ago, Igor_U said:

What is the value of your underbalance?

If you read the SB carefully you will noticed that with old (-1) weight manual calls for 1.57-1.75 lb underbalance and replacement weight (-17) calls for 1.09-1.3 lb underbalance. All I had to do is replace the weights and the solid weight (-17) being heavier came up within spec. No filing or adding lead. 

That’s another question. Why does a part change due to corrosion issues change the static balance specification given for a particular model/ serial number? I understand how your balance changed but not why without any other dynamics to the aircraft. Was the under balance  amount a problem before corrosion? 

 I’ll have to locate my service manual to remember my exact spec data. Understand mine are 4 ribs, not 9 so they may have different dynamic response than yours.

 This one has added lead

[Igor_U]

31 minutes ago, Kelpro999 said:

That’s another question. Why does a part change due to corrosion issues change the static balance specification given for a particular model/ serial number? I understand how your balance changed but not why without any other dynamics to the aircraft. Was the under balance  amount a problem before corrosion? 

 I’ll have to locate my service manual to remember my exact spec data. Understand mine are 4 ribs, not 9 so they may have different dynamic response than yours.

 This one has added lead

 

I don't think corrosion has anything to do with it. I know the 68F underbalance value (with -17 weight) is same as the SB20-345A is calling for so that's nothing new. They mast have had some engineering data at the time. Also less underbalance is safer for Flutter so that's that.

I see in your profile that you own M20C. Did you have a hybrid weights (-1)? One or both? 

 

[Kelpro999]

47 minutes ago, Igor_U said:

I don't think corrosion has anything to do with it. I know the 68F underbalance value (with -17 weight) is same as the SB20-345A is calling for so that's nothing new. They mast have had some engineering data at the time. Also less underbalance is safer for Flutter so that's that.

I see in your profile that you own M20C. Did you have a hybrid weights (-1)? One or both? 

 

 I didn’t have hybrids. Only checked balance for paint reasons. That’s when I discovered balance adjustment methods are not published or I couldn’t find any. This leads me to believe the balance tolerance is greater than previously assumed. Have you noticed any flight characteristic changes from hybrid to non-hybrid? Probably not until reaching the end of the envelope 

[Igor_U]

I see, that explains it. I always wondered if my plane's elevators (and other controls) were properly balanced by the paint shop back in 2007. And I forgot to check that before removing hybrid weight from the elevator. 

[Kelpro999]

22 minutes ago, Igor_U said:

I see, that explains it. I always wondered if my plane's elevators (and other controls) were properly balanced by the paint shop back in 2007. And I forgot to check that before removing hybrid weight from the elevator. 

Yikes!
 I found nothing to indicate mine had ever been touched, no sanding marks or anything. That’s why I was very reluctant to “balance” them but specifications are real  so….. now seeing weight of hybrid vs non leaves me skeptical of what is real.

[Flyman2456]

Anyone have issues with the rivets from the parts kit not being long enough? Shop said they just swell inside and then the head is even with the skin. 

[Kelpro999]

3 hours ago, Flyman2456 said:

Anyone have issues with the rivets from the parts kit not being long enough? Shop said they just swell inside and then the head is even with the skin. 

If that’s new rivets then they are completely wrong. I had what would have been same problem balancing mine. Mooney p/n rivets were so short no attempt was made. Buying longer than needed allowed cutting down during practice / testing until proper fit obtained. If those are new struck rivets, removing may be problematic for same reason claimed. At this point welding to the flat head and pulling may be the better way. Creativity will get them out. Striking stuck fat rivets usually makes them fatter.

 Photo of rivets I started with before cutting.

[Kelpro999]

3 hours ago, Flyman2456 said:

Anyone have issues with the rivets from the parts kit not being long enough? Shop said they just swell inside and then the head is even with the skin. 

A curious question, did you record before removal balance data? Compare old vs new part weight? 

[Flyman2456]

10 minutes ago, Kelpro999 said:

A curious question, did you record before removal balance data? Compare old vs new part weight? 

I dont think they recorded the weight but I can ask. Idk why they didnt give longer rivets in the parts kit. 

[Kelpro999]

2 minutes ago, Flyman2456 said:

I dont think they recorded the weight but I can ask. Idk why they didnt give longer rivets in the parts kit. 

Recording data was part of the SB and the spec changes are creating some confusion, maybe just me …. but the short rivet thing is something else raising an eyebrow. I have an early C with non hybrids  that had balance discrepancies before and after paint then rivet length issues. You also won’t find published balance weight altering methods other than filling to make lighter from Mooney. I wonder, like you, if others are going to have similar length issues. 

[Igor_U]

4 hours ago, Flyman2456 said:

Anyone have issues with the rivets from the parts kit not being long enough? Shop said they just swell inside and then the head is even with the skin. 

Ouch, not good.

Do you know what is the length of the rivets in the kit?

I bought my rivets from Maxwell and they were Dia. 3/16" x 1 5/8" long. They were long enough to form a good head and yes, there's some swelling as hole diameter was larger then the rivet.

 

 

[romeotango]

The rivets in the kit are 3/16 x 1 3/8. I have 1.27" from top of washer to top of washer.

I think they messed up.

[ShuRugal]

5 hours ago, Flyman2456 said:

Anyone have issues with the rivets from the parts kit not being long enough? Shop said they just swell inside and then the head is even with the skin. 

wtf?  did the shop just blindly buck all three without making sure they were sticking out the correct amount first???

[Flyman2456]

2 hours ago, Kelpro999 said:

A curious question, did you record before removal balance data? Compare old vs new part weight? 

Weight comparison. No filing was needed to bring the balance into limits per the SB even though new weight is much heavier. 

Edited March 24, 2023 by Flyman2456

[Kelpro999]

20 minutes ago, Flyman2456 said:

Weight comparison. No filing was needed to bring the balance into limits per the SB even though new weight is much heavier. 

50% heavier weights yet no other mention about why it’s ok in the SB other than new balance specs. No other aerodynamic changes made. Doesn’t this seem odd? 

[Kelpro999]

7 minutes ago, Flyman2456 said:

The static unbalance 20-22inch pounds is still the same as the maintenance manual (at least for the F model) and that is what they got with the new weights. 

Soo…. the arm remains the same and the weight increased by one pound yet balance is still ok. Raises the question that if adding a pound some time in the past would have been ok? Were they always overly unbalanced that much?