Frustrated - Surfaces Won't Balance

[thinwing]

Just now, thinwing said:

That's the way I see it also   A simple make me balance weight grog!should do it but the reason I brought up the balancing procedure itself was that Any a and p that didn't. Know owners could produce their own parts made  me suspect his ability

 

[ArtVandelay]

That's the way I see it also   A simple make me balance weight grog!should do it but the reason I brought up the balancing procedure itself was that Any a and p that didn't. Know owners could produce their own parts made suspect his ability

Not quite, you need to insure it meets design criteria, so owner can either get design specs or just provide original to reverse engineer.

So it becomes make me one of these, you should enter your own log entry stating you provided part no. xxxxxx.

If you can't just say make me a doohickey without providing some guidance, you have to be part of the process, so later if part fails because it was made wrong, the responsibility is squarely on you.

[carusoam]

For ideas on owner produced parts...

Look for engine  controls, throttle, mixture, prop 

There have been a lot of cables made by the original supplier to Mooney when Mooney was unable.

Mooney owners still need parts.  If the factory can't make them and the drawings are available get the details you need to have them made the right way.

some of the factory drawings are missing important details.  I found one detail missing in the instrument section of the MM for my 65C.  Drawings were hand made back in the day. Editing a drawing to put a calibrated hole in MP line never Happened for the C. Calling the factory got me the details I needed to have the part made...  Bill Wheat was the Man, back then.  Stacy is our go to guy now...

Get data, get part made, document part in the log during installation, mechanic must be in agreement with the part and its installation.  It is a flight control.

PP thoughts only, not a mechanic...

Best regards,

-a-

[cliffy]

With respect toward "drawings".  When we speak of "drawings" we are not referring to "figures" in the MM. What we need are the actual "drawings" from the engineering drawers at Mooney. Every part made for a certified airplane will have an "Engineering Drawing" describing in detail exactly what goes into making that part. Such things as spring material, wire diameter, number of coils, compression at such ans such a compression depth, all dimension detains of the housing, etc, etc.

Every "drawing " has a part number and a control system for changes, has a sign off from engineering, etc etc. Unless we can reverse engineer the part we need the actual drawing to be legal.

As to throttle cables and Mixture control's we can ( as many have, me included) go to someone like McFarland and give them a "drawing" of our making showing length, throw, thread size, etc (just like the blank drawing they send out) and then say " make this part using all the steps,material and process that you use to manufacture other "certified" controls. Then they make the part that you designed using certified materials and methods  for that part. A legal owner designed part. Unless you know for sure what the "certified" material is, its heat treat, etc. it won't be a legal part. 

As to the sign off- you, as the owner designer, should sign the log book saying you designed this part and then the A&P MUST determine if it meets his criteria as a safe and legal part to install and sign off the installation. You are both on the hook for it. 

Again, lots of info on the net on what makes a LEGAL owner produced part.  There are very specific steps that must be complied with to make it legal. This ain't your Dad's 56 Chevy you're working on in the back yard. .  Liability attaches!

[LevelWing]

6 hours ago, cliffy said:

Lets start at the beginning -

You are sure you are following the MM by model AND serial number for your surfaces?

Yes.

What condition are you balancing in - 

        Correct orientation, correct side up?

Yes.

        With or without the steel bellcrank arm on?

Off.

       Are there any "repairs" to the surfaces? Patches? Non factory skin laps? Any repairs ever to the surfaces?

No.

       Any Bondo on the surfaces? 

No.

      What figures are you working with for the math?     Arm length to where the scale is pressed, weight on the scale?

I don't recall the actual numbers off the top of my head but it's all from the most recent manual.

      Pictures of your set up would help    Not trying to knock who ever is doing it but maybe something is being missed or done wrong 

No pictures at the moment, but I'll try and get some.

Let's try an go over everything before you go wild on making parts . It balanced at one time even if it was when it left the factory.

 

 

6 hours ago, MooneyMitch said:

I just went through this process last week with my rudder balancing during the paint process.  Rudder was over top limit before and after stripping.

After much deliberation and consultation, mechanic simply removed top rudder cap, calculated needed additional weight and molded a new lead piece to top cap piece and installed the new lead piece up against forward end of existing lead rudder weight and reinstalled top cap.  New paint installed and we're good.  My newly painted vertical stabilizer is shown in my site photo.  Hope this helps you.  

Incidentally, a '64 E model is in the paint shop at this very moment with the same issue................rudder out of balance as removed from aircraft prior to paint stripping process.

Thanks. Interesting that this has happened to a few people here.

[takair]

4 hours ago, LevelWing said:

 

Thanks. Interesting that this has happened to a few people here.

Cliffy has the right idea.  Some mechanics will try to balance the surface generically and try to get it to sit level statically.  Note that the balance is a measured balance....using a scale at the point called out in the manual.  It is possible that some folks are trying to over correct and come away with the impression that the surface was never balanced.  The first time I tried to balance a surface, this was the case.  In some cases you will never get there....  Getting to the book value is much easier, but not as obvious.

[MooneyMitch]

Per the aircraft painting facility, rudders being out of balance with specs of a specific aircraft is not that uncommon.  

Because of that, it's standard practice for the shop to check and document balance data on each flight control once that unit is removed from the aircraft prior to going through the painting process.

Regarding my situation, the balancing technique, specific aircraft data, equipment and the process used by the paint facility was verified by our local FBO mechanics, who also possess much experience in flight control balancing.

[RobertGary1]

14 hours ago, DonMuncy said:

No. My understanding is, anyone can make owner produced parts as long as the owner is involved in the process. Telling the person making it, how, what materials, etc.

I think that's right but it doesn't sound like the case here if I understand. The A&P went directly to Mooney to get diagrams. 

 

-Robert

[LevelWing]

4 minutes ago, RobertGary1 said:

I think that's right but it doesn't sound like the case here if I understand. The A&P went directly to Mooney to get diagrams. 

 

-Robert

As I understand it based on my conversations with both Mooney and my mechanic, Mooney doesn't have the diagrams for the parts needed. They had the specifications, which they gave to my mechanic, but not the diagrams themselves. We should be good to produce our own part based on what I'm reading in the FARs and through the various links/anecdotes here.

[cliffy]

I think I see an issue but I have to spend some time later today to verify it. Have a meeting shortly so I can't get to it right now.

[cliffy]

OK lets recap a couple of points that are not clear right now.

When you say the surface won't balance just what are you referring to? When it is sitting on the knife edges and the trailing edge of the surface is held level with the bolts on the hinge side, which way does the surface go when you let go? Up or down?

It is supposed to go down, and by a certain amount of torque. That is the unbalance force in pound/inches. 

Can you verify that the trailing edge does in fact drop down when released after being held level with the hinge line on the knife edges?

It should not stay level or move up.

If the surface does in fact move down when released can you supply the figures that you get (the weight that you measured) and the arm( the distance that the scale was from the c/l of the hinge bolts on the knife edges) that you measured the weight on? The weight should be measured when the surface is level with the hinge line.

Section 27-91-00 in the Mooney J manual; is the start of a very good description of how to balance the control surfaces. The C model manual does not do a good job of this and the J manual superceeds  it. You can find it on line free. 

This section applies to all previous Mooneys EXCEPT the torque of  unbalance force is different per model/S/N

It also says to balance check the surface with the control arm bolted on and the tail light in place (in the case of the rudder). 

The control horns should point up for the elevators and the rudder. The ailerons are balanced up side down.

Awaiting your response

[LevelWing]

Just thought I'd post an update on this. The issue was never owner manufactured parts (I was out of town when I posted this originally which complicated things). The issue was making the part itself. I think we've now found a way to do that. With luck, we'll have the part made within the next couple of weeks and it'll balance.

@cliffy,

Does the J manual specifically state that it supersedes all previous model manuals and will suffice? I don't recall seeing that in there. I know the J manual provides a lot of extra leeway and ability to modify as necessary, but i don't recall seeing the ability to use it in place of the C model manual.

Thanks for all of the responses and help. Hopefully I'll have some pictures to share soon of all the work that went into this.

Edited March 31, 2017 by LevelWing

[Sean S]

On 1/29/2017 at 0:22 PM, thinwing said:

what are they made of?if they are riveted in place ,prob not lead are they simple steel stamping?plates?

On large aircraft, the weights are made of depleted uranium. The procurement of which is highly controlled: https://www.nrc.gov/reading-rm/doc-collections/cfr/part040/part040-0025.html

[cliffy]

If you look at the Title Pages of the J manual you will see where it says that that manual superceds other manuals and it lists which models it covers (at least mine does), and I have both the C manual (it sucks) and the J manual.  

Just for my clarification, you are not trying to balance these surfaces so that they do not move when released while being held level on the knife edges, correct? They are supposed to drop down with a certain amount of force to be "in balance". 

[jash767]

Hello, did any of you all find a place that will make balance weight to your specs? If so could you send me the information? 

[Austintatious]

On 1/29/2017 at 10:07 AM, LevelWing said:

About 18 months ago we embarked on a journey to paint the plane (C Model). We did all the prep work ourselves to include the sanding and stripping of the control surfaces. Our friend painted it (he's experienced in aircraft painting) and it turned out beautifully. Except the control surfaces wouldn't balance. More specifically, the elevators and rudder won't balance. The ailerons were no issue and are back on the plane. We re-stripped the control surfaces thinking maybe there was too much paint on them. As it turns out, even stripped, the surfaces won't balance. I've contacted numerous people for help and there doesn't seem to be much luck. I'm now asking the MooneySpace community for their advice/opinions on what should be done. N201MKTurbo has been very helpful during this process, it's just unfortunate nothing has worked thus far.

We need to add weight to the elevators/rudder but Mooney apparently doesn't make the parts anymore and suggested we find a salvage/junk yard for the parts. We're currently in the process of doing that, but it would seem others should have it. My mechanic has contacted the big shops, including Lasar and Beegles along with Mooney itself. I'll post the part numbers in the event anyone has a lead on them here. Some of you may remember me asking for a particular Mooney manual a while back, which is directly related to this. The J model manual will tell you to add weights where necessary but the C model manual will not.

1ea. P/N 460011 Rudder balance weight. Mounts with 4 rivets. Minimum actual weight of 3.55 lbs. (56.8 oz.)

2ea. P/N 460011 Elevator balance weights. Mounts with 3 rivets. Minimum actual weight of 3.50 lbs (56.0 oz.)

I appreciate any advice/guidance you all can provide.

On 1/29/2017 at 3:08 PM, thinwing said:

No Drawing so how do plan to define the shape and dimensions.?

 

I made a fared tail weight for my glider using smooth on products to make a female mold, I then poured lead into the mold.

You can make a male mold out of wood/  The nice thing is you can go by trial and shave off more and more wood until you have the exact shape you need.  You then make it as smooth as possible by filling priming and sanding.  Then a clear coat, then mold release and then do the female mold.

The weight I made was very complicated and I had to take a mold off of the glider first to start my male mold.

I will try to find a picture and some of the videos I used to learn how to do it.

 

OK, here are some pics.  You can see how complicated this part was... It had to bolt on with existing bolts and it surrounds a composite spring for the tail wheel and had to leave room for it to move.  Also, using the TLAR method I was spot on with the 5 lbs I was targeting. I did make a hollow portion in it to allow about 6 ounces more to be put in if needed.  It may be worth stating that I have made my own fishing weights for years so I am pretty familiar with lead density.  If you are not you may need to be more calculated.  Of course you can always drill out lead to lighted it if needed.

 

Here is a video on how to make molds

 

 

[Pete M]

FYI, there are letters of interpretation issued by faa counsel that cover owner produced parts. They are very broad. Duplicating a part and an a&p sign off are all that is required for owner flown part 91 ops. Owner providing part and qc of part covers owner required participation. Obviously one may not produce and sell the parts. 

[Kelpro999]

Resurrecting an old thread. I had same balance issues with my “C”. After much research I ended up lead braising to the existing weight and hit center of unbalance range for my SN. Used auto wheel weights of approx. same lead alloy.