Those d*@# belly skin screws (1999 Ovation)

[rogerl]

who owns it

Edited March 14, 2021 by rogerl
Fix SMM/IPC links; Thanks A!

[KB4]

Critical at least where rods sit behind the inspection panels like the ones under leading edge near sump after annual I found 1 screw that was too long and was touching the rod.  For belly just order a few from spruce until you find the right size combo.  Surely some of belly pan screws are still serviceable. 

When you remove any screw, clean it up before installing.  Take a shop towel spray some tri flow in it put threaded part of screw where you just sprayed, and spin away with your screw gun cleans em up fast and makes for easier install and removal later.  @StevenL757  gave me that awesome tip.

[PT20J]

I don't have the IPC for your airplane but 53-30-00 for my J lists all the screws. Some are PK (sheet metal) and some are various sizes of machine screws -- you just have to figure out which ones go where as the IPC is not very clear on this. There is a theoretical corrosion issue with stainless steel, but there is so much more area in the aluminum (anode) than the stainless (cathode) that it's not really a problem. https://www.bssa.org.uk/topics.php?article=89. I use stainless steel screws and when I remove them I put them in a zip lock bag with some WD-40 (or LPS3 or Corrosion X -- it doesn't really matter). They go in easily and come back out easily. A common mistake that makes them difficult to remove is over torquing them.

Skip

[carusoam]

Roger,

Haven’t seen you around lately...

Your SMM and IPC look funny... cross linked with your prior references...

I was going to read what you were reading to find out if I could do any better.
 

Might be my iPad...

+1 for ziploc bags, WD40 for cleaning the old screws, and A sharpie for writing on the bag... their last known address...

Best regards,

-a-

[Guest]

On 8/8/2020 at 11:09 AM, rogerl said:

Already reviewed this and this, still in a quandary.

1999 Ovation.  Belly panel screws - after 20-odd years of annuals some replacements are called for.  The monocoque/semi monocoque nature of the beast means these are potentially structural elements.

Have SMM and IPC.

1) Nobody seems to offer "kits" for these newer models (that's ok, don't want 20x more screws than I need anyway).

2) Can NOT find a hard reference in the SMM or IPC to what screws are needed where (53.30.00)

Am I just not looking at the IPC "right"?  The closest I can come seems to be listings for the wing inspection panels, but there are different lengths (possibly because of mix-ups from previous annuals - you know how that can go).

Is the expectation that you can just figure out the correct dimension?  I was taught that you need to be able to reference EVERYTHING...

Lengths in some of these instances seem to be critical, as too-long could interfere/abrade control structures, gear mechanisms, fuel pump/lines ... not to mention thread/pitch ... sometimes not obvious if the pitch is wrong or the screws are just worn.

In addition ... materials - not sure if SS is ok in all circumstances ... will that make for binding problems later?  Cad-plated for lubricity?  Dissimilar metals problems?

Recommendation or reference to overcome my IPC/SMM blindness would be really appreciated.

You should need Camloc 2700 series studs for the composite belly panels.

 

Clarence

[GeeBee]

I just consulted my recently from the factory procured copy of the M20R/S parts manual which covers all S/Ns and all they show is the composite panels with the Camloc fasteners. They do refer to it as the "smooth belly" installation. Unfortunately they show no other installations. You may have an orphan there on this matter. Maybe one of those ownership change things where the documentation is scarce. Might have to call the factory.

 

 

[carusoam]

So...

Lets see if we are talking the same parts...   aka Smooth Belly...

Only being a PP, I am short of real mechanic’s skill...

But, I did find the only reference I could find regarding belly panels and the two page parts list that goes with this...  used revision G, the one Roger updated above, I believe...

#1 and #2 seem to be the removable panels...

There are two types of screws listed...

• AN530-8R8.... 6  https://catalog.monroeaerospace.com/item/all-categories/an-screws/an530-8r8-1
• AN526-1032R8.... 13 https://catalog.monroeaerospace.com/item/all-categories/an-screws/an526-1032r8-1

So... with these details... we get screw type - screw size - screw length, not sure if it included materials of construction with that...

Next... cross reference with another resource like aircraft spruce to see if SS or zinc clad are additional options to this part number....

Best regards,

-a-

[PT20J]

A picture showing the panels you are talking about would help here.

[chriscalandro]

I think it’s the 832 but it might be the 1032. 

Edited August 9, 2020 by chriscalandro

[PT20J]

Look in the IPC 53-30-00. Find the item number on the drawing associated with each panel. Then look on the part number listing pages after the drawing and find the item number. There should be multiple lines with the same item number, one of which will be the screws. On mine, they are AN507-1032R6 (the newer part number would be MS24693-270 http://skybolt.com/wp-content/uploads/2017/12/Skybolt-AN-MS-NAS-Hardware-12-7-2017.pdf).

BTW, the Mooney structure is tubular steel covered with non-structural sheet metal panels except for the trailcone which is semi-monocoque, so none of these panels require structural fasteners. But kudos for recognizing that there is a difference.

Skip

[carusoam]

Skip,

Can you check the drawings and screws and part numbers I posted above...

I’m pretty sure they are what Roger is asking for...

Let me know if I missed something... I’m still re-learning the details... 

Best regards,

-a-

[PT20J]

Try page 53-10-00

Skip

[Guest]

47 minutes ago, rogerl said:

Just aft of the nose gear, cover the boost pump.    The nose gear door shares two screws, but those are a little smaller and probably referenced since they secure the gear door piano hinge as well.

Looks like 8-32 & 10-32 countersunk screws.

From the IPC a few pages before your pages.

[PT20J]

So, suppose you didn't have the IPC. You can always take a screw to the local hardware store and match it up to determine that it is, say, an flat head Phillips 10-32, 3/8" long. Now that you know what it is, you can order some aircraft equivalents from your favorite supplier.

 

Skip

[Guest]

One of my biggest gripes with maintainers is re-using old worn out hardware.  It’s far cheaper to throw it away than it is to drill it out when it’s stripped or worse have your screwdriver slip out and scratch the plane.

Clarence