How to cover hole from ADF Antenna?

[Browncbr1]

Skates,  it’s a bigger job than it looks like, so better do it right and cleanly the first time.  The problem is that it is inside the fresh air plenum which is a total PITA due to the vent door linkage and louvre vents.   If you just drill them out and put in blind rivers, you’ll hear the annoying little pieces of aluminum debris vibrating in the plenum in cruise.  

If I had to do it all over again, I would have just committed to fabricating a new plenum with eyeball vents and just yank all that crap out of there so a bucking bar could fit to allow flush rivets.   I will be doing this when I eventually do the slopes windshield mod 

Edited December 20, 2018 by Browncbr1

[Shiny moose]

For temporary fix just leave it there, you will need a doubler either way, plugging the hole or installing another antenna. As Brown stated its a bigger job to do it correctly

[M20F-1968]

I second the reference to AC 43.13.  The repair is called a nickel and dime patch and is just that, a a smaller aluminum piece which just fits into the hole you are patching (of the same thickness of the skin you are patching) riveted to a larger piece which is riveted to the inside of the skin being patched.  There are requirements in 43.13 showing degree of overlap, number of rivets needed and rivet spacing.  The rivets can be countersunk and should be.  Once the patch is done, a bit of filler and pain and you will not know it is there.  A good A&P will know how to do this.

John Breda

[MBDiagMan]

The fuselage is a structural component.  River in a doubler.

[N201MKTurbo]

38 minutes ago, MBDiagMan said:

The fuselage is a structural component.  River in a doubler.

Not in our Mooneys ahead of the baggage compartment. The steel tube structure is the load bearing member. The skin is just a faring.

[HRM]

17 hours ago, Skates97 said:

I have a hangar neighbor that is building a plane and is really good with sheet metal who I could have help with the permanent patch, plus an A&P that would look it over and sign off on it. That will most likely be the permanent solution.

The orphan has been there for the two years I have had the plane, and every-time I see it I want to do something about it...

Yep, you hit on the best plan (IMNSHO) and yep, I completely understand the orphan metaphor, BT 

[EricJ]

13 hours ago, Skates97 said:

Speaking of running a bead around it, I have seen that my two Com antennas have what is left of a bead of something around them that could be redone. What is the best to use for that? 

My forward comm antenna had very little sealant left and the last time I flew through rain it started acting up.  I had to take the airplane back to the avionics shop for some warranty work and asked them to do a proper seal job on it.   They had put my GPS system in and the sealant around the GPS antenna looked great.

They globbed some rtv around it and called it done.   Didn't even do a very good job of dressing it.

There's other stuff that can be used, but even the 43.13 bible says put rtv around it.

[N201MKTurbo]

1 hour ago, EricJ said:

My forward comm antenna had very little sealant left and the last time I flew through rain it started acting up.  I had to take the airplane back to the avionics shop for some warranty work and asked them to do a proper seal job on it.   They had put my GPS system in and the sealant around the GPS antenna looked great.

They globbed some rtv around it and called it done.   Didn't even do a very good job of dressing it.

There's other stuff that can be used, but even the 43.13 bible says put rtv around it.

I use tank sealant. 

The ground connection is usually through the screws. I will take the antenna off, completely clean the antenna and the skin until they are shiny bright with scotch brite. I will put a bead about a 1/4 in from the edge on the antenna and smear some on the skin with my gloved finger. Screw the antenna on and wipe the extruded sealant off and then a quick wipe with a paper towel moistened with MEK. Looks great with no ugly bead of RTV, never leaks and lasts forever.

[jaylw314]

19 hours ago, Yetti said:

When I asked the grump IA about this.  He said a stainless machine screw and a stainless fender washer was the answer.  There was enough hardware from all the antennas and such to make this happen.  The holes were on the bottom of the plane.  For the top might want to run a bead around the fender washer.  Quick and simple.

Hmmm, that seems like a recipe for dissimilar metal corrosion.  Stainless steel will sacrifice aluminum given time and moisture, I think

[Yetti]

3 hours ago, jaylw314 said:

Hmmm, that seems like a recipe for dissimilar metal corrosion.  Stainless steel will sacrifice aluminum given time and moisture, I think

which is why the grumpy IA is not in favor of replacing all the panel  screws with stainless.

[MBDiagMan]

7 hours ago, N201MKTurbo said:

Not in our Mooneys ahead of the baggage compartment. The steel tube structure is the load bearing member. The skin is just a faring.

Yep, didn’t think about the cabin framework.  This isn’t your Fathers Cessna.  I stand corrected.

[lithium366]

Bumping the thread with my use case: I am installing Dynon + GNS430w and I want to install GNS430W antenna (GA35) instead if KA 92 since the hole pattern is the same but it is too close to the VHF. My plan is to move VHF to the belly and use this spot for Dynon GPS antenna but I am not sure how involved this will be assuming I will need to fix VHF antenna holes first. It is right on the seam. Can someone point me to the right place in the AC as to how such repairs on seams are usually done? 
 

 

[EricJ]

6 minutes ago, lithium366 said:

Bumping the thread with my use case: I am installing Dynon + GNS430w and I want to install GNS430W antenna (GA35) instead if KA 92 since the hole pattern is the same but it is too close to the VHF. My plan is to move VHF to the belly and use this spot for Dynon GPS antenna but I am not sure how involved this will be assuming I will need to fix VHF antenna holes first. It is right on the seam. Can someone point me to the right place in the AC as to how such repairs on seams are usually done? 
 

 

AC 43-13 Chpt 4 section 4 has the metal repair stuff including sheet metal, etc., for patches.

[0TreeLemur]

When I had a MSC remove the fore ADF mount they fabricated a metal patch.  Held in by screws with some kind of sealant involved.

[N201MKTurbo]

13 hours ago, lithium366 said:

Bumping the thread with my use case: I am installing Dynon + GNS430w and I want to install GNS430W antenna (GA35) instead if KA 92 since the hole pattern is the same but it is too close to the VHF. My plan is to move VHF to the belly and use this spot for Dynon GPS antenna but I am not sure how involved this will be assuming I will need to fix VHF antenna holes first. It is right on the seam. Can someone point me to the right place in the AC as to how such repairs on seams are usually done? 
 

 

  You should get someone who is good at sheet metal to do it. There is a guy here who does sheet metal for AA during the day and does it here on the side. He would knock that patch out in 15 minutes. 
 

You could just make a flush plug for the coax hole and a backing plate that hits the 4 screw holes, hold it in place with 4 screws through the screw holes and drop a couple of #3 flush rivets to hold the plug in place.

[Jsno]

Looks like a good location for a future gps antennae

 

[Jerry 5TJ]

Or a top transponder antenna for your future diversity Mode S upgrade. 

[lithium366]

27 minutes ago, Jerry 5TJ said:

Or a top transponder antenna for your future diversity Mode S upgrade. 

Already on a belly with ADS-B in antenna! 

[Old Chub]

For Lithium 366

"My plan is to move VHF to the belly and use this spot for Dynon GPS antenna but I am not sure how involved this will be assuming I will need to fix VHF antenna holes first."

You may want to look into a GPS/COM antenna combo like I did.    I don't like punching any more holes in the fuselage skin than I absolutely have to.

I have two GPS/COM antennas on top in the same positions you show for your two antennas (one com and one GPS).  

 

 

[lithium366]

25 minutes ago, Old Chub said:

For Lithium 366

"My plan is to move VHF to the belly and use this spot for Dynon GPS antenna but I am not sure how involved this will be assuming I will need to fix VHF antenna holes first."

You may want to look into a GPS/COM antenna combo like I did.    I don't like punching any more holes in the fuselage skin than I absolutely have to.

I have two GPS/COM antennas on top in the same positions you show for your two antennas (one com and one GPS).  

 

 

I know this is confusing for me: GNS430W installation manual mention these combo antennas but at the same time in their IFR installation requirements they only specify 3 antennas: GA 35, 36 and 37.A&S also says I have to stick with these 3 models

If I could install a combo antenna I would still have to repair a VHF antenna old holes first and then I will be left with an obsolete KA-92 that I will have to patch, too, in order to replace it with Dynon GPS. 
 

Finally my understanding is that FAA and avionics manufacturers prefer VHF antennas to be on the other sides of the fuselage. This is why I think I will just relocate an antenna to the belly

[Old Chub]

This would be your call but my GPS/COM antennas covered the old com and antenna and the old location of the non-waas gps antenna so I had no additional patches.

Our brand new aircraft that we produce here at the company I work for uses the GPS/COM antennas on Garmin installations.   I believe you will find the GPS/COM antennas meet the same TSO as the antennas called out by Garmin in their II's.  

 

[M20F-1968]

On 12/19/2018 at 12:35 PM, Skates97 said:

I thought about that but was not very appealing.

This was what I was thinking, just throwing it out there to see if there was an easier way that I hadn't considered.

Nickel and Dime patch - likely wet riveted -  This is the only proper repair, unless you want to change the skin of course.

John Breda

[M20F-1968]

On 12/19/2018 at 11:58 AM, N201MKTurbo said:

The proper way would be to rivet a doubler to the underside of the skin, then cut out a piece of aluminum the size and shape of the hole and rivet it to the doubler.

 

 

 

Sorry, I quoted the wrong post.

Nickel and Dime patch - Any A&P can do it.  Wet rivet with some PRC to keep water out.  Only repair to do, unless you want to change the skin (which you do not want to do).

John Breda

[Nokomis449]

I am ashamed of each and every one of you.  @Skates97 started this post over 3 years ago and not ONE PERSON has asked him how many knots he gained.
I'm guessing 10 but I tend to be MooneyConservative.

[Jerry 5TJ]

15 hours ago, lithium366 said:

Already on a belly with ADS-B in antenna! 

A diversity transponder uses two antennas, one on top of the airplane and one below. Probably not needed in the USA in the near term but many countries including Canada are scheduled to require diversity transponders to permit satellites to replace ground radar sites.