Test fit a replacement doghouse cover

[phxcobraz]

My old doghouse cover is on its last legs. No amount of RTV or aluminum tape was saving it.
Grabbed a sheet of aluminum and fabbed up a replacement. It’s a bit rough still and I’ll probably redo it in a thicker plate, or add some doublers for reinforcement, but there is far less gaps to let air escape. The thinner sheet does conform better however. 
 

Before:

 

After:

[EricJ]

Looks nice.   I think your last pic didn't post for some reason, though.

 

[phxcobraz]

1 minute ago, EricJ said:

Looks nice.   I think your last pic didn't post for some reason, though.

 

There was 3 total. Let me try again. 

[EricJ]

Apparently it worked the first time...there's an oddball filename that appears at the end that looks like it was intended to be another pic.

Looks good, anyway!   Nicely done.

[Greg Ellis]

14 hours ago, EricJ said:

Apparently it worked the first time...there's an oddball filename that appears at the end that looks like it was intended to be another pic.

Looks good, anyway!   Nicely done.

The oddball file name looks like it may be that map of the US of all the states he has been too. The file name looks like a list of state abbreviations if you break them down into their 2 letters.  The pic just isn’t coming through.

[Fly Boomer]

19 hours ago, phxcobraz said:

Grabbed a sheet of aluminum and fabbed up a replacement

Good job on the new one, but the effort that has gone into keeping the old one alive impresses me too.

[phxcobraz]

12 minutes ago, Fly Boomer said:

Good job on the new one, but the effort that has gone into keeping the old one alive impresses me too.

Yea when I got it 4yrs ago it was barely holding together with doublers and RTV and slowly disintegrated. Not sure why nobody took the time to make a new one. It probably only took me 45min start to finish. 
The other side is in great shape. Not sure how this one became so damaged. 

[phxcobraz]

3 hours ago, Greg Ellis said:

The oddball file name looks like it may be that map of the US of all the states he has been too. The file name looks like a list of state abbreviations if you break them down into their 2 letters.  The pic just isn’t coming through.

Strange. I disabled that a while ago. Didn’t want to keep up with updating it. Changed it to see if that helps. 

[rwabdu]

Just wondering, is this considered a field modification? Just need a mechanic sign off to be legal? 

[phxcobraz]

1 hour ago, rwabdu said:

Just wondering, is this considered a field modification? Just need a mechanic sign off to be legal? 

Correct but it’s not a modification. It’s an owner produced replacement part. 

[Skates97]

I added an L-shaped brace, similar to what you have on the front left side, but going front to back, mounted to the main cover along the edge where the spark plug cover ends. It helps keep the main cover from flexing up and down.

[phxcobraz]

1 hour ago, Skates97 said:

I added an L-shaped brace, similar to what you have on the front left side, but going front to back, mounted to the main cover along the edge where the spark plug cover ends. It helps keep the main cover from flexing up and down.

Interested in seeing that if you have a picture. I added 2 tinnerman nuts and screws to the main cover where it previously had cracked a bit around near front cowl to reinforce. 

[cliffy]

It  has always amazed me the "troubles" talked about here on MS about dog house problems

The entire unit is mostly flat aluminum with some bends. Any A&P should have been taught the 

skills to "repair" the entire box without too much problem. Its simple sheet metal/rivet work. 

This ain't rocket science here. Its 90 year old technology and skills!

We shouldn't need to fly around with a dog house in bad shape.

Are we to assume that A&Ps today can not do this simple kind of work?

I just left  an  A&P (not working professionally as an A&P) replacing all the flap tracks on a C-150

and he were doing a good job from what I could see. 

Simple sheet metal and rivets  That's all it is.

Very frustrating to hear this all the time. Maybe its not now the vocation I came into 60, years ago.

[cliffy]

5 hours ago, phxcobraz said:

Correct but it’s not a modification. It’s an owner produced replacement part. 

Its actually a "repair" using an OPP part that still needs the OWNER to sign off in the log book correctly on how "he" participated in the design

and IF he installed it he still needs to sign it off again as the installer who installed it under "Preventative Maintenance" 

Normally an OPP part is "designed " by the owner and then verified as to qualification for installation by an A&P and installed by 

an A&P BUT that is not the only way to install an OPP part, 

[phxcobraz]

1 hour ago, cliffy said:

It  has always amazed me the "troubles" talked about here on MS about dog house problems

The entire unit is mostly flat aluminum with some bends. Any A&P should have been taught the 

skills to "repair" the entire box without too much problem. Its simple sheet metal/rivet work. 

This ain't rocket science here. Its 90 year old technology and skills!

We shouldn't need to fly around with a dog house in bad shape.

Are we to assume that A&Ps today can not do this simple kind of work?

I just left  an  A&P (not working professionally as an A&P) replacing all the flap tracks on a C-150

and he were doing a good job from what I could see. 

Simple sheet metal and rivets  That's all it is.

Very frustrating to hear this all the time. Maybe its not now the vocation I came into 60, years ago.

I think a lot of A&Ps are just so slammed with work they won’t do anything not deemed airworthy unless an owner requests it. Add to that apprentice A&Ps doing much of work and cheap or unaware owners and you get a system where if it’s hanging in by a thread it gets passed up. 
The previous 2 owners of this plane didn’t fly it much but 20-30hrs a year and pretty much did the bare minimum but they did overhaul the engine which was nice. Another opportunity they could have replaced it but didn’t. 
This is just my observation as an owner though. I am sure it varies place to place. 

[Skates97]

2 hours ago, phxcobraz said:

Interested in seeing that if you have a picture. I added 2 tinnerman nuts and screws to the main cover where it previously had cracked a bit around near front cowl to reinforce. 

Not the best picture but zoomed in on one I found scrolling through. 

[jamesm]

I was having hard time finding 'U' clip tinnerman nutplates, and got tried trying ones the dropped  or gotta away ones. so I nutplated all mine.

now I don't have to hear the sound of the falling tinnerman nutplate between cylinders and then playing a game of hide and seek  trying find out where they went.

I only tried to use RTV  for filling the relief holes and bend gaps. The aluminum cover look much better than aluminum/duct tape.

[phxcobraz]

51 minutes ago, jamesm said:

I was having hard time finding 'U' clip tinnerman nutplates, and got tried trying ones the dropped  or gotta away ones. so I nutplated all mine.

now I don't have to hear the sound of the falling tinnerman nutplate between cylinders and then playing a game of hide and seek  trying find out where they went.

I only tried to use RTV  for filling the relief holes and bend gaps. The aluminum cover look much better than aluminum/duct tape.

Good idea.

I bought 10-20 of each type/size off aircraft spruce a while ago so I have extras. I’ve lost a few off the front cowl panels from time to time. 

The ace hardware by me also has them I found but I haven’t bought any yet. 
I have a bunch of nut plates too so I could see doing that at some point. I’ve replaced a bunch of stripped ones in my avionics access panels.

[47U]

On 9/1/2024 at 12:26 PM, phxcobraz said:

My old doghouse cover is on its last legs.

Advise caution using a big flat washer which compresses the slip joint between #1 and #3 cylinders.  There might be a crack developing in the #3 baffle.  On my doghouse I filed out the slip joints to make space for the washers.

But only after my IA pointed out that the #2 cylinder baffle had cracked.   Which then I got to do the patch and then I filed the slip joints to make clearance for the flat washers.  

 

[phxcobraz]

15 minutes ago, 47U said:

Advise caution using a big flat washer which compresses the slip joint between #1 and #3 cylinders.  There might be a crack developing in the #3 baffle.  On my doghouse I filed out the slip joints to make space for the washers.

But only after my IA pointed out that the #2 cylinder baffle had cracked.   Which then I got to do the patch and then I filed the slip joints to make clearance for the flat washers.  

 

Good eye, that seems like a good way to reinforce the area. I'll check it out next time I am at the airport. 

[cliffy]

Just to be a bit nit picky with a smile  :-)

The AC Spruce tinnermans come with an "NAS" qualification cert  A1789-8Z-1D (or such ) and the hardware store ones do not. 

All hardware used on certified aircraft need to come with a design cert even if they look like the same design (AN, MS, Space Qualified, etc)

Again I'm just being nit picky here but I've been that way for 60 years in this business. 

[Fly Boomer]

On 9/2/2024 at 8:43 PM, cliffy said:

Any A&P should have been taught the skills to "repair" the entire box without too much problem.

I have only recently become aware that there are several ways to become an A&P and, if an A&P got there by working as an "apprentice" to another A&P who didn't know how to do certain repair tasks, I can see how this could happen.  On the other hand, if the A&P got there by working with another A&P who knew some of the more arcane skills OR went to a great A&P school, there would be a better chance of knowing some of these things.  Also, just having the tools at your disposal can make certain tasks a bunch easier -- it's amazing to see the variety of machines in a shop equipped for essentially every sheet metal task there is.

[phxcobraz]

2 hours ago, cliffy said:

Just to be a bit nit picky with a smile  :-)

The AC Spruce tinnermans come with an "NAS" qualification cert  A1789-8Z-1D (or such ) and the hardware store ones do not. 

All hardware used on certified aircraft need to come with a design cert even if they look like the same design (AN, MS, Space Qualified, etc)

Again I'm just being nit picky here but I've been that way for 60 years in this business. 

They are also cheaper from Spruce so I don’t know why you would buy from anywhere else unless you were in a pinch. 

[EricJ]

3 hours ago, Fly Boomer said:

I have only recently become aware that there are several ways to become an A&P and, if an A&P got there by working as an "apprentice" to another A&P who didn't know how to do certain repair tasks, I can see how this could happen.  On the other hand, if the A&P got there by working with another A&P who knew some of the more arcane skills OR went to a great A&P school, there would be a better chance of knowing some of these things.  Also, just having the tools at your disposal can make certain tasks a bunch easier -- it's amazing to see the variety of machines in a shop equipped for essentially every sheet metal task there is.

Exactly.   The breadth of experience of an A&P is totally dependant on the context of their background.    I know a number of A&Ps who got their certifications by experience letters and taking the tests, and I helped a friend study for the tests to do just that a couple years ago (he passed).   It is very possible that you could put a fairly simple sheet metal project in front of many of them and it'd be the first time they'd tried anything like that.   OTOH, Most A&P schools do cover just about everything at least briefly, and some of the instructors at the school that I went to would make that point, that by the time you got out of that school you'd touched an example of pretty much everything.   Most A&P schools use some variation of the same sheet metal project in that class, where you build a small 'control surface' from bulk sheet metal, and by the time you're done with that you have reasonable confidence to tackle basic sheet metal fabrication and repairs.   You also have an appreciation for the sorts of details and nuances that make an experienced practicioner very valuable.   

[DXB]

On 9/2/2024 at 9:43 PM, cliffy said:

It  has always amazed me the "troubles" talked about here on MS about dog house problems

The entire unit is mostly flat aluminum with some bends. Any A&P should have been taught the 

skills to "repair" the entire box without too much problem. Its simple sheet metal/rivet work. 

This ain't rocket science here. Its 90 year old technology and skills!

We shouldn't need to fly around with a dog house in bad shape.

Are we to assume that A&Ps today can not do this simple kind of work?

I just left  an  A&P (not working professionally as an A&P) replacing all the flap tracks on a C-150

and he were doing a good job from what I could see. 

Simple sheet metal and rivets  That's all it is.

Very frustrating to hear this all the time. Maybe its not now the vocation I came into 60, years ago.

I fear you're about to get slammed with a lot of doghouse fabrication requests (don't worry you're safe from me - I'm not quite ready to cross the Rockies to get mine fixed ).  My engine is out for overhaul at the moment, and the guy doing the removal / reinstall on the field seems to be open to doing some sheet metal work - fingers crossed and wallet open.   I even bought a doghouse from the same year C with most parts in good shape, so it should be minimal fabrication.