Mooney 20F Side Window Mod

[TTaylor]

I am getting ready to do the mod on our 20F.  I have Mooney parts numbered 340285-007 and 340285-008 but not sure how they should be installed with the new windows.  I have not found a good parts image for the 1976 F's that has the one piece windows.  Can anyone give me details or images on the change so I can discuss it with my mechanic.

 

 

 

 

[N601RX]

I can take some pictures tomorrow. The vertical placement has to be correct or it will cause problems. It has to be high enough to clear the window after it is installed and allow for the correct edge distance on the drilled window mounting screws. At the same time it can't be too high or it will prevent the window trim from laying down correctly. It was mostly a trial and error process. Double sided tape works well until your sure its correct.

[TTaylor]

Thanks!  Any pictures would be a great help to understand what we need to do.

[TTaylor]

Thanks to N601RX for sharing photos.  We started the process yesterday.  I have added a gallery where I will post photos of the steps.

 

http://mooneyspace.com/gallery/album/13849-rear-window-mod-20f/

[Marauder]

Post a whole bunch of pictures Tim! That is one of the mods I really want to do. Makes the plane look much more modern. Are you going to try to round the corners as well? When you are done, I'm going to pick your brain on this...

[carusoam]

Have y'all seen the pictures that George posted years ago? I think they may have gotten lost with one of the MS revisions.

I believe he had them done in NJ at the MSC. prior to going to Japan.

Best regards,

-a-

[carusoam]

This is George's album, but I only see the finished product....

http://mooneyspace.com/gallery/member/6885-georgeperry/

-a-

[jamesm]

Do windows come with pre-drilled  holes ?

 

James '67M20C

[N601RX]

No, they have to be trimmed, drilled and countersunk.

[TTaylor]

Updated the gallery today with images of the stringer install.

 

For anyone doing this I would recommend looking at an opened up 20J if you can.  You might also be able to use the clip method to hold the windows in rather than the screws.  We are going to use the screws but if I had more time I would consider looking at the clips used in the 1976 and later planes. 

 

I am installing 1/4" windows, if I was doing it again I think I would go with the 3/16" as a little easier to fit and the 1/4" feels very thick after removing the 1/8" originals. 

 

I will add the last images after the windows are installed.

[jamesm]

I am just curious .... What is the purpose of  the additional angle 'L" bracket  above the rear passenger seat rear windows ?

Is that need for the short body M20C models ?

Is it  because the thicker plastic/glass?

 

Thanks,

James

'67M20C

[TTaylor]

I am just curious .... What is the purpose of the additional angle 'L" bracket above the rear passenger seat rear windows ?

Is that need for the short body M20C models ?

Is it because the thicker plastic/glass?

Thanks,

James

'67M20C

The stiffener or stringer as I called it provides extra support for the longer window in the F and later models that only use one rear window. To make the modification you remove a center support that tied all the way down to the lower window rail. You can see what is left of it in some of the first images. To carry and transfer that load the stiffener is added above the window and tied to the bulkhead behind the seats.

[N601RX]

Looks good. The plane will look completely different when you get them finished.

[1964-M20E]

Maybe too late now but if you install some small pieces in the corners to make them rounded it will give you a much newer look if that is what you are looking for.  My 67F has this and most people think it is a much newer plane.

[TTaylor]

Updated the album today. Installing the 0.25 Solar Gray Windows in all side windows.   No time to try rounded windows yet, maybe after a new windshield and cowling mod .  Always something to do. 

 

http://mooneyspace.com/gallery/album/13849-rear-window-mod-20f/

[scottfromiowa]

Looks much improved. I countrsunk my plexi and used flush screws instead of rounded in my E. Did you find getting the old sealant off and removing old screws to be a B.I.T.C.H? I sure did. Enjoy!

[Marauder]

Tim -- can you give us a ballpark of what this mod will cost you at the end of the project? I really like the looks, do need glass and wonder if I should not do the mod while I have the glass out.

[TTaylor]

Chris,

 

Rough numbers:

 

Parts from Mooney $200

 

Glass for four windows $1000 to $1350 depending on options (I would go with 3/16" rather than 1/4" if I did it again).  You can also save money by installing the vent window hardware yourself from your old window.  We got new hardware.  I ordered from Great Lakes Aero and they made the rear windows 1/8" larger all around because we were drilling them rather than using clips like the newer models.  I have heard that you can get a better discount using your mechanic and going through Chief Aircraft but i did not try that.

 

I am lucky that our mechanic let us work with him and do most of the grunt work.  I likely have about four hours of his time and about thirty of our time to clean the old material out, drill holes, install the windows, etc.  We ended up drilling each hole six times; pilot, intermediate, twice with step drill (once from each side) and then a bevel with a counter sink on each side.  There are about 150 holes total in the four windows.  We debated sealant and decided to go with Dow 795 in bronze.

 

The windows are brilliantly clear after our old hazy green ones, that was the reason we started the project.

[Guest]

When I replaced the four windows in my E model I started with 1/4" solar gray, then machined a step in the perimeter of the window allowing the window to fit flush with the skin. I also dimpled the skin and counter sunk the window to accept the dimple. The result was an almost completely smooth surface. A lot of work but worth the effort.

Clarence

[jetdriven]

When I replaced the four windows in my E model I started with 1/4" solar gray, then machined a step in the perimeter of the window allowing the window to fit flush with the skin. I also dimpled the skin and counter sunk the window to accept the dimple. The result was an almost completely smooth surface. A lot of work but worth the effort.

Clarence

 

Did you flush fit the windshield as well? I am considering doing that.

[DonMuncy]

I'm interested in how you machined the step for the windows. The jig set-up to make the step precise without the risk of scratching or otherwise screwing up the plexiglass sounds above my capabilities.

[jetdriven]

I did that when I redid my boat windows. It was easy, clamp a 1x2 to the window and run a router down it. However I have no idea the right way to machine a step in my new 747$ windshield.

[TTaylor]

Updated the image gallery today with the trim modifications.

 

1. Cut out the center columns and sanded to shape

2. Laid up glass to cover the opening

3. Several rounds of filler and glass to final shape

4. Painted with SEM paint

[Guest]

I did not machine the step in the windshield. I bought the kit from SWTA but because they were quite rare I decided not to try it.

To machine the step in side windows I screwed a 1X2 smooth pine board on its narrow edge to a piece of good quality plywood. I clamped this plywood to a table saw with the edge of the board over the edge of the saw blade so that the blade sticks out past the edge of the the wood by about 0.050". The saw blade should be a new very fine tooth(60 plus) blade.

I placed the window into the opening and with a marker drew a line on the window following the opening in the aluminum. I measured from the edge of the window to the line and added 1/32" to this dimension. Now at the saw raise the saw blade up through the plywood and pine board to this dimension. This dimension will likely be different for each side for each window.

Now comes the nervy part, start the saw and very carefully hold the window vertically and against the side of the pine board. Carefully and smoothly feed the window past the blade, which will very nicely cut out the required step. This process is repeated for all four sides, and then again for all of the windows. Practice on your old windows to build your nerve. Try the window for a slightly loose fit in the opening, adjust he saw if needed.

My E model windows were held in with flush #8 screws, once the window fit the opening I drilled and counter sunk the window to accept the dimpled skin. I used Johnson's floor wax as a lubricant for all hole drilling and counter sinking, dipping the drill bits and counter sink quite often. Again practice on your old windows.

Once all windows were machined and cleaned to removed all wax residue, the inside of the aluminum skin was cleaned as well I mixed my PRC sealant and installed the windows with all new screws. Be careful not to over tighten them. Once installed I used a soft plastic scraper to smooth the sealant filling in the 1/32" void leaving a nice clean black line around the edges.

Good luck with it.

Clarence

[Marauder]

Updated the image gallery today with the trim modifications.

1. Cut out the center columns and sanded to shape

2. Laid up glass to cover the opening

3. Several rounds of filler and glass to final shape

4. Painted with SEM paint

Tim -- awesome job and you are making it REALLY hard for me not to do this mod! Well done!

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