Rear Observation Windows

[Neverquit]

I've been keeping my progress to myself lately jumping from one thing to another. Can't say I'm at a particular chapter. But I just wanted to post something to show that some mods are easy, fast, and add a personal touch.

 

This is certainly not my idea. But here's how I did it:

 

Cut out the shape of hole you want. This one is almost 6 -12. Make it so there's remaining glass and foam around it to retain some original strength. I did mine when the strakes were upside-down. I reinforced around the area with 2 extra UND tapes and one extra BID reaching from bulkhead to fuse then from bulkhead to bulkhead. Not real science but comforting for me.

 

I installed the 1/4 inch Lexan similar to the rear canopy windows. I sanded the lexan edge about 3/4 deep both sides (be sure to make the Lexan 3/4 in. larger than the opening around the perimeter) and added 1 layer of UND.

I installed them in the cutout and filled the voids with flox. The Lexan is not as thick as the 3/8 strake surface so the flox is feathered to the edges. You might get away with micro as well but I think the flox will be better to bond the outside glass to the inside. I didn't save the perimeter cutout like the plans canopy windows. Instead I added 1 inch then 2 inch BID tape around the perimeter and peel plied on the inside. I added weights to the windows to get a good close bond to the outside of the strake.

 

This whole project took me about 5 hours to do both sides. The most difficult was digging out that foam for the bottom flange.

[steve]

looks good Mr Normin, but is that primer i see ? on the hole bottom?

what year did you start ?

[Edge 513]

Those look great! and will be great looking through.

[Waiter]

I used Lexan for my strake windows. Over the years, theyve become scratched and dirty. I find that I can't buff out the scratches and now wish I had used regular plexiglass.

 

Any thoughts on this?

 

Waiter

[argoldman]

I used Lexan for my strake windows. Over the years, theyve become scratched and dirty. I find that I can't buff out the scratches and now wish I had used regular plexiglass.

 

Any thoughts on this?

 

Waiter

Ya Wait,

 

Lexan, although stronger in some respects than plexiglass, in my understanding, is much more prone to scratches and harder to repair. Have you tried any of the commercially available windshield restorers??

 

You probably have to sand down to 800 grit, then graduate to finer and finer then use the polishing systems. Try that on some scrap lexan to see if it will work.

 

What thickness of plexi are people using for the strake window?

 

I am considering this modification, but in my plane, the rear seat will most of the time be occupied by baggage, air, or my 80 Lb. Goldendoodle (Grover).

[Marc Zeitlin]

I used Lexan for my strake windows. Over the years, theyve become scratched and dirty. I find that I can't buff out the scratches and now wish I had used regular plexiglass.

 

Any thoughts on this?

Yup. Polycarbonate (the generic name for which Lexan is one trade name) is a lousy material to use for this purpose, for exactly that reason - it scratches really easily. Acrylic (the window and canopy material, usually referred to by one trade name - plexiglas) is a far better choice, not least of which for the reason that it CAN be polished if it does get scratched, which it will do far more slowly than polycarbonate.

 

This has been discussed many times on the COZY mailing list and is in the archives. People think "Oooh, Lexan is bulletproof - it must be a good material for windows". But it's not - at least in this case. Especially for a window on the bottom of something that will have other crap put on top of it. Big mistake.

[MoneySink]

I used Lexan for my strake windows. Over the years, theyve become scratched and dirty. I find that I can't buff out the scratches and now wish I had used regular plexiglass.

 

Any thoughts on this?

 

Waiter

Hi Waiter,

 

I used this product for taking scratches out of my acrylic fish tank:

 

(Rainbow Lifegard Acrylic Scratch Removal Kit 72000)

http://www.marinedepot.com/ps_viewitem.aspx?idproduct=RB1551&child=RB1551&utm_source=mdcsegooglebase2&utm_medium=cse&utm_campaign=mdcsegooglebase2&utm_content=RB1551

 

You should be able to restore your strake windows close to its original condition.

[krwalsh]

Just a thought, but it seems that whatever material you choose, you could easily buy the thin, self adhesive laptop screen protectors and put it over the Lexan or Plexiglas window BEFORE it gets all scratched up. Then , when your window gets scratched later, you simply remove the scratched screen protector and replace it.

[TMann]

Don't know about Lexan but Plexi, Mother's Mag Polish does a great job.

[Neverquit]

This has been discussed many times on the COZY mailing list and is in the archives. People think "Oooh, Lexan is bulletproof - it must be a good material for windows". But it's not - at least in this case. Especially for a window on the bottom of something that will have other crap put on top of it. Big mistake.

I wouldn't say, "big mistake". I do live in detroit. Anyway, I'll have to be careful with my bulletproof windows getting scratched from carelessness. Otherwise they probably won't break in the even of an off-field landing and one less thing to fix.

 

While I have Mark's attention, I've read some guys (not to say who) have gone as far as putting the strake windows in nearly full area size? This seems to me a bit risky with lots of untested loss of strength in that area. Has anyone seen this or know its safe to do?

[Lifessamsara]

If the strake windows are not flush wih the inner surface and are lower, consider making a thin protective panel for when you have baggage in the strake. Id suggest that you line it with a soft fabric on the window side.

 

Bruce.

[longez360]

If the strake windows are not flush wih the inner surface and are lower, consider making a thin protective panel for when you have baggage in the strake. Id suggest that you line it with a soft fabric on the window side.

 

Bruce.

Agree 100%. This also accounts for passengers who don't necessarily want to see down.

[Edge 513]

Good idea.

Also maybe make the covers attach in the corners with some velcro tabs.

Covers would be a good idea no matter what your window is made of.

[steve]

I used Lexan for my strake windows. Over the years, theyve become scratched and dirty. I find that I can't buff out the scratches and now wish I had used regular plexiglass.

 

Any thoughts on this?

 

Waiter

its all in the paper(water). clean is the key

sand it with 1000 for about a day (this is the last chance you'll have to remove any flaw at all) then go up in grit IE 1500, 2000,4000...polish with a fine grit. all rags need to be cotton with no thread or seams.

bad windows may need 400 but you'll be sanding with 600 for two days to remove the 400 .