Plexiglass Panel Overlay - 170A

How to keep the Cessna 170 flying and airworthy.

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brian.olson
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Joined: Mon Aug 14, 2017 12:04 pm

Re: Plexiglass Panel Overlay - 170A

Post by brian.olson »

Gary - I would be curious to that as well. My research was very myopic to my particular aircraft and pretty much to the exclusion of everything else. Thankfully I have a talented daughter who is a graphic designer and was able to track down a current font that is pretty much dead-on. Ryan (and Bruce) have both spent incalculable time looking at the entire 170 line and the twists and turns each panel and placard have taken over the years. Their collective knowledge on the subject is master-level.
Brian
1950 170A
N5762C s/n 19716
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Jim Collins
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Joined: Tue Oct 17, 2017 1:34 pm

Re: Plexiglass Panel Overlay - 170A

Post by Jim Collins »

The panel overlay in my plane could use replacement. From the work I have seen done on this message tread, has anybody created any Cad files of the acrylic with outer dimensions and hole pattern locations with the artwork as well? I have access to a laser cutter/engraver and would like to make a new one. I would have to edit the files slightly as over the years, the location and names of some of the controls has shifted. Another thing I would like to do is to make the overlay in 2 sections so all I have to do is loosen the controls, remove the old overlay and place the new one underneath. I wanted to avoid having the remove everything as that would be a lot of trouble.

Thanks

Jim Collins
C170B N2488D
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brian.olson
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Re: Plexiglass Panel Overlay - 170A

Post by brian.olson »

Jim Collins wrote:The panel overlay in my plane could use replacement. From the work I have seen done on this message tread, has anybody created any Cad files of the acrylic with outer dimensions and hole pattern locations with the artwork as well? I have access to a laser cutter/engraver and would like to make a new one. I would have to edit the files slightly as over the years, the location and names of some of the controls has shifted. Another thing I would like to do is to make the overlay in 2 sections so all I have to do is loosen the controls, remove the old overlay and place the new one underneath. I wanted to avoid having the remove everything as that would be a lot of trouble.
Jim - I used a program called Affinity Designer, which is a less-expensive version of Adobe Illustrator (cost me $25). I exported the file as a .SVG file which was then loaded into the laser cutter. Send me a PM with your email address and I'll be happy to send you both the design file and the .SVG output file, and you can modify as you see fit.

I would "not" recommend splitting the acrylic in two. I did that as part of the templating process just to confirm placement, but after watching the cables being installed this week the acrylic is actually a very important part of the integral acrylic/aluminum panel, and there is bit of force exerted on it from each cable's attach point. Having a split piece will cause it to quickly crack. Just my opinion, however - and since this is all a great big experiment it might be interesting to see what happens if you give it a try, as it would substantially reduce the amount of time needed to replace the acrylic panel.

Regards -
Brian
1950 170A
N5762C s/n 19716
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Jim Collins
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Joined: Tue Oct 17, 2017 1:34 pm

Re: Plexiglass Panel Overlay - 170A

Post by Jim Collins »

Thanks Brian,

I sent you an e-mail so you could forward me the files you have to play with. I also don't know if the split overlay idea will work or not. I was planning to place the split lines around the controls as much as possible to support the pressure and to solvent bond the sections together. May work, may not.

Thanks again

Jim Collins
C170B N2488D
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n2582d
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Re: Plexiglass Panel Overlay - 170A

Post by n2582d »

Would it work to place a bushing - maybe a flanged bushing - slightly proud of the plexiglass in each (enlarged) push/pull control cable hole in the plexiglass panel? Taking the compression load off the plexiglass would help prevent cracking there.
Gary
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GAHorn
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Re: Plexiglass Panel Overlay - 170A

Post by GAHorn »

n2582d wrote:Would it work to place a bushing - maybe a flanged bushing - slightly proud of the plexiglass in each (enlarged) push/pull control cable hole in the plexiglass panel? Taking the compression load off the plexiglass would help prevent cracking there.
So, now we’re not just discussing simple preventtive-maintenance (interior/uphostery refurbishment), we’re now discussing flight and engine controls modifications? :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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brianm
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Re: Plexiglass Panel Overlay - 170A

Post by brianm »

brian.olson wrote: Sun Oct 03, 2021 8:06 pm The final copy of the acrylic panel has been completed and installed during 62C's annual inspection. The panel was cut/engraved on a Glowforge laser cutter/engraver. I tested three different suppliers for the acrylic, but the final acrylic was sourced from Glowforge itself and I determined it to be the best. It is 1/8" thick. As near as I can tell it is UV-resistant. The original acrylic that was in the plane measures 3/16" thick (see "future considerations" section below).
Hi Brian,

I just found out my local public library has a laser cutter that the public can use. While getting trained on the equipment they mentioned that extruded and cast acrylic engrave and cut differently. Cast ends up with a cloudy/milky finish in the engraving and extruded is clearer but isn't as tough. I'm planning on trying both, but do you recall what you used?

Also, are you sure that your original was 3/16" thick? I have a '48 and I believe the overlay is original. It is every bit of 1/4". The holes for the cables are 3/8" diameter but with a counterbore that is 1/2" diameter by 1/16" deep, leaving the flange on the cable flush when installed. I also got a brief look at an overlay from a 140 and I didn't have my calipers with me but it appeared to be the same (the '48 and the 140 have the same part number). Could just be a model-year thing.
Brian M
N2669V - '48
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