Windscreen replacement

How to keep the Cessna 170 flying and airworthy.

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c170b53
Posts: 2560
Joined: Mon Apr 22, 2002 8:01 pm

Re: Windscreen replacement

Post by c170b53 »

I left that out as I didn't think it popular as they say " my bad". I had a look at their website and that method, is the window thicker? I've also helped long ago install a window that used 4 plexi screws (large diameter) from the inside top to hold the window. Maybe that's the same window as yours but I thought that method also used a hook strip. So your right there are other ways's to do it. I do like the LP product for fit but fit also is influenced by the cabin I guess.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
bat443
Posts: 129
Joined: Wed Aug 01, 2007 4:41 am

Re: Windscreen replacement

Post by bat443 »

Yes the windshield with the center strip is .120 (1/8) inch and the STC windshield without is .187 (3/16) inch. I installed the STC windshield in a 185F and previous owners of the 170A and 170B I currently own plus a 170B I owned previously all have the Great Lakes STC windshield without the center strip. I have had no problems with any of them. I will have to say that the location of the supplier and the ability to pick up the windshield rather than have it shipped I am sure was a factor in all of the installations as they were all installed here in Michigan. Only a 2 hour drive for me and probably the same or less for the previous owners.

Tim
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cessna170bdriver
Posts: 4115
Joined: Mon Apr 22, 2002 5:13 pm

Re: Windscreen replacement

Post by cessna170bdriver »

Jim,

I used the Great Lakes windshield when I replaced mine in 1984, and liked it so much I went with them again in 2010 (even though I had to have it shipped to California...). IMHO, it is easier to install than adding the whole new strip along the top.
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
ghostflyer
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Joined: Mon Apr 21, 2008 3:06 am

Re: Windscreen replacement

Post by ghostflyer »

Just a little tip to decrease the amount of FOD when drilling out the rivets for a windscreen change . Obtain the widest masking tape you can ,and stick it to underside where the the rivet tails are and really make sure the tape is sealed around the rivet tails and then drill out the heads of the rivets . The sticky side of the tape captures most of the rivet tails and swarf . Put the tape on in 8 in lengths . Duct tape can be used instead of masking tape also .
Plus as previously suggested make up nut plates about 10 ins long . A little more fooling around but makes the job easier and better presentation . The added support under the skin stops dished skin due to the rivet process plus added support for the windscreen .
c170b53
Posts: 2560
Joined: Mon Apr 22, 2002 8:01 pm

Re: Windscreen replacement

Post by c170b53 »

Bat443 and Miles, sounds like it's G.L. Shield is the way to go. I had to make a bucking bar to rivet my LP back in when I replaced it and the whole process was time consuming.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
ghostflyer
Posts: 1423
Joined: Mon Apr 21, 2008 3:06 am

Re: Windscreen replacement

Post by ghostflyer »

Another little tip when replacing the windscreens. At the top of the screen where it meets the fuselage, there will be a ridge created as the screen doesn't fit flush with the top layer of skin . What we do is mask about 1 in from the top of the fuselage across the screen and mask along the top of the fuselage on the edge . A filler is made up using RTV 3145 which is grey in color. This spread across the screen to provide a small ramp for the air flow. After about 2 hours remove the masking tape and with very soapy water , using your finger smooth the RTV . After curing for a day or so I then tape over the whole lot with aluminium tape and smooth it down with a round hard tool.
Now doubt I will hear people saying the RTV ( silastic) releases a acid on curing that will make the wings drop off and the propellor to fall off in flight . This RTV is approved to be used on a number of aircraft plus its main area of adhesion is on the perplex . It stops water leaks at the top of the screen BUT it cuts down the wind noise in th cockpit in flight .
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GAHorn
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Re: Windscreen replacement

Post by GAHorn »

Yes... common RTV is bad stuff for Plexiglas... if it is common RTV (not familiar with the "green" stuff mentioned).... most RTV uses ammonia to "cure". (Can't you SMELL it?)
Ammonia RUINS Plexiglas/Acrylic windows. It causes brittle cracks and crazing. That is why using Windex with ammonia and other ammonia-containing glass cleaners is death to plastic windows. (It may be one reason auto headlamp lenses become "foggy" and require corrective treatment because someone used Windex with ammonia or drove it thru a carwash that did so.)
Don't even use RTV inside your airplane or the ammonia may craze the plexi.
'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. ;)
c170b53
Posts: 2560
Joined: Mon Apr 22, 2002 8:01 pm

Re: Windscreen replacement

Post by c170b53 »

George I know what you're writing but this sealant Dow Corning 3145, is nice stuff. It's non corrosive and as well didn't affect my screen. I did read the spec sheets and adhesion to plastics isn't it's strong point but it has remained intact on my plane.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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