c170A-b windshields

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butchpilot170
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c170A-b windshields

Post by butchpilot170 »

Hi 170er's ! Anybody know if the one piece windshield (needs no center strip )of a 170b work in a 170A ?
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c170b53
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Re: c170A-b windshields

Post by c170b53 »

Probably, but.....search the forums, tons of advice. Just finished installing a windshield and as you would think, the more you do something the more you realize what you're doing which might make you whince when you reflect back on what you did in the past.
I think someone recently posted "better is the evil of good" When fitting windshields it's amazing how much evil is involved
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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Bruce Fenstermacher
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Re: c170A-b windshields

Post by Bruce Fenstermacher »

In a word yes they are the same. And they could all be swapped. But no they aren't either.

First ALL windshields are one piece. Earlier windshields for the '48 and A were flatter. Only die hard 170 folks would notice this. The center strap is what holds all of then into the top of the fuselage.

If you do not install the center strap you must have some other method to attach the windshield to the fuselage top. There are a few different methods depending on who manufactured the windshield. Removing the center strap is a major alteration so there needs to be an approval such as the STC sold with a new windshield.

Windshields are custom fit to each airframe. A used windshield might fit fine in another airframe, it may also have been trimmed to small for the recipient.

Between the fit and paperwork hassle a used windshield doesn't seem to be the best deal under most circumstances.
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cessna170bdriver
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Re: c170A-b windshields

Post by cessna170bdriver »

In my experience, it's the wing root fairings that actually do the majority of holding the windshield in place, and the center strip mostly just adds stiffness to the 1/8" thick early windshields. I say this because the t-shaped piece that connects the outer strap to the airframe at the top of the windshield was broken on my airplane for 1200 or more flying hours. I will admit that my windshield may have lasted much longer with the strap properly tied into the airframe, as it eventually cracked starting at the right wing root fairing, I assume from repeated flexing.
Miles

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Bruce Fenstermacher
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Re: c170A-b windshields

Post by Bruce Fenstermacher »

Mine was broken as well and remained that way. No one seemed concerned as most don't understand exactly the purpose of the strap. Should the windshield break out leaving the airframe in the air I understand most aircraft won't fly due to drag that can't be over come. I would not Under estimate the importance of windshield security.
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GAHorn
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Re: c170A-b windshields

Post by GAHorn »

Bruce is correct on this. One of the first accidents of which I was made aware of was a windshield improperly secured at the top and it popped out in flight. (You'd think relative wind should keep it in-place, but the opposite is true.) Full power could not keep the airplane in the air and it crashed. (Wish I could find that but IBM/Microsoft strikes again.)
'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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ghostflyer
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Re: c170A-b windshields

Post by ghostflyer »

There is 2 thicknesses of windscreens available , I ordered and fitted the thickest that's available plus there is a company now produces a windscreen that is also UV protection and tinted . I have been told this manufacture is the best but when you get the product there is still the blood sweat and tears in fitting it . Going by my customers reports the best tint is blue and not the the green or gray. I ordered the blue for mine and the thickest but when opened the box it's the right thickness but clear. The freight here was almost twice the cost of the windscreen so the clear one went in . The top of the windscreen is secured by 4 or 5 screws to the fuselage but the holes through the windscreen has silicone rubber inserts. My windscreen has survived one bird strike so far [small bird][seagul]. It's very important to follow manufactures instructions to the very letter. I have seen the sides of the windscreen secured to the fuselage ,this is a no no and the windscreen should slide or move in the slots . I have also seen windscreens with the felt coated with grease. The grease attacks the perplex allowing it to craze or crack . There is a special lubricant available . Well we will not get into the using silastic as a sealant debate also. That would take a page or two.
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GAHorn
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Re: c170A-b windshields

Post by GAHorn »

If you mean RTV by the term "silastic" .... yes. In fact, using RTV anywhere near the Plexiglas can be a problem because those products use ammonia as a curing agent. (Yep. That's the smell all right.)
Ammonia crazes plastic/acrylic windshields and windows.

And the Cessna windshields "float" within their frames. :P One can witness this taxying on a rough field as the airframe flexes. Some aircraft seal their windshields with Pro-Seal type sealants (like the Baron I once owned) and turf runways will eventually crack them because they cannot move. (The people who did that installation had to replace that windshield three times inside the same number of years until they quit using the hardening-sealant and used a flexible one.)
'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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ghostflyer
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Re: c170A-b windshields

Post by ghostflyer »

While we are talking about RTV,s not all RTV,s give off ammonia but one RTV that I use on windscreens with the blessing of some aircraft manufactures is Dow Corning 3145 RTV MIL -A- 46146. It gives off a gas being formaldehyde. This happens until cured. AND NO YOU DO NOT PUT IT IN YOUR MOUTH . But seriously there are hundreds of dangerous chemicals in a aircraft and you have to use common sense when using them . There is another sealant called Mastic and that can affect unborn children. So when you are using glues , lubricants , fuel etc ,wear protective gloves / eye protection and clothing.
The best thing to do is your home work as there are many types of proseals on the market for sealing windscreens correctly and don't not use a tank sealant sealant to seal a windscreen.
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nippaero
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Re: c170A-b windshields

Post by nippaero »

How about 3M Strip Caulk to seal the gaps?
1952 170B
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Bruce Fenstermacher
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Re: c170A-b windshields

Post by Bruce Fenstermacher »

No need to reinvent the wheel or use up what you might have squirrel away in your hanger. When you buy the windshield, buy the felt and sealant from the windshield manufacturer.

LP Aero supplies the felt and I supplemented that with their recommended green strip sealant.This are especially useful in filling large gaps in Cessna installations, their web site states. Green, 1/8" x 1/2" x 25' roll - Cessna sealant 579.6 (Presstite) SP-5796. One roll will easily do a windshield and have enough to squirrel away in your hanger for the rest of your life. I use it to seal the removable aluminum panels on the aft roof of the 170.
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ghostflyer
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Re: c170A-b windshields

Post by ghostflyer »

When I seal up a windscreen I use a fiberglass reinforced tape and tape the gap between the wing and fuselage and that area where the windscreen is shaped towards the leading edge of the wing .its to stop any air flow entering the cockpit.
The wing fillets have a coating of green felt to rub against the windscreen also . Is there a reason to seal those rear top wing panels ???
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GAHorn
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Re: c170A-b windshields

Post by GAHorn »

If the "shoulder blade fairings" are closed up at the lower edges they will collect water over the years.
You'd think a riveted edge would allow drainage, but a tight fit, coupled with years of dirt, will seal that seam and allow water to congregate.
Ideally, there will be a slight "vent"... bent into the lower edge to allow water to escape.
'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. ;)
bagarre
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Re: c170A-b windshields

Post by bagarre »

ghostflyer wrote:When I seal up a windscreen I use a fiberglass reinforced tape and tape the gap between the wing and fuselage and that area where the windscreen is shaped towards the leading edge of the wing .its to stop any air flow entering the cockpit.
The wing fillets have a coating of green felt to rub against the windscreen also . Is there a reason to seal those rear top wing panels ???
I did that same thing to help keep out the cold air.
One day, flying home from Pittsburgh, the tape gave way and created a 120 mile an hour kazoo.
Never did find that sear cushion.
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Bruce Fenstermacher
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Re: c170A-b windshields

Post by Bruce Fenstermacher »

My partner who's owned my 170 since the 60's uses a green wool Army GI blanket to cut a gasket that fits tightly under the wing fairing and around the windshield somewhat sealing the gap between the windshield and the wing. Works pretty well.
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