The International Cessna^® 170 Association

Ok just of the phone with LP Aero. It is important to note and it was by their rep that they don't actually install their windshields. So the info he was going to give was not from company first hand experience but from feed back from their many customers.

The rep said that you can use the felt by itself as the instructions say. But your likely to get leaks as Cessna was notorious for. He said you can substitute the Cessna Presstite sealer for the felt and you can use the sealer all the way around the window bottom, sides and top. He recommended at least using sealer on the bottom. He also said the sealer does not harden and the windshield will float as it is required. I pressed him on this and asked that if I sealed the windshield all the way around that it would float and LP Aero would not consider the windshield incorrectly installed. He said that was the case.

He also said you can use both the felt and the sealer on top of the felt as the Cessna Service manual says you can and there will be no ill effect.

So there you go. Seems you can do no wrong with the sealer. More or less, some here, none there, or put it everywhere. The LP Rep said just don't drill and put screws through the windshield.

Thanks for the research, Bruce! I fitted mine today in placed the felt around all the edges. I will put the tacky stuff on the upper and lower retainer areas to prevent the mentioned leaks.

Finally got to my hangar to check the stuff I had used on my window. The stuff is Sternson RCA 5000-s. turns out they were been bought out in the M&A craze. The sealant is a one part poly sulphide type. I probably used it ten years ago and it's still soft and pliable in the nozzle.

The windshield is in. Pretty easy actually. Took two of us about 7 hours. Here is what we did.

First to recap we replaced the stock windshield with LP Aero's STC's single piece windshield. Our windshield had already been replaced at least once so the bottom strip was held in by screws with speed clips which we reused. Since I didn't need a wrench to hold the speed clips under the instrument panel, just my fingers, we could pretty easily reach them all threading my arm through and around all the wires, instruments and radios without removing anything. I could have done it with a socket to remove nuts if that is what was there but it would have been harder.

The old top strip that needs to be removed for the new strip that holds the windshield in rather than the center strip. This was easy but took some time to drill out the old rivets. One thing that happened, at least with our aircraft was that the front spar spread as the rivets were removed. We had to use a drift pin to realign it when assembling with the new strip and clecos. No big deal but we had to keep it in mind.

We decided to use screws to install the top strip rather than buck in new rivets. You could use a rivet squeezer to install the rivets but one would have to grind quite a bit off the squeezer to get it to align straight which I did not want to do. We could have bucked them but decides the screws would be better because if the windshield should need to come out at some point it would be a matter of loosening the screws to drop the strip and pull out the plexi.

As for the seal we decided to use the felt all around. Then we used the Cessna Prestite green sealer on the bottom of the window only. We covered the bottom strip holes in the fuselage with one strip so these holes will be sealed. We put a second strip on the fuselage near the top of the inside lower lip under the felt and we put a third strip between the first two slightly favoring the inside by overlapping to insure a seal.

On the outside strip we but the sealer near the top over the felt to seal any water running down the windshield from getting under it. The bottom of the top strip seals to the sealer we already put down over the holes in the fuselage sealing any water getting under the windshield from the lower edge.

There was minimal trimming of about a 1/2" required on the center of te bottom which we did easily using a 4" belt sander to sand it down. We also took about 1/4" off one side at the wind root and the same about in the back edges to insure the windshield would not touch it.

One of the hardest things while working on the windshield was trying not to lean on the top cowling and bending it. It mades a great shelf but it has no strength. If I did this job again I'd remove it or cover it with a protective board. We did have carpet on it but that didn't stop me from adding a crease to the cowl.

Our door pins are easy to pull and remove the doors. We still did not remove them for this job. I'd probably remove the doors if I do this again.

The last tip. When I ran the felt of the side I naturally stopped at the wing root curve because that is where the slot stops. What you are left with (on every windshield) is a little hole about the diameter of a pencil. If you ran the felt around the wind root curve about an inch then cut a few small felt strips and layered then on top in this area it would fill this hole. As it was I used little felt strips to bridge the hole after the windshield was installed. On my old windshield I'd filled these same holes with putty.

We did have one small glitch. The bottom of one side of the wing root fairing area of the windshield was not 90 degrees from the side of the windshield but drooped down. It was to low compared to the wing to install the metal fairing strip between the wing and the windshield without placing pressure on the plexi. A quick call to LP and a picture emailed got us detailed instructions exactly how to use a heat gun to heat the area required to move the fairing area of the windshield where we needed it. Sounded scarier than it actually was. But don't just heat a formed plexi windshield without knowing what and how to do it because the plexi has memory and will try to flatten out. Despite the little glitch I'm very happy with the quality of the LP windshield, new top strip (which was pre-pilot drilled), the install instructions and support.

Sounds like yours went pretty much just like mine. I only had help installing the screws, so I took a little longer. I am very happy with the results, though. Would rather not have to do it again, but if I do, it will be with less anxiety going into the project.

KS170A wrote:Would rather not have to do it again, but if I do, it will be with less anxiety going into the project.

Yes Josh I agree. It just was not that big a deal. The anxiety comes because you are handling an expensive part in the windshield that can be easily damaged.