Windshield

[Lee]

Hi ... I have a slight crack in the windshield ... co-pilots side ... cross shaped ... about 1 1/5" long on each "leg." I am thinking about replacing the windshield. I have seen posts regarding the installation of a windshield (STC) that has the center strap removed. Any thoughts on this with regard to structural issues and how is the windshield secured without the center strap? I could go that route and mount the compass on the glare shield. Thoughts? R/Lee (N1967C)

[Bruce Fenstermacher]

My thoughts. Just about everyone today who replaces a windshield, removes the strap per an STC. This is the route I took.

The method used to secure the windshield without the strap depends on the STC used. The LP Aero STC mimics what Cessna did in later years. Adds a strip of aluminum to the top of the fuselage that a ridge in the windshield slips into and is engaged. Cee Bailey windshields use a different mounting method which you can see here: http://www.cessna170.org/forums/viewtop ... ley#p69801

Most every manufacturer offers windshields for straps or without and in different colors and thicknesses. When it comes to their STC I don't think any better than the other or one easier than the other to install. Comes down to what mod you want too do to your aircraft. Color and thickness are also personal.

I think it boils done to shipping. You end up buying the windshield from the closest manufacturer in a color and thickness they offer and use their STC cause shipping is less.

[jonesronc]

Cessna170bdriver has a good write up:

http://cessna170.org/forums/viewtopic.p ... eld#p70209

I recently replaced my C180 windshield with the Great Lakes one-piece solar grey, works great. I went with rivnuts on the final install. I didn't like Presstite or Butyl tape for the lower seal adjacent to the windshield, as every time I cleaned the windshield it would drag some of the Presstite up and onto the windshield, smearing it. I ended up covering the gap with Proseal PR-1422B-2, and found this writeup helpful:

http://www.cessna172club.com/forum/ubbt ... mber=87928.

It's also a great time to remove a rotting cover and put a glareshield in. I used Selkirk: https://www.backcountrypilot.org/me/my- ... 097-jrc111.

HTH

[bagarre]

We purposely elected to keep the center strap in place since its an integral part of the 170's character.

I need to replace the windscreen on 95D (along with all the windows) and we're going the same route.
It's an easy place to mount your compass (or GPS).
I think the look is better but that's probably because it's what I'm used to looking at.

I will be using slightly tinted glass all around and 2" bubbles on the side tho.

[cessna170bdriver]

We purposely elected to keep the center strap in place since its an integral part of the 170's character.

Have you ever flown a 170 without the strap? I felt the same as you and put the strap back on at my first windshield replacement in 1984. 26 years later I talked myself into installing the thicker windshield and left the strap off. It was hard to believe the improvement in visibility!

The right compass mounts nicely on the glare shield. If you are a REAL originality nut, it goes in the panel.

[Watkinsnv]

I went with the full blown side bubble windows. everyone loves them.

[GAHorn]

If you're a real originality nut you'll leave the center strap installed. Not only does it not bother me, it is a piece of structural strength I find more comforting than screws and potential water leaks along the top. (And the compass belongs in the panel in certain models.)

[ghostflyer]

My 1 cents worth on this one is go for the thickest windscreen you can buy. It's quieter and more protection if bird strikes . A tint is good also . PLus one of the windscreen makers claim that one he makes is also UV filters. I have just had a look at the instructions for fitting my windscreen and its still screwed at the top of the fuselage regardless and the centre strap can be fitted for cosmetic reasons .

[Lee]

I am leaning towards the LP windshield. As for originality, I have so many STCs incorporated that originality went out the "window" a long time ago. If Cessna has not had any problems with the windshield coming out and is similar to the LP modification, then the LP should be OK. I would appreciate any comments by those who have installed the LP windshield with respect to the way the top strip of aluminum which the windshield is fastened to is attached to the fuselage. In particular, does any of the work involve the carry through spar? LPs directions and figures are no the clearest. (And it may be obvious once I start taking the old windshield out) TNX R/Lee

[Metal Master]

I am leaning towards the LP windshield. As for originality. I have so many STCs incorporated that originality went out the "window" a long time ago. If Cessna has not had any problems with the windshield coming out and is similar to the LP modification, then the LP should be OK. I would appreciate any comments by those who have installed the LP windshield with respect to the way the top strip of aluminum which the windshield is fastened to is attached to the fuselage. In particular, does any of the work involve the carry through spar? LPs directions and figures are no the clearest. (And it may be obvious once I start taking the old windshield out) TNX R/Lee

I have installed probably a dozen LP Aero windshield including my own 170, actually I lost count years ago. The entire channel gets rivet into the forward flange of the forward carry through spar. The flanged lip is easy to install except for the outer edges that are above the door post structure. I have special bucking bars made for those areas. As well as a special angled bucking bar for the area between the door post brackets.I install the channel lip before I install the windshield and then use wedges to get the wind shield under the lip ala the later Cessna maintenance manual procedure.. The windshield will have to be fit before the channel is riveted in place using Clecos to hold the strip in place during fitting. Riveting the channel in place after the windshield in place makes riveting the outer ends a near pain. Make sure the fit is the way you want it be fore riveting the channel in place. PS I absolutely do not like the CEE Bailey window installation with screws through the top of the windshield. If my opinion matters. But it is easier to install.
Jim

[Lee]

Jim ... I preferred the LP installation for the reason mentioned regarding screws in the other installation. Can screws and nuts or Rivnuts be used in lieu of rivets on the LP windshield? If rivets have to be used, could you describe the bucking bars you had made up? I appreciate your comments regarding the sequence to be used in the installation. Did you have to do much trimming? (I had some "fun" with a glider canopy installation several years ago in that regard) TNX R/Lee

[c170b53]

Like Jim, I've done both methods of the LP windshield. I've installed the strip and windshield then riveted before I knew better and used the slip method. Once the windshield is in retained at the top you can still pull it forward out of the side channels and trim to fit the sides and bottom. Take your time. The best fit is after the wings are on and you can trim to make it fit, minimizing the mismatch at the roots.

[Lee]

Actually, my wings are on ... to look at a picture of the bird, you would think I just had the cowling off and the interior out. It is a little more than that as I pulled the instrument panel out and removed the instruments from the panel as I want to fabricate a new panel. I could probably let the windshield go for now but, as long as I have gone this far, I think replacing the windshield makes sense. It will, no doubt, be an amusing project! I am going to buy a set of paint cutters (wish I had done this earlier for the wingtips) as I do not want to chip the paint removing screws. Any thoughts on pulled rivets or Rivnuts? R/Lee

[n2582d]

... Any thoughts on pulled rivets or Rivnuts? R/Lee

Lee, It is legal to use rivnuts to attach the lower retaining strip. I elected to install nutplates with NAS1097AD3 rivets. In hindsight I wish I would have installed the nutplates on a couple of aluminum strips which would be mounted under the boot cowl like Jim writes about here. This would have reduced the number of holes in the boot cowl.

[bagarre]

If I remember correctly, 81D had nut plates.