Savannah windshield

[mcrowley]

Well... as ya'll say.. I stuffed up my windshield installation and get to cut out a new one from lexan. The one with my kit was about 2mm. Now that I have an "opportunity" to upgrade, would going to 3mm be an advantage? Any downsides? Thanks all.

 

 

[Kyle Communications]

I will be fitting a 3mm one to Mabel when I get to it. Its much tougher to fit but dont fret I had 2 goes at my first one when I built the XL. I wasnt happy with it so I took it off and redid it. Mine does have a small crack in it now which I stopped with a 1mm drill bit and it hasnt gone any further. There is a ICP video that shows how they do it. I didnt do it that way. I ended up anchoring the front down near the dash then pulling it around with straps the second time. I dont have any rivets in my screen on the front bars> will see if I can find a picture

 

 

[Kyle Communications]

 

 

 

 

 

 

 

[mcrowley]

Kyle, I see you have a gasket or rubber strip between the windshield and the front bars? Are you planning on the same install technique on Mabel?

 

 

[JG3]

We've replaced several windscreens. We find 2mm plenty thick enough and still easy to work and cut with tin snips. The original was 1.5mm. Note: When using the original as a pattern to cut out the thicker one, leave an extra 12mm on the door post edges, otherwise the new one will be several mm short. Trim to suit after drilling and clecoing the door posts. Drill 4mm holes for the 3mm rivets to reduce stresses. Riveting the front down tubes creates concentrated stress points that can start cracking, so don't rivet them. After the door posts are riveted, force a dense foam strip between the down tubes and the screen. We find the foam material about 8mm thick used for concreting expansion joints to be ideal. Poke it in with a screwdriver, thus tensioning the polycarb. Works really well.

 

 

[Kyle Communications]

Kyle, I see you have a gasket or rubber strip between the windshield and the front bars? Are you planning on the same install technique on Mabel?

Yes exactly the same although I did learn a few things with the first one. but essentially yes. Just the 2 holes at the bottom and drilled and tapped for 3mm stainless bolts. This makes it so much easier to hold the screen in the right place. JG is is certainly correct on the hole sizes. This is a must otherwise you will get cracks in the lexan. The stri against the bars is a door gap filler material. It works a treat so you are not drilling into the front bars

 

 

[rankamateur]

This is a must otherwise you will get cracks in the lexan. The stri against the bars is a door gap filler material. It works a treat so you are not drilling into the front bars

Did you fit the strips after the initial install to tighten everything up or during the initial install?

 

 

[Kyle Communications]

During the install

 

 

[rotax618]

I replaced the 2mm windscreen on a friends Sav VG with a 3mm screen, The original screen couldn’t be used as a template because the thicker screen didn’t bend the same, you have to allow a larger margin and pull the screen into shape, mark and trim.

 

 

[rollerball]

3mm is overkill IMO - just not necessary and just adds weight. I had to replace my Sav's windshield after having a pipe fall off while pumping fuel into the left hand tank and as soon as the fuel hit the Lexan it crazed immediately. I replaced mine with 2mm Lexan and used all the same rivet holes and as my screen is not attached along the front lower edge in any way, I replaced the (two - one each side) pop rivets in the front struts. Why wouldn't you? I did pop a small black rubber tap washer between the plastic and the strut on each side though. Perfect job, in fact better than before. Sourced a new rubber strip to go along the bottom front edge and carefully sealed between it and the fuselage surface after carefully cleaning and repainting the latter. And while I was at it, I also re-covered the top of the panel in a swish padded black leatherette as you can't easily get at it with the screen in place. But I still haven't found a nice edge strip for the inboard end, around the top of the panel, that doesn't contain metal and distorts the compass reading, although I've been out of the loop for a few months because of my health, so will soon be back on the job.

 

 

[IBob]

Really good info here: this is looking like one of those jobs that's no trouble at all...second time around...)

 

 

[mcrowley]

E

 

Really good info here: this is looking like one of those jobs that's no trouble at all...second time around...)

exactly!! ;-)

 

 

[rotax618]

3mm is unnecessary, the success of an aircraft is not what you can add but what unnecessary stuff you can eliminate. The designer of the Sav was careful to eliminate excess weight in the structure by using materials which have the necessary section modulus resist the loads that will be applied to the structure in all regimes of the Sav’s flight envelope plus a safety margin.

 

In aircraft design it is easy to make something strong enough but it is clever to make something light enough.

 

 

[IBob]

Mark, I just completed the trial (cleko/drilling) fitting of the cockpit roof. This should now be ready for final fitting when I get there.

 

The manual next moves on to fitting the windshield. Is there any reason I should not also do a trial fitting, drilling etc of that at this (pre painted) stage of the build?

 

Thanks.

 

 

[Kyle Communications]

Actually the windscreen is one you really do need to trial fit...its a real pain to get it right. Another set of hands wouldnt go astray either. I did mine by myself with some tension straps like on the wings but smaller ones...I ended up drill another set of holes later after repulling mine around. It is really a crappy part of the build. perseverence is the word and attention to detail especailly right at the very front of the screen at the bottom where it meets the cowling deck

 

 

[IBob]

Actually the windscreen is one you really do need to trial fit...its a real pain to get it right. Another set of hands wouldnt go astray either. I did mine by myself with some tension straps like on the wings but smaller ones...I ended up drill another set of holes later after repulling mine around. It is really a crappy part of the build. perseverence is the word and attention to detail especailly right at the very front of the screen at the bottom where it meets the cowling deck

Thanks.

I must be doing something wrong, as....so far....it seems to be sitting pretty good with just the straps on.

 

I'm doing it with the fuse almost on the ground (150mm dummy wooden block u/c) and the tail high, which probably makes it a lot easier to see and wrangle?

 

The lower screen makes it's own natural line, I'm just not sure how much bow to leave in the upper screen..............???

 

 

[Kyle Communications]

I used a rubber strip from Bunnings between the cabin front bars and the inside of the screen. There needs to be a reasonable "tightness" of the screen around the front bars but when you do this the front middle of the screen at the bottom wants to crawl up the front bars..just becare f that..that was my trap and it changed the mounting holes at the cabin side rails...I actually chopped off about another 6mm off each side after the second attempt at getting mine on

 

 

[IBob]

I used a rubber strip from Bunnings between the cabin front bars and the inside of the screen. There needs to be a reasonable "tightness" of the screen around the front bars but when you do this the front middle of the screen at the bottom wants to crawl up the front bars..just becare f that..that was my trap and it changed the mounting holes at the cabin side rails...I actually chopped off about another 6mm off each side after the second attempt at getting mine on

I was concerned that if the mid upper screen was pulled too flat it may be more likely to vibrate in the air. But I'm guessing I'm not likely to get it that flat.

Yep, I can see the upward creep you're talking about. Makes sense to get those front bottom fixings in to prevent that, then.

 

Okay, end of day here.

 

Looks like an interesting session for tomorrow morning...)

 

 

[Kyle Communications]

Thats why I put those 2 of 3mm tapped holes in there...then I did not have to put rivets into the front bars

 

 

[IBob]

That hole in the top skin that the front bars go down through extends well forward of the line of the windscreen and won't be covered by the seal. And I believe Perry's is the same.

 

I will have to make a patch. I wonder what changed?

 

 

[Kyle Communications]

no there is a unnamed part that goes in there...sort of looks like a bow tie

 

 

[Kyle Communications]

just so happens it is sitting here on my desk :)

 

 

 

[IBob]

no there is a unnamed part that goes in there...sort of looks like a bow tie

Same shape as elongated segment of an orange, with a couple of broad recesses cut in the curved side?Looks to be intended to fit behind the windshield.

 

 

[IBob]

Yep, that's the part. Fits behind the windshield but does nothing to close the hole in front of the windshield.....(

 

 

[Kyle Communications]

What hole?..that should fill the spot where the bars go through the top deck. There is a small gap of course where the bars go through..the windscreen should fit in front of those holes