Lexan Installation

So, I'm kind of proud of my windshield installation and wanted to share. I could never get the glass windshield to fit properly, so I scrapped it in favor of a piece of 1/4" Lexan.
First I used aircraft style captured nuts (1/4" X 28 ) that I got from Pegasus Racing and riveted them around the perimeter. I figured I might want to remove the windshield at some point without having to drill out rivets. Next, I used 1/2" self-adhesive foam weatherstrip.
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I then used the glass windshield as a template and cut the Lexan with a skill saw. I used a belt sander to dress the edges. Using a tape measure and a Sharpie, I marked out a 1" border on the PVC cover, with a 2" border on the bottom. I used an Exacto blade to trim away what I marked, then painted it (on the back) with black Krylon.
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This is what it looked like when I pealed the rest of the PVC cover off, after the paint dried.
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I used button head machine screws with black rubber washers underneath, and this was the result-
http://i209.photobucket.com/albums/bb222/roval41/th_IMG_20130413_170258_463_zps1cf8b282.jpg

I have abosolutely no idea why the images are not showing up, but it is starting to iritate me.

So, I'm kind of proud of my windshield installation and wanted to share. I could never get the glass windshield to fit properly, so I scrapped it in favor of a piece of 1/4" Lexan.

First I used aircraft style captured nuts (1/4" X 28 ) that I got from Pegasus Racing and riveted them around the perimeter. I figured I might want to remove the windshield at some point without having to drill out rivets. Next, I used 1/2" self-adhesive foam weatherstrip.
http://i209.photobucket.com/albums/bb222/roval41/IMG_20130413_144649_989_zpsa5537555.jpg

I then used the glass windshield as a template and cut the Lexan with a skill saw. I used a belt sander to dress the edges. Using a tape measure and a Sharpie, I marked out a 1" border on the PVC cover, with a 2" border on the bottom. I used an Exacto blade to trim away what I marked, then painted it (on the back) with black Krylon.
http://i209.photobucket.com/albums/bb222/roval41/IMG_20130413_144649_989_zpsa5537555.jpg

This is what it looked like when I pealed the rest of the PVC cover off, after the paint dried.
http://i209.photobucket.com/albums/bb222/roval41/IMG_20130413_162059_635_zps13cc6548.jpg

I used button head machine screws with black rubber washers underneath, and this was the result-
http://i209.photobucket.com/albums/bb222/roval41/IMG_20130413_170258_463_zps1cf8b282.jpg

That better?

First you shame me with your immacualte rebuild of "Dad's Panoz", then you make me feel stupid because of my lack of computer skills. Why don't you just come by and kick me in the nuts? (Laughing out loud)

Yes Brian, thats a lot better. I USED to be able to do that on the previous version of photobucket, now something wierd is happening. Anyway...thanks!

Trick is to just look at the code and do it manually. I just quoted your post and then manually edited the links. It had a bunch of extra crap in there. You just want the URL for the image between the image tags i.e. the .

Good idea on the riveted on captured nut things. I was going to use nutserts, but these look like a much better option for doing stuff in the plastic.

EDIT - If you're using photobucket it already gives you one option with the IMG tags around the url. You don't have to add them again, nor do you have to use the forums "insert IMG" icon thingy. If you do that you'll have extra sets of img tags wich cause it to fail. Just past the url with IMG tags into the text area and you're good to go.

self lock nut plates.... I chose the 1/4-28's. The only issue was the holes for the rivets were too small, so I spent a bit of time on the drill press, but it all worked out in the end.
https://www.pegasusautoracing.com/productselection.asp?Product=MS21047

PS, I would order the machine screws from them too. I couldn't find them at my local Ace Hardware, and could only buy them in bulk from Fastenal.

https://www.pegasusautoracing.com/productselection.asp?Product=631

Ace Hardware did have the self-adhesive weather strip. It gav the lexan a soft mating sruface and kept the edges nice and flat between each fastener.

self lock nut plates.... I chose the 1/4-28's. The only issue was the holes for the rivets were too small, so I spent a bit of time on the drill press, but it all worked out in the end.
https://www.pegasusautoracing.com/productselection.asp?Product=MS21047

PS, I would order the machine screws from them too. I couldn't find them at my local Ace Hardware, and could only buy them in bulk from Fastenal.

https://www.pegasusautoracing.com/productselection.asp?Product=631

Ace Hardware did have the self-adhesive weather strip. It gav the lexan a soft mating sruface and kept the edges nice and flat between each fastener.

Looks very professional, nice work.

Kel.

One thing I tried that I really like is a "limo" tint across the upper part of the windshield. really cuts down on the sun in the eyes. It is surprising how far down you can come with it and not interfere with your field of vision. I figured out how far by sitting in the seat and marking the low point allowing for a little margin for looking ahead on down hills. It came down almost 12 inches at the lowest point at the pillars. I don't see why it couldn't be done using the black paint on the inside surface.

Mike

One thing I tried that I really like is a "limo" tint across the upper part of the windshield. really cuts down on the sun in the eyes. It is surprising how far down you can come with it and not interfere with your field of vision. I figured out how far by sitting in the seat and marking the low point allowing for a little margin for looking ahead on down hills. It came down almost 12 inches at the lowest point at the pillars. I don't see why it couldn't be done using the black paint on the inside surface.

Mike

I'm a little surprised by that. I figured since you sit so far back and under the upper roof line it wouldn't be an issue. So far that I'm a little concerned with running high-banks like Daytona and Homestead. then again, I haven't raced the Panoz yet. In my recollection, I have to look up through the windshield to see more than a few hundred yards in front of me. I had a windshield banner on my Mustang that I peeled off after my first venture at Daytona. Nothing like driving blind on 33 degree banking. I have a tinted face shield that I leave halfway open. All I have to do is tilt my head down slightly and I can look through the tint. Worked in the past, but I'll keep your suggestion in mind.

At 6'4" I need every bit of view/vision I can get. No tinting for me.

I'm sure that driver height, seat and mounting and high banks all have to be factored in. I'm 5' 11" and have the the original GTRA seating. I've had it on Barber, TWS and TMS and it is highly effective. The limo tint is not 100% blockage, but I've never been close to having to try to look through it. TWS has 23 degree banking on the oval, but we do not incorporate that into the 2.9 mile road course. It does have some nice elevation changes as does Barber. TMS incorporates turns 3 and 4 in their long road course. It has 24 degree banking and wasn't an issue. Folks who want to try a banner out could probably experiment with tape.

I wear glasses and a clear face shield. I don't like sun glasses or tinted shields as I have problems seeing the PI screen and the rear view screen. That maybe why I like the limo tint banner so much.

Mike

I suppose its something I'll get used to when I actually get the car out on the track, but the seating position for me is awkward. I'm 6'2". I have a custom built UltraShield Containment road race seat. I mounted it right on the floor. The seat that came in the (school) car was on mounts well up off the floor and my head/helmet was hitting the roof. Now the steering wheel position, shifter position, and pedals are all very comfortable, but I have a hard time sensing where the front of the car is. Its like I'm sitting in the back seat of my old car. I'm sure its something inherent to the Panoz, Vettes and Vipers. Of course, I haven't raced any of those (yet) I'll adjust/adapt, but it just feels foreign to me, as if I should be sitting further forward. Anyway.....

Not really an issue w/ the Vette (very low hood line, great view), somewhat with a Viper (higher hood line, but very cramped inside). The Pano had a very very high hood/fender line that just takes getting used to, but it has tons of room inside. With the seat on the floor I have issue with my elbows hitting the the left "shelf" and tunnel when steering. With the seat higher in the correct position for my dad I have more arm room, but the steering wheel is a little low.

If I were setting the car up 100% for me I'd actually raise the steering column and make it more horizontal.

Nice job, but it flexes a lot and I predict will crack around the screws and break free... sorry.

Alsd this retention will not pass tech in most bodies. You could add the required retention clips (metal covers that hold the window in).

The orginal design allows the glass or Lexan to "float" in the windshield space depending on air flow and car flex which is pretty extreme.

We broke several glass windows trying to hold them in too tight and swapped to Lexan with supports. Good luck hope it works. Looks pretty.

Kevin

Mark, Kevin makes a very valid point. The amount of screen movement will depend on screen thickness and car speed & wind direction.

If you have enlarged the holes in the screen that the fasteners pass through this will help prevent cracking out from the holes (i.e. 5/32" hole through the lexan for a 1/8" fastener etc). I did lots of canopy work on aircraft a few years back and that was the trick to stop them cracking post panel replacements.

I have found my screen moves around a lot over the course of an endurance race. We often have to reposition or replace the foam pads under the retainer clips on the screen as they work their way out.

Kel.

So it sounds like the two of you recommend using the "stock" metal triangle retainer tabs to allow movement? I'm about ready to install the body and have the lexan trimmed. I was going to do some sort of screw in fastener similar to the OP, but am re-thinking that and may just use the existing tabs.

Kel, what do you use as your foam pad material? We would like to start with new ones under the retainer clips.

So it sounds like the two of you recommend using the "stock" metal triangle retainer tabs to allow movement? I'm about ready to install the body and have the lexan trimmed. I was going to do some sort of screw in fastener similar to the OP, but am re-thinking that and may just use the existing tabs.

Brian, this is an engineering call. If you are going to screw the window in, the install design will have to be spot on in all details and essentially you will be experimenting. Further work may be required down track to get it right (possibly at the cost of a screen or two due cracking).

The tab option works well and there are enough cars going quick to prove the design at all levels. Screen thickness and internal support are the key areas to focus on to avoid cave in at speed. Now proven though with multiple different solutions across the cars.

I have a spare screen in the attic that I thought I would have needed by now so happy with the solution we have.

Kel.

Kel, what do you use as your foam pad material? We would like to start with new ones under the retainer clips.

Charlie, it is a thin medium density with adhesive back. You must be getting pretty excited about tracking the car now....!!

Kel.

This is cut and pasted directly out of the SCCA General Competition Rules. What am I missing?

h. All cars may use a standard safety glass windshield, mounted
in the stock location and at the stock angle. In addition to
any other method of retention, the windshield shall be secured
within the specifications of GCR Section 9.3 Windshield
Clips. Polycarbonate windshields such as Lexan are allowed.
Alternate windshields must be of 6mm minimum thickness.
Alternate material windshields must be identical in size and
curvature to the original glass component. Alternate material
windshields must have in addition, three (3) inner supports to
prevent the windshield from collapsing inward. These supports
must be 0.75” by .125” minimum straps of aluminum.
Spacing between these inner supports must be eight (8) inches
minimum. In place of clips, polycarbonate windscreens may
be mounted using a fastener spaced a minimum of every 12
inches across the top and sides, with a minimum of four across
the bottom. Alternatively, the bottom may be captured in a
channel.

So it sounds like the two of you recommend using the "stock" metal triangle retainer tabs to allow movement? I'm about ready to install the body and have the lexan trimmed. I was going to do some sort of screw in fastener similar to the OP, but am re-thinking that and may just use the existing tabs.


Brain, do NOT try and use triangle tabs to retain a Lexan windshield unless you are mounting them every 12" or so, or unless you are gluing the windshield down first. It will come flying out by the second turn, IMO. I have done two polycarbonate windshields on SCCA cars, one on Tom Ellis GT1 Mustang and another on a GTA Monte Carlo. I've done several running circle track. SCCA techies are much stricter than NASA and USAC. Most lexan windshields are riveted in, some (like mine and Toms) are screwed in. Never an issue with tech. My concerns in the original post was that the fiberglass channel of the roof wasn't strong enough. I'm a big boy (280+) and I can lean my full body weight on the windshield now and it does not move at all. Its not going anywhere and it WILL pass tech. On some of Brian G's videos you can see his windshield bowing in severally at Daytona. I believe his is riveted in.



I think Kevin misunderstood what I did or what fasteners I used. Also the key word here is polycarbonate. You can put it in a sheet metal brake and bend it over 90 degrees without cracking. If you use plexi-glass, it will crack and is therefore illegal in most sanctioning bodies.

Brain, do NOT try and use triangle tabs to retain a Lexan windshield unless you are mounting them every 12" or so, or unless you are gluing the windshield down first. It will come flying out by the second turn, IMO. I have done two polycarbonate windshields on SCCA cars, one on Tom Ellis GT1 Mustang and another on a GTA Monte Carlo. I've done several running circle track. SCCA techies are much stricter than NASA and USAC. Most lexan windshields are riveted in, some (like mine and Toms) are screwed in. Never an issue with tech. My concerns in the original post was that the fiberglass channel of the roof wasn't strong enough. I'm a big boy (280+) and I can lean my full body weight on the windshield now and it does not move at all. Its not going anywhere and it WILL pass tech. On some of Brian G's videos you can see his windshield bowing in severally at Daytona. I believe his is riveted in.



I think Kevin misunderstood what I did or what fasteners I used. Also the key word here is polycarbonate. You can put it in a sheet metal brake and bend it over 90 degrees without cracking. If you use plexi-glass, it will crack and is therefore illegal in most sanctioning bodies.

We have used the standard "triangle" retainer clips to hold my shield in without issues. It has been in the car like this for over 3 seasons without a problem. It was made by a local aircraft workshop out of lexan and was hot molded off a glass screen for added rigidity.

The weakness in the installations as previously discussed on the site many times is the windshields bowing inwards. Whether this occurs and to what degree is determined by the material you use, thickness of the material used, internal supports used and max speed of the car.

Personally I really like how you have engineered your screen and I really hope it works out. As you have said, lexan is not prone to cracking like Perspex.

Kel.

Molding the windshield to the correct curvature is interesting. I found pre-molded windshields but they were incredibly expensive compared to doing one myself.

I used he exact same supports that NASCAR uses and the Lexan is .250". The supports are from Five Star Race Bodies who I consulted with. The other two cars I worked on at Dawson Motorsports in Sebring already had Lexan in them, and we were merely replacing the scratched ones. I paid close attention to the GT1 install, and the GTA install was on a Howe Chassis with a Five Star body. I'm confident in my install on my Panoz. As previously stated, it is remarkably rigid.

I never would have thought that retaining clips meant for glass would work on polycarbonates. Clearly your experience proves that it does.

We have the 1/4" pre-formed Mustang piece from 5-star and the aluminum supports. I'll give it a whirl with the existing tabs to avoid another custom project on this project.

On the exterior my install is factory Panoz. I used some thick truck bed tonneau cover foam with double sided tape on the bottom with the std. aluminum triangle mounts. I made curved "T" supports for the inside that match the curve of the lexan. They are made from extruded aluminum that I had run thru a special roll form. My buddy owns a window mfg. and they do this for arched window frames. I also braced the supports to the roll cage. No more issues at 190MPH.

If I don't get my car out of storage soon I am going to explode!!!!

this is what I really like about forums. i get a concensus of opinions. I never would have considered using clips, vs. fastening the perimeter of the Lexan. Clearly others have used clips without issues. I never wouldve thought that would be enough.

Molding the windshield to the correct curvature is interesting. I found pre-molded windshields but they were incredibly expensive compared to doing one myself.

I used he exact same supports that NASCAR uses and the Lexan is .250". The supports are from Five Star Race Bodies who I consulted with. The other two cars I worked on at Dawson Motorsports in Sebring already had Lexan in them, and we were merely replacing the scratched ones. I paid close attention to the GT1 install, and the GTA install was on a Howe Chassis with a Five Star body. I'm confident in my install on my Panoz. As previously stated, it is remarkably rigid.

I never would have thought that retaining clips meant for glass would work on polycarbonates. Clearly your experience proves that it does.

I was a bit lucky on the cost side with molding the screens Mark as the aircraft shop is owned by a friend that helps with the car. They do excellent work and at very reasonable cost. It was such a good deal I had 2 done so that I had a spare.

Also got them to mold a side window while they were at it. Was an attempt to improve aeros at speed and provide added security while trailering. Did not work out so well for racing as affected airflow in the cabin and sucked in fumes from engine area. Race without it now but fit for overnight at track and for trailering etc.

Kel.

Also got them to mold a side window while they were at it. Was an attempt to improve aeros at speed and provide added security while trailering. Did not work out so well for racing as affected airflow in the cabin and sucked in fumes from engine area. Race without it now but fit for overnight at track and for trailering etc.

Kel.

I would love to put at least a passenger window in, but the SCCA won't allow it.

Probably obviuous but alternate windshields are any "non glass" so with Lexan you need the 3 center supports and either clips or other fastners. You will need the center supports for sure as the window will "inbow" several inches when going fast w/o it. Also for protection.

We used the standard Panoz glass mounting tabs for Lexan and added 3 center supports. This met national scca tech although they gave us grief for the tabs being triangular and not square. They let us off etc, but picky.

This set up worked fine and we used standard foam backed weather strip tape from any hardware store...

Kevin