TINTED WINDSHEILD QUESTIONS

[EDMO 1078]

My FARs are packed away from my move from Alaska, and probably out of date anyway.

Question for anyone with documentation:

What light transmission amount is required for windsheilds by the FAA?

Another question:

The commercial green and smoke windsheilds that are legal have what light transmission?

The reason I am asking, is because I cant fly at night anymore without a medical, and want to use a light bronze tint for windsheild - the same tint I have used for windows before.

I also plan to use the very dark bronze for my skylight because of the intense sun heat we get here in "Mizery", and I know that everything except the windsheild is legal, and want to comply with regs on that.

ED in MO

[High Country 69]

Ed here is what I found in the FAR's regarding windshields it didn't specifically say how "dark" it could be there is a link at the bottom to where I copied this from. Someone else may have better info than I do, if so lets hear it. hope it helps. I saw a real nice home design in idaho city recently that had a nice smoke windshield first time I had actually seen that. It was a real lite gray and seemed to work great for the front. While on the topic where might one look to get the smoke lexan?

FAR's

Sec. 25.775 — Windshields and windows.

(a) Internal panes must be made of nonsplintering material.

(b) Windshield panes directly in front of the pilots in the normal conduct of their duties, and the supporting structures for these panes, must withstand, without penetration, the impact of a four-pound bird when the velocity of the airplane (relative to the bird along the airplane's flight path) is equal to the value of V C,at sea level, selected under §25.335(a).

© Unless it can be shown by analysis or tests that the probability of occurrence of a critical windshield fragmentation condition is of a low order, the airplane must have a means to minimize the danger to the pilots from flying windshield fragments due to bird impact. This must be shown for each transparent pane in the cockpit that—

(1) Appears in the front view of the airplane;

(2) Is inclined 15 degrees or more to the longitudinal axis of the airplane; and

(3) Has any part of the pane located where its fragmentation will constitute a hazard to the pilots.

(d) The design of windshields and windows in pressurized airplanes must be based on factors peculiar to high altitude operation, including the effects of continuous and cyclic pressurization loadings, the inherent characteristics of the material used, and the effects of temperatures and temperature differentials. The windshield and window panels must be capable of withstanding the maximum cabin pressure differential loads combined with critical aerodynamic pressure and temperature effects after any single failure in the installation or associated systems. It may be assumed that, after a single failure that is obvious to the flight crew (established under §25.1523), the cabin pressure differential is reduced from the maximum, in accordance with appropriate operating limitations, to allow continued safe flight of the airplane with a cabin pressure altitude of not more than 15,000 feet.

(e) The windshield panels in front of the pilots must be arranged so that, assuming the loss of vision through any one panel, one or more panels remain available for use by a pilot seated at a pilot station to permit continued safe flight and landing.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25–23, 35 FR 5676, Apr. 8, 1970; Amdt. 25–38, 41 FR 55466, Dec. 20, 1976]

http://www.risingup.com/fars/info/part25-775-FAR.shtml

[EDMO 1078]

Robert,

Thanks for the info. One FAR used to list the minimum light transmission for windsheilds and side windows.

When I put the lightly tinted bronze side windows and dark bronze sunroof in my Ercoupe, the IA at my next annual made me read a newspaper thru the side windows before he would pass them. This test is not in FARs, but practical, I guess. There is very little difference from the inside when looking out, but sure helps to keep the sun heat out.

BTW: When I used to have Certified planes, my favorite FAR was 21.303(b), if I remember right. This lets "owner made" parts to be installed in a plane, provided that they are "equal to, or better than" original parts. It further states that the owner does not actually have to make the parts, but must cause them to be made. This was a great deviation FAR, IMO. Of course we dont need it for AB-experimental planes.

ED in MO

Edit: Forgot to answer your question: Most any plastic vendor can get smoke or other color sheets.

There is a real cute Pink, if you are so inclined. HA!

Sometimes you can get Lexan, and others may have Plexiglas which is less desireable until you want to break your way out of a wreck, then you dont want Lexan.

Hopefully, you will never need to do that - so stick with Lexan which is less prone to cracking.

I dont think that "off-brands" are as good as the original "Lexan", so try to get that brand even if it costs a little more.

I used to buy my bronze from Cadillac Plastics, but sure that Grainger and other companies have the tinted sheets.

Edited 4 Jul 2012 by Ed In Missouri

[EDMO 1078]

Just for info: I found the specs on the light bronze tinted Lexan - Light transmission is 88%.

Dont know what the gray (smoke), or light green tint transmission is, but any vendor should have specs on it.

My Dark Bronze Plexiglas sunroof material gives Light (UV) BLOCKAGE of 76 or 88% depending on tint used.

Probably about the same for Dark Green, or other dark transparencies?

AND, TO CORRECT my mistake earlier: Grainger does NOT have tinted plastics. sorry about that.

I found CADILLAC PLASTICS online, but there should be a local vendor who can save you shipping.

ED in MO

Edited 21 Jul 2012 by Ed In Missouri

[High Country 69]

In case anyone was wondering here is a bit more info on different color lexan

the info can be found here- http://www.eplastics.com/Plastic/Plexiglass_Acrylic_Sheet_Bronze_Grey_Smoked_Gray_Colored

PLEXIGLAS® SOLAR TINT SERIES

Solar Energy and Visible Light Transmittance

Color_______Solar Energy___Visible Light

Colorless_____85%__________92%

Gray 2064____36%__________27%

Gray 2074____24%__________12%

Bronze 2404__56%__________49%

Bronze 2412__35%__________27%

Bronze 2370__20%__________10%

Thickness tolerances are plus/minus 10% on acrylic sheet. Thickness can vary throughout the sheet. Normally we see plus/minus 5% or less differences. Use this list as a guide converting fractions to what is actually produced industry-wide.

1/8" = .118" = 3mm

3/16" = .177" = 4.5mm

1/4" = .236" = 6mm

3/8" = .354" = 9mm

1/2" = .472" = 12mm

3/4" = .708" = 18mm

1" = .944" = 24mm

[EDMO 1078]

In case anyone was wondering here is a bit more info on different color lexan

the info can be found here- http://www.eplastics.com/Plastic/Plexiglass_Acrylic_Sheet_Bronze_Grey_Smoked_Gray_Colored

PLEXIGLAS® SOLAR TINT SERIES

Solar Energy and Visible Light Transmittance

Color_______Solar Energy___Visible Light

Colorless_____85%__________92%

Gray 2064____36%__________27%

Gray 2074____24%__________12%

Bronze 2404__56%__________49%

Bronze 2412__35%__________27%

Bronze 2370__20%__________10%

Thickness tolerances are plus/minus 10% on acrylic sheet. Thickness can vary throughout the sheet. Normally we see plus/minus 5% or less differences. Use this list as a guide converting fractions to what is actually produced industry-wide.

1/8" = .118" = 3mm

3/16" = .177" = 4.5mm

1/4" = .236" = 6mm

3/8" = .354" = 9mm

1/2" = .472" = 12mm

3/4" = .708" = 18mm

1" = .944" = 24mm

NOT SURE if these are the LIGHT bronze, gray tints. Or for Lexan? The figure I got were different. Have to check my material numgers for the light Bronze - will let you know then.

ED in MO

Edited 4 Aug 2012 by Ed In Missouri

[EDMO 1078]

Cant locate color code sheet for Lexan - Cadillac # is 9600, I think. Clear, Solar gray, Light Bronze - .080 to .500 thick.

NOW, I have stumbled on something in Lexan called "MAKROLON" which is referred to as "complies with FAR.......?

Got to check on this when I get time.

ED in MO

Correction: 9034 is the one listed as having the tints. There are several varieties of GE Polycarbonate - One is listed as "bendable"?

Another is more of this , another is more of that? Enough to make you wish you hadnt started looking !

Makrolon is the same types of Polycarb as produced by BAYER. The FAR has to do with flamability, wouldnt worry about any of these.

Need more info - try looking it up....I'm done.

ED in MO

Edited 5 Aug 2012 by Ed In Missouri