Reflective Heat Insulation for King Air windows?

[satpak77]

RE:

http://sportys.com/PilotShop/product/12011

We have heard yes, no, yes, no, on whether this is "approved" or "suitable" for use (via custom cutting with scissors) on the inside of the King Air cockpit glass.

Side glass and front windshield.

Thoughts ?

 

[jet2work]

This is Gulfstream's take on those type of sunscreens. Are the King Air's windows manufactured by PPG or GKN?

ALL (ATA 56): Use of Internally-Mounted Reflective Foil Sunscreens
By Denny George, Customer Support Mechanical Systems Group
At last week's Customer Advisory Board meeting, at which PPG (manufacturer of the windshields) was a featured supplier, an operator asked PPG about their recommendation for using reflective sunscreens on his aircraft.

PPG does not recommend the use of internally-mounted, reflective foil sunscreens for use in aircraft with windshields they manufacture. The long-term effect of using this type of sunscreen on PPG windows is not known. When used in aircraft to help keep cabin temperatures down while the aircraft is parked, there is a potential for the internal temperature of the windshield to rise due to reflective heat/UV, possibly resulting in damage to the windshield. Possible side effects are air bubbles or delamination caused by this overheating condition. Either one of these conditions could adversely affect visibility through the windshield.

Neither does PPG recommend the use of an externally-mounted sunscreen.

If windshield covers are used, it is recommended that both the outer surface of the windshield and the contact surface of the cover be thoroughly cleaned to remove any debris that may scratch the outer surface of the windshield.

These recommendations from PPG Industries should be taken into consideration before using such devices.

If your aircraft is in warranty, and Hawker Beech will warranty a delaminated windscreen, then I would say go ahead and use them. They do reduce cockpit temp, and that is probably beneficial for your avionics. Probably every OEM will tell you not to use them.

 

[LongBoarder]

We used them on a King Air F90 once... and after a long hot weekend away we found the windows to be a bit dis-colored... and the color matched that of the sunscreens.

I would try to find something not foil... I have used the hoop type... shade in general will help.

LB

 

[340drvr]

Interesting question.......
I've used the "hoop-and-silk" type of shades, too, in a King Air, they worked fine to cut the heat. Never thought about how the foil type could harm the glass, though the recommendation for the polarized side windows is to always leave them open to avoid heat build-up in between the panels.

 

[Sandhawk]

I recommend the hoop kind as well - heck, even a couple of Low charts don't work too bad!

 

[DieselDragRacer]

FWIW: While 2 totally different animals it's worth mentioning the reason you don't tint laminated or double paned building glass darker than 35% is the possibility of too much heat reflection back through the glass which can cause seals to pop and glass to delam.

About 15 years ago 3M had an issue with their 35% commercial film where it was reflecting too much heat and popped millions of dollars of double paned glass both in residential and commercial applications.

The moral is too much heat reflection is bad news for laminated or paned glass regardless of the application.

 

[FastJP4]

Low emissivity (low e) is a quality of a surface that radiates, or emits, low levels of radiant energy. All materials absorb, reflect and emit radiant energy. Emissivity is the value given to materials based on the ratio of heat emitted compared to a blackbody, on a scale of 0 to 1. A blackbody would have an emissivity of 1 and a perfect reflector would have a value of 0.
Reflectivity is inversely related to emissivity and when added together their total should equal 1. Therefore, if asphalt has an emissivity value of 0.90 its reflectance value would be 0.10. This means that it absorbs and emits 90% of radiant energy and reflects only 10%. Conversely, a low-e material such as aluminum foil has an emissivity value of 0.03 and a reflectance value of 0.97, meaning it reflects 97% of radiant energy and emits only 3%. Low-emissivity building materials include window glass manufactured with metal-oxide coatings as well as housewrap materials, reflective insulations and other forms of radiant barriers.
Materials surfaceEmittanceAsphalt0.90-0.98Aluminum foil0.03-0.05Brick0.93Concrete0.85-0.95Glass (unglazed)0.95Fiberglass/cellulose0.80-0.90Limestone0.36-0.90Marble0.93Paper0.92Plaster0.91Silver0.02Steel (mild)0.12Wood0.90

 

[satpak77]

I recommend the hoop kind as well - heck, even a couple of Low charts don't work too bad!

the low charts work pretty good, I agree....

 

[ultrarunner]

I know it's not for everyone, but we use one of these all the time, and IMHO, it is the ONLY way to go! Especially when regularly attending margarita latitudes.

http://www.aircraftcovers.com/index.php?cPath=899_1073_1081&tplDir=fallback