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Marvin Kaye wrote:
Posted for "Tom Gourley" <tom.gourley@verizon.net>:
The Inertial
Navigation Unit, one of the two boxes that makes up a complete system, has
reasonable specs; up to 24,000 feet and operating temperature from 32F to
105F.
I would hardly call that reasonable. And 32F is the "standard atmosphere" at about 7,500 feet. 105F is essentially 40C. It is way too low for real life use. Temperatures in excess of 80C behind the panel are well documented. On a "normal" warm day of 35C, you can see temperatures well in excess to 45C in locations where you would normally install a box. Places like Phoenix routinely get over 45C in the shade during the summer. Just to put things in perspective, a box with those temperature specifications would not even get past the front door to talk to an automotive company, let alone any aviation company. Does this mean the tablet, or Mobile Computing
Platform as it's called, will stop working above 10,000 feet. I doubt it.
Wrong answer. Hard drives count on an air cushion to keep them from touching the spinning disk. The damping of the air resistance against lateral movement of the head is also taken into consideration when designing the closed loop control for positioning the head. As you get high, the air thins and both the cushion as well as the damping decrease The result is failure to seek if you are lucky, a hard crash if you are unlucky. This is not just theory, but is well documented. Also, the denser the drive, the more susceptible it is to altitude related problems.
The second issue is cooling. Cooling of the CPU. Colling of the power supplies. Cooling of the graphics chip. Cooling of the backlight.
Of course, you can ignore all of that and boldly press on -- many do. Maybe you will get lucky and things will work for you, maybe not.
Regards,
Hamid
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