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Glider pilots have simialar requirements - they need screens readable in bright dailight, which is most of their flights (really, if you are under a cloud for extended ammount of time, you are either rapidly loosing height as there are not thermals anymore or are entering a cloud on top of a thermal, which should be avoided at all costs due to gliders being VFR only) to display maps and navigation apps.

The problem is that most gliders are not very rich & fly on shared hardware of the local flying club. So there is no incentive for manufacturers to build a device for this kinda small and nit very afluent community.

IIRC a couple years ago some of them we using hacked Kobo devices.