phone, arguably, but there are a world of other toys useful to recording instructional flights and documenting trips, cameras, audio recording, navigation, weather, approach plates etc... waiting for it.. 'you could always use a map, blah...' i do, but the point is, used properly these devices can be good to help students benefit from debreifing their lessons, useful as nav aids, useful in the event of a radio failure (most new top end head sets providing bluetooth calling, give the tower a
phone call and coordinate your runway crossing or state your intentions etc...)
I think it's understandable that there are uses for electronics that are not catered for as standard as the aircraft were designed before the gear was.
I wouldn't take a chance that a phone or something else not essential for flight my be slowly damaging itself or maybe the wiring in the helicopter while I'm blissfully unaware in the front.
Quite my reason for asking here as opposed to the 'suck it and see' approach, non essential? probably, but so is the flight and it's associated risks in many cases. Good fun worth documenting, yes please
Eye in the sky...
Gaseous & Tailboom - I agree that often it may be fine, but even the products that I have seen that have voltage regulators included designed for car use often stipulate an input range of approx 11v-18v.
With regards to the 24v-12v lorry voltage convertors etc... surely they are still not correct, because although the battery voltage is 24V the main bus in the R44 II is running at 28V from the alternator, and so surely are the components, the schematic clearly shows that the aux power feed is direct from the 28V bus... this is why I have gone for the 28V-12V from Sportys that EN48 linked
Aucky