We didn’t know what a C-2400 LP was before we saw [David’s] video below, but it turned out to be pretty interesting. The device is an aircraft compass and after replacing it, he decided to take it apart for us. Turns out, that like a nautical compass, these devices need adjustment for all the metal around them. But while a ship’s compass has huge steel balls for that purpose, the tiny and lightweight aviation compass has to be a bit more parsimonious.
The little device that stands in for a binnacle’s compensators — often called Kelvin’s balls — is almost like a mechanical watch. Tiny gears and ratchets, all in brass. Apparently, the device is pretty reliable since the date on this one is 1966.
The brass compensation device was stripped, but you can still buy the unit for about $80, so it was possible to repair the device. [Dave], however, put a more modern compass in his cockpit. Of course, these days you don’t actually need a floating magnet to make a compass.
Turns out, the Earth’s magnetic field isn’t a stationary target, and — eventually — the poles are going to flip again, or at least that’s what scientists say. These days you can get a compass with other instruments all in one little package.