NavList:

Fergus. RAF Mk2s are great.  They even wink at you after five or ten seconds to let you know they're running (above aircraft noise).  The lighting will run on two AA batteries.  You may not even need that in the daytime with a 2A Bubble Sextant.  I can't remember; I've only got a 2B and a 2C Pendulous Reference Model.  Go straight into the sextant plug if you're using 3V.  The mounting needs 28V. It drops the sextant supply down to 3v inside the mounting.  The only thing you must never ever do (not even once!) is change the timer knob when the sextant's running, or you'll have a can of loose cogs on the front.  Always start with more shades in than you need and lighten up if necessary when you find the Sun.  Leave the bubble knob fully backed off when not in use.  It's interesting that after a brief flirtation with almost all-electric works inside the Mk1, they reverted back to the tried and tested clockwork of the MkIX for the Mk2s.  DaveP