NavList:

Major Mike.  Obtaining a mounting is the difficult bit.  I had to wait until the Dominie went out of service when a friendly crew chief liberated one for me for my Smiths Mk2s from an airframe destined for fire practice.  Until then, I lashed the sextants to the top platform of a pair of 7ft opening steps, and I stood on the bottom step to steady things and to operate the sextant.  I still haven’t got a mounting for my Kollsman. The good thing about RAF sextants is that although they ran off the 28V bus bar, the lighting input was dropped to 3Volts.  I think that there must have been so many spare bulbs (like hens teeth now) for the ubiquitous RAF MkIX left over after WW2 that someone decided that all future sextants would run on the same 3V pea bulbs just to use them up.  I run my Mk2s from two AA batteries soldered together with + and – leads pushed into the appropriate sockets of the input lead.
I’ve just been playing with my Kollsman, which I’ve not used seriously so far.  It looks as if the bulbs are 28volt, but they’re of a variety of which I’m sure you can obtain at a lower voltage.  As far as I can see, clockwork Kollsman shouldn’t need electrical power in the daytime.  I lashed up 3 x small 9v batteries in series to try the lighting, but they soon ran down.  I’m not sure if this was because two of the batteries were pretty worn out to start with, or because there’s a heater inside running in parallel and stealing all the power.   Sorry about the bubble size; it needs a serious talking to.  I was slightly disappointed that my Kollsman doesn’t seem to wink at you after 5 or 10 seconds to let you know the sextants running over the noise of the aircraft like the Smiths, or did I not notice it.  Dave

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