NavList:

David, Found a YouTube https://www.youtube.com/watch?feature=player_detailpage&v=cj8nb0voswA

about a T-43 training flight.  About 7m 30s there is a good look at the sextant mount.  It looks like yours.

John H.

Thanks for the link John.  That's a standard mount with an azimuth winder and counters, which are very directional to view.  As far as I can see the instruments show them at 410kts TAS, M0.72, FL280.  You wouldn't want to open the hatch like that (I notice he didn't show the sextant!) with a Smith's mounting; its aperture is roughly twice the area.  Not that you'd be able to; the Smiths has interlocks.  You wouldn't just let the sextant rush up either.  You had to let it up slowly, or the rest of the crew would have heart attacks when it thumped against the fuselage.  The RAF never really went for flying more than two student navs at a time, but on the rare occasions they did. they did, they did it bigtime.  The Valetta T3 (Googleable) proudly sported six, yes six, astrodomes. DaveP