Aircraft Periscope
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The Vulcan had a periscopic sextant for astro navigation. There were 2 sextant ports, either side of the canopy - if you look at the top of the fuselage just behind the pilot's circular porthole windows, you will see a small bulge with a flat top. This was where the sextant appeared.. .. .The Vulcan also had 2 built-in periscopes, the viewing eyepieces were folded into the rear crew worktable between the nav plotter and the AEO. The viewer could be selected to show the top or bottom surfaces of the wings. Wicked for fighter affil! If you look at the lower fuselage between the entrance door and the nose landing gear, you will see a small blister, with a rear-facing window - that is the lower lens assembly. There is a similar one on the upper fuselage.
The VC10 has a few periscopes:. .- A periscopic sextant that can be fitted through a small (3" diameter) hatch on top of the cockpit. .- A 'regular' periscope that can be fitted in one of two similar hatches at the top of the fuselage in the aft galley, situated on the left and right side of the dorsal fin. With a tiltable lens in the periscope it is possible to view the entire tail, all four engines and the trailing edge of the wings. .- There is a third periscope hidden below the floor of the rear galley, this is just a simple 2" tube with a small mirror at the bottom that drops down into the rear freight hold to check for smoke or fire when the smoke detectors go off for that area. Without any ability to extinguish a fire in there the FE could just lie there watching to see if it would extinguish itself...
Speaking of VC-10s and sextants, I am reminded of a story involving a bored tech crew member who was also house-proud. Apparently he hit upon the idea of making up a vacuum cleaner hose which he attached to the sextant aperture and proceeded to "Hoover" the flight deck. The story goes that it worked a treat until the hose became obstructed and the entire contraption was sucked inside out through the sextant opening where it proceeded to flail against the fuselage. I've often wondered if it's true or an embellished urban legend.
If it has cross hairs in the viewfinder it could be the wind/drift indicator that the nav used in the Shack. It was just behind his seat so he could swivel around and peer down at the ogsplash passing by underneath, and align the cross hairs with the drift. A great assistance when it was the only nav aid available in the middle of the Indian Ocean.
Unfortunately navs (as is their wont!) sometimes forgot what was going on - and on one famous occasion asked the pilot to "Come Left 60 degrees for wind check". he was most put out when the pilot refused - because we were passing 500ft on GCA to land at Gan!
Happy Days!
Unfortunately navs (as is their wont!) sometimes forgot what was going on - and on one famous occasion asked the pilot to "Come Left 60 degrees for wind check". he was most put out when the pilot refused - because we were passing 500ft on GCA to land at Gan!
Happy Days!
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Doomsday - if you photograph the instrument and also its box and post it on this thread, then you may well find one of us can positively identify it. Then you can definitely claim your free beer!
Yes, Him
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They're also used (or used to be) on ground radar heads to check ( about yearly) that the thing is actually pointing north etc when it shows north on the screen.
