WWII RAF Navigator's Compass

[lawrence_n]

Here's something you don't see every day! I picked up this 02A (though the compass reads 02T) compass. To my untrained eye, it looks to be in wonderful condition complete with its original transit box. I'd love to find a source for the operating manual and learn a little more about this compass. It looks like the sort of thing that would be mounted in the navigator's station where there was the small dome for the navigator to do star sights. The moveable parts are very reminiscent of a naval sextant. Any comments, ideas of value, or general information would be most appreciated.

[browningautorifle]

Best I could find is a description of how to... "The O.2.A. is a table or pedestal mounted compass used by an aircraft observer. The compass bowl contains the rotating compass card which would be suspended in damping fluid. The azimuth circle is affixed to the compass body, and is released by unlocking (by turning) the toggle and sliding a small brass piece along its rim, which lifts a metal retaining peg from its hole. The circle is then rotated to place its glass mirrored prism toward a navigational target, such as the sun (with care taken to raise the darkened lenses). The direction of that target is then viewed through the prism, being reflected upward from the floating compass card. The text on the compass card is reversed so that it is legible in the prism mirror. The mounting bracket is located on the bottom of the compass. There is a small round bubble/spirit level on the azimuth circle to ensure that the compass is mounted on level."

And a couple examples being sold for value comparison... https://aeroantique.com/products/com...13685476819033

Purchase WWII-era Observer Optical » Boat House Collectables

One on Ebay that asks 335,00 EUR And one that didn't sell elsewhere for R2,650 00.

[lawrence_n]

Thank you! As always, your input is most appreciated. I did find the example to which you provided the link. Sadly, it's not exactly the same as mine, having a different lens arrangement. I haven't been able to find an exact exemplar.

[Bob Womack]

American navigators had a similar compass but it stayed with the plane and was "swung" at base for accuracy. They were sometimes mounted on top of the navigator's table and sometimes sunk in the table with a rubber, hinged mat that covered them.

Bob

[Peter Laidler]

Is it prismatic......? As in looking at a distant star (for a star fix) while able to read the degrees deviation at the same time? Interesting bit of kit

[browningautorifle]

Interesting bit of kit

I'm surprised since it's an instrument, your shop crew never had them come in for service or calibration or whatever they needed. Unless they went out so far back...

[Peter Laidler]

We didn't deal with aircraft instruments except for those on the single pioneer or twin pioneers - or twin-pins as they were called. We did deal with the prismatic compasses though....., zillions of them. These were always 'swung and calibbrated

I understood that a lot of the RAF stuff like calibrated instruments was all sent back to the UK for repair etc to the manufacturers for certification. Mind you, some of the RAF plotters couldn't find their way up to the big radar station in Malacca in the dark........

[Sapper740]

Interesting piece! Is there a way of setting the declination for the part of the world you're in or did navigators simply factor that into their heading?

[lawrence_n]

Interesting piece! Is there a way of setting the declination for the part of the world you're in or did navigators simply factor that into their heading?

As far as I can tell with a cursory examination, the magnifying lens has a graduated zero centre setting and gradations left and right so maybe that was its purpose. What I find interesting is the bulls eye level on the right side. Given that I don't know of too many aircraft in WWII that sat level on the tarmac, I can only assume that when you took it out of the box it mounted onto some kind of gimbal that would keep it level. I'll try to get some more pics of the mechanism. The point on top of the long black lens is the forsight for the "V" sight on the magnifier and that lens folds down toward the compass card. I'd love to see a manual for this thing!

[tj214]

The RAF Museum (or IWM) might have the AIR publication for this device. Not likely posted online, but you can contact them and ask them to search their collections.