dark light

Can anyone ID This Compass Please?

These pics were sent by a friend of mine, but as it does not have 12 cylinders and a prop, I thought I should pass it on to the real experts!

The AM Ref is 6A/1078 and it also carries the marking “SO2 Compass”

I assume it to be from a sight of some kind?

Cheers.
Pete

Member for:

19 years 1 month

Posts:

566

Send private message

By: CSheppardholedi - 4th June 2007 at 19:25

I did find a mention of it in a 1935 aeronautical compass report from the NASM archive. It is near the end of the report and has attached graphs comparing compasses of the period.

Here is that link, a bit of a monster. Found it by Googlingthe following
s.o.2 observers compass

http://209.85.165.104/search?q=cache:nJDibVdf5JoJ:ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091626_1993091626.pdf+s.o.2+observers+compass&hl=en&ct=clnk&cd=7&gl=us&client=safari

The reference reads
**********************
Opposite extremw of performance are shown in
6gures 32, 33, and 34 by the British S. O. 2. compaas
and the French Morel Petit model 28 compass. The
low Overswing and low swirl of the S. O. 2. compass are
Dbtai.nedby the use of an extremely light and relatively
Eragilemagnetic card. It has been the experience of
tie authors that thisimtrument is too fragile for service
use. The magnetic moment is so low that the pivot
must be in perfect condition if excessive friction is to
be avoided.
On the other extreme, the Morel compass
tms a very heavy floated card and a high magnetic
moment. Practically all American compasaea have
characteristic between the British and French ex-
tmrnes. Of the American compasses in this report,
Drily the
hravy7111and IX and the two KT compasses
have cards with floats

**********************

Member for:

19 years 1 month

Posts:

1,096

Send private message

By: MerlinPete - 4th June 2007 at 18:43

Many thanks Alan.

Even with that information, I notice that there does not seem to be anything about it on Google.

Pete

Member for:

19 years 1 month

Posts:

702

Send private message

By: 682al - 31st May 2007 at 08:53

Not from a sight, it’s an Observer’s Compass, Type S.O.2.

Observer (O) Type Compasses:-
These are primarily intended for taking bearings from aircraft. Types O2 and O3 were fixed on mountings in the Observer’s position (Standard Type O5) and bearings are taken by directing sights on an azimuth circle onto the object and reading the compass card through a reflecting prism.

Sign in to post a reply