Quadrant sight

If you try to find an image of a Quadrant Sight via your browser you will probably find nothing!

Although my picture below, taken in the Quadrant Shelter on Pulau Tilor (Song Song Range, Malaya) island in 1962 is grotty you should be able to see the main components:



The tube on top is not a telescope but has a ring and bead sight. The tube is pivoted and the black knob is used to swing it through an arc of up to 90 degrees.

The name 'quadrant' comes from the base frame which is shaped in an arc and to which is attached a graduated brass scale which reads from zero in the centre up to 45 degrees left or right. The base frame is installed so that when the sight is at zero it points at the target. A built-in spirit bubble enable the frame to be set level with adjusting screws.

In use, the operator watches for a bomb burst then swings the sight to align with the centre of the observed burst. The angle of the sight is then read off the scale as (for example) '16 Left' or '28' Right' which plot is passed to the Master Quadrant Shelter by telephone or radio. A second sight in the Master QS records the same burst. Thus, two readings are taken and used to plot the position of a bomb burst on a large scale diagram of the bombing area. By simple triangulation at the point the two lines cross it is possible to use a protractor to quickly determine the angle and distance from the target. This was then passed to the attack aircraft as (example) ' Your last bomb - 125 feet at 2 o'clock'

It was not unusual for bombs to fall out of the 'plot' due to release error and, even if seen would be reported as 'Your last bomb not observed'

In an effort to placate aircrew who would winge that their bomb was closer than that, our sight were modified by mounting a redundant Mk 3 Reflector Sight (aircraft) on top of the tube. This was successful since it projected a 'graticule' at infinity which for quicker and more accurate sighting.

PNK;38585 wrote:

My first thought was that everything looked low tech for 1962 but then again why not if it works.

As you say, you can't find pics on the web.... until now.

Is that a large binocular on a pole in the corner?

The simple solution always prevails! But, like I say, a few months after I took that pic we did a 'Command Modification) which installed a reflector sight on top of the tube.

Now that Paul has lightened the image I too can see the object in the left corner which was a huge pair of Ross military binoculars of around 20 power with swing-in filters circa 1942. But, they were no really usable due to an internal fungus attack on lenses or prisms which made for crappy viewing.

Also on the table - apart from fags, matches, ashtray and tea mug - is a Field Telephone which means the photo was taken in the Song Song South Quadrant, not the Tilor Quadrant since there was no-one to connect to! Radio only.

Thanks Paul for the 'lightening'. I tried it in Picasa but settled for the original.

Same thing in monochrome.

PNK;58236 wrote:

ISadly most searches on bombing range related items lead to posts on AiX.

Says a lot for AiX though :cool:

Graham

Our sights at Tain(and I guess the other ranges) had a pair of binocualrs mounted on the top. And we had a fibre optic "gizmo" to the right which gave the angle of the bomb burst.