Sector Clock at Wyton and Castle Hill House

The sector clock as it hung in a hallway at RAF Wyton, 2007


The following description of a sector clock is taken from the excellent display at Thorpe Camp museum. The museum is located near Woodhall Spa and Coningsby, home to 97 Squadron aircrew before and after the Bourn period, and contains much 97 Squadron material.

“Included on the clock in addition to the usual 12 hour dial was an outer ring of minutes numbered at five minute intervals, an inner ring extending the 12 hours to 24, and a repeated pattern of three colours. These colours were a stroke of genius. Initially set at 10 minutes per colour, a sighting placed on the display table at Sector HQ would be given a coloured disc appropriate to the time of the sighting. By the time the clock had moved on to the third colour the sighting marker with its old colour could then be removed. Bearing in mind intruders were only tracked by continuous fresh sightings this method kept the display table clear of redundant information and the Defence Control  a good idea of ‘time in the air’ at a glance. ”

Later the colours were reduced to five minutes, as can be seen in the PFF clock.

 Another piece of romantic history gone west?

Above was the original description of the clock as posted on our website in 2007, which sparked off various responses.

Dennis Yates emailed just before Christmas 2007 to say that he did not think that the sector clock in the photos of Bennett and the one which hangs on the wall today at RAF Wyton are the same clock.
Hello Jennie, Whilst researching an old RAF sector clock which I have recently acquired I noticed the one shown on your website which is reputed to be from RAF Wyton. However, I am sorry to be the bearer of bad news but if you look very closely at the photograph it is NOT the one shown in the ops room at PFF HQ because most obvious is the fact that most of the numerals are written differently, ie: the ‘tail’ on number 6 is not at the same angle, the 8 is more squat, the 2’s are not as rounded and the RAF crest is much closer down to where the hands come through the dial. I am certain if the original photograph can be compared more closely to the one you have, other differences would become apparant too, nevertheless, for all of that it is a nice example.
Regards,Dennis A Yates.

Dear Dennis
Thank you very much for your email. I will compare the two clocks more closely when I have a moment, but I am not sure that I entirely agree with you at first glance.
The clock in colour is definitely on the wall at RAF Wyton because I took the photo myself in July this year, so unless the RAF have done a switch they ought to be the same clock. I also think that the differences in the numerals may be due to different angles of camera shot and lens, however perhaps when I enlarge both photos considerably I may be converted to your opinion – I am always glad to get the correct information, even if it is at times rather disappointing!!.
Best wishes – Jennie

Hello Jennie, Thank you for getting back to me. I accept that the clock is on the wall at Wyton but am certain it is not the one pictured in the ops room photograph. Unless they are inspected closely all sector clocks look the same and furthermore all RAF stations had more than one example because they had to be exchanged quickly in case of damage or needing repair. The only way to be certain it is the same clock would be if a record of the serial number of the one hanging at Wyton exists and it could then be checked against that in the photograph, in the absence of which it can only be hearsay. Meanwhile I wait with interest the results of the closer examination you mention. Finally, please find attached an image of my sector clock which is by Potts of Leeds dated 1929 and the oldest recorded example known to exist.

Steven Hanglands then joined the controversy on 12th January 2008:
I’ve been reading the emails regarding the sector clock at Wyton which you have added to the site. I blew up the photos of both clocks and smoothed out the pixels. The point the chap makes about the number 8 being squat is incorrect, its proximity to the triangle and the bold line denoting the forty minute/second mark is identical in both pictures. The point he makes about the RAF crest being closer to the spindle is most probably attributable to the hands in one photo being below the 3 o’clock – 9 o’clock level. The point he makes about the ‘tail’ of the 6 is the only point he has, but I guess unless you’ve actually seen it, its a bit subjective.

The Last Word on the Subject?

I think the last word on the subject must probably go to Andy Campbell, curator of the PFF Museun, who emailed in February 2011 as follows:

I stumbled across your old article on Wyton’s Sector Clock versus the one Bennett had at Castle Hill House. They are definitely two different clocks, why? Well several of the comments have identified that the numerals are different, and they are, furthermore, the RAF crest is slightly higher on Wyton’s version (in-line with a line struck between the bottom of the 22 & 14), also the “20” is in a slightly lower in Bennett’s clock than Wyton’s.

These features are all consistent with the Type 1 & Type 2 Sector Clocks. Wyton’s being a Type 1 and Bennett’s group clock installed in July 1943 being the later Type 2 model. I believe the Type 1 was introduced in 1938 and the Type 2 in 1943. Lastly, I feel it is unlikely that Bennett would have removed Wyton’s Clock to furnish his own Ops room – why would you when you could have ordered a new one? There were also Royal Observer Corps Sector Clocks which didn’t have the RAF crest.

No idea what happened to Bennett’s clock, I can only assume it adorns somebody’s wall somewhere.

Hope this helps, albeit a little late in the day.