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S244

Page history last edited by Alan Hartley-Smith 6 years, 8 months ago

Input from Graham Wing

The S244 Noddy operated at S Band and used the SR1000 Transmitter. The really interesting part was the servo-control system with enormous thrusts being produced from only millivolts of error. I was probably one of the only people to clock a hostile at 100,000 feet over Norway in the 60s. I learned afterwards that he was not so hostile and went by the name of Garry Powers as I recall. I have several pictures of operational Nodding monsters from all over NATO.

 

Input from Alan Matthews

I designed the height extractor for the S244 when I worked at Pottery Lane during 1958/1959. The display part of the system was created by John Sellers/Nick Tovey/and myself and we all worked for Fred Kime and Peter Max.

About 35 of these together with S247 back to back L and S band search radars were sold to NATO following a demonstration at Rivenhall. Other customers also had "Big Oily Noddies" and I am sure many people know about this notorious and highly accurate equipment.

 

A few more memories of the S244/S269 Heightfinders
The S244 had an open structure to support the reflector (40ft x 7ft) but the reflector assembly of the later version was a big "box" section which would have been lighter and stiffer.

I can remember an engineer called Mike Smith swinging around like a monkey on the rear of the S244 as he worked on the very troublesome rear ram assembly.

I believe the main mechanical designer of the heightfinder system was called Frank Henchie who was nicknamed Graucho because he was short with a moustache and looked like Graucho Marx. I was most impressed with him when I saw this most unlikely person wearing a tweed suit (with waistcoat) and brogue shoes climbing rapidly to the top (over 60ft up) of the nodding part of the S269 and standing there, hands in pockets, casually smoking his pipe and surveying the surrounding countryside.

Around 1959 a big demonstration was made at Rivenhall to a large group of high-ranking NATO officials who were brought there by coach. A very good lunch had been laid on in a marquee, etc. Unfortunately the coach driver did not know that a big ramp had been laid across the road by the heightfinder to protect crossing cables and when the coach pulled up most of the visitors were holding their heads after having been projected into the roof of the coach - not a good start for the show.

I was in Hut 28 with the display equipment, which typically developed a fault just before the group came in. Luckily we found a broken cable behind the heightfinder display console but I had to crouch behind the console in the dark, holding the wires together while the equipment was demonstrated!!

However it all worked out OK in the end and the Company made a big sale to NATO which kept many of us in work both here and throughout the NATO countries for many years.

This equipment had an incredible performance and the huge assembly could be moved through 180 deg horizontally and stopped within a fraction of a degree in 4seconds - faster than any ships' guns at the time and real state-of-the-art, while the big reflector could be "nodded" through 30° (variable) (depending on target range) in about 2 seconds.

During the development the servos were being "sorted" by very clever engineering consultant called George Tchaikovsky (grandson of the composer); he had dreadful problems with the system going into oscillation, etc. There had, of course, to be an interlock to prevent the reflector being other than vertical when the system was being turned because the inertia of it would do great damage during the rapid accelerations and stops in azimuth. Unfortunately one day the interlock failed and the forces generated with the reflector at 30° twisted the two big vertical legs on which the reflector was mounted - this was really serious engineering!

 

Height Measurement System for the S244

 

by Alan Matthews

 

As mentioned previously I worked for Peter Max, Fred Kime and John Sellers on the development of the height range display and height indicator system for the S244 at Broomfield, from 1957 (or so) until 1959, at Baddow, after the Radar Development Group moved there.

John Sellers ran the project and I, Norman Morton and Nick Tovey did the development work; later in 1959 we did the demonstration for NATO at Rivenhall in Hut 28 of the display system. I believe Jack Hobbs of Field Services did the installation.

 


Hut 28 demonstration: At the displays are Don Beckett, Derek Jeffries and Alan Matthews on the height display, which was connected to the S244 Heightfinder, with Norman Morton at the plotting board.

John Sellers designed the display with its curved timebase so that height was linear, vertically, on the display. I designed what was effectively an early digital voltmeter, so that a horizontal mark could be moved with a joystick to bisect the target, which should appear between two vertical lines at the target range. When bisected and the height request made, my machine measured the vertical voltage and, by means of 3 x 10-position telephone switches, high-accuracy resistors and comparator circuits, these switches set themselves to positions which reflected the voltage to within one part in one thousand. The height could therefore be displayed on neon indicator tubes to the nearest 100ft in 100,000 ft (Hopefully!). Nick Tovey at the same time devised an electromechanical programmer, which passed the X and Y positions of the targets to a resolver which fed them to the Height-finder as range and bearing and then fed the heights from my machine back to the PPI operator who had made the height request, where each had a numerical height storage box.

The curved timebase, if I remember correctly, was made by integrating the sawtooth to make a square law (parabola?) and adding a portion to the vertical sawtooth to allow for both the earth's curvature and
refraction.

We were worried that at maximum slew and nod rates the operator accuracy at bisecting the targets might degrade as a function of time at the display and the rate of nod/slew.

I therefore built a crude simulator comprising an electrically triggered pendulum attached to a magsllp as installed in the heightfinder to produce the display scan which could be activated at pre determined rates. This then also triggered Ledex switches with resistors which produced a semi-random set of voltages to simulate random targets to be bisected by the operator. In this way, in a week or two of experiments we found out how well an operator could cope under the worst of conditions and determined the maximum data rate from the S244.

Largely because of this, I was designated to fit the first magslip and set it up in the Heightfinder pivot mount – not a good job for someone without a good head for heights.

As an anorak I think I still have the circuit tolerance calculations I did for the numerical  height calculator in about 1958 when I was 22…

 

S244 - a demanding specification

 

from John Brown

When I moved across from Baddow to Radar Division in June 1959, Peter Max the Chief of Systems Group, gave me the additional role to liaise with Felling to become the specialist within the Division on the new range of radars which we were offering in our tenders, and some of which were already under contract (S255,S247,S266, and S244);  I was also responsible for allocating numbers to the derivatives;  accordingly, I liaised closely with Frank Henchie and his team at Felling during a fraught period.
The S244 required height data rate was aimed to meet the NATO/SHAPE spec., issued in 1956, of 15 heights per minute on random targets.  To achieve this rate of performance called for hydraulics for both slew and nod, and a slew time of 2.5 secs, and 1.5 secs for the nod cycle. During development and
the trials at Rivenhall (which I was close to), it was found necessary to change from the Keelovite pump to the Vickers, and because of the enormous hydraulic pressures involved, to go to 3-ply pipes. You will recall my account of the demonstration at Honninsvaag for the SHAPE-observed acceptance tests, and the demands on the local electricity supply in order to establish that 15 heights/min could be achieved. In that year (1961) the first four S244s were successfully handed over to meet our pledge to the RNoAF. I readily agree with you about the consumption of Shell fluid (indeed, there is probably an abundance under the Rivenhall airfield), but the S244 and its successor, the 269, established a high reputation in NATO, and I am certain with other Authorities as well.

 

Comments (1)

Ian Gillis said

at 4:24 pm on Feb 14, 2016

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