The "History of Engine Electronics"
The following chapters were written by Bill Williams and were originally featured in the "TASS Newsletter" way back in 1992.
TASS was the Engineering Union back then, later becoming MSF and more recently I believe it now forms part of the Unite union.
The articles go back to describing the start of electronics how Lucas York Rd came about in the 1950's and finish when Bill retired.
These articles have been reproduced from archives and may contain some reproduction errors although we've attempted to correct obvious spelling errors, others are as the author wrote them.
We hope you enjoy reading them and if you have any feedback then please let us know via the usual method - the Contact Us form on the web site.
If the electronics industry of today can trace its origins to one particular event then I think that that event must have been the appearance of the valve.
Common knowledge says that Lee de Forest invented the valve. It also says that James Watt invented the steam engine and Marconi the radio. The truth is that they were all associated with well publicised developments of work carried out by earlier experimenters.
Most of the late 19th and early 20th century workers who produced devices which we now recognise as early valves were attempting to produce a device for amplifying the signals in telephone lines to enable communication over long distances. De Forest however set out to produce a better detector for radio. He would have used the words, wireless telegraphy, later shortened to wireless. Radio did not become common usage in Britain until World War II, my father still says wireless.
Paradoxically what de Forest produced was an amplifier; it also proved to be a switch on oscillator and many other useful things. De Forest did not call his device a valve he called it the Audion. The name valve came from an earlier worker Ambrose Fleming who called his device an oscillation valve, later shortened to valve.
Both De Forest's and Fleming's devices were modified electric lamps and both utilised effects described by Edison in 1881. De Forest's Audion was a modified incandescent lamp with a metal plate sealed inside and between this metal plate and the filament a wire grid. When the filament was heated by passing a current through it electrons were emitted and could be collected at the plate by applying a positive charge to attract them. To reach the plate the electrons had to pass through the mesh of the grid.
A negative charge on the grid could control the electron flow to the Plate. This ability to control the electron flow in a circuit at will, using negligible energy at the control terminal, founded a new branch of engineering; "Electronics". Again the word was not in common use until the 1950's. If in the 1940's you said you were in electronics you usually got a blank look, or some one better informed would say "Oh, you mean wireless".
De Forest's first 3 electrode Audion was tested in December 1906 and patented in 1908. De Forest was dismissed from the wireless telegraph company and given the patents of his device, which was considered worthless, in lieu of severance pay. In 1909 the Audion detector was first advertised for sale (Note; detector not amplifier).
If one of these early Audions worked very well on test it was marked with an 'X', all others were marked 'S'. A letter from De Forest to a disgruntled customer states "X grade Audion bulbs are not wilfully made, but simply occur in the testing process and so their supply is beyond our control".
The industry we work in was beginning to take on a familiar form.
Soon after the first true electronic component, the Audion Valve was advertised for general sale in 1909 as a wireless detector, other workers made it function as an amplifier, an oscillator and a hetrodyne converter.
One of the early applications in the U.S.A. was as a telephone repeater (line amplifier). The lines in America had previously been too long to connect the telephone system from coast to coast. In Europe the phone lines were shorter, but Britain, France and Germany had empires and navies which needed wireless telegraphy.
To satisfy the growing demand for valves, companies in Europe and North America set up manufacturing plants. This caused an even faster growth in the legal profession when de Forest sued everyone for infringing his patent. De Forest in turn was sued for infringing Fleming's patent and in the end everyone had to pay the Marconi Company who had bought the Fleming patent and hadn't made a single valve. Thus a great deal of money was made from the manufacture and sale of valves but not by the people who made and sold them.
Wireless telegraph transmitters for ship to shore and intercontinental traffic operated at low frequencies of the order of tens of kilo cycles. The stations comprised 100KW plus spark exciters and vast aerial arrays of which the still operational Empire Telegraph Station GBR at Rugby (500KW, 16KHz) is typical.
Early valves operating as high frequency oscillators could produce only a few Watts and were therefore no competition for 100KW sparks.
As a consequence the use of valves in wireless telegraphy was at first confined to receiving. This limitation was overcome as an indirect consequence of an assassination in Sarajevo which precipitated World War I.
Telecommunications went to war in 1914 in the form of the field telephone. This invention enabled generals to lead their armies from behind by linking H.Q. with the front line trenches. Another invention, the high explosive artillery shell, chopped telephone lines into short lengths. Many brave men died to re-lay the lines and the artillery immediately cut them again. Without the telephone, generals could neither know what was happening at the front or issue orders. The continuation of hostilities was at risk; unless something could be done the war might stop.
If wires could not survive, wireless it would have to be. 100KW sparks and 750 foot masts were considered inappropriate from front line trenches. Short waves requiring only short aerials and low power would however be adequate for the short distance required. Here was a new job which the valve could do. The military electronics industry was about to be born.
When World War I began the principle military users of wireless telegraphy were the navies of Europe and the U.S.A. The high power spark transmitters, their generators and aerials were of such a size that they could only be mounted in a large warship. The trench warfare in Europe demanded highly portable short range communications. A job for the valve.
When this requirement became urgent the Commandant of the French, Radiotelegraphic Militaire remembered that a 3 valve amplifier had been purchased in the U.S.A. before the war for evaluation but no report had ever appeared. A search was instituted and the amplifier was discovered in the basement of a store house. Using the valves from this amplifier as a basis, a valve suitable for military use in either a receiver or a low power short wave transmitter was developed.
This valve was designated type TM (Telegraphic Militaire).
Samples of the T.M. were sent to England where they were found to have the required electrical characteristics but due to inadequate rigidity of the electrodes were considered too fragile for trench warfare. A redesign of the TM with better supported electrodes was produced by B.T.H. at Rugby and designated the R type. One feature of the TM was retained unmodified. The four pin base of totally French origin was for ever after known as the British four pin base. The T.M. is of course often referred to in British books as the French R type.
The R type became the first military approved, standardised, mass produced, electronic component. It was used as a detector, high frequency amplifier, low frequency amplifier, oscillator, modulator and hetrodyne detector.
Several million valves were produced in World War I. By 1918 one plant alone was turning out 1000 per day.
By 1917 two way radio had taken to the air. Its principal use was for artillery spotting. By observing the fall of shells from the air the aim of the guns could be corrected. Before radio the observer in the aircraft had to communicate with the gunners by signal lamp. This required the pilot to circle above the guns thus indicating their position to the enemy gunners. Consequently spotting planes were frequently fired upon by both sides.
The early aircraft radios were powered by wet lead acid batteries stacked round the observer. They sometimes added to his discomfort when the pilot performed aerobatics in combat.
A most desirable development was a wind driven generator mounted on the wing struts of the biplane aircraft to power the radio without batteries. To maintain the generator output constant against varying air speed a valve electronic regulator was built into the casing. This innovation was very successful. 4500 of these electronically regulated generators being produced in 1918.
Here was a dedicated generator for aircraft electronics using electronics in a control circuit as distinct from radio, in quantity production 64 years before F.A.D.E.C. The engineers reported that the greatest problem was packaging the electronics to resist the vibration generated in flight. A problem still exercising our minds today.
The valve transmitters which were developed in World War I could send speech and music, but were considered to have very limited range. The powerful spark transmitters which had long range could only send morse code.
When the war ended large quantities of government surplus wireless parts became available and a large number of men trained in their use were discharged from the armed forces. This gave a huge boost to the numbers of a band of experimenters who had made important developments from 1879 onwards;- The Radio Amateurs.
The Radio Amateurs were very reluctantly licensed to experiment with their home made equipment constructed from the government surplus parts. They were allocated the 440 metre band which was confidently expected to yield a maximum range of only a few miles. British amateurs were also forbidden to make the "CQ call" which is the international request for any station hearing the signals to reply. The British amateur would switch on his transmitter and call "Testing - testing". Foreign amateurs hundreds of miles away aware of the British amateurs problem would hear and give signal reports.
These demonstrations of the unexpected range of relatively low powered medium wave transmitters set off public broadcasting in the U.S.A. and a rapidly growing industry sprang up to manufacture components and receivers for the general public.
In Britain the government at first attempted to suppress broadcasting. At one time the Marconi Company had their licence suspended for transmitting music.
Without broadcasting to listen to there could be no market for radio receivers for the general public and it looked as if the embryo British electronics industry which had grown from almost nothing to a world leader during the war was doomed.
Eventually the government was forced to yield to mounting pressure and the British Broadcasting Company (not the present B.B.C. which is the British Broadcasting Corporation) was formed from the six most powerful of the British wireless companies and given an absolute monopoly of broadcasting.
In August 1922 the B.B.C. began public broadcasting services throughout the U.K., the object being to promote sales of receivers made by the wireless companies. There was a 10 shilling licence and only B.B.C. approved receivers and components were legal. These parts carried a B.B.C. approved stamp for which a royalty was charged. It looked as if the six companies had a licence to print money. There was however, a way to get an unapproved receiver - make it yourself!
By April 1923 the Home Office estimated there were 60,000 approved sets and at least 200,000 illegal ones in use. This would soon grow to 2 million. To provide parts for the D.I.Y. activity a components industry sprang up and many of today's big names made their first appearance.
Valve sets were expensive, a government surplus R type valve was 14/6d. (two days pay). The working mans wireless set was the crystal set, which could be made for a few shillings. Its detector was a piece of semiconducting mineral (the crystal) in contact with a fine wire. (Popularly called the cats whisker) Real cats whiskers, being non conductive, didn't work and this gave great relief too many cats.
One W Schottky published a paper on the physics of the metal to semiconductor junction. It was a super fast switch. It could not however amplify and would therefore never replace the valve.
The forced development of valves and circuits during World War I resulted in practical radio telephony. The post war application of these advances, was public broadcasting, the objective being to create a mass demand for broadcast receivers and thus provide a market for the technology developed for the war effort.
Unfortunately in spite of the mass production techniques developed during the war radios at the start of broadcasting in 1922 were far beyond the pocket of the working man. A Marconi 5 valve radio cost the price of a modest house. Even a government surplus R type valve for the D.I.Y. enthusiast was more than two days average wages. Consequently the most common form of receiver in the early broadcast era (1922-1927) did not use the valve. Instead they used the semiconductor crystal detector which was based upon natural mineral crystals costing only a few pence.
Although they were used in millions in early broadcast receivers from 1922 onwards this was not the first use of semiconductors. David Hughes the first radio amateur used one in 1879 in an experimental-receiver which was probably more than one million times more sensitive than the famous coherer detector demonstrated nine years later. The coherer however was well publicised and was the principal radio detector until 1906 when a large number of workers in different countries rediscovered crystal detectors at about the same time.
The only users at this time were the commercial telegraph companies and the military to whom the cost of a detector was not a prime factor. Therefore these users quickly changed from crystals to first Fleming's oscillation valve which was much more stable and then to de Forest's Audion which also provided gain and the valve reigned supreme until the advent of public broadcasting in 1922. In the history of electronics semiconductors appear briefly in various forms at least five times before they finally come to dominate the industry in the 1960's.
A consequence of the popularity of the cheap crystal set which satisfied the bulk of the demand for receivers was a negligible development of valves or components during the first 5 years of broadcasting. Valve circuitry made great advances in this period but only in the laboratory or as receivers for the rich. In 1926 valves were little improved upon the R type originating in 1916 which was still in current production.
It is a recurrent theme in the history of electronics that a period of stagnation is ended by a political decision. This time it was the replacement of the British Broadcasting Co. by the British Broadcasting Corporation which was to supply a public broadcasting service supported by a licence fee and thus free of commercial interests. The new BBC began regional broadcasting, giving listeners a choice of programmes and by so doing revealed the fatal weakness of the crystal set. It was a most unselective device. Given only one station within its limited range on each waveband it was adequate. With a choice of programmes it received them all at the same time. Within a year the crystal set was almost extinct.
A huge demand unlocked the funds for development and progress was incredible. In one year valves were developed to ten times the performance for one tenth of the power consumption and the price dropped. In five more years all the components and techniques required to achieve television, radar, computers and electronic control systems were developed and available in a low cost mass produced form. The tools of our trade now to hand. The next great steps forward would be made in response to the demands of World War II.
The rapid expansion of public rr in the late 1920's lead to a demand for radio receivers of greatly improved sensitivity and selectivity to enable reception of the hundreds of stations which had appeared worldwide. This demand caused an explosive development of electronic components with the result that by the early 19:70's almost every component function used in electronics today, was available in a low cost mass Produced form.
Many of these components were only slightly inferior in their electrical parameters to those we use today, and some were actually superior. The Principal differences between these early components and those we use today were that passive components were larger and active functions were realised with valves instead of semi conductors. It was therefore theoretically possible to achieve any circuit function of today's electronics, providing that size and power consumption were not critical factors.
Technical publications of this period show that a few engineers had begun to apply these components in circuits quite separate from radio. Often these new developments were considered to be of limited use because electronic circuitry was still synonymous with radio. From the perspective of history, we can now see that radio engineering was always only a specific application of electronics but it was at this time that electronics emerged as a separate engineering discipline.
Exactly how significant some of these new applications of radio components were can now be judged with the benefit of hindsight. The cathode ray oscilloscope, a tool of physics since the 1870's (the name Cathode Ray tells us that it pre-dates the discovery of the electron) was fitted with a Y amplifier and a synchronised time base to become the electronic engineer's most useful tool. High speed bistable relays were developed, originally for the very limited application of binary frequency division. Precision differential dc amplifiers were developed initially to enable biologists to measure minute potentials developed by nerves. You can find reference to this in old journals listed under 'Biological Amplifiers'. Dual gate control circuits and electronic position and speed servos are also among numerous techniques used in our modern control systems which first appeared at this time.
BY the mid 1930's, Adolph Hitler had come to power in Germany and Europe was moving inexorably towards the first war in history in which electronic engineering was to be a decisive factor in determining the outcome. In the UK Frank Whittle was working on the development of the jet engine and Robert Watson Watt on radar. The roots from which the Engine Electronics Division of LA would eventually grow were now firmly established.
The military requirement of World War II found many new applications for the electronic circuitry which has appeared as a by-product of the radio boom of the 1930's. Some of the most far reaching of these developments came about in response to what at first may appear to be quite unrelated military demands. One such development was the electronic digital computer.
The electronic computer was developed first in Britain as an aid to deciphering coded radio messages and later in the USA, initially to improve the effectiveness of anti aircraft fire. What both problems required was a means to perform computations much faster than mechanical calculations.
The British computer development was shrouded in official secrecy, whereas the American work was highly publicised with a result that it is a commonly held belief that computers were first invented in the USA. The British work is now probably principally remembered in the "Turing Machine" (A machine in which the solution to any problem could be expressed as the response to a series of questions which could be answered yes or no and thus render it susceptible to binary logic.) A M Turing lead the British Team.
It is said that one day during the London blitz Winston Churchill sent for the commander of the anti aircraft guns defending London and demanded to know why the guns were not firing at the German bombers. The commander replied that his guns had fired 80,000 shells without scoring a hit and as an invasion seemed imminent he felt he should conserve ammunition.
Anti aircraft guns had to be aimed at a tiny speck in the sky manoeuvring in 3 dimensions at an appreciable fraction of the velocity of the shell from the gun. Even worse the shell was exploded by a mechanical fuse which counted the number of revolutions of the shell. This had to be set with a spanner before the shell was loaded so that the gunner had to guess the distance from the gun to the target when the gun was fired before even loading the gun. If the fuse setting was not perfect the shell might be aimed dead on and explode 100 yards short or miss by a few inches and explode 100 yards to far or even hit and pass right through without exploding causing only minor damage.
The answer to both problems was electronics. A predictor to calculate the future position of the target, point the gun and fire it at the right instant and a proximity fuse which measured the distance to the target and exploded the shell when it passed inside a lethal radius. The American predictor project began the development of their digital computer. The proximity fuse was a British development.
In 1943 Lucas Formans Rd began to produce millions of 40mm shell nose cones in black Bakelite. The workers were told it was a scheme to save metal. The real reason was that they had to be transparent to radio waves. Inside the cone in a cavity about 1 inch diameter by 1 inch deep was built a tiny short range radar set using valve electronics, complete with batteries, robust enough to fire from a gun. The proximity fuse was in production, when South East England was attacked by the V1 flying bomb, a much smaller and faster target than a bomber. Light anti aircraft guns aimed by radar fed predictions almost invariably destroyed any V1 coming within their range with less than 10 shells. An expenditure as high as 10 was often a consequence of rate of fire putting several shells into the air at the same time.
The relevance of the computer to the evolution of the modern engine control is obvious but why mention the proximity fuse? A few years after the events I have narrated I asked why we couldn't fly electronic engine controls and was told that valve electronics (the only kind we had then) would always be much too big and fragile. I didn't think proximity fuses were either big or fragile but the story of the big fragile valve equipment was used to delay flight standard electronic controls for many years.
One of the most significant developments of World War II was the gas turbine engine or the jet engine as it was popularly called.
In Britain the development team was led by Frank Whittle.
One of the first problems Whittle's team had to overcome was developing a combustion system which could burn large quantities of fuel in a very high velocity air stream and do it within a volume which was only a tiny fraction of that required by existing oil burners.
It was decided that it would be necessary to inject the fuel under high pressure and atomise it into a fine spray of controlled droplet size in a concial jet which diverged at a well defined angle.
The only existing technology which could accomplish this was the Diesel injector. Lucas had subsidiaries specialising in Diesel pumps and injectors and were therefore a logical choice to develop a fuel system for the Whittle engine. So began Lucas gas turbine engine fuel systems which grew into Lucas Gas Turbine Limited.
The early fuel systems were simple and mechanical. A variable displacement pump controlled by throttle pressure drop, the throttle, the burners and a simple centrifugal governor comprised the basic system.
Flight standard engines also required a barometric pressure control to compensate for air density and a jet pipe temperature limiter.
All of these functions were satisfactorily realised with mechanical systems except jet pipe temperature limiting. Here methods such as mercury boilers with capillary and bellows or differential expansion between quartz rod and stainless steel tube were much too slow. Electronics was the obvious answer.
By 1947 electronic controllers using radio receiver type valves had been demonstrated controlling engines in ground test cells. These controllers were also used to provide speed governing and altitude compensation.
A specimen of these early controllers still survives (Type L.A.S. Serial No 3). This has been rescued from the rubbish tip more than once where it was thrown as old junk. I think it may be one of the oldest electronic fuel control systems on earth. The J Lucas label suggests it is pre Lucas G.T.E. I hope that it may be preserved for posterity before I retire and no one is left who loves it enough to fetch it back from the tip again.
In spite of the successful demonstration of electronic controllers, extreme prejudice against electronics on engines was the norm among engine manufacturers; even today vestiges of that prejudice are evident. As a consequence the widespread use of electronics in flight standard controls was delayed by perhaps 20 years. Only in temperature control, where mechanical systems were too slow, was electronics much used.
The prejudice against the thermionic valve caused the amplification for these systems to use magnetic amplifiers "because they were robust". In practice a device with thousands of turns of 1 thou wire and a core which deteriorated if stressed was not robust. The magnetic amplifiers helped to confirm the engine manufacturer's worst suspicions of
electronics. Consequently until the early 1960's the principal activity of the electronics labs at Shaftmoor Lane and Honiley was instrumentation for fuel systems and engine development.
In 1951 I left Lucas Electrical at Great King St. to join the small Electronics Lab which had been formed at Shaftmoor Lane. The Lab was a small outbuilding with a corrugated iron roof on the edge of the railway embankment in a corner of the scrap yard (where the multi storey car park now stands). With my arrival we were five. One other of those five, Peter Phelps, is still with us. Two benches, one Oscilloscope, three Avo's and several cardboard boxes of government surplus bits almost filled our little shed and left just room to move about but it was a very tight squeeze. Component supplies were improvised by a trip to the nearest government surplus shop (Resistors 6d a hundred, valves 6d to 1/6d each).
One got the impression that we were there because electronics was the thing of the future, therefore Lucas had better have some. Opinions as to our functions varied. A few said that there was nothing which could not be done with the new wonder science, but couldn't actually think of anything that needed doing. Some had no doubts that we were there to provide a free radio and T.V repair service. The majority regarded us with varying degrees of suspicion. A few were quite paranoid, suspecting that we had come from outer space to take over their world. In a way they were right!
At first we got some very strange but interesting projects which included a machine for selecting perfect ball bearings for fuel pumps and an electronic X,Y plotter, one of the very first and a machine with performance unsurpassed to this day. Many of the early projects were concerned with instrumentation of hydraulic systems, where the low inertia and almost instantaneous response of electronic instrumentation, combined with recording oscillographs, permitted the detailed study of phenomena previously inaccessible. Often our oscillograph records were greeted with incredibility by the hydraulics engineers, who could not believe that pressure waves at two points in the same pipe were in antiphase or that two parts of a solid metal structure could instantaneously go in opposite directions.
The electronics engineers supplied not only oscillographic records and interpretation but often advice upon the modification of hydraulic controls, which they readily saw as analogous of electronic feed back systems. Sometimes, when all else failed, the electronics engineers advice was acted upon, more in desperation than in hope and often it worked. Electronic instrumentation became a growth industry. The Lab moved from the shed in the scrapyard to new spacious accommodation in the main building (would you believe shared with the typing pool?) and we recruited some more engineers. Since valve electronics were mounted on metal chassis involving much sawing, drilling and panel beating, we were soon moved out of the typing pool. Our activities in instrumentation grew and branches were established at Honiley under one R W Rigby, and at Marston Green with myself, Jim Hadley and Trevor Hudson.
Paradoxically, this expansion in electronic activity so improved hydraulic controls that electronic fuel system controls were less desirable and thus their advent was delayed.
The first widespread application of electronics at Lucas Gas Turbine was instrumentation for the development of hydraulic and mechanical engine fuel controls. Occasional attempts at electronic control systems were made and demonstrated in ground test runs, but were never seriously considered for flight.
Electronic recording of all kinds of engine and fuel systems parameters under dynamic conditions however, contributed greatly to the understanding of the control of gas turbine engines, leading to hydraulic control of greatly improved speed, accuracy and stability. Consequently, instrumentation and recording became a principle activity of the electronics laboratory, which by 1957 had grown to about 20 people on three sites.
At about this time, a new electronic activity became increasingly important. Simulation in which control systems were modelled in analogue computers. The first of these designed and built in the lab at Shaftmoor Lane was called L.E.G.T.A.C. - Lucas Electronic Gas Turbine Analogue Computer.
By programming an analogue computer to model an experimental engine, and using its speed signal output to control a variable speed drive, a real fuel system comprising pump, throttle, controls, even burners (not lit of course) could be evaluated under dynamic conditions without expensive engine running. Overspeeds, surges and instabilities could all be investigated on a real fuel system without hazarding an expensive engine and test cell.
Clearly the advantages of this technique were very great and it soon became an important project.
The combination of analogue computer and high power speed servo, lead by stages to electronic engineering on an heroic scale. At Honiley, the analogue computer filled a large room and the power amplifier which drove a 150HP low inertia motor supplied peak currents in excess of 1000A 1440v. Commanding a step change of speed on this rig could transiently dim the lights over an appreciable area of rural Warwickshire.
The big analogue computer could of course equally well be patched into engine control systems. Thus much useful data was obtained and some very convincing demonstrations of electronic fuel system control given. The remaining major problems standing in the way of flight standard electronic controls were prejudice and high reliability miniature electronic components.
By the early 1960's, the silicon planar process was being developed to solve the second problem. The first, I suspect, had to await a new generation of aircraft engine designers.
With the coming of silicon planar transistors and components which were then designated sub miniature (now standard size) in the 1960's, some of the obstacles to the acceptance of electronic fuel system controls were overcome. More efficient engines with more stringent control requirements caused electronics to be considered desirable and it began to look as if the day of the electronic fuel system controller had dawned.
The only technology for circuit construction then available was discrete components built onto printed wiring boards (PWB), then a fairly new invention. Some of us had grave doubts about the integrity of PWB which proved justified. Consequently, some early systems were built on feed through insulators on metal chassis. With discrete components an op amp with associated network occupied an entire board and the amplifier development was a major task.
The prejudice against "fragile" electronics was still rife, therefore electronics had to resemble civil engineering to be acceptable. A popular construction was to embed the circuit into a block of quartz loaded epoxy with heavy metal bushes into which bolts could be inserted. The result resembled a grey concrete brick in both appearance and density. No doubt the components would remain entombed in concrete preserved against any onslaught less than a pneumatic road drill or high explosive for centuries. Steel toe caps were advisable for protection against dropped circuit boards. Naturally circuit changes were required at intervals of less than centuries. This need produced the strange spectacle of electronics engineers attacking concrete blocks with hammers and chisels.
It may sound a strange way of making circuits but it was what the customer wanted and we found ourselves moving from an R&D outfit towards production. Inevitably a production facility became established as a separate function to the laboratory and John Chance left the lab to become foreman of the new department.
Having finally established a flight standard control system in production with a truly monolithic structure (some would say megalithic). The next criticism from the anti-electronics lobby was lack of temperature resistance. (If a mechanical system can run red hot then electronics must be inferior if it can't run red hot too!)
In a short time electronic component temperature ratings had risen from 50/70�C to 85�C and then 125�C, therefore extrapolating, we set a target of 300�C for future control systems. In pursuit of this aim a group was set up to develop active metal thick film circuits on ceramic capable of jointing by welding, to substitute for PWB's. I went to Group Research to develop a complementary range of thin film hybrids to fit on the ceramic boards (they soon become universally called tiles). The postulated silicon carbide semiconductors and high temperature capacitors required to complete a 300�C circuit are still not available twenty years after. Lacking these parts compromises were made including soldered joints and what was intended to be a revolution in circuit construction became an expensive way of producing high integrity 125�C circuitry. If a military demand ever funds the necessary components the potential remains.
Looking back over the last fifteen years it seems to me that no revolutionary changes comparable to those of the previous fifty years have taken place. I think that what has happened is that as a group we have grown from a small R & D outfit to a medium scale production facility. Simultaneously our technology has matured and stabilised and we have passed from revolution to evolution.
Perhaps that is a personal subjective impression but a few weeks ago I looked at a set of exhibits prepared for one of our York Road conducted tours. The exhibits were labelled in the decade of their origin; the sixties, the seventies and the eighties. I saw rows of similar printed wiring boards with components of similar appearance. In general the components and construction techniques were the same. From 1965 to 1983 only the integrated circuit types had changed.
Had a similar exhibition been mounted to illustrate products from 1950 to 1965 the exhibits would start with valves on metal chassis and pass through igermanium discrete semiconductors on metal chassis through discrete silicon devices on printed wiring boards, discrete devices embeded in resin blocks to thick and thin film hybrid circuits and finally to integrated circuits and hybrid packages on printed wiring boards.
It remains only to chronicle that last part of the journey from the roots of our industry in Leed deforest's Audion valve of 1909 to Lucas York Rd 1984;
By the late 1960's our first electronics production facility at Shaftmoor Lane had expanded to fill all the available space.
The Laboratory had already overflowed into various other sites. A group in a temporary wooden building on the Group Research site was working on the first digital systems. In the main research building a few of us were developing thin film circuitry and others were working on thick film technology at a newly acquired site at Cranmore Boulevard.
P laps were far advanced to consolidate a combined development and production facility on a single site at Cranmore Boulevard when the Rolls Royce collapse of early 1971 removed our principle customer and therefore the need for an expanded facility. Instead the production unit faced the trauma of contraction through forced redundancies.
Engineering fortunately was retained in its entirety to develop new business and the process of rebuilding began, Engineering and a reduced production facility moved to the Marston Green site. The clean room however was too expensive to move and thin film production remained at Shaftmoor Lane.
Electronic sales slowly recovered and production began to expand once more. Engineering too expanded as new products entered the development phase.
Eventually saturation of the accommodation at Marston Green was reached and rumours of a move to a new site became rife.
After rumours of a move to Coventry, then Fordhouses and a sell out to Marconi we were relieved to hear of a move to a new �5 million factory at York Road and here we are 800 strong, from 5 of us in a shed in 1951.
In my memories the best times were the early days 1951 to 1956 and 24 years at Group Research in the late 1960s developing thin films. Perhaps distance lends enchantment?
Considered against the time scale of my roots pieces I shall very soon be no longer in the story. I wonder if any of the younger people will continue the story and tell of early days at York Road when it was all just beginning?