Arthur G. Booth

Arthur G. Booth had a distinguished career as a design engineer. His career began at Wolverhampton, working for the Clyno Engineering Company, and later A.J.S. After A.J.S. went into voluntary liquidation he moved to Singer Motors Limited and later Humber Limited. He ended up as Chief Consulting Engineer to the Rootes Group and was Chairman of the Automobile Division of the Institute of Mechanical Engineers. The following section is taken from his Chairman's address, which was delivered at a meeting of the Automobile Division at the Institute on 9th October 1956. As the complete address is quite long, we have only included the sections that are about his time in Wolverhampton, to reduce the time taken to download.

His daughter, Mrs Eileen J. Stephens has kindly given us a copy of the paper and some of her father's photographs and we would like to thank her for allowing us to include them here.

An extract from the address of the Chairman of the Automobile Division

Experiences During Forty Years of Automobile Design

By A. G. Booth, M.B.E. (Member of Council)

Arthur G. Booth, when at Clyno.

My engineering career began in 1912, when I joined The Clyno Engineering Co. of Wolverhampton, as a draughtsman. In 1922 I became Chief Engineer and held the position until the Company went out of existence in the early 1930's during the trade slump which claimed so many victims at that time. That was followed by three years from 1932 as co-Designer and Engineer with Singer Motors, Ltd., who by a happy coincidence have now become part of the Rootes Group.

Finally, early in 1935 I joined Humber, Ltd., as Chief Engineer, responsible to the Group Director for the design (excluding bodywork) of Humber, Hillman, and Sunbeam Talbot cars, and military vehicles, a position held until recently when I was appointed Chief Consulting Engineer to the Rootes Group. Thus, my career has been divided roughly into three periods; the first with a young and enterprising company, which like many others was unable to weather the economic blizzard of the 1930s; and the second and third periods with two of the earliest producers of cars in Great Britain.

The first ten years with The Clyno Engineering Co. included car and aircraft engine design and planning, but the greater part was on motorcycles, from small two-stroke models to large and powerful 6- and 8-h.p. twin-cylinder side-car combinations, which were at that time a very popular mode of transport. Speaking with some experience, I can say that motorcycle design as I knew it was at least as intricate and as technical as that of cars and aero-engines. I found that the subjects of engine performance, suspension, roadworthiness, weight reduction and cost, were quite as important as in cars, and whereas in the latter we worked in three dimensions, a motor cycle was virtually in two dimensions in a plane of very little thickness with space limitations and very fine clearances. I can only compare it with hanging everything on a very short clothes line!

A Clyno combination that belonged to the Booth family.

The cover of a Clyno booklet from 1913. It shows a Dragonfly engine on the top left, a Vickers-Clyno machine gun carrier on the top right, Fort Works on the bottom left and Ashes Works on the bottom right.

I soon discovered the need to consider customer reaction to every exposed part in terms of appearance and finish as well as of engineering function, from the engine and other units right down to the merest nuts, bolts, wires, and clips. As an enthusiastic motorcyclist, I developed something of a flair for engines, and to my joy I found a considerable amount of this type of work coming my way on two-stroke and four-stroke models. It must be admitted that apart from the economic value, I had no great liking for the two-stroke engine but its construction was so different from that of the four-stroke that it added a touch of variety to my duties.

The latter half of that first period, in which I was made responsible for the design and engineering of the Clyno cars, presented altogether new and at first unfamiliar problems. It was not a case of modifying an earlier vehicle with years of experience behind it, but of starting from scratch and developing an entirely different line of business. Management in those days expected the designer to know his job and to do his development work on the drawing board, with only a small amount of experimental work.

A Clyno combination.

Out in the wilds with a Clyno combination.

Perhaps it was fortunate therefore that our experience was gained in the first two years on a relatively small, but rapidly growing, output. Owing entirely to the hard work and enthusiasm of a very small team of engineers and production men, the first prototypes were in the Motor Exhibition of 1922 within four months of the commencement of the project.

That achievement, from a zero start, included the design and manufacture within the factory of every unit on the chassis, except the well-tried and excellent 1,368 cu. cm. Coventry Climax engine which was fitted. When we were fully geared for volume production our output reached very high figures for those days, and by 1930 a total of approximately 50,000 cars of all types, of a rating from 9-13 h.p., had been produced.

Another Clyno combination in the Lake District.

The 1914-18 War Period

On the outbreak of war all preparations for the manufacture of a Clyno motor car, on the design of which I was engaged, were suspended, and that particular car project was abandoned for all time.

A Vickers-Clyno machine gun carrier.

In collaboration with Vickers, Ltd., we designed and produced mobile machine-gun equipment carrying driver, gunner, machine gun, armour, and ammunition, on a modified version of the Clyno motorcycle combination. Its rugged nature and case of manoeuvre made it highly suitable for active service in the field, and many were supplied to the British and Russian forces.

A Vickers-Clyno machine in action.

Earl Haig inspecting the Vickers-Clyno troops.

Vickers-Clyno troops in action.

A Dragonfly aero-engine.

With the Vickers-Clyno equipment well established in the factory, our attention was then turned to other wartime priorities, and we were soon engaged on development contracts for new type aero-engines, one of which was in collaboration with Vauxhall Motors, Ltd., for a large water-cooled twelve-cylinder V-engine. During that period I was privileged to work under the direction of the late Mr. L. H. Pomeroy, President of the Institution of Automobile Engineers for the Session 1934-35, and of Mr. C. E. King, who was in charge of the project throughout the design and prototype stage, and who later became Engineering Director of Vauxhall Motors, Ltd. My most interesting memory of that engine was the design for the fabrication by welding of the cylinders, complete with hemispherical head, overhead valve ports, and water casing, all from steel billets and pressings, and I learned from that experience that for those methods there was no future in the automobile industry.

Unfortunately, the engine was abandoned and valuable time was lost, but the knowledge gained proved very useful for the work which followed.

We were next engaged, with other companies, under the parentage of the Sheffield Simplex Motor Works, Ltd.,
on what I believe to be one of the first aero-engine shadow schemes for the manufacture of the 300-h.p. 'Dragon-fly' nine-cylinder air-cooled radial engine, from the prototype stage to large-scale production of the complete unit.

Dragonfly engines in production at Pelham Street.

Machining Dragonfly engine blocks.

As a member of that planning team I was fortunate in having as colleagues two lifelong friends, Mr. S. C. Poole, to whom I owe some of my early training, and our esteemed member of Council of the Automobile Division, Mr. C. M. van Eugen. That was my first experience with production planning, which was put through in record time and detailed to an unusual degree because of the link with other factories, and I mention it merely to show what was done forty years ago.

I have not seen these methods used elsewhere, probably because they are somewhat laborious. The components were planned stage by stage from the raw material to the finished article, each successive operation being represented by a small-scale drawing, appropriate to its immediate shape and machining dimensions, and bearing references to gauges, jigs, and tools, which were detailed at the same time, or to particular heat treatment or other operations.

The prototype Clyno car.

A small-scale drawing of a Dragonfly connecting rod in readiness for the milling operation.

The design of the engine for production purposes, the planning of the equipment and machine loading, and the interchangeability of the parts which we achieved, would do credit to more modern times. Until then interchangeability within very fine limits as we understand it today, had not been one of our strong points, but wartime activity greatly accelerated the development of methods for higher production and greater precision, from which the automobile industry was to benefit in the following years.

If all this seems commonplace today, it must be remembered that in 1914 there was little experience of the of aero-engines in Great Britain, and we certainly had none in The Clyno Engineering Co., but as a result of the needs of war we entered the years of peace better equipped to meet the demands that were to come in the 1920's.

Some Engine Developments

In my experience the advances in the design of British automobile engines from 1920 onwards have been steady and as progressive as in any other section of car design, and more impressive than is generally realised. Principles of operation and construction are very similar but the improvements in detail, materials, performance and efficiency have been considerable. Much of this is due in no small measure to the research carried out by Sir Harry Ricardo and others, whose services to the industry have been of incalculable value. On the production side, there have been striking changes in methods, processes, and in accuracy of manufacture, particularly in the last ten years.

A Clyno 4 cylinder 1,600 cu. cm. engine and clutch.

Another view of a Clyno 4 cylinder engine from 1927.

Some may deplore the change from the personal skill of the operator to that of the production machine, but it is only by these means that quantity production can be maintained without loss of quality. That skill of the operator exists today in much greater abundance than ever before, but it has been transferred from manufacturing operations on the product to manufacture of precision production equipment. Reverting to the design of the products in which I have been interested, I have selected one or two items for general comment. For Clyno cars a number of four-cylinder side-valve engines up to 1,600 cu. cm. capacity, were manufactured by the Company or exclusively for them by Coventry Climax Engines, Ltd., to their own designs and those of The Clyno Engineering Co., under an excellent arrangement which gave full consultation on matters of design and manufacture.

Those engines progressed through all the normal developments of the time, including early changes from ball and roller bearing main journals and splash lubrication to plain bearings and pressure lubrication, from cast iron to aluminium pistons, and from two to three bearing crankshafts, all of which had a considerable effect on the efficiency and smooth running of the engines.

By today's standards the cone clutch was not good but it gave reasonable service, probably because in those days we had not arrived at flexible engine mountings. A point of long standing interest on all Singer engines is the chain-driven overhead camshaft, which dates back in thought to 1912-13, when it was first introduced on the prototype Clyno engine by the chief car designer, Mr. S. C. Poole, with results that were so encouraging that he used it on the new engines he designed when he joined Singer Motors, Ltd., in 1920. The design was still very much the same when I joined the company in 1933, and has given such good service throughout the years that it has been retained to this day. As a junior member of the staff on the 1913 design, I well recollect the element of doubt we had when we introduced the overhead camshaft vertical chain drive, I think for the first time on a British engine, using a Coventry 'Duplex' roller chain with external adjustment. It is such experiences that have justifiably established the roller chain on British engines against the competition of the inverted-tooth chain, the helical spur gear, and other forms of drive.

Transmission Developments

While developments throughout the years in other sections of automobile design have followed a reasonably progressive pattern, I consider those of the transmission have received more thought and caused more disappointments than all the others put together. In the 1920's when straight spur gears and 'crash change' were usual and gear changing was an art considered to be the accomplishment of the good driver, there was relatively far more reason for criticising the lack of progress than there is today. That state of affairs persisted in most British designs at least until 1930, and I am sorry to say that for the Clyno cars I was more concerned about the prevention of tooth chipping by metallurgical processes than by a new form of gearbox to simplify gear change. Strangely enough, our main concern was not about the design of the gearbox, but where to locate it, and what type of propeller shaft to use, the latter providing the greatest difficulty. No proprietary types of propeller shafts were available in those days, and as we had no experience in the manufacture of the open type we decided on the well-established practice of torque tube and enclosed shaft drive, with the gearbox mounted at the front and the axle at the rear of the tube.

Clyno torque-tube transmission and control.

As the whole transmission unit was anchored to the frame cross member by a large ball and socket arrangement on one side of the front of the gearbox, there were problems of gear-lever movement due to swing of the axle, while at the same time we were asked to meet a popular demand for right-hand gear control, both of which were dealt with in the simple manner shown. The drive from the engine to the gearbox was completed by a short shaft with flexible Hardy couplings, the use of which in that application proved quite satisfactory with a mechanical centring device. In my opinion the outstanding development of those early years was the production in Great Britain, from 1927 onwards, of the Hardy-Spicer open-type propeller shaft with fully-sealed mechanical joints. That solved a long-standing problem and made obsolete the type of drive used on the Clyno car, while at the same time opening the way for the more general use of unit construction of the engine and gearbox. I have referred to the lack of improvements in transmissions during the 1920's, and in my view the growing popularity of the motor car in that period forced the pace during the 1930's when many progressive changes in gearing took place, including the so-called silent gearboxes with constant mesh helical gears using sliding dog engagement, which were later superseded by different types of syncromesh.

Brake Developments

Clyno front wheel brakes, 1924-29.

It is my experience that until the last few years there has been very little difficulty in maintaining the power and efficiency of brakes to meet the requirements asked of them by improvements in other parts of the car, but lately the demand for further increases in power and speed, mainly in the more powerful vehicles, has taxed all the designer’s efforts, particularly with modern styling.

From 1922 to 1925 the cars with which I was concerned had braking on the rear wheels only, a feature which was common to the majority of cars. A parking brake on the transmission was often used, but most cars had twin rear brakes side by side in drums of considerable width, linked respectively to the hand and foot control. In order to avoid drum distortion and minimize the weight we departed from this method by using narrow drums with two pairs of shoes interlaced on the Timken principle and mounted on short pivots with cams set at 90 degrees to each other.

It may seem strange to those brought up on four-wheel braking that we should be satisfied at one time with rear brakes only, but speeds were relatively low and as cars were few in number there was little traffic congestion.

In 1924 for the first time on Clyno cars we offered front wheel brakes as an optional extra at a low price, but buyers were wary of the skidding problems that might be created and there was not much sales response. However, by 1925 with twelve months' satisfactory experience, front wheel brakes were standardised on all models, and we were so convinced that it was the right thing to do that we adopted 12-inch brakes on the front and 10-inch on the rear with a 55/45 ratio. That was a lavish- specification for 11- and 13- h.p. cars with an unladen weight of under 20 cwt.

As an example of the reaction in some quarters to four-wheel brakes, I had great difficulty in obtaining the approval of the Licensing Authorities for front-wheel brakes on cars for taxicab contracts, and also encountered a legal objection from New Scotland Yard on a technical point because we removed the second pair of handbrake shoes from each rear drum. They were quite unnecessary with four-wheel brakes consisting of two separate systems operated by the foot, with limited compensation, and with the handbrake interconnected to the rear only, in such a manner that the failure of any part would still leave one full set in action. Shortly afterwards the wording of the Regulations was amended to put the matter beyond doubt. The companies using the transmission parking brake quite naturally took the opportunity of discarding it. Most firms made their own brakes in those days, and for Clyno cars we developed a new front axle with our own braking system, the shoes being operated by a cam with a lever outside the backing plate and operating immediately below and on the centre-line of the kingpin, which avoided any interference from the swing of the stub axle. This type of design gave good service on approximately 40,000 cars, and was also adopted on a well-known Continental model.

In my view one of the greatest advances in brake design came with the production in Great Britain during 1927 of the hydraulically operated Lockheed brake with internal expanding shoes, which I believe was first fitted by Mr. F. G. Parnell on the Triumph Seven car of that period, although earlier versions with external band brakes had previously been used. It is fortunate that that method of brake control was available before the mass production of independent front wheel suspension, as apart from its inherent technical advantages it simplified the designer’s installation problems, as was amply proved on the Singer and Rootes Group models. Now this method has practically supplanted all others throughout the world.

Design for Comfort and Safety in Car Suspension

No matter how much we may feel that our roads are inadequate today, we must admit that the surface conditions are generally good, at least by comparison with those of the 1920's when there was little thought for the comfort of the few who used them, and when road engineering was in infancy. Likewise, by today's standard there was little that could be said in favour of the suspension system on our cars, yet they became popular despite discomfort for the passengers.

The weight distribution was all wrong, with engines well back in the frame, with the rear passengers over the axle, and with little luggage accommodation except for unsightly luggage racks. I think it can be claimed with justification that we have progressed a long way since then. On Clyno cars we used quarter-elliptic springs which had the advantage of low unsprung mass, until front-wheel brakes demanded semi-elliptic springs to deal with brake reactions.

A Clyno logo.

For all the good they did, the shock absorbers could have been discarded after less than 5,000 miles of service, and there was little to choose between one make and another. The only real improvement during that period came in 1924-25 with the change from small-section high-pressure tyres to large-section low-pressure balloon tyres, which started a trend in development that has been repeated in later years.

The new fabric bodied, 2 door Clyno 9 leaving Bushbury Works, with some of the Clyno staff. 3^rd from the right with his hand in his pocket is Arthur G. Booth himself. Third from the left at the front (directly above the number plate) is Frank Smith.

Arthur G. Booth in later years.

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