Merlin

Chapter Four

Primum movens –

‘Prime mover’ – a new engine for a new century

A nine-cylinder Gnome rotary engine, circa 1916. The inlet valves are hiding in the piston crowns. (Wikimedia Commons/US Library of Congress)

Those Magnificent Men in their Flying Machines was a 1965 comedy caper film that featured authentic flying replicas of early aeroplanes. In it, the English press baron Lord Rawnsley puts up a £10,000 prize for the winner of a 1910 London-to-Paris air race. Many of the pioneer aircraft and their piston engines can be seen flying, but the authenticity of the cars, aircraft and sets is somewhat let down by feeble performances and a predictable script. Watching the stunt pilots getting these contraptions into the air gives an idea of just how dangerous this new sport was. Landing them again was potentially lethal.

As the Wright brothers built up their flying hours they ran into an engine problem. As they rotate, in-line four-cylindered engines’ pistons stop and start all at the same time, and as a result such an engine can never have perfect balance. The vibrations of their engine were so bad that they threatened the structure of the aircraft. More power was needed, too, so the brothers increased the power of the four-cylinder engine to 25 horsepower by 1906, and in 1908 they made a six-cylindered engine of 39 hp.

Six-cylindered engines are smoother because the crank throws are at 120° to each other instead of the 180° of a four-cylinder. This means that paired pistons are at equal distance from the centre of the engine (nos 1 and 6 cylinders, nos 2 and 5, nos 3 and 4), and they are always moving together, which results in good balance in the reciprocating mass. The overlapping torque is generated every 120°, which helps for smoothness, too. However, you cannot keep adding cylinders in a line indefinitely – the crankshaft grows so long that it starts to twist and vibrate. This is because as each cylinder fires it imparts a slight twist to the crankshaft, rather like winding a spring. This sets up a torsional vibration that eventually snaps the crankshaft. The Wright brothers did not dare to run their new six-cylinder engine at the high revolutions at which this vibration set in. It was left for others to solve this problem.

One way to avoid a long crankshaft is to use a short four-throw crankshaft with a bank of four cylinders, then add an extra bank of four cylinders and pistons at 90° to the first bank, driving the same crankshaft and sharing big-end journals. And this is exactly what the French engineer Léon Levavasseur did when he invented and patented the V8 engine, the elegantly built and named Antoinette 8V.

Levavasseur was a fine arts student who clearly had an eye for aesthetics. He switched to engineering and started building petrol engines for motorboats. His V-shape motors fitted neatly into the bilges of a boat, as V-shaped steam engines had before them. In 1903 he persuaded the French industrialist Jules Gastambide that his engines would be light and powerful enough for speedboats and for the aircraft that were clearly on the horizon; furthermore, he suggested that the engine should be named after his patron’s daughter: Antoinette.*

Levavasseur had patented a fuel-injected 8-litre V8 engine, a machine now so identified with the American muscle-car culture of the Sixties that it might come as a surprise that it was invented by a Frenchman. It was rather more beautiful than the average Detroit cast-iron lump; for a start each cylinder was surrounded by a thin water jacket made of electrolytically deposited copper, and these contained water that was turned to steam by the heat of the cylinders. This rose through copper pipes and was evaporatively cooled back to liquid water. The fuel was injected into each inlet port through a decidedly modern-looking stack of inlet pipes. When all the copper was polished this was a lovely piece of sculpture. The power, though, was only 50 hp, a figure that could be achieved today by a motorbike of only a quarter of 1 litre: 250 cc. By 1904 most of the prize-winning speedboats in Europe were running the Antoinette 8V engine.

Aircraft designers need lightness as well as power, though, and the specific power was 4.6 lb per hp, half that of the Manly engine. The Antoinette 8V was fitted into the first French aircraft, 14b (Quatorze-bis), built by the Brazilian aviation pioneer Alberto Santos-Dumont. This aeroplane refused to take off with its first engine, and so an Antoinette 8V was fitted instead.

On 13 September 1906 at the Bois de Boulogne, Quatorze-bis was just able to take off, and it flew for around 5 metres (16 feet) and reached a dizzying altitude of 70 cm (28 in). Many still claim that this was the world’s first true powered flight, as the aircraft took off and landed on its own undercarriage wheels, whereas the Wright Flyer took off from a launch rail, leaving a wheeled dolly on the ground.

This beauty of an engine was definitely the first to power an aeroplane flight in Britain, though, and this happened at Farnborough in 1908. But it was still too heavy for its limited power.

At this point we should briefly consider the arguments between air and water cooling, a battle between wind and water which was later epitomised by the competition between the Bristol Hercules air-cooled radial engines and the Rolls-Royce Merlin water-cooled engines of the Second World War. As we know, internal combustion engines have a vast amount of waste heat to dispose of, particularly from inside the cylinder head where most of that combustion is happening. For a small single-cylindered motorbike engine, simple cooling fins all around the cylinder and head will suffice, as you can check yourself the next time you see a suitable bike parked up.

Weight is the first consideration for aero-engine designers, and so it is natural for them to be attracted to air for cooling; after all it is cheap, light and easily obtainable. The fact that you need four thousand times more air volume than water volume to remove the same amount of heat doesn’t matter: you can suck it up and eject it as you fly along. You will be carrying less weight around if you let air do the cooling.

There were other advantages of air cooling that soon became apparent as the nascent aero industry arose and the first decade of the century gave way to the second. Although the first aero engines were water-cooled, the most popular early aero engines were the air-cooled French Gnome rotary engines, designed and built by the French brothers Louis and Laurent Seguin. Based on a German single-cylinder design, their purpose-built aircraft engine had seven cylinders and produced the same 50 horsepower as the Antoinette 8V, but it weighed 44 lb (20 kg) less. It was launched in 1909 as the rotary Gnome Omega, and it was so utterly different from the V8 Antoinette that it is hard to believe that they shared anything at all in common.

For a start, instead of having stationary cylinders and a revolving crankshaft, the Gnome had a stationary crankshaft fixed to the aircraft, and the crankcase, cylinders and propeller all whirled around like a demented Catherine wheel. As a result the finned cylinders and cylinder heads were efficiently cooled by churning through the air. An amateur mechanic examining a Gnome rotary for the first time might be foxed by seeing only a single exhaust valve at the top of each cylinder. Where was the inlet? The secret was that the inlet valve was hidden in the crown of the piston, and the fuel and air mixture was inhaled through the hollow crankshaft into the crankcase and up through this valve. The Gnome was delicately made – each cylinder barrel had a wall thickness of only 1.5 mm – and yet it had been machined out of a solid steel billet, fins and all; a huge machining job. Like the Wright Flyer’s engine,† the Gnome had no throttle, and if the pilot wanted fewer horses all he could do was to switch the ignition off with a joystick-mounted control. The torque reversals produced by this technique exerted terrific strains on the aircraft.

These rotaries dominated the early aviation scene partly because they were light, and this was a by-product of the circumferential layout of the cylinders, which saved a lot of crankcase weight. They were also smooth-running, well balanced, and suffered no vibration. Vibrating engines quite literally shook those early aircraft apart. Watching a vibratory engine running on the ground is quite a sight; the whole machine seems to be a blur.

There was a further advantage of the air-cooled engine: in wartime a bullet or piece of shrapnel might break off a cooling fin without affecting the running, whereas if a water jacket, pipeline or radiator was punctured it would stop the engine in minutes. They were so popular that more than 1,700 Gnomes were built across Europe.

These rotary engines were memorable in many ways. Apart from all the ironmongery spinning around, which would disconcert a car-owner, the rotary also flung castor oil around in a half-burned spray. This stuff has the most delightful, evocative smell, but after breathing it in for a while pilots found they were attacked by violent diarrhoea, an affliction difficult to cope with at altitude in a cramped cockpit wearing tight-fitting breeches.

There were disadvantages of air cooling that emerged as the number of cylinders multiplied. The last cylinders in an in-line row would be shrouded by the others and wouldn’t feel enough of the cooling draught. They would start to grow too hot, and shortly afterwards a piston would seize inside a cylinder and the whole thing would then clank to a halt. There were disadvantages, too, of rotary engines. The weight of the whirling mass of metal resulted in gyroscopic precessions which had a dangerous effect on the aircraft’s manoeuvrability – imagine trying to steer a bicycle with a spinning flywheel attached to the handlebars. As rotary engines grew more powerful and heavier this effect became so pronounced that the aircraft fitted with them became almost unmanageable.

In 1908 Fiat in Italy produced its delectable SA8/75, a lightweight air-cooled V8 aiming at a specific power of 3.3 lb/hp and in fact achieving a 150 lb engine delivering 50 horsepower. This was a featherweight delight, with gearwheels like cobwebs, slender valve-rockers, and even a hollow camshaft to save vital weight. Sadly it suffered from overheating like so many in-line air-cooled engines, partly because the Fiat engineers insisted on discharging the hot exhaust gases into the cooling airflow. Renault also produced an air-cooled V8 of 80 hp and solved the overheating problem by the use of an excessively rich fuel mixture: the petrol literally cooled it from within. It was more reliable but inefficient.

The French were at the forefront of this new technology; the little 20 hp Anzani that Blériot used to cross the English Channel in 1909 was built in Paris. The British were next to get in on the act, with Gustavus Green designing a 60 hp aero engine. Germany was relatively slow to get going, but then ran national competitions which were successful in producing good designs. On the Kaiser’s birthday in 1912 it was announced that he was to award a prize for the best German aero engine, and this was won by a Mercedes engine which embodied a construction technique they had copied from a French Panhard engine of 1903 and the Antoinette 8V. It consisted of separate steel cylinders surrounded by welded-on cooling water jackets, and the engine was upside down, with inverted cylinders hanging below the crankcase.

Other European nations realised the importance of the new prime mover and hundreds of companies started making internal combustion piston engines of all configurations. All at once the steam engine looked heavy, dirty and outmoded.

Why did modern science arise in Europe? What was it about Europe that made the pace of progress so furious? How, for example, did powered flight advance from the Wright Flyer to the Spitfire in just 30 years? The answer goes back to Galileo. Modern science developed at the time of Galileo in the late Renaissance, namely the application of hypotheses to Nature, the use of the experimental method and the acceptance of a mechanical model of reality. Hypotheses of the medieval past tended to be vague (‘God created everything’) and numbers were manipulated in number mysticism a priori instead of being used to measure experiments a posteriori. For all his inventive genius, Leonardo da Vinci still lived in the old world, but by his mathematisation of hypotheses about the universe Galileo broke through the walls and shaped a new world.

Europe was ready for it. The Enlightenment incorporated science and reason, and these intellectual shifts made the British culture, in particular, receptive to new mechanical and financial inventions. The first Industrial Revolution began in Britain with textile spinning, steam power, iron making and machine tools at the forefront, all capitalised by central banks and stock markets and protected by patents until this small island off the coast of Europe was so wealthy that it acquired the largest empire the world had ever seen. Once the northern cities where the wealth was generated echoed with the tramp of thousands of boots into the mills and factories every morning, and streets were lined with fine new stone buildings along the Mersey, the Clyde and the Tyne. Now those same mills stand empty with the eyeless gaze of smashed panes, and charity shops line the streets where once they stamped ‘Made in England’.

The second Industrial Revolution at the beginning of the twentieth century is our subject: mass production on assembly lines, new steel-making processes, the rise of the internal combustion engine and the invention of cars and aircraft. Intense competition arose in Belgium, Germany and France, and they raced to industrialise at the same pace. Some prophesied war. The stage is now set for the birth of an extraordinary company: Rolls-Royce, the maker of the Merlin.

* In the same year the daughter of the owner of the Daimler Motors corporation gave her name to the cars: Mercedes. Hitler perhaps never realised that his favourite Mercedes-Benz parade car was named after the granddaughter of a rabbi.

† The Wrights didn’t fit a throttle to their engines until 1913. A butterfly throttle restricts the air/fuel mixture to the cylinders, and is usually a centrally pivoted metal disc that allows the mixture to flow to the cylinders.

Chapter Five

When Mr Rolls met Mr Royce

Charles Stewart Rolls at the wheel, circa 1905. ‘Charlie Rolls was the strangest of men and one of the most loveable.’ (Hulton Archive/Getty Images)

Rolls-Royce is perhaps the most prestigious manufacturer’s name of all. The genius of Henry Royce and the flair of Charles Rolls together with their determination to make the best car in the world resulted in the immortal 40/50 Silver Ghost, whose engine led them on to the manufacture of aircraft engines. That expertise led to the subject of this book, the Rolls-Royce Merlin.

There have been many books written about Rolls-Royce over the years, at least 100 or so about the cars or aero engines or both, and dozens that devote thousands of words to biographies of the leading personalities. But few seem to get to the nub of the matter: what exactly was so special about this company and its products?

I have great respect for the old British engineers. I can just remember them, serious men of the middle class, adept with micrometer and slide rule. Often classically schooled, they named their companies Acme, Invicta, Phoenix, Vulcan. They may have done this because they were looked down upon by the literary and administrative elite as being ‘trade’ (compare that with the situation in Germany, where a fully trained engineer earned the right to the honorific ‘Doktor’). The corrosive effect of Britain’s old caste system held back our finest scientists and engineers, as C. P. Snow, a chemist and novelist, lamented in The Two Cultures and the Scientific Revolution.1 Victorian schooling had overemphasised the humanities in the form of Latin and Greek at the expense of scientific education.

Alan Turing’s wartime work at Bletchley Park on computing led him to crack German Navy Enigma machine codes, and he is now regarded as the father of theoretical computer science and artificial intelligence. However, he struggled to be accepted at Sherborne, his public school. His headmaster wrote: ‘If he is to stay at Public School, he must aim at becoming educated. If he is to be solely a Scientific Specialist, he is wasting his time at a Public School.’2

For this ignorant attitude we can probably thank Thomas Arnold, the headmaster of Rugby school and an immensely influential educationalist, who wrote:

rather than have [physical science] the principal thing in my son’s mind, I would gladly have him think that the sun went round the earth, and that the stars were so many spangles set in the bright blue firmament. Surely the one thing needful for a Christian and an Englishman to study is Christian and moral and political philosophy.3

This medieval outlook led to the British political and administrative elites being deprived of vital preparation for managing the scientific world, as we will see in that most scientific of wars: the Second World War.

And Rolls-Royce was the most scientific of British engineering companies.

When Mr Rolls met Mr Royce they each found the man the other had been looking for. The story of how they met is a locus classicus in the history books, on hotel plaques and over 11,000 webpages: how electrical engineer Henry Edmunds accompanied Charles Rolls to Manchester on a train with a dining car on the morning of 4 May 1904. They got off the train and met Henry Royce in the Midland Hotel. Manchester tour guides still stand outside the Midland Hotel, point to the two plaques and repeat this story: ‘Here’s where Rolls met Royce.’ And every year on 4 May Rolls-Royce enthusiasts celebrate the event at the hotel.

But it isn’t true. What Edmunds actually wrote was this: ‘I remember we went to the Great Central Hotel at Manchester and lunched together. I think both men took to each other at first sight, and they eagerly discussed the prospects and requirements of the motor industry which was then in its earliest infancy.’

There was no Great Central Hotel in Manchester. Neither Rolls nor Royce mentioned the meeting. And the assumption of historians has been that the men left the train at the Central Station and walked into the hotel next door, which Edmunds must have mistakenly called ‘the Great Central’. However, as the author Ed Glinert points out, there was no train with a dining car arriving in time for lunch that week that stopped at Central Station. The only such train they could have caught was one that stopped at London Road (now Piccadilly) Station, which was the Great Central Railway’s Manchester headquarters, not Central Station. Glinert writes:

I consulted Kelly’s Post Office Directory for 1904. First, I verified that under ‘Hotels’ there was no Great Central Hotel. Then I turned to the entries for the surrounding streets. Under ‘London Road’ there was the usual Edwardian paraphernalia – tobacconist, blacksmith, draper, ostler, French polisher – then there was the entry for ‘London Road station’, an entrance from the street below the station, and right bang next door ‘the Great Central Refreshment Rooms’ – just the kind of smart, no nonsense place two hungry men, with no time to waste, might meet a third to do a bit of business.4