History Podcasts

Neville Barnes Wallis

Neville Barnes Wallis

Neville Barnes Wallis, the son of a doctor, was born in Ripley, Derbyshire, on 26th October, 1887. After leaving school at sixteen he started work in a shipyard on the Thames. In 1908 he transferred to a shipyard in Cowed and began designing ships.

In 1919 Wallis was recruited by Vickers to design airships. Together with his longtime friend, H. B. Pratt, he designed the R.9, the R23 and the R.26. He was also chief engineer on the R.80. Unlike the traditional Zeppelin, this airship had a streamlined look. However, in 1921, the Chief of Air Staff decided to bring an end to building airships.

Vickers continued to feel that airships had commercial potential and in 1924 Wallis was commissioned to produce the R.100. It was larger than any other airship built and did not make its maiden flight to Canada until 1930. Later that year the R.101 crashed killing 48 members of its crew. Airships were now considered too dangerous and the project came to an end.

Wallis was now given the task of designing planes. This included the Wellesley that went on to set a non-stop distance record of 7,158 miles in 1938.

With the threat of war Wallis began work on the Wellington Bomber. One novel feature of the Wellington was a vast coil that could be used to detonate magnetic mines safely from the air.

Wallis designed the bouncing bombs that were used by Guy Gibson and the 617 Squadron to successfully breach the Mohne and Eder dams in the Ruhr during the Dambusters Raid on 16th May 1943. The rotating bouncing bomb skipped over the water and exploded while sinking to the base of the retaining wall of the dam. It produced heavy floods and badly damaged German production in the Ruhr.

When the decision was taken to concentrate on area bombing Wallis began looking at the design of bombers that could drop heavy bombs. The adapted Avro Lancaster was able to drop two bombs developed by Wallis, Tallboy (1944) and Grand Slam (1945).

After the war Barnes was chief of aeronautical research and development at the British Aircraft Corporation at Weybridge (1945-71). However, several of his projects, including a cargo submarine, were not built.

Neville Barnes Wallis died at Leatherhead on 30th October, 1979.


Some Links to Web Sites about Sir Barnes Neville Wallis

Christopher Wallis was the fourth and youngest child of Sir Barnes Neville Wallis. Christopher's character, determination, and inventive skills must owe a great deal to his father, but Christopher was always disappointed that Sir Barnes was mainly known for his work on bombs, including of course, the bouncing bombs of the Dambusters.
His early working life had been in designing ships and airships, including the R100 built with his Geodetic structure technique, also used in many aircraft such as the Wellington.
His later working life (as Head of R&D for Vickers-Armstrong) took him to supersonic transport, swing-wing aircraft, and a whole variety of other technologies, now accepted as part of the modern world.


Credit © Science Museum / Science & Society Picture Library - All rights reserved.

This 1965 photo shows Sir Barnes Wallis with reminders from many aspects of his inventive career.

Sir Barnes was born in 1887, did not retire until 1971, and died in 1979, eight years after work started on Lacey Green windmill. He would therefore have been well aware of the scheme to save the windmill that his younger son had embarked upon, at the age of 36.
I have therefore compiled a list of some web sites where you can read about Sir Barnes Neville Wallis, so you can hopefully find out more about the variety of projects in which he was involved.
Inevitably, since first compiling this list in 2006, some have disappeared, so they have either been removed from this list, or marked: [not now available]
The following are in no particular order (but if you only look at one, then I recommend the first on the list):
(all the links on this page are set to open in new windows or tabs)

Iain Murray is a lecturer at Dundee University, and one of his heroes is Sir Barnes Wallis. His website on Barnes Wallis is now under its own domain, and contains an amazing amount of information on all aspects of the work of Sir Barnes Wallis. It also includes an incredibly compehensive list of places where you can read about or find items associated with Barnes Wallis. Iain Murray deserves congratulations on his vast website. (www.sirbarneswallis.com)

This was established in 2014, replacing the Barnes Wallis Memorial Trust which had been founded in 1986. They aim to inspire, inform, and educate people about the work and achievements of Sir Barnes Wallis. Amongst its trustees are Christopher Wallis's sister (Mary) and son (Humphrey). (www.barneswallisfoundation.co.uk)

The Surrey Village where Sir Barnes Wallis lived. (www.effingham.co.uk) [not now available]

Some history starting with Sir Barnes Wallis's birthplace at Ripley in Derbyshire. (www.rocassoc.org.uk/open/items/gr08/barnes_wallis.htm)

Images from the Science Museum Library, many showing Sir Barnes Wallis's study (In Feb 2018 there were 19 images available. From Home Page search for: Sir Barnes Wallis (www.scienceandsociety.co.uk)

Brief History of Sir Barnes Wallis's work. (www.bbc.co.uk/history/historic_figures/wallis_neville_barnes.shtml)

Wikipedia article on Barnes Wallis. (https://en.wikipedia.org/wiki/Barnes_Wallis)

Biography Online article on Barnes Wallis. (https://www.biographyonline.net/military/barnes-wallis.html)

The Famous People article on Barnes Wallis. (https://www.thefamouspeople.com/profiles/barnes-wallis-6442.php)

It is probably easier to read this as the pdf version, available underneath the photo of Barnes Wallis

Images of Sir Barnes Wallis at the National Portrait Gallery. (https://www.npg.org.uk/collections/search/person/sir-barnes-neville-wallis)

Lucy Moorcraft's Project on Barnes Wallis

A 2001 project from a Bristol University undergraduate (www.chm.bris.ac.uk/webprojects2001/moorcraft/Barnes Wallis.htm) [not now available]

This page ( SirBNW.php ) was last updated on 15 February 2018.

The Chiltern Society is a Registered Charity No 1085163 and a Company Limited by Guarantee Registered in England and Wales Registration No 4138448.


Biography of Barnes Wallis

A British aeronautical designer and military engineer, best known for developing the “Bouncing Bomb” used by the Royal Air Force in Operation Chastise during World War II Barnes Wallis was born on 26 th September 1887 in Ripley, Derbyshire, England to Charles Wallis and Edith Ashby. Among his other inventions was his version of the geodetic airframe and the earthquake bomb.

Trained as a marine engineer, Barnes Wallis soon found his real calling in the aviation industry. After a stint as a marine engineer, he switched to designing airships and engaged himself in aircraft development for Vickers. He played a crucial role in the development of the R100, the largest airship ever designed then. Following aircraft designing, Wallis concentrated his energy on bomb designing. He realized that the best way to destroy Nazi Germany’s ability to wage war is through bombing. Wallis came up with the plan of the Dambuster raid that served the purpose with less risk of causalities. For the same, Wallis invented a bouncing bomb that attacked the dam walls of the Ruhr valley, disrupting German factories and their hydro-electric power. Though the bombing did not cause much physical damage, it indeed damaged the German forces psychologically. Throughout the latter life, Wallis engaged himself in aeronautical research.

Childhood, Family and Educational Life

Barnes Wallis, in full Sir Barnes Neville Wallis, was born on September 26, 1887, in Ripley, Derbyshire, England to Charles William George Robinson Wallis (1859-1945) and his wife Edith Eyre Wallis née Ashby (1859-1911). He was the second of the four children born to the couple. His father was a doctor who moved his family to London when Wallis was two years old.

Barnes Wallis was educated at Christ’s Hospital in Horsham and Haberdashers’ Aske’s Hatcham Boys’ Grammar School in southeast London. At the school, Wallis developed an affinity for mathematics and science and decided to become an engineer. He left school at the age of 17 to work at an engineering company at Blackheath, London in 1905. He subsequently changed his apprenticeship to J. Samuel White’s, the shipbuilders based at Cowes on the Isle of Wight. He originally trained as a marine engineer.

In 1922, Wallis obtained a degree in engineering via an external program at the University of London.

Personal Life

Barnes Wallis met his cousin-in-law, Molly Bloxam, at a family tea party, in April 1922. She was 17 and he was 34, and her father forbade them from courting. They were married on 23 rd April 1925 and remained so for 54 years until his death in 1979.

The couple was blessed with four children: Barnes (1926-2008), Mary (1927-2019), Elisabeth (b. 1933) and Christopher (1935-2006), and also adopted Molly’s sister’s children when their parents were killed in an air raid.

For 49 years, from 1930 until his death, Wallis lived with his family in Effingham, Surrey, and he is now buried at the local St. Lawrence Church together with his wife. His epitaph in Latin reads “Spernit Humum Fugiente Penna” (Severed from the earth with fleeting wing).

Career and Works

At the age of 17 Barnes Wallis leave school to start work in January 1905 at Thames Engineering Works at Blackheath, southeast London. He subsequently changed his apprenticeship to J. Samuel White’s, the shipbuilders based at Cowes on the Isle of Wight. Wallis trained as a marine engineer before joining the airship (dirigible) department of Vickers Ltd. in 1913 as a designer. Eventually turning to aircraft, he employed his geodetic system in the Royal Air Force’s (RAF’s) Wellington bomber in World War II. His researches into detonation effects led to his inventing the rotating bouncing bomb that, when dropped from an aircraft, skipped over the water and exploded while sinking to the base of the retaining wall of a dam. This type of bomb, used during World War II by the RAF on the Möhne and Eder dams in Germany’s industrial Ruhr area, produced heavy floods that slowed industrial production.

During 1920-30s Wallis was an active designer and designed many prominent aircraft models such as the R100 spaceship. His major breakthrough, however, came during World War II when he developed what came to be known as the “Bouncing Bomb”. He also pioneered, along with John Edwin Temple, the use of light alloy and production engineering in the structural design of the R100. Nevil Shute Norway was the chief calculator for the project, responsible for calculating the stresses on the frame.

Meanwhile, in 1922, Wallis took a degree in engineering via the University of London External Programme. When World War I broke out, Wallis was briefly unemployed as Admiralty refused to expend money on airship development. He decided to serve the army but was recalled by Vicker’s airship development team.

Barnes Wallis developed a special kind of bomb that would be powerful enough to break the concrete structure of the dams. It would have to be dropped from a very low height and once dropped, it was specially programmed to defuse only after sinking to a certain depth within the water and not on immediate contact with the surface. The testing phase was conducted using a swimming pool and a scaled down bomb. The next tests were secretly conducted at the beaches of Kent, which were initially unsuccessful. After some setbacks, it was deemed viable and granted final approval.

Wallis moved to the Vickers aircraft factory at Brooklands. Therein, his geodetic design was employed in all the pre-war aircraft designs of Wellesley, Wellington, and Warwick in fuselage and wing structure. When the Second World War broke out, Wallis was appointed as the assistant chief designer at Vicker’s aviation section. He soon realized the need for the strategic bombing to cripple the enemy’s ability to start the war. For the same, he penned a paper, ‘A Note on a Method of Attacking Axis Power’.

Wallis produced not only the dambuster bombs but also the 12,000-pound “Tallboy” and the 22,000-pound “Grand Slam” bombs. He was also responsible for the bombs that destroyed the German warship Tirpitz, the V-rocket sites, and much of Germany’s railway system. Wallis was chief of aeronautical research and development at the British Aircraft Corporation at Weybridge, Surrey, from 1945 to 1971.

Early in 1942, Wallis began experimenting with skipping marbles over water tanks in his garden, leading to his April 1942 paper “Spherical Bomb-Surface Torpedo”. The idea was that a bomb could skip over the water surface, avoiding torpedo nets, and sink directly next to a battleship or dam wall as a depth charge, with the surrounding water concentrating the force of the explosion on the target.

The bomb was codenamed “Upkeep” and the mission itself was called the “Dambusters Raid”. It took place on the night of 16th and 17th May 1943 and was conducted by a special squadron of the Royal Air Force. It caused massive damage to two dams and caused immense flooding in the area. Although industrial facilities were not as affected as anticipated by Wallis, and several of the bombers were lost, the mission has declared a success because of the panic it caused amongst the Germans and the confidence it brought to the Allied Forces. Some of his other prominent designs include the “Tallboy bomb” and the “Wellington bomber”.

Following the success of the bouncing bomb, Wallis came up with ‘Tallboy’ and ‘Grand Slam’ bomb. While the former weighed 6 tonnes, the latter was 10 tonnes. They were used on strategic targets such as V-2 rocket launch sites, submarine pens, large civil constructions and the German battleship Tirpitz. At the end of Second World War, Wallis returned to Brooklands as Head of the Vickers-Armstrongs Research & Development Department. He dedicated his latter half of the career in designing futuristic aerospace projects such as swing-wing technology, supersonic flight and so on.

In the 1950s, Wallis developed an experimental rocket-propelled torpedo codenamed HEYDAY. It was powered by compressed air and hydrogen peroxide and had an unusual streamlined shape designed to maintain laminar flow over much of its length. He designed non-misting glassless mirror made out of non-flammable and unbreakable polyester. Tests were conducted from Portland Breakwater in Dorset. The only surviving example is on display in an Explosion! Museum of Naval Firepower at Gosport. He acted as a consultant for the building of the Parkes Radio Telescope in Australia, in 1955.

Barnes Wallis also proposed using large cargo submarines to transport oil and other goods, thus avoiding surface weather conditions, in the 1960s. He also proposed a novel hull structure which would have allowed greater depths to be reached, and the use of gas turbine engines in a submarine, using liquid oxygen. In the end, nothing came of Wallis’s submarine ideas. During the 1960s and into his retirement, he developed ideas for an “all-speed” aircraft, capable of efficient flight at all speed ranges from subsonic to hypersonic. Wallis continued to innovate even after the end of the war, including a design for a mist proof glassless mirror.

In 1971 Wallis designed an aircraft that could fly five times the speed of sound and needed a runway only 300 yards (275 meters) long however, it was never built.

Awards and Honor

Barnes Wallis became a Fellow of the Royal Society in 1945 and was knighted in 1968. Wallis also received an Honorary Doctorate from Heriot-Watt University in 1969.

Wallis was awarded the sum of £10,000 for his war work from the Royal Commission on Awards to Inventors.

Death and Legacy

Barnes Wallis breathed his last on 30 th October 1979, in Effingham, Surrey, England at the age of 92. He was buried at the local St Lawrence Church. Other than the official funeral, a memorial service was held in his honor a year after his death at St. Paul’s Cathedral.

The highpoint of Wallis’ career came with the invention of the bouncing bomb, named Upkeep, which was used by Royal Air Force, during the Dambuster raid of May 1943. Named Operation Chastise, Wallis’ bouncing bomb was used to attack the dam of Mohne, Eder, and Sorpe in the Ruhr area during World War II. He believed that by breaching the dam wall they would destroy Nazi Germany’s industrial base and thus disrupt the latter’s war schemes.

His grief at the loss of so many airmen in the dams raid was such that Wallis donated the entire sum to his alma mater Christ’s Hospital School in 1951 to allow them to set up the RAF Foundationers’ Trust, allowing the children of RAF personnel killed or injured in action to attend the school.

For his remarkable contribution as an inventor and engineer, Barnes Wallis has been commemorated vastly. He has public houses named after him. Furthermore, a building in Nottingham Trent University bears his name. His statues, busts, and plaques adorn numerous sites across the globe. The Yorkshire Air Museum has a permanent display of the Dambusters raid. It comprises of a replica bouncing bomb and the catapult used to skim stones to test the bouncing bomb theory. To keep the visitors well-informed, a brief history of Wallis’ work is also displayed. There are roads, drives, and squares named after Barnes Wallis. He has been the fictional character of several books. Interestingly, in golf, a shot that bounces over the surface of a water hazard has been named Barnes Wallis.


Barnes, Neville Wallis.

An English scientist, engineer and inventor. He is best known for inventing the bouncing bomb used by the Royal Air Force in Operation Chastise, the "Dambusters" raid.

26-09-1987, Ripley, Derbyshire.

30-10-1979, old age 92, Effingham, sussex.

- Buried

Cemetery of St Lawrence Churchyard, Effingham, Surrey.

- Medals

Barnes, Neville Wallis, born on 26-09-1887 in Ripley in Derbyshire. When aged two, his father’s work as a doctor took him to London where the family moved to New Cross Road. Both Barnes and his eldest brother John spent many hours in a workshop in their house making whatever they could – including paper toys for their sister Annie. Wallis was educated at Christ’s Hospital in Horsham, West Sussex. Here he built on his talent for Mathematics and Science and by the time he had finished at Christ’s, Wallis had determined that he would become an engineer. His first job was working for Thames Engineering Works – a firm that made ship engines. In 1908, he moved to the John Samuel White’s shipyard in the Isle of Wight. In 1913, he joined Vickers – a company that was to become synonymous with airship and aircraft development. However, when the first war broke out, Wallis found himself unemployed as the Admiralty decided not to spend anymore money on airship development. He tried to join the Army but failed the eyesight test. He did pass another medical in a different section of the Army by memorizing the eye test chart – before the actual test! Just at this time, the Admiralty decided to reconvene Vicker’s airship development team and Wallis was recalled from the Army. Wallis was very much involved in the development of the R100 truck. When World War II broke out, Wallis believed that the quickest way to defeat Nazi Germany was to destroy its industrial base. Without factories, the Nazi war machine could not be supplied. The most important industrial area in Germany was the Ruhr. It was also very heavily defended by anti-aircraft guns and searchlights. A ‘normal’ bombing raid risked heavy casualties. Wallis developed in his mind a plan for a raid by a small, highly trained team of expert fliers, navigators, bombers etc who could fly so low that radar would not pick them up and hit, with pin-point accuracy, their target. In his mind, those targets should be the dams that held back the mighty waters of the Ruhr. If these dams were breached, the water would destroy anything in its path. Wallis, here with Guy Gibson set himself the task of designing a bomb so special that it would break up the reinforced concrete that made up the Ruhr dams. The bomb needed to be dropped at an exceptionally low height so that it hit a dam, did not explode but sank into the water. At a given depth, a fuse would break and the bomb would explode. The shock waves created by the bomb would be accentuated underwater and, Wallis believed, would be enough to destroy the dam. The first tests of the bomb were done in a large indoors pool with a scaled-down bomb. The experimental indoors tests were a success. When a life-size one was dropped under the greatest of secrecy in the waters off of the beaches of Kent, the first test was a failure (as were those that followed it) and MOD personnel remained skeptical about any success for the ‘bouncing bomb’ Wallis believed that the plane, which came in unusually low, was flying too high and asked the crew to fly in even lower for the next test. His gamble, and the crew’s piloting skills, worked – the bomb bounced and bounced so, in its imaginary situation, it would have cleared any nets that protected the dams in the Ruhr. In May 1943, the Dambuster Raid took place. 617 Squadron, commanded by Guy Gibson , VC, attacked the Ruhr Dams using the bomb invented by Barnes Wallis. The actual physical impact of the raid will always be open to debate. The huge psychological impact of the raid, however, can never be doubted. Wallis, however, expressed his view that the raid, having cost eight Lancaster bomber crews out of nineteen, may not have been worth the losses. Wallis also invented the ‘Tallboy’ bomb that was used to penetrate the U-boat pens on the west coast of France. He also developed one of the mainstays of Bomber Command – the Wellington bomber, used so often in bombing raids over Nazi Germany. Wallis continued inventing things after the war. He invented a glass less mirror that did not mist up – and put forward ideas for swing-wing planes.

Framework of a Barnes Wallis airship under construction, c 1920s.

Your Easy-access (EZA) account allows those in your organization to download content for the following uses:

  • Tests
  • Samples
  • Composites
  • Layouts
  • Rough cuts
  • Preliminary edits

It overrides the standard online composite license for still images and video on the Getty Images website. The EZA account is not a license. In order to finalize your project with the material you downloaded from your EZA account, you need to secure a license. Without a license, no further use can be made, such as:

  • focus group presentations
  • external presentations
  • final materials distributed inside your organization
  • any materials distributed outside your organization
  • any materials distributed to the public (such as advertising, marketing)

Because collections are continually updated, Getty Images cannot guarantee that any particular item will be available until time of licensing. Please carefully review any restrictions accompanying the Licensed Material on the Getty Images website, and contact your Getty Images representative if you have a question about them. Your EZA account will remain in place for a year. Your Getty Images representative will discuss a renewal with you.

By clicking the Download button, you accept the responsibility for using unreleased content (including obtaining any clearances required for your use) and agree to abide by any restrictions.


Unsung boffin's secret wartime base in county by Giles Rees

I started visiting the Welsh border area in the mid-1980s, an exercise in visiting the ancient home of the Whitneys at Whitney-on-Wye, Herefordshire. Several years later, Mary Ann and I rediscovered Nevil Shute ("On the Beach" was required reading for us in the Cold War years of the late 1950s in the USA). However, only recently, did we learn of a connection between Barnes Wallis, Shute's senior on the R100 project, and the Welsh border area we've been enjoying for almost 25 years.

From an article in the Hereford Times, 14 September 1984:

In the old grounds of a Herefordshire country house two squat, apparently unexceptional bungalows are up for sale. Built before the war, moss has settled on their roofs and the paint of their white-washed exteriors is peeling. Tomcats prowl at dusk in the shadow of the crumbling water tower which used to service the properties.

When you push open the front doors a tiny flurry of moths escapes. Inside, the rooms are empty and cool and in the case of "Longhills," the first bungalow well proportioned. You expect the same to be true of "Castleton," the second - there is a little community of four or five altogether - especially with its carefully tended gardens.

It is not. "Castleton" is the joker in the pack. Irregular wall patterns tend to shut out the light, and long, narrow, gloomy rooms with off-centre windows betray an institutional almost chamber-like construction. A vast double garage comprising half the building seems strangely top heavy and outside again you might begin to notice how ranks and tangles of trees shelter, almost conceal, the spot.

The house is Winforton House, Winforton, in West Herefordshire. The "bungalows" are the former Herefordshire headquarters and laboratory of probably wartime Britain's most important and least known scientist: Sir Thomas Merton KBE. On the old Ordnance Survey maps they are referred to as "The Laboratories".

Until now the facts of the extraordinary life of this MI5 scientist, gifted inventor, art connoisseur and friend of the likes of Churchill and Barnes-Wallis, have either remained undisclosed or have been gathering dust on the bookshelves of specialist libraries.

As the anniversary of The Battle of Britain passes, how many people realize that it was a Herefordshire man whose inventions helped engineer eventual victory? And most military experts agree that had the Battle of Britain been lost, a Nazi invasion of mainland Britain in 1940 would have been little more than a formality.

Perhaps it is in keeping with Merton's elusive character, that he has been left out in the cold, while his peers have basked in the glow of their own cathode rays and become household names. In 1923 a wealthy Oxford professor, Dr Thomas Ralph Merton FRS bought the Winforton Estate, Herefordshire. The estate included Winforton House and a three mile stretch of salmon fishing on the Wye, to which he soon added his own private laboratory in the house's grounds, "camouflaged" by the little village of servants' bungalows that surrounded it.

Though his major achievements were yet to come, Merton had already distinguished himself in the First World War - in MI5. Asked personally to join by General Sir Frederick Browning, Merton was the first scientist ever employed in the Secret Service and operational, under Commander Cummings "C", he first cracked the secret writing used by German spies and then himself invented a new secret coding for British agents.

Merton's inventive genius might have remained largely hidden had it not been again called into action with the approach of World War II. And it was a lab at the bottom of a Winforton back garden (admittedly a rather grand one) which was the womb for four major inventions that contributed so much to the defence of Britain, and for which Merton has received so little public recognition. When Merton was at work, the lab was strictly forbidden territory for all but his assistant Frederick Morris. But Margaret Holland, head housemaid at Winforton 1935-41, and John Evans, whose father was Merton's chauffeur, couldn't resist snatching a look. "Castleton" then had its own darkroom, red tiled floors, tables and desks, and was littered with bits of metal and machinery. John remembers watching Morris - a tall, thin, silent man - glassblowing.

It was in this lab, "somewhere in Herefordshire", that Merton, a member of the Air Defence of Great Britain Committee, originated the long persistence radar screen which helped save the country in The Battle of Britain. Characteristically he has received little credit for this because a year later someone else came up with the same idea - and won the patent.

Later Merton discovered that by using a special gas the speed of fighter aircraft in battle could be accelerated by 45 mph - a tremendous increase for the planes of the day. With the aid of his friend Sir Stafford Cripps, it was adopted and the discovery came just in time to counter Hitler's flying bombs, the "doodlebugs."

There is something of the mythical garret boffin about Thomas Merton as a schoolboy he had a fully equipped lab at home. And his range finding device which enabled fighter pilots to find the optimum distance for destroying flying bombs - not too close to be blown to smithereens and not too far away to be innocuous - shows this more than most.

Appointed chairman of the committee whose brief was to scientifically combat the flying bomb Merton produced the diffraction range finder in his Winforton lab, in only 24 hours. He later referred to it as a "simple device."

Simple or not Sir Thomas' "device" repelled the "doodlebugs." The record bag was on August 24 1944 when out of 101 flying bombs approaching the English coast, 97 were brought down.

Merton was also responsible for a black paint reducing the light reflected from bombers in a searchlight, to less that one per cent. Again with total humility Merton said: "This was after some opposition, adopted and must have saved a good many lives."

Before and during the war, Winforton House became a great centre for the Mertons many scientific friends and a rendezvous for the leading figures of the age. In 1935 a certain gentleman name of Winston Churchill and his wife, come to Winforton. Merton's eldest son John painted a portrait of Sarah Churchill while the inventor and future Prime Minister shot game in Winforton Woods. Secluded and comfortable, scientists Knights including Harold Hartley, Henry Tizard, Ronald Ross and Alfred Egerton, and Lords Cherwell, Berkeley and Rayleigh all came to Winforton to relax - and work.

Margaret Holland says: "Ostensibly they came to shoot grouse - that was the cover. But they were here for the laboratory as well."

One particular scene sticks in her mind, that of the scientists mulling around and talking to each other in the middle of the huge Winforton lawn, where saplings have now taken root. Even on the coldest of days they would meet and converse there rather than in the house.

She recalls in her puzzlement questioning the butler about this. "Walls have ears," he loftily replied.

The real importance of the friendships Merton was forming became apparent when he was drafted in to advise various government ministries after the outbreak of war. . Not only had the help of his influential friends enabled Merton to force through his own ideas for the good of the country, but now he could become the champion of others, in the face of bureaucratic suspicion and resistance.

As chairman of the Tribunal of Scientific Advisers to the Ministry of Supply, Merton was overseer of all inventions that came before it, and as such, an anonymous but key figure behind the development of the war's most glamorous invention the bouncing bomb.

Week after week in 1942, Merton met Neville Barnes Wallis in London, and a close bond developed between the two.

Twice Barnes-Wallis attended preliminary testing of the bouncing bomb including the dropping of dummy bombs, at a Welsh dam which resembled the Mohne - the Ruhr dam in Germany which was one of the ultimate targets. But here the records become temporarily rather thin.

Why does Barnes Wallis' biographer vaguely tell us the dam is one Nant-y-Gro, Wales? And even more remarkable, why did Ministry of Defence experts give a reference for this "dam" which was a wooded slope in south-west Wales? Nant-y-Gro is in fact a tiny riverlet feeding the giant Caban Coch reservoir in the Elan Valley, where initial testing of the bouncing bomb took place in 1942.

Still, given the closeness of his Herefordshire home, his position on the tribunal, and his friendship with Wallis, Merton would almost certainly have been present at the testing. John Evans well remembers his father returning home at all hours after driving Merton on "missions".

When questioned by his young son, the chauffeur would give away nothing. This complies with orders given by Barnes-Wallis at the time, who became paranoid at the possibility of German agents discovering his plans he even had the Secret Service investigate one of his own colleagues. But Wallis' fears were justified after a secret midnight swoop on a pub in the Usk village of Llangynidr had captured two enemy spies posing as an English army officer and his manservant. They had been staying at the pub - only 40 miles from the testing location - and were transmitting information to a source in Surrey, under cover of library books.

The pensive mood of the time was reinforced with the knowledge that Hitler's deputy Rudolf Hess, was incarcerated in a former asylum near Abergavenny - only a few miles away.

Throughout his detention, Hess believed that a plot was being conceived to take him back to his Fuhrer. In October 1945 he did indeed fly back to Germany on a De Haviland Rapide from the RAF airfield at Madley. But it was to Nuremberg and the Nazi war crime trials.

It might be said that the bouncing bomb had a suitably explosive birth. Bitter personal feuding between Wallis and other scientists led to an almighty showdown. After a flaming row with the Vickers boss who wanted him "off the case," Wallis went to Merton for consolation.

Only now did Merton realize the strength of the "enemy within" and begin to draw upon the resources of the alliances he had formed. He was a key figure in a scientific elite who fought to keep Wallis' plans alive. Ultimately Merton could have gone to the War Cabinet, or Churchill himself but had no need when Air Marshall Sir Arthur "Bomber" Harris came over to his camp - and the project survived.

As for the rest, all is pretty well known and has been a staple ingredient in the diet of schoolboys since the smashing of the Mohne dam in May 1943. But perhaps in as the credits roll from now on, there will be a mention for the brilliant but retiring gentleman whose unremitting advocacy of the Wallis plans in the highest circles, alone brought them to realisation.

When he wasn't busy changing the course of world history, Thomas Merton was a member of the Wye Board of Conservators, a Justice of the Peace (sitting on the Bredwardine bench)and a vice-president of the Hereford and District Angling Association. In 1939 he caught the second largest salmon ever taken from the Wye naturally like all great catches records of the monster's weight vary from 54 to 63 lbs. Merton also became treasurer of The Royal Society for 17 years.

Merton acquired art as well as offices, and was one of the few private collectors in the world to own two Boticellis. Margaret Holland remembers only being allowed to give the painting a whisk over with the feather duster.

Mary Ann and I visited Mr. Weaver at the "Castleton" bungalow on Friday, 17 July 2009. Mr. Weaver purchased both "Castleton" and "Longhills" bungalows in 1984. His daughter resides in "Longhills". The bungalows are situated behind Winforton House, which was occupied by Professor Thomas Ralph Merton during the years when Barnes Wallis was conducting his experiments on the bouncing bomb. The main living quarters at "Castleton" occupy Merton's main laboratory area the garage and guest bedroom in the bungalow occupy the area where the water tanks used by Barnes Wallis in his experiments once resided. Mr. Weaver will be 80 years of age in three weeks.


19 March 1945

Pilot Officer P. Martin’s Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over the railway viaduct at Arnsberg, Germany, 19 March 1945. © IWM (CH 15735) The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. © IWM (CH 15374)

19 March 1945: Modified Avro Lancaster B Mk.I Special heavy bombers of No. 617 Squadron, Royal Air Force, attacked the railway viaduct at Arnsberg, Germany, using the 22,000 pound (9,979 kilogram) Grand Slam earth-penetrating bomb. The bomb had been first used just days before, 14 March, against another railway viaduct.

The Grand Slam was the largest and heaviest aerial bomb used during World War II. It was designed by aircraft engineer Barnes Neville Wallis, and was scaled up from his earlier, smaller “Tallboy.” (Wallis also designed the “Upkeep” Special Mine used to attack hydroelectric dams in the Ruhr Valley in 1943.)

The Grand Slam bomb dropped by Flying Officer Martin’s Avro Lancaster explodes underneath the railway viaduct at Arnsberg, Germany. Bomb craters from previous unsuccessful attacks are visible in this RAF photograph. © IWM (CH 15378)

Wallis’ idea was that a very heavy, supersonic bomb could penetrate deep into the earth and detonate, causing an “earthquake” which could destroy nearby heavily protected targets.

Tall Boy and Grand Slam Deep Penetration Bombs (British Explosive Ordnance, Part 1, Chapter 7)

The Grand Slam bomb (officially, “Bomb, D.P. , 22,000-lb., Mk I”) was 25 feet, 5 inches (7.747 meters) long and had a maximum diameter of 3 feet, 10 inches (1.168 meters). When fully loaded with the explosive material, Torpex, the bomb weighed 22,400 pounds (10,160 kilograms).

Completed bomb casings for Wallis’ smaller 12,000-pound “Tallboy” deep penetration bomb. The individual weight is stenciled on each casing. (Tyne & Wear Archives)

The bomb case was cast of steel at the Clyde Alloy and Steel Company, Glasgow, Scotland, then, after several days of cooling, machined to its precise shape. The casing made up approximately 60% of the bomb’s total weight. At the nose, the casing had a wall thickness of 7.75 inches (19.685 centimeters).

A “Bomb, Deep Penetration, 22,000 Pounds”—the Grand Slam—lifted by a crane at a Royal Air Force bomb dump. © IWM (CH 15369)

The bomb case was filled with approximately 9,200 pounds (4,173 kilograms) of molten Torpex, with a 1 inch (2.54 centimeters) topping of TNT. Torpex was an explosive designed for torpedo warheads and depth charges. It was made up of approximately equal quantities of two other explosives, Research Department Formula X (RDX), 42%, and trinitrotoluol (TNT), 40%, mixed with 18% powdered aluminum and wax. The resulting combination was approximately 1.4 times more powerful than TNT alone. About one month was required for the explosive to cool after being poured into the bomb case.

Because of its size and weight, the only Allied bomber capable of carrying the Grand Slam was a specially modified Avro Lancaster B.I Special, flown by No. 617 Squadron, Royal Air Force, “The Dambusters.”

Wallis intended for the Grand Slam to be dropped from very high altitudes so that during its fall, it would go supersonic. The bomb had large fins that were offset 5° to the right of the centerline to cause it to rotate for stability. However, the bombers could not carry it to the planned release altitude, and it was typically dropped from approximately 9,000 feet (2,743 meters). Its very sleek design did allow it to come close to the speed of sound, however, and its stability made it a very accurate weapon. The bomb was capable of penetrating 20-foot-thick (6 meters) reinforced concrete roofs of submarine bases. ¹

Arnsberg railway viaduct following Grand Slam bombing attack.

Barnes Neville Wallis, Esq., M. Inst. C.E., F.R.Ae.S., Assistant Chief Designer Vickers-Armstrongs Ltd., was appointed Commander of the Most Excellent Order of the British Empire (Civil Division), by His Majesty, King George VI, 2 June 1943.

Sir Barnes Neville Wallis C.B.E., was knighted by Her Majesty, Queen Elizabeth II, 13 December 1968.

Sir Barnes Neville Wallis C.B.E.


19 March 1945

Pilot Officer P. Martin’s Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over the railway viaduct at Arnsberg, Germany, 19 March 1945. © IWM (CH 15735) The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. © IWM (CH 15374)

19 March 1945: Modified Avro Lancaster B Mk.I Special heavy bombers of No. 617 Squadron, Royal Air Force, attacked the railway viaduct at Arnsberg, Germany, using the 22,000 pound (9,979 kilogram) Grand Slam earth-penetrating bomb. The bomb had been first used just days before, 14 March, against another railway viaduct.

The Grand Slam was the largest and heaviest aerial bomb used during World War II. It was designed by aircraft engineer Barnes Neville Wallis, and was scaled up from his earlier, smaller “Tallboy.” (Wallis also designed the “Upkeep” Special Mine used to attack hydroelectric dams in the Ruhr Valley in 1943.)

The Grand Slam bomb dropped by Flying Officer Martin’s Avro Lancaster explodes underneath the railway viaduct at Arnsberg, Germany. Bomb craters from previous unsuccessful attacks are visible in this RAF photograph. © IWM (CH 15378)

Wallis’ idea was that a very heavy, supersonic bomb could penetrate deep into the earth and detonate, causing an “earthquake” which could destroy nearby heavily protected targets.

Tall Boy and Grand Slam Deep Penetration Bombs (British Explosive Ordnance, Part 1, Chapter 7)

The Grand Slam bomb (officially, “Bomb, D.P. , 22,000-lb., Mk I”) was 25 feet, 5 inches (7.747 meters) long and had a maximum diameter of 3 feet, 10 inches (1.168 meters). When fully loaded with the explosive material, Torpex, the bomb weighed 22,400 pounds (10,160 kilograms).

Completed bomb casings for Wallis’ smaller 12,000-pound “Tallboy” deep penetration bomb. The individual weight is stenciled on each casing. (Tyne & Wear Archives)

The bomb case was cast of steel at the Clyde Alloy and Steel Company, Glasgow, Scotland, then, after several days of cooling, machined to its precise shape. The casing made up approximately 60% of the bomb’s total weight. At the nose, the casing had a wall thickness of 7.75 inches (19.685 centimeters).

A “Bomb, Deep Penetration, 22,000 Pounds”—the Grand Slam—lifted by a crane at a Royal Air Force bomb dump. © IWM (CH 15369)

The bomb case was filled with approximately 9,200 pounds (4,173 kilograms) of molten Torpex, with a 1 inch (2.54 centimeters) topping of TNT. Torpex was an explosive designed for torpedo warheads and depth charges. It was made up of approximately equal quantities of two other explosives, Research Department Formula X (RDX), 42%, and trinitrotoluol (TNT), 40%, mixed with 18% powdered aluminum and wax. The resulting combination was approximately 1.4 times more powerful than TNT alone. About one month was required for the explosive to cool after being poured into the bomb case.

Because of its size and weight, the only Allied bomber capable of carrying the Grand Slam was a specially modified Avro Lancaster B.I Special, flown by No. 617 Squadron, Royal Air Force, “The Dambusters.”

Wallis intended for the Grand Slam to be dropped from very high altitudes so that during its fall, it would go supersonic. The bomb had large fins that were offset 5° to the right of the centerline to cause it to rotate for stability. However, the bombers could not carry it to the planned release altitude, and it was typically dropped from approximately 9,000 feet (2,743 meters). Its very sleek design did allow it to come close to the speed of sound, however, and its stability made it a very accurate weapon. The bomb was capable of penetrating 20-foot-thick (6 meters) reinforced concrete roofs of submarine bases. ¹

Arnsberg railway viaduct following Grand Slam bombing attack.

Barnes Neville Wallis, Esq., M. Inst. C.E., F.R.Ae.S., Assistant Chief Designer Vickers-Armstrongs Ltd., was appointed Commander of the Most Excellent Order of the British Empire (Civil Division), by His Majesty, King George VI, 2 June 1943.

Sir Barnes Neville Wallis C.B.E., was knighted by Her Majesty, Queen Elizabeth II, 13 December 1968.

Sir Barnes Neville Wallis C.B.E.


Wooden ‘Mosquito’ and Luftwaffe Battlefield

The Mosquito was an unarmed bomber with a crew of two, able to carry a bigger bombload farther than a B-17. It was also a fighter-bomber and a night fighter with an eight-gun nose battery. It was the most productive photoreconnaissance aircraft of the war. A high-speed courier. A weather-recon airplane. A carrier-qualified torpedo bomber (though too late to see combat). A pathfinder and target-marker for heavy bombers. The war’s most effective extreme-low-altitude intruder. A multiengine trainer and a high-speed target tug. A decoy frequently used to convince the Luftwaffe that three or four spoof-raid Mosquitos dropping chaff were a bomber stream of Lancasters.

Mosquitos were built in 33 different variants during WWII and seven that were introduced after the war, at a time when everything else with a propeller was being shunted off to reserve and training units.

The de Havilland Mosquito was the anti-Fortress, a bomber proposed to the Royal Air Force with speed as its salvation, not guns. Many forget that the Mosquito turned out to be the first of its kind and the B-17 the last of its line. Never since have bombers truly been armed defensively. The B-29 had four remotely controlled turrets until Curtis LeMay stripped the guns from them, preferring to carry bombs and fuel rather than guns made pointless by air superiority. B-52s had a tail battery—quad .50s and then a 20mm rotary cannon—but in 1991 that station was eliminated. Neither the RAF’s Canberra nor its V-bombers had a single gun. Neither did the F-117 stealth bomber, nor the B-1 and B-2. Since the day when the Mosquito went naked, guns on a bomber have been like tits on a boar.

De Havilland began design of the Mosquito on its own. Neither Geoffrey de Havilland nor his same-named son, who became the Mosquito’s chief test pilot, had any interest in dealing with the government, for their company had thrived during the 1920s and ’30s by concentrating on the civil market, where airplanes were bought because they got a job done, not because they met some blithering bureaucrat’s specifications.

The senior de Havilland also had a champion: Air Marshal Sir Wilfred Freeman, who is often casually characterized as “a friend of de Havilland’s.” Which he certainly turned out to be, but the initial connection was that Freeman had commanded a squadron of de Havilland DH-4s during World War I and became a huge fan of that airplane. The DH-4 was one of the best single-engine bombers of the war—faster than many fighters—and remained in service with the U.S. Army Air Service as late as 1932. Freeman was confident that the de Havillands knew what they were talking about when it came to airplanes. He pushed hard enough in favor of the Mosquito that the airplane became known among its detractors as Freeman’s Folly. Lord Beaverbrook, the Crown’s aircraft production czar, three times ordered him to shut down early Mosquito manufacturing. Fortunately, Beaverbrook never put it into writing, so Freeman ignored him.

Still, it wasn’t easy for de Havilland to convince the Air Ministry that an unarmed wooden bomber faster than any contemporary fighter was the answer to Bomber Command’s needs. The obvious riposte to this too-neat theorization was that the enemy would inevitably develop faster fighters. The British could see what Germany had done in grand prix automobile racing and had no illusions about the country’s technological prowess. This proved to be true to a degree when advanced versions of the Fw-190 and the nitrous oxide–boosted Me-410 became operational, and absolutely true when the Me-262 twin-engine jet flew. But nobody had anticipated the mid-1940s plateau of propeller effectiveness and compressibility problems that would limit conventional fighters to speeds roughly equivalent to the Mosquito’s no matter how extreme their horsepower. The Mosquito was fast in 1940 and remained fast in 1945.

In April 1940, U.S. Army Air Forces General Hap Arnold brought to the U.S. a complete set of Mosquito blueprints, which were sent to five American aircraft manufacturers for comment. All were contemptuous of the British design, none more so than Beechcraft, which reported back, “This airplane has sacrificed serviceability, structural strength, ease of construction and flying characteristics in an attempt to use construction material that is not suitable for the manufacture of efficient airplanes.” Beech couldn’t have gotten it more wrong if they had tried.

Mosquitos were internally coated with traditional marine varnishes, not nearly as waterproof as modern polyurethane coatings. So there were cases of Mosquito structural failures caused by simple wood rot—some among de Havilland of Canada–built airplanes, which were sometimes found to suffer from poorer workmanship and lower quality-control standards. A few Mosquitos—a total of 212—were also built in Australia, but that country had even bigger problems, with only a tiny cadre of aviation engineers and technicians to depend upon. The first 50 Australian-built Mosquito wings were so badly glued they had to be rebuilt.

The Mosquito was not an easy airplane to fly. As combat aircraft historian Bill Sweetman wrote in his book Mosquito, it was “a slightly nervous thoroughbred which could perform impressive feats in the hands of the courageous and competent…but would occasionally deal out a kick or a bite.” Its power-to-weight ratio and wing loading were both high, and its Vmc—the speed that needs to be maintained to assure rudder effectiveness with one engine feathered and the other running at full power—was, depending on load, an eye-watering 172 mph or more, probably the highest of any WWII twin. The much-maligned B-26 Marauder had a Vmc of about 160 mph.

The biggest gun ever mounted in a Mosquito was a 57mm cannon called the Molins gun. It had a 25-round, rapid-fire ammunition feed designed and built by Molins, a formerly Cuban company that had become the world’s largest manufacturer of cigarette-making and -packaging equipment. The 75mm gun mounted in hardnose B-25G and H Mitchells was obviously larger, but it had to be manually reloaded by the bomber’s navigator, so its rate of fire was about one-sixth that of the Molins gun. Many doubted that the Mosquito’s structure could withstand the Molins’ recoil, but de Havilland needed just one day—the time it took the factory to saw the nose off a crashed Mosquito, mount the 12-foot-long gun and test-fire it—to prove them wrong. The barrel recoiled 18 inches and hosed out a gout of flame 15 to 20 feet long, but the wooden airframe was flexible enough to dampen the shock.

Mosquitos that carried the Molins were called “Tsetses,” after the deadly African fly. Their specialty was sub-hunting in the Bay of Biscay. The bay was so shallow that the German subs had to dash across while surfaced, and Tsetses picked off enough of them that soon the subs could only travel at night. Tsetses also destroyed more than a few Luftwaffe aircraft, and the effect of a 57mm projectile on, say, a Ju-88 was devastating.

Another unusual weapon was the Highball, a Mosquito-size version of Barnes Wallis’ famous Dambuster bouncing bomb. It was developed for use against Tirpitz, the German battleship hidden away in a Norwegian fjord. The Highball was to be spun up in flight—two were carried in the open bomb bay of each Mosquito—by power from a ram-air turbine, which must have been one of the first-ever uses of a RAT. Highballs would be dropped at very low altitude to bounce over the torpedo netting that protected Tirpitz and then crawl down the hull to explode well below the waterline.

WWII Bouncing Bomb Tests at Ashley Walk, New Forest 1943 Code named ‘Highball’. A type of ‘Bouncing Bomb’ designed by Dr Barnes Wallis. Spherical (ball like) in shape it was designed to be used against large ships. Two of these could be carried and deployed by a single De Havilland Mosquito aircraft. In 1943 the Ashley Walk Bombing Range in the north of the New Forest near Godshill was used as a test and training range for inert versions of the bomb. A target, No.3 Wall Target, was specifically constructed on the range for these tests.

Barnes Neville Wallis was born the son of a doctor on 26 September 1887 in Ripley, Derbyshire. Wallis worked first at a marine engineering firm and in 1913 he moved to Vickers, where he designed airships, including the R100. In 1930, Wallis transferred to working on aircraft. His achievements included the first use of geodesic design in engineering, which was used in his development of the Wellesley and Wellington bombers. When World War Two began in 1939, Wallis was assistant chief designer at Vickers’ aviation section.

In February 1943, Wallis revealed his idea for air attacks on dams in Germany. He had developed a drum-shaped, rotating bomb that would bounce over the water, roll down the dam’s wall and explode at its base. The bomb was codenamed ‘Upkeep’. Impressed with the concept, the chief of the air staff, ordered Wallis to prepare the bombs for an attack on the Möhne, Eder and Sorpe dams in the important German industrial region of the Ruhr.

Operation Chastise, the ‘Dambusters Raid’, was carried out on the night of 16 – 17 May 1943 by the specially created 617 Squadron of the Royal Air Force, led by Guy Gibson. Two of the dams – the Mohne and Eder – were breached, leading to serious flooding in the surrounding area, although industrial production was not significantly affected, and 8 of the 19 bombers which took part were lost. The most significant result was the hugely positive effect on Allied morale.

A bouncing bomb is a bomb designed to bounce to a target across water in a calculated manner to avoid obstacles such as torpedo nets, and to allow both the bomb’s speed on arrival at the target and the timing of its detonation to be pre-determined, in a similar fashion to a regular naval depth charge.

The inventor of the first such bomb was the British engineer Barnes Wallis, whose “Upkeep” bouncing bomb was used in the RAF’s Operation Chastise of May 1943 to bounce into German dams and explode under water, with effect similar to the underground detonation of the Grand Slam and Tallboy earthquake bombs, both of which he also invented.

The success of the operation to destroy a number of reservoirs in Germany which became known as Operation Chastise, the RAF had a very special method. The specialty of this operation began with the use of selected squadrons, the use of specially modified Avro Lancaster bombers. The crew was selected from various countries (Canada, US, New Zealand, UK), the tactics that were deployed were also specialized, and used specially designed bombs. As planned, the attack would be carried out at night during the full moon when the lake water was at its peak.

On the night of 16-17 May 1943, Wing Commander Guy Gibson led 617 Squadron of the Royal Air Force on an audacious bombing raid to destroy three dams in the Ruhr valley, the industrial heartland of Germany. The mission was codenamed Operation ‘Chastise’. The dams were fiercely protected. Torpedo nets in the water stopped underwater attacks and anti-aircraft guns defended them against enemy bombers. But 617 Squadron had a secret weapon: the ‘bouncing bomb’.


Related Videos

Dam Busters Royal Premiere

Princess Margaret attends premiere of the film "Dam Busters" in aid of RAF Charities.

Dam Busters Reunion

Dam Buster survivors meet in London's Criterion Restaurant.

London - Dambusters Aka 25th Anniversary Of The Dam Busters

Real life "Dam Busters" attend screening of film, alongside film star Richard Todd.

Second "Dam Busters" Premiere Reel 1

The Second 'Dam Busters' Premiere is attended by the Duke and Duchess of Gloucester.

Second "Dam Busters" Premiere Reel 2

The Second 'Dam Busters' Premiere is attended by the Duke and Duchess of Gloucester.

Dam Busters Remembered At Biggin Hill

617 Squadron, the Dam Busters, are reunited

The Dam Busters Premier And Re-Union

Two items covering the premier of the film "The Dam Busters" attended by Princess Margaret.

List of site sources >>>