SPECIAL NOTICE 16TH MARCH 2020- Due to the CORONAVIRUS crisis all U3A meetings in person are currently suspended until further notice.

We meet at Exning Road Club on the first Monday of the month at 10.30am.

Hello everyone, I hope you are enjoying midsummer – already! Where has the year gone? The following
task combines both presentation and ‘quiz’ into one activity or event which will be July’s presentation and quiz. You may have noticed that our quizzes are developing and becoming more advanced in style, relying more on your views and opinions and less on each of us being able to ‘regurgitate’ facts. So here it is:-

Select a one hour standalone TV programme with a technical and/or technological emphasis.
Write an account of the events described or portrayed, emphasising their significance and placing them in an appropriate context.

1. I shall do the task as well, both as a presentation and as an example of how the work might be undertaken.
2. The task above could be set out simply as ‘Pick a technical TV programme, watch it and write about it!’
3. My choice of programme is ‘Death on a Comet: The Rosetta Mission’
a. I will begin with reasons why I have chosen this programme
b. Then where it sits in the wider space exploration programme
c. Who organised it, why and how
d. What did it set out specifically to achieve – which is not the same as what it did
e. Areas in which it was successful or not
f. What future developments might be in this direction
g. The degree to which the TV programme was successful and enjoyable.
h. Any other matters which may appear during the work.

You will of course do as much or as little as you wish. You could easily write 5,000 words or just fill the back on an envelope.

There’s no such thing as failure – only successes not yet achieved!

20 June 2020

27 June 2020
My response to the above task would look like this, I think. I knew very little about this so it did need a lot of research. Unfortunately much of that was in very technical language, so I have tried to simplify it both for my sanity and yours.

Enjoy yourselves.

link to Rosetta Essay


This time the questions are more cryptic, about engineering principles and procedures. The answers are not simple in most cases.

Below are answers to the third WWW quiz. These were in the most part contributed by Joanne and Steve Garner with a few additions where I felt that there was another valuable aspect. It was difficult and few people have sent in detailed written answers although I am pleased that a number of the group have looked at the quiz. Even if you didn’t actually do the quiz, you might like to look through the answers.

Wings, Wheels & Water: QUIZ III – Steve and Joanne’s answers with a few additions from Tim: these are in italics.

A. Who was Mr Bessemer and what did his converter convert? How did it work? Why was it so important?

He was an English inventor from a Huguenot family, who played a significant role in establishing the town of Sheffield as a major industrial centre.

His converter, patented in 1856 enabled the removal of impurities from pig iron to convert it into steel. The egg-shaped converter was tilted down to pour molten pig iron in through the top, then swung back to a vertical position and a blast of air was blown through the base of the converter in a dramatic fiery ‘blow'. The converter was tilted again and the newly made steel was teemed or poured out. The first converters could make seven tonnes of steel in half an hour.

It was of enormous industrial importance because it lowered the cost of production steel, leading to steel, a much stronger material being widely substituted for cast iron. Development of the electric arc furnace and oxygen blowing techniques rendered the Bessemer Converter obsolete in the late 1960s.

B. What links AF, BSF and BSW but what are their differences? What other letter-series might join these and why?

Screw threads are one of the fundamental principles of engineering. They convert rotary motion or direction to linear motion or direction.. Some need to be very strong above all, while others need to be highly accurate. The amounts of pressure a bolt must exert varies and in some cases it is the continuous rotation that is crucial, for example in the use of the Archimedean screw.

They all relate to thread sizes. AF (Across Flats) is in millimetres; BSF (British Standard Fine) has the same thread angle as the BSW, but has a finer thread pitch and smaller thread depth; BSW (British Standard Whitworth) is an imperial-unit-based screw thread standard, specified by a 55° thread angle and a thread depth of 0.640327p and a radius of 0.137329p, where p is the pitch.

In the 1950s Metric threads, and spanners marked with their Across Flat (AF) size in millimetres were very rare, except in continental Europe. Because Ford cars were designed to American standards, they used American screw threads, which were termed National Coarse (NC) and National Fine (NF). They were similar to the English versions, but had a 66deg thread angle. Due to problems in WW2 with thread sizes, the sizes of these American threads were 'unified' between Britain, Canada and America and, from about 1960 they became UNC and UNF. The British retained spanners marked with BSW and BSF sizes, which related to the thread diameter, not the across flats (AF) size used commonly but incorrectly by the Americans for their UNF and UNC screws. In fact, each spanner was marked with both Whitworth and BSF sizes, which are directly related but not the same. (Joanne thinks that this means that some are bigger than others!)

These other letters could possibly join the series:
MM (Millimetre)
BSC (The British Standard Cycle) standard which replaced the Cycle Engineers' Institute (CEI) standard was used on British bicycles and motorcycles. It uses a thread angle of 60° compared to the Whitworth 55° and very fine thread pitches.
BA (British Association screw thread) standard is sometimes classed with the Whitworth standard fasteners because it is often found in the same machinery as the Whitworth standard. However, it is actually a metric based standard that uses a 47.5° thread angle and has its own set of head sizes. BA threads have diameters of 6 mm (0BA) and smaller, and were and still are particularly used in precision machinery.

C. What is this formula about and why might it be important? L = (1/2) d v2 s CL

It is a formula for calculating an aircraft's lift capabilities:

L = Lift, which must equal the airplane's weight in pounds
d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table.
v = velocity of an aircraft expressed in feet per second
s = the wing area of an aircraft in square feet
CL = Coefficient of lift, which is determined by the type of airfoil and angle of attack and itself requires another formula to calculate it.

Using the lift equation, and the lift coefficient given above, one can calculate the amount of lift produced at a given velocity for a given wing area. Or, for a given velocity, you can determine how big to make the wings to lift a certain weight.

D. Why did the ‘unsinkable’ Titanic, sink? What scientific principle(s) were involved?

The ship was believed to be travelling too fast (in order to fulfil a quick crossing time) and failed to spot and avoid an iceberg. Although the ship had been designed to stay afloat even if four of its 16 watertight compartments were breached, the iceberg's glancing blow caused the ship's hull plates to buckle along its starboard side, and water soon began to fill six of the watertight compartments. Some metallurgists who have studied the disaster believe that its hull was fastened together with poorlycast wrought-iron rivets. When the ship hit the iceberg, they believe these rivets popped off, effectively “unzipping" the hull at the seams. So, when 38,000 tons of water filled its bow, pushing the stern up 11 degrees out of the water, the ship was loaded beyond its capacity and cracked in two.
The principles involved were that of buoyancy and flotation. The filled flotation compartments meant that the Titanic became heavier than the weight of the water it was displacing.

The ship was constructed around a series of watertight compartments, any 4 of which could be holed without the ship sinking – in theory. Although the watertight bulkheads extended well above the water line, they were not sealed at the top. If too many compartments were flooded, the ship's bow would settle deeper in the water, and water would spill from one compartment to the next in sequence, rather like water spilling across the top of an ice cube tray.

E. What was originally 4’8” and why was it that size. Who added ½” and why did they do that?

4’ 8” was the initial gauge for railways, set to accommodate the existing gauge of hundreds of horsedrawn freight wagons that were already in use on the wagonways in the mines. The railway used this gauge for 15 years before a change was made to the 4’ 8½” gauge.

It is said that 4’8” was the width between the shafts of a Roman chariot.

George Stephenson used the 4’ 8½” gauge for free movement to reduce binding on curves for the Liverpool and Manchester Railway. The success of this project led to Stephenson and his son Robert
being employed to engineer several other larger railway projects. Thus the 4’ 8½” gauge became widespread and dominant in Britain.

F. Where is this painting, what does it depict and what is significant about both the place and the image?

The painting depicts the Madeley Wood (or Bedlam) Furnaces, which belonged to the Coalbrookdale Company from 1776 to 1796. The picture has come to symbolize the birth of the Industrial Revolution in the Ironbridge Gorge, Shropshire. (It is held in the collection at the Science Museum, but Steve used to have a copy as a poster on his wall!). Ironbridge is the site of the first bridge fabricated from cast iron (and we stayed in a Landmark Trust property that directly overlooks the bridge!). So did I! Unfortunately, they were working on the bridge and it was shrouded in white plastic tarpaulins.

The painter (Philip Jacques de Loutherbourg) presents the iron foundry as a vision of Hell, and it is both a celebration and a warning. The smoke from the chimneys is not only a symbol of economic productivity and wealth but also a noxious indicator of industrial pollution. Coalbrookdale, possibly the world's first coke-fired blast furnace, was then a site of considerable controversy. The renowned agriculturist Arthur Young described the surrounding countryside as ‘too beautiful to be much in union with the variety of horrors spread at the bottom; the noises of forges, mill, with their vast machinery, the flames bursting from the furnaces with the burning of coal and the smoke of the lime kilns’.

G. What was ‘the Great Stink’, what caused it, who was particularly offended by it, who cured it and how?

The Great Stink was an event in central London in July and August 1858 during which the hot weather exacerbated the smell of untreated human waste and industrial effluent that was present on the banks of the River Thames. The problem had been mounting for some years, with an ageing and inadequate sewer system that emptied directly into the Thames.

Those offended: Queen Victoria and Prince Albert attempted to take a pleasure cruise on the Thames, but returned to shore within a few minutes because the smell was so terrible. According to Hansard, the Member of Parliament (MP) John Brady stated that members were unable to use either the Committee Rooms or the Library because of the stench. The scientist Michael Faraday described the situation in a letter to The Times in July 1855: shocked at the state of the Thames, he dropped pieces of white paper into the river to "test the degree of opacity". His conclusion was that "Near the bridges the feculence rolled up in clouds so dense that they were visible at the surface, even in water of this kind. ... The smell was very bad, and common to the whole of the water; it was the same as that which now comes up from the gully-holes in the streets; the whole river was for the time a real sewer."

The smell, and fears of its possible effects, prompted action from the local and national administrators who had been considering possible solutions for the problem. The authorities accepted a proposal from the civil engineer Joseph Bazalgette to move the effluent eastwards along a series of interconnecting sewers that sloped towards outfalls beyond the metropolitan area. Bazalgette's plan introduced the three embankments to London in which the sewers ran—the Victoria, Chelsea and Albert Embankments.

Bazalgette's work ensured that sewage was no longer dumped onto the shores of the Thames and brought an end to the cholera outbreaks; his actions are thought to have saved more lives than the efforts of any other Victorian official. His sewer system operates into the 21st century. The story doesn’t quite end there. A collision between a passenger cruise ship and collier resulted in many casualties. Post mortems found that many of these had in fact died from ingesting the foul water discharged at that point, just an hour earlier. A source at the time said: ‘Two continuous columns of decomposed fermenting sewage, hissing like soda-water with baneful gases, so black that the water is stained for miles and discharging a corrupt charnel-house odour, that will be remembered by all ... as being particularly depressing and sickening.’

H. Who built a railway and a ship called the Great Western? Why were they called that and where were they intended to end up? What scientific principles convinced the architect he should build exceptionally large ships?

They were built by Isambard Kingdom Brunel.

The Great Western Railway was a British railway company that linked London with the southwest and west of England, the West Midlands, and most of Wales. SS Great Western of 1838, was a woodenhulled paddle-wheel steamship, the first steamship purpose-built for crossing the Atlantic (the Bristol to New York route), and the initial unit of the Great Western Steamship Company. She was eventually sold to the Royal Mail Steam Packet Company and was scrapped in 1856 after serving as a troop ship during the Crimean War. Brunel’s idea was a rail/sea route linking London to New York.

One principle that Brunel understood was that the carrying capacity of a ship increases as the cube of its dimensions, whilst the water resistance only increases as the square of its dimensions. This meant that large ships were more fuel efficient, something very important for long voyages across the Atlantic. He also used sails, which were not just to provide auxiliary propulsion, but also were used in rough seas to keep the ship on an even keel and ensure that both paddle wheels remained in the water, driving the ship in a straight line.

I. Henry Ford wrote in his autobiography, "Any customer can have a car painted any colour that he wants so long as it is black". Why was this? How did his production methods increase productivity and lower costs?

Ford suggested the use of black from 1914 to 1926 due to the low cost, durability, and faster drying time of black paint in that era. Paint choices in the American automotive industry were shaped by the development of the chemical industry. These included the disruption of dye sources during World War I and the advent, in the mid-1920s, of new nitrocellulose lacquers that were faster-drying and more scratch-resistant, and obviated the need for multiple coats.

The relatively low price was partly the result of Ford's efficient fabrication, including assembly line production instead of individual hand crafting. The knowledge and skills needed by a factory worker were greatly reduced by using an assembly line process in which parts are added as the semi-finished assembly moves from workstation to workstation in sequence until the final assembly is produced. Whereas previously some six people built a complete car, now each workman only carried out one operation at each point. By mechanically moving the parts to the assembly work and moving the semifinished assembly from work station to work station, a finished product can be assembled faster and with less labour than by having workers carry parts to a stationary piece for assembly. As a result, Ford's cars came off the line in three-minute intervals, much faster than previous methods, reducing production time from 12.5 hours before to 93 minutes by 1914, while using less manpower. There were multi production lines with sub-assemblies being created which came together to create a finished vehicle, like the branches of a tree in reverse. For example, the engines were produced on their own line. In the early lines the cars were hauled along by men from station to station while Ford calculated the most efficient system.

J. Who designed ‘The Wooden Wonder’? Why was it wooden and why was it a wonder?

The DH.98 Mosquito is a British twin-engine, shoulder-winged multirole combat aircraft, designed by the de Havilland Aircraft Company.

The wooden monocoque (structural skin) construction not only saved weight and compensated for the low power of the de Havilland Gipsy Twelve engines used by this aircraft, but also simplified production and reduced construction time. It was a multi-use aircraft, e.g. daytime tactical bomber, high-altitude night bomber, pathfinder, day or night fighter, fighter-bomber, intruder, maritime strike, and photo-reconnaissance. (Joanne knew this one as Eddie Chapman aka Agent Zig-Zag pretended to sabotage the de Havilland factory in Hertfordshire where they were being produced, in his role as double-agent).

The Mosquito was a private venture project by DeHavilland, not government funded and therefore the usual supplies and suppliers were not readily available. The favourite material, duralumin, was in very short supply as it was used in most aircraft, particularly the Spitfire, Stirling, Halifax and Lancaster. It was also quite difficult to work and required well trained workers. There were no limits on timber and in addition, the area around the factory in Hertfordshire was well known as a centre for furniture and piano manufacture and there weas therefore a plentiful supply of well-qualified and experienced wood workers. Unfortunately, adhesives were not what they are today, and that, combined with the use of wood resulted in no flying examples surviving long after the war. (There are now two rebuilt models flying.) Although initially fitted with the DH Gipsy 12 engines, these were later changed for the legendary Rolls Royce Merlin which gave the Mosquito its superb performance.

They were known to the enemy as ‘the Night Devils’. One of the tactics was to lurk near German airfields at night. When the landing lights were switched on for an aircraft to land, the Mosquito would pounce. They were fitted with an array of weapons making them deadly.


We are delighted to present another piece by Steve Garner, following on from Tim’s piece last month on the 50th anniversary of the Apollo 13 moon mission. As always, Steve takes us in various intriguing directions.
Perhaps group members might like to send observations or questions. I am sure Steve will have follow-up comments and responses. Enjoy!
see link: Space and Lunar Surface Travel


We seem to be getting slightly out of kilter with monthly presentations but here is what I think is probably June’s presentation on Scapa Flow, by Stephen Garner. Many thanks Steve for yet another fascinating presentation.
see link: Scapa Flow Review
This will be followed up by a quiz on the information in the presentation: that will be coming shortly.


For those still looking out for ‘What the Dambusters did next’, it will be along soon, I promise. I have had technical problems...


And here it is AS PROMISED ...

click the link


We have had Jeeps & SUVs in January and February’s subject was Women in Space, which looked at the increasing role women have played in space exploration since the 1930s. Then in March the topic was water- based: the Americas Cup, the top ocean racing competition and one that Britain has never won. The session on the America’s Cup came as a change and appealed to members of the group who had spent at least part of their youth on the water. Sailing is a minority sport and a very minor spectator sport so members of the group had less background knowledge than is often the case.

The programme followed the plan at the beginning of 2020, featuring two talks by the Co-ordinator. Sadly, the subsequent programmed meetings are now suspended.

For Reports and pictures see our Facebook page.


We now have a feature entitled 'UPDATES' which is an opportunity for anyone to raise any matters that they have seen anywhere, updating information from a previous topic. These UPDATES may be as long or as short as you wish and take any form. the idea is to encourage members of the group to take a more hands-on or participatory part in each event.



There will be at least one outing for the group, using the 'Gredley Provision', which provides free transport to and from attractions. Gredley trips are so called because the U3A is provided with a mini-bus belonging to the Gredley Charitable Trust. There is no charge to U3A members taking part..

Tim Young 01638 612216;

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