Feedback - your letters

In this 'innovative' issue you provide more Comet evidence; managing wind; and a blotchy infrastructure for electric vehicles. So pour yourself a cup of radioactive coffee, take a few minutes out, and enjoy...

Is innovation overrated?

Please could we stop using the words 'innovative' and 'creative' merely to imply approbation? Innovation means making something new - and new things, whether ideas or physical objects, are not necessarily good or even profitable. The Comet was an innovation, but de Havilland did not get it right and the company no longer exists. The Minor and the Mini were innovations, but however good their conception they were not the commercial successes that could have saved British Leyland.

Innovation and creativity are, of course, quite useful words in the fields of fashion and marketing, where absence of meaning is an advantage. In the serious world of engineering design, the words are redundant. Design produces something new and so engineering design is by definition innovative. But innovation is only a small part of design. Unfortunately, we have come to believe that innovation is the clever bit and once the idea is presented, lesser men can turn it into a useful and profitable product.

Putting too much emphasis on the value of innovation gives engineers a false model of design; a model which history shows is untrue. From Watt to Whittle, it has taken ten or more years to turn an original, good idea into a saleable product. In every case the solution to the first problem generated more problems; the solutions to these new problems generated yet more problems; and so on. Even when the product was in the field, unforeseen problems presented themselves for solution. Design is much better thought of as problem solving.

Engineering design has a great deal in common with Darwinian evolution. A product changes over the years, hopefully through successful 'mutations' that are not accidental but are generated by professional engineers.

Innovation has its uses, but what we really need is sound professional engineering. With luck, experienced engineers will predict some of the problems that have not been foreseen by the innovator. They will recognise problems when (or preferably before) they occur but, more importantly, they will apply the disciplines needed to solve them.

It could be argued that finding solutions to problems is innovative, but solving engineering problems needs an understanding of the physics involved. This is professional engineering and it requires knowledge and experience as well as wit. If we stop worrying about innovation and creativity, we might return design to a discipline which creates saleable projects.

Don Leech FIET, Swansea

Managing wind

GD Cutler (Letters Vol 4 #7) exaggerates the problems associated with obtaining energy from intermittent wind power sources.

Turbine rated power is of necessity a compromise between energy capture and capital invested, with the intention of minimising the overall cost per unit of energy. Modern wind turbines cut in at around 3-4m/s; below this speed there is insufficient power available to justify operating the turbine. Above cut-in the power rises with the cube of wind speed until rated power is attained. Rated power (be it 1.5MW, 2MW or whatever) is reached at approximately 12-14m/s, depending on machine type. Beyond rated power the turbine pitches its blades to 'spill wind' up to around 25-28m/s when the mechanical loads dictate that the turbine must shut down in order to avoid damage. Averaged over a year the capacity factor of an onshore turbine is typically 25-30 per cent, with offshore somewhat higher, but it should be generating useful power for over 80 per cent of the time.

When wind is progressively added to an established power system its natural variability can be amply accommodated by varying the output of existing power stations. A large proportion of the wind plants are operated by companies that also operate power stations, so they are able to choose which to run on an economic basis; wind usually wins. Opinions vary as to the percentage penetration that can be accepted in this way without the need for radical storage solutions, but the consensus seems to be that 10 to 20 per cent should be manageable.

Dr PD Hopewell FIET, by email

Defining function

Alistair Fox (Letters, Vol 4 #7) asks whether your report that, during bad weather earlier this year in the UK, the national rail enquiries website "received 16 times its normal demand, but continued to function, though not all users could get access" may be a redefinition of 'function'.

A key issue for any system is to ensure the specification is clear about the functional and the non-functional requirements. A function is a set of inputs, the behaviour, and outputs and these drive the application architecture of a system. Functional requirements describe the system behaviour - what it does.

Non-functional requirements specify overall characteristics such as cost, reliability, and capacity in the case of the aspect of the national rail website which Alistair Fox writes about. Non-functional requirements drive the technical architecture of a system and impose constraints on the design or implementation of the system. Non-functional requirements specify the criteria that are used to assess the operation of a system - how well it performs.

Many systems fail (to function) in operation because of inadequate specification of the non-functional requirements. This is something all those involved in design and implementation need to be aware of.

Barry Faith FIET, Wimborne, Dorset

Engineering's example

A resounding 'Hear Hear' for the views expressed by Andrew Lamb of Engineers Without Borders in his 'If You Ask Me' column 'Don't just sit there' (Vol 4, #6). I only wish more people shared his view point.

I too believe that we are consuming resources at an unsustainable rate. We should be living by the maxim 'reduce, reuse, recycle' and returning to some of the principles of living that featured during the Second World War such as growing your own vegetables, recycling metal etc.

Could E&T play a part by featuring sustainable gadgets rather than expensive (in terms of resource and money), needless electronic gizmos?

Sarah Dale CEng MIET, Mold, Flintshire

Lessons from Comet

Nick Spurrier's article on engineering disasters and what we have learned from them ('Hard Lessons', Vol 4 #7) was very interesting, but misses the exact reason and root cause of the Comet aeroplane failures, as it was explained to me at the Production Engineering Department of Loughborough College of Technology in the early 1960s.

The fatigue failures around the windows in the fuselage did not occur on the prototypes, manufactured by 'hand', and drilled. For production, punching of the holes was introduced which caused the stress-raisers which led to in-flight failure.

So I would classify the reason for the disaster as "modification of design during construction", not "being the first in its field" as it is categorised in the article.

Ray Greaves CEng MIEE, by email

As a student many years ago, I visited the site where the Comet airframe was being tested to the point of failure. The outcome of this and examination of recovered wreckage revealed that the airframe cracks had started at the corners of the windows, the design of which concentrated the stresses, and could have been avoided.

According to a recent TV documentary, the designers of the Comet opted for the de Havilland Ghost jet engine rather than the more powerful Rolls-Royce Avon. As a result the aluminium airframe gauge had to be reduced to compensate, which contributed to the airframe failure.

A further sad outcome was the end of the UK as an independent major aircraft manufacturer with the American economy benefiting from our jet engine invention and our front runner mistakes in the Comet design.

D Duncan, Porthcawl, Mid-Glamorgan

Nuclear 'spark of hope'

To describe the 1986 Chernobyl nuclear plant explosion rather than the Bhopal disaster in India of 1984 as "the most catastrophic engineering disaster in history", as Nick Spurrier does in 'Hard Lessons', is questionable. A different perspective is provided by the environmental scientist Dr James Lovelock, who has noted that at the height of the Cold War the superpowers let off hundreds of nuclear explosions in the air, bathing us in fallout equal to a Chernobyl accident every week for two years.

The fall-out from the radioactive cloud that swept western Europe was really nothing, only one-tenth of a chest X-ray or ten days on holiday in the Alps. Yet 368 hill-farmers in the UK in 2005 were still unable to move or sell sheep because radiation they absorb from the grass exceeded the official limits. What does this limit amount to? It's the same as the radioactivity of one kilogramme of coffee or 1/30th of a kitchen smoke detector.

James Lovelock concludes that irrational fears of catastrophic accidents and radiation are exploited in the same way that churches not long ago preyed on our fears of hellfire:

"The anti-nuclear agenda being pushed by groups like Greenpeace and Friends of the Earth and by Green Party politicians pursue goals in which neither environmental good sense nor science play a part - a strange way to defend the Earth! Unless we stop fretting over tiny statistical risks - even if they exist - and focus instead on protecting the planet we live on, our prospects look bleak. And they will be much worse for our children and grandchildren. In this electric world, nuclear energy is our one spark of hope."

Nuclear new build may not be a favoured option of many, but in the present somewhat fevered atmosphere of debate on UK energy policy, such observations based on reason and scientific knowledge seem especially relevant.

MA Laughton FREng FIET, London

Ship shape

In 'Hard Lessons' (Vol 4, #7), Nick Spurrier points out that, partly in light of the foundering of the Swedish ship the Vasa in 1628, the topsides of British Royal Navy vessels were curved inwards "to bring the weight of the cannon nearer the centre line of the vessel".

Surely this would make no difference to stability, as for each port side cannon there was an equivalent starboard side and together they could be represented by a double-weight cannon on the centre line, no matter what was the beam of the deck upon which they were mounted.

Further such tumblehome would decrease the ultimate stability of the vessel because, as the ship keeled over further, the centre of buoyancy would not move out so far and so the righting moment arm would be shortened.

AB Bryce MIET, Newton-le-Willows, Lancs

Getting to the point

I read numerous articles, all of which infuriate me, about the development of electric cars. If any government managed to get a network of charging points around the cities, how do we get our vehicles to them?

I travel from north Essex to London on an unreliable, dirty and overcrowded train, so to use my car would be nice. Scenario: I buy an electric car with a range of around 100 miles and travel the 80+ miles to west London. I then need to find a vacant charging point for a reasonable period during the day. If I have to travel to a site within the course of the day, the chances are I am not getting back to north Essex at night.

The people who think up these wonderful ideas must all live in cities. Do they think the only inhabited parts of the country are London, Birmingham, Manchester and Leeds?

Ray Osborne MIET, by email

Metering misery

I estimate that in the UK around half a million domestic utility bills are issued every working day. The suppliers do not appear to use any system to deal with obvious errors in their billing, even though these could readily be detected by the billing software.

It is negligent of a supplier to issue a bill containing an obvious error without at least issuing a covering letter inviting the customer to discuss the matter and, meanwhile, postponing any enforcement proceedings.

Utilities appear to rely on customer complaints to trigger investigations into billing errors. Sometimes this works. But complaints are very wasteful and they undermine goodwill. Sometimes the errors are not noticed, and the customer is overcharged. This is verging on fraud. An unexpected high bill, or even an unexpected low bill, can cause misery and may be verging on harassment.

In my work as a voluntary advisor at my local Citizens' Advice Bureau I have already this year dealt with three examples, involving three different suppliers. The enormity of the consequences of these careless bills compels me to describe them in detail.

In one case the meter reading was wrongly carried forward from one billing period to the next (on the same bill) resulting in double charging for 172 hundreds of cubic feet of gas at £135. In another, the meter reading '5417' - correctly (not disputed) supplied by the customer (aged over 80) - had been entered as 5147 leading to an apparent negative consumption in the final quarter and an annual reconciliation showing minus £4.13 charged for the whole year's gas. This led to a refund of over £200 which the customer neither expected nor understood. So she twice asked the supplier to investigate and confirm the refund, as she relied on them to do her budgeting. They twice confirmed that the money was hers to spend, so she spent it on her grandchildren. Three months later she got a bill which was £300 higher than expected, as that previous bill should have been for around £100.

In the third case a person of pensionable age, living alone and still in full-time employment, received a bill that showed she had consumed 9,704 kWh in the last 67 days, equivalent to almost four years' normal use. The bill was £700 more than expected. Some readers will have already guessed that this was due to an error of 10,000kWh in misreading a dial-type meter, but the supplier continued for five months to assert "our bills are correct". On Christmas Eve she received a letter telling her that a Court order would be obtained to enter her home (while she was at work) by drilling the locks, in order to fit a pre-payment meter, after which she would have to pay the supplier £350 to get the new keys to her home.

Fortunately, a friend was able to recognise the problem and explain it to the supplier, who then issued a corrected bill. But this was not the end of the story. Apparently the hand-held equipment used by meter readers can actually amend a correct reading in order to make it consistent with an earlier erroneous reading. So the lady received a further three highly elevated bills. Fortunately she now has a modern electricity meter.

I have detailed these examples to show how the distress caused, together with the effort spent by both parties in handling the complaint, are out of all proportion the the extra effort needed to check the bills for gross errors and take appropriate action.

I have found that the regulator, Ofgem, is unwilling to deal directly with the public, and I have been advised by Consumer Direct to raise this issue through my Member of Parliament. But I would like first to invite E&T readers who might be involved in specifying or implementing billing/metering systems to comment on this issue. Are there any utilities who can claim "We check your bills"? If not, why not?

John Chambers FIET, Tadworth, Surrey

What really happens

'What would you do?' (Vol 4, #7) reports a theory gaining support among risk experts that, when a disaster strikes, people behave in unexpected and irrational ways. It then goes on to say that the tacit assumption used to be that people respond instantaneously when an alarm goes off and that that doesn't happen.

Could I just say that, if that is the case, then the risk experts have a lot of catching up to do since every NCO in every armed force all the way back to Roman times would probably have told them that if they had bothered to ask.

Reid Thomas, MIET, Cranleigh, Surrey

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