Wednesday, 6 January 2010

An Enduring Myth

There is a cherished notion, held close by UK aviation enthusiasts, that Britain, at the end of World War 2, had an aviation industry that was second to none and was only prevented from capitalising on it by the self serving attitudes of trade unions (supported by the Labour party) and the short sightedness of governments, (also Labour) who toyed with the industry and spitefully prevented it from developing numerous world beating aircraft.

TSR2 Online
Wiki on TSR2
Cancelled projects

The reality of it is rather different as the parliamentary record of the day, Hansard shows. Sir William Robson Brown (Conservative) in the parliamentary debate on the 1966 Plowden report on the British aircraft industry made the following statement:
“Production costs in the (British aircraft) industry  are something which I cannot comprehend. With wage costs 40 to 50 per cent. lower than they are in the United States, our manpower production costs are 2½ times higher.”

Now it was customary in debates on British industrial productivity, in the days when industrial productivity played a significant part in the British economy, to demonise the unions, but that’s only part of the story. In order to see why British production costs were so high, compared to the USA and other countries, we have to go back to 1798 and Eli Whitney.

The concept of interchangeable parts is often credited to Whitney. Although historians are still debating who actually came up with it, this concept, the American_system_of_manufacturing  is defined as a way of using standardised, identical, interchangeable parts, manufactured to a consistent tolerance. Interchangeable parts were a turning point in industrialisation. Prior to this all manufactured items had been the work of skilled craftsmen making bespoke articles and the parts and pieces were usually anything but interchangeable.

With the invention of the automobile American manufacturers quickly embraced interchangeable parts. Henry Ford was proud to proclaim that no files were used on his production line, all the parts fitted perfectly, and were interchangeable. This had the further advantage that spare parts could just bolt in, again without rework.

However, there are significant initial costs in mass production, drawings have to be very carefully prepared with all dimensions and tolerances specified in great detail, and components made to much higher tolerances if they are to be quickly assembled without rework. Often tooling, parts which must be manufactured in order to manufacture and form other parts, must also be made. Consequently the start up costs are much higher.

In Britain cars were seen as the costly playthings of the wealthy volume manufacture was not anticipated, and the American approach did not find favour. The resultant high unit costs made this a self fulfilling prophecy and in Britain making cars in high volume took ages to catch on.

So, while 1930s Germany was stamping out the first Beetles priced so that workers could drive them on the new autobahns, the British car manufacturers remained proudly elitist and held on to methods which called for a level of ‘fitting’ during assembly. This approach was presented as a virtue, the low volume luxury car makers held that their cars were built by craftsmen  and this was promoted as exclusivity.

The British aircraft industry of the 1930s worked in a very similar way to its car manufacturers. And, borrowing the rational, they held that skilled fitters were essential whenever airframes and aero engines had to be manufactured. When the war was imminent and the British government wanted to increase aircraft production big problems were encountered when experienced mass producers attempted to adopt the aircraft industries' drawings and processes. Even relatively straight forward sub-assemblies such as bomb racks, when sent out to be manufactured by manufacturers such as Hoover and Electrolux, created problems. The supplied drawings were not always complete and tolerances were insufficient to define parts that could be assembled without extensive hand rework. The subcontractors ended up redrawing the original blueprints produced by the aviation big boys such as Avro and Handley Page to the standards that were customary in vacuum cleaner manufacture.

Even the drawings of the famous Rolls Royce Merlin engine, which was eventually manufactured in in huge quantities, had to be extensively reworked for volume production.  Engineers from the Ford Motor company told Rolls Royce that their tolerances were too wide for volume production.  Over 20,000 Rolls Royce drawings had to be redrawn, over a year, to meet the production methods of the volume car manufacturer. As a result the man hours to produce a Merlin engine fell from 10,000 to under 3,000. Rolls-Royce_Merlin

This is not to say that the designs of the Merlin and aircraft like the Spitfire were flawed, aerodynamically they were not, but the manufacturing depended on skilled fitters who carried much of the design and production process in their heads and knowing how to bend, hammer and file the components to fit. This had a big effect on productivity. The German Messerschmidt 109 took about 4,000 man hours to manufacture compared  to 14,000 man hours for a Spitfire. You’ll probably find people who’ll tell you the Spitfire was a better plane but I doubt that even the most rabid fan will claim that each Spitfire was worth three 109s, and, as Stalin put it, Quantity has a quality all of its own.

When the war ended Britain was left with a huge and experienced aircraft industry. It had priceless experience in the new field of jet propulsion and privileged access to German wartime research. Yet the manufacturing techniques hadn’t changed much. The English Electric Canberra impressed the United States Air Force to the extent that they subcontracted the American Martin aircraft company to produce them under license. The US built aircraft was called the B57 and with this design Martin found that all the British drawings had to be reworked before the aircraft could be manufactured. Despite the lessons from Ford and the other volume manufacturers, for the British aircraft industry there just wasn’t an incentive to change. The industry had spent the war years on  cost plus work with the government as the only customer. Higher costs actually meant higher profits and this was a disincentive to spend money on tooling and up front engineering.

Huge and fragmented, Britain’s post war aircraft industry lost ground while the American industry went from strength to strength. The British Comet, the worlds first jet airliner, was hit by a series of accidents attributed to a design error in the windows of the pressurised cabin. Yet what startled Americans when they visited the Comet factory in Hatfield were the production methods. The Boeing visitors thought they would spend more on tooling for a one off prototype than the British were using on the production line.

In a bid to try and snatch back a technical lead Britain joined with France to make the supersonic airliner Concorde. Major aircraft assemblies had to be produced in Britain and France and they had to fit together precisely. Finally the British aircraft industry had to produce drawings and processes to completely define what was to be made, no longer could craftsmen sort things out on the shop floor - everything had to fit first time. As the sixties continued more multinational projects were started, the Jaguar, Tornado and the various civil Airbus types. The legacy of Concorde was to force the British aircraft industry to reach beyond cottage industry manufacturing and work at world class levels. It took a while, and in the early days of the joint Italian, German and British Tornado it was the British manufactured parts of the work share that had fitting problems. But Britain only caught up as the bar was being set still higher. All the big American aerospace companies were engaged in Apollo project, subsequently the best in the world got immensely better.

In more recent times much of what remains of the British aircraft industry has been engaged building the Nimrod MRA4. This is a rework of an earlier aircraft which itself was derived from that 1960s Comet airliner. This project has now cost the UK tax payer £3.6 Billion, for nine aircraft. For reasons that probably seemed like a very good idea at the time, only about 80% of the airframe is brand new, with sections of the airframe inherited from the 1960s build. This has caused some of the huge overspend. The legacy airframe components were difficult to integrate with the new build elements and they give an insight into just how bad the older generation aircraft were. There were differences of up to 4 inches in length between parts of the legacy fuselage components. By comparison, for the Boeing B777, which first flew 15 years ago, Boeing claim each aircraft to be within 3/100th of an inch of each other over a fuselage length of 200 feet.
Nimrod Lewis Page     Boeing

The American system of manufacture really started something, at least in mechanical engineering. There are those who maintain that software engineering has yet to reach the same formal level. Much of the industry is still dependent on skilled craftsman carrying the design in their heads. But not, at least, in the aircraft industry. Software for use in aircraft systems IS subject to formal controls and rigorous testing. Formal engineering methods are imposed on the industry for safeties sake, and this is largely thanks to the American FAA who set the standards, effectively world wide. Software standards tend to be imposed by brute force testing methods more exhaustive than scientific. Perhaps it will take another major initiative like the Manhattan project or Project Apollo, before true software engineering becomes a reality but at least there are parts of the industry moving in the right direction.


  1. This is an important statement of the kind of historical truth that gets over-ridden by the 'default myths'. You didn't investigate this yourself did you? (If so, I'm impressed, and you should probably write a book about it).
    People cling to myths that make them feel good, and often don't look too deeply into some of the reasons why of the past. In truth, both stories probably have an element of falsehood, and an element of truth, the past is complex and never comes neatly down to one thing.
    There is, however, another way at at looking at this. There is a tension between modern industrial methods and human dignity. Although they are far more efficient, 'mass engineering' techniques reduce their practitioners to 'interchangable parts' too. I think this probably was behind a lot of the british fear of these techniques. Suddenly the craftsman, who knows his art to a high-standard, is replaced by many low-skilled workers, each working on a tiny part of a large project, and each interchangable with another if need be. Individuals can no longer produce anything, and everything is made by 'machines made of people'. It works, it's efficient, but suddenly we are all cogs.

  2. Hi Colum,
    The comments regarding the Merlin are well told in Sir Stanley Hooker's biography. The airframe production information is derived from various sources.
    There may be a book there but a better one would be one that considers the entire scope of how industry and the armed forces coexist. Defence procurement is seen, in the UK at least, as much a matter of job creation as military neccessity.

    I take your point regarding the craft school versus mass production but I think that as far as civil aviation is concerned I'd sooner trust my precious body to an aeroplane that is exactly like the aeroplane that went through certification, rather than one that just has a passing resemblance!

  3. Voted this post 'good' 'cause I learned a lot from it.

    Got to read some of the newer stuff you've posted, you've been very active since I last checked.