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Aerospace Bristol is a new industrial heritage museum and learning centre being developed at Filton, to the north of Bristol. It will tell the story of the region's world-class aerospace industry - past, present and future. The Aerospace Bristol project is being run by the Bristol Aero Collection Trust.

Archive blog

Bristol Aero Collection Trust’s collection embraces objects and archives relating to the Bristol Aeroplane Company, its predecessor and successor companies (the ‘Bristol family’ of companies) and its workforce. Hear all about our news and discoveries. 

Final Month of the Project: Guest Posts!

Martha Lewington

The cataloguing project is coming to an end, and by this time next week will have ended completely. For the final blog post, we have some guest posts by volunteers who have worked on the project. Each volunteer was invited in for a few hours to research a subject of their choosing from the archive, and here are the results of their research:

First, a post about the Anti-Concorde Project by Maggie, who has been helping with the open afternoons:

Frightened fish and depressed chickens: was Concorde’s sonic boom as bad as people feared?

One of the aspects for which Concorde is most famous is the sonic boom. What exactly was it, why did it cause so much trouble in the plane’s early life, and was it really as bad as people feared? Some of the documents in the Concorde archive give a fascinating insight into the phenomenon.

First, though, let’s remember that Concorde isn’t the only aircraft guilty of this – every craft that flies supersonically can generate the sound. A sonic boom is caused when an object travels faster than the speed of sound and creates shock waves as it moves through the air, a little like the waves caused by a boat passing through water. Perhaps the word ‘boom’ isn’t the best word to describe the sound: rather, it can resemble a thunderclap, the firing of a bullet or the crack of a whip. The booms are loud and can cause vibration that is potentially damaging to buildings. This is why Concorde was not allowed to fly supersonically over land, only over water.

The following archive documents can allow us to trace this part of Concorde’s history.

1. The Anti-Concorde Project

The ACP was founded by an environmental activist named Richard Wiggs; he and many others were concerned about the environmental cost of supersonic passenger transport. They repeatedly questioned whether this new development was necessary and justifiable: here we see perhaps the most visible clash of environment and technological advance at a time when environmentalism was less prominent than it is today. Wiggs assembled an advisory committee containing many distinguished and notable academics, and their campaigns led to some major benefits for the air travel industry: research into the phenomenon of the sonic boom, which brought about a reduction in their intensity; and foregrounding people’s concern about aircraft noise, which resulted in more restrictive noise limits for aircraft and airports. Here are extracts from two of their publications (the underlining is their own emphasis).

(1) Special leaflet for distribution at the Concorde exhibition at Charing Cross, March 25th–April 25th, 1968

SONIC BANGS

The Concorde will make very severe sonic bangs all the time that it is flying supersonically. Many airlines will not buy Concordes unless they are allowed to fly them supersonically over land. This means – over Britain. And this means for the people of most of Britain – thunderous bangs every half-hour or so of the day and night.

These bangs will wake sleepers, frighten babies, startle surgeons, damage buildings, cause accidents, and intrude into every aspect of private life.

These are facts, proved by experience in the USA, France, and other countries.

Restriction of supersonic flying to routes over the oceans is no solution: the economic factors are all against it, and it would produce intolerable conditions for people on ships.

(2) ACP Information Sheet: Series 2, no. 1; April 15th, 1968

The Deputy Medical Adviser to the Greater London Council, Dr G. S. Wigley, speaking at a Symposium on Major International Airport Location Problems … on April 5th 1968, said that he was “very fearful of Concorde”, in respect of the great size of its engines and its “long and loud subsonic approach”, and of the sonic bang problem.

Dr Wigley referred to the fact that if Britain sells Concordes, some of the buyers will want to fly it supersonically across Britain, and “we are going to be faced with very considerable problems of sonic booms which I would guess would lead to severe anxiety in an unacceptably high proportion of the population. Unpleasant stimuli applied erratically and without warning are a classic prescription for anxiety neurosis and depression.”

The document goes on to detail reports of damage caused by sonic booms, such as the collapse of a gasholder in Dijon in France, and damage to a courtroom in Kansas, USA, where a trial was interrupted when a sonic boom blew out the windows of the courthouse and of other buildings nearby. The ACP collected newspaper articles to bolster their case, such as The Times of August 21, 1967, which reported a farmhouse in Brittany being ‘boomed down’ and goes on to state that ‘three people were killed. Admittedly they were apparently only farm workers, and some will think that they were properly sacrificed to speed’. (Attitudes of the time!) Ten other people in France had already been killed by sonic booms, the article states.

Picture: Documents of the Anti-Concorde Project

Picture: Documents of the Anti-Concorde Project

2. Concorde Flight Trials: Preliminary Report on Ground Overpressure Recordings and Observations in the Sultanate of Oman, August/September 1974 (Surveys of people living under the test flight paths)

The development of the Concorde project coincided with testing on the effects of the sonic boom phenomenon. Several test supersonic flights of military aircraft were carried out in the USA in the early 1960s, over Missouri, Oklahoma, Chicago, Milwaukee, Pittsburgh and the Edwards Air Force Base in California. Sceptics expected animals to be killed by shock leading to heart failure, but the National Research Council’s findings were that animals were affected more by the test observers than by the booms!

In late August into early September 1974, BAC Filton also carried out supersonic testing over areas of Oman as part of Concorde’s flight trials. Residents were provided with pre-printed questionnaires, ‘Report Form to be used by Observers for each Sonic Bang Event Made by the Concorde’, which they were asked to fill in whenever they were disturbed by a boom. People were asked to note down what was happening at the time they heard the boom (example replies: asleep, gardening, in conversation) and any occurrence that resulted from it (example replies: it woke them up, rattled the bedroom door, but did not interrupt conversation). Respondents were asked to reply ‘Very / Somewhat / Not at all’ to these three questions:

  • Were you startled?

  • Did you consider the event loud?

  • Did you consider the event annoying?

The Concorde archive contains several of these responses, which make surprising reading. Analysis of 36 questionnaires shows the following:

Capture.JPG
 

The fact that two-thirds of respondents were ‘not at all’ bothered by the sound confounds the expectations of the Anti-Concorde Project!

Pictures: Surveys of people living under the test flight paths in Oman, 1974 (survey credit: BAE Systems)

Pictures: Surveys of people living under the test flight paths in Oman, 1974 (survey credit: BAE Systems)

Surveys

3. BAC/Aerospatiale, ‘Supersonic Flight and Sonic Boom’, 1973; Fact Sheet, 1973

Our final documents give reassurances to some of the concerns raised in the early ‘doom-mongering’ publications. BAC/Aerospatiale’s document ‘Supersonic Flight and Sonic Boom’ (1973) describes tests conducted on ‘terrestrial and aquatic fauna’ (animals and fish), which found that the hatching rate of both fish eggs and hens’ eggs was not disturbed by booms, and that ‘seismic experiments have also shown that fish were not frightened by booms of intensity close to 1,000 times greater than Concorde-type booms’. As for chickens, one test subjected a brood of chickens to six Concorde-intensity booms per day for a month, with the finding that ‘there was no collective hysteria or phenomena of depression or shock through fright, but only a startled reaction which wore off during the experiment’.

As people had earlier (in the 1960s tests) reported structural damage to their homes, broken windows, cracked plaster, smashed teacups and the like, there was concern that large, shell-structure buildings such as cathedrals could be at great risk of damage. However, BAC/Aerospatiale reported that where such damage occurred, it was caused by booms ten times greater than that of Concorde during cruise. Their Fact Sheet of 1973 further calmed people’s fears. The danger, they wrote, was no greater than that caused by the vibration of a passing lorry or, indeed, the lowest notes of the cathedral organ!

Maggie Aherne

August 2019

And next a post on the Bristol Scout by Duncan, who has been helping out with various tasks such as preventative conservation, repackaging, listing and recording data:

The Bristol Scout and the Foundation of the British & Colonial Aeroplane Company

As a project volunteer I’ve been assisting the Project Archivist, with preventive conservation, documentation and repackaging of boxes of archive material covering a range of Bristol companies and aircraft from World War 1 and before through to Concorde. Among them are documents relating to the Bristol Scout, an early aircraft in the production line of the original Bristol aviation firm, the British & Colonial Aeroplane Company. One particular box includes a lovely hand written letter dating to 1915 from well-known company Chief Designer Frank Barnwell, then newly promoted, to Sir Stanley White, co-founder of the company alongside his father Sir George White. In it Barnwell discusses a report on the Bristol Scout, an aircraft he co-designed with colleague Harry Busteed, and outlines several of his proposed changes to its design. It’s a nice snapshot of the early days of the company as it had only been founded in 1910 and the Scout, designed and first flown in 1913 and 1914 respectively, was one of the company’s earliest projects. It came only a matter of a few years after its very first venture, an ultimately unsuccessful plane on licence known as a Zodiac in 1910, and its first in house design, the renowned Bristol Boxkite, in 1911.

The Scout was initially a pre-war racer but was adapted for wartime reconnaissance use with excellent results by the Royal Flying Corps and the Royal Naval Air Service (which would merge in 1918 to form the RAF as we know it today). Barnwell started his career in the secret X division of the company in 1911, left the company at the outbreak of World War I to enlist in the Royal Flying Corps and was then sent back from service in 1915 to become Chief Designer as mentioned above due to is pre-eminence in the field of aircraft composition. He would go onto design the company’s other important First World War aircraft, the outstanding Bristol Fighter, and stay with the company for the rest of his life designing other remarkable aeroplanes such as the interwar Bristol Bulldog and the Second World War light bomber Bristol Blenheim. His untimely death at the age of just 57, fitting in a strange and sad way as it was at the controls of a plane he himself had designed, was in 1938.

Image credit: BAE Systems

Image credit: BAE Systems

So with 378 boxes catalogued (a figure than has grown from last September due to the need to repackage many boxes), 9 open afternoons completed, a year’s worth of blog posts and more Concorde facts learnt than any one person needs to know, the project is complete!

Keep an eye on The National Archive’s Discovery portal for information about the 378 newly catalogued boxes

A big thank you to Maggie and Duncan who helped along the way and to Archives Revealed for making this project possible.

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