Experimental (archery) bows (2 No) made from pre-stressed concrete for Professor Alan Harris of Imperial College, London (c.1975). The bows each weigh 1.992 kg. In November 2010 Professor Roland Paxton asked Professor Edwards how well the bows compared with the wooden one on which they were modelled for firing arrows and he said they were about the same – both very effective!
Alan Harris (1916 – 2000) was a pioneer of pre-stressed concrete and for his Inaugural Lecture in the mid 1970’s as Professor at Imperial College, London he had pre-stressed concrete bows made for him by Arthur Edwards. Arthur Edwards wrote:
“Their [the bows] birth came about one morning when, as was his want, Alan Harris popped into my office to see how things were going on. This time however he produced a copy of an Archery Magazine opened at a drawing of a normal competition wooden bow with details of dimensions and structural characteristics. Alan said he would like to present a pre-stressed concrete bow producing as near as possible these behavioural characteristics at his Inaugural Lecture in about six months. Hint taken and I set about trying to produce the goods. Eventually the bows were cast in pairs back to back with a space between. Two pairs were produced in the final casting. Each pair was externally pre-stressed by wrapping together and then the wire stuck to the concrete surface. When dry the wires were cut at the external face of the concrete. Of course this had to be done with the firing wire having to take some of the force so that each bow became a self-stressed unit. The divisions marked on the ruler are in centimetres. The dimensions chosen were to make the characteristics of the concrete bow as close as possible to the wooden one. This in turn defined the size of the aggregate used.
The bows were made in the Concrete Laboratory at Imperial College (London) to my design and specification and under my supervision. The technical staff helped significantly throughout.“
An article about concrete bows was published in the Journal of the Society of Archer-Antiquaries, 2016, Volume 59 pages 46-48.