Bright Hopes for Plastics in Bus Body Design
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"IF one remembers that plastics generally are about five times lighter than steel, and thus tighter than aluminium, it must 'be obvious that such materials must have an interest ing future in the hands of competent designers." This remark was made by Mr. C. C. Bailey, M.1.Loco.E.„ M.I.P.E., bodyworks manager of Leyland Motors, Ltd., in an address to the Leyland Motors Engineering Society.
He presented a paper entitled "Plastic and Its Uses in Passenger Service Vehicles," which had been prepared jointly by Mr. Bailey and Mr. H. C. Gillvray, chief body designer. Mr. Bailey qualified the statement quoted by pointing out that plastics could be used in place cf metals only when the strength-weight ratio and the section modulus were each in favour of the contemplated plastic.
He foresaw wider use of plasties for-interior and exterior Attishes, and the possibility of bonding metal members together by plastic cements, instead of welding or riveting.
Mr. Bailey pointed out that phenol-bonded, plywood , materials had recently returned to the limelight because of the use of phenol and other similar glues. The reason why. these materials were not employed extensively, for structural parts of public-service vehicles, although they were success • 10 fully employed in aircraft, was that there was a vast difference in design between the aeroplane and the bus. It was necessary to be able to repair a bus body easily and quickly, because minor accidents were frequent. Stresses set up in the structure when the bus travelled over uneven roads were uncushioned and, therefore, severe. He thought that in the future it might be possible, with careful design, to use plastics and plywood to advantage if suitable methods of joining one section to another could be found.
Turning to the subject of plastic glues, Mr. Bailey said that it was now possible to bond, with amazing success and simplicity, two metal surfaces, such as steel or Hid uminium. where tensile test would show that the parent metal would fail beforethe bond. He quoted the results of some remarkable tests of this kind which had been carried out.
In addition to coverings for handrails, coloured pressed lamp covers and synthetic paints, plastics found many other applications in public-service vehicles. , Phenol paints were being developed toresist cigarette stubbing and to combat wear over a longer period Those plastics had many advantages over the other materials used-in the past; the,y were almost impervious to water and resisted damage to; a far greater extent.