From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical explanation of tyre construction, focusing on the fabric 'tissue' (warp and woof) and the generation of heat through friction.
| Identifier | ExFiles\Box 1\7\ B001_X15 20 46 50 59-page135 | |
| Date | 1st August 1920 guessed | |
| -2- is not a homogeneous and indivisible element as a metallic thread, but a combination of a certain number of elements which are held together by interlocking of their particles. What does the weaver do with such a thread? He combines a methodical entanglement which realises what we call a "tissue". To speak with greater accuracy he stretches out on his loom a series of vertical parallel threads, the whole of which is called the "Warp" (whose length is the length of the tissue itself). By means of the "Shuttle" he assembles together these threads by a new series of smaller thread, parallel but horizontal, the whole of which is called the "Woof", which is consequently the same width as the tissue. Therefore, the ordinary tissue is a kind of "matting" the elements of which pass alternately over one another. It may be seen that in a tissue the active elements, that is to say, the element which works, is the "warp" threads. The woof threads have no other object than to strengthen the former to enable them to be handled, cut and applied in various manners without scattering them. The result of this is that if one wishes to realise a strong tissue he will have to diminish as much as possible the importance of the woof, and to reinforce on the contrary the defensive value of the warp. Now we must bear in mind that the pneumatic cover is composed not only of a single layer of cotton tissue, but of several layers super-imposed and stuck together by means of rubber solution. It is easy to understand that when passing over an obstacle, and even on account of an uninterrupted crush successively undergone by all the points of the tread all these elements slightly move upon one another, them come back to their previous place, and so on. A series of friction is therefore induced inside the tyre with the result that the temperature is raised. This can easily be tested by simply placing the hand, even in winter, on a tyre which has just | ||