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).
Letter to Mr. Humphrey Symons regarding tyre inflation pressures for driving on sand.
| Identifier | ExFiles\Box 114\4\ scan0017 | |
| Date | 29th January 1937 | |
| A 121 D.{John DeLooze - Company Secretary} R.{Sir Henry Royce} CO., LTD. NWHF/MC.3. Contd... SHEET NO. 2. 29th January' 37. Humfrey Symons, Esq. hard sand inflation pressures of 20 - 25-lbs./sq.inch may be used, when soft sand is encountered inflation pressures may be dropped to say 10-lbs."sq.inch., when the soft sand has been negotiated the pressures can be increased again, lowered again for soft sand, and so on. In this way the minimum amount of running is done at low inflation pressures with consequent reduction in power consumption for long stretches of a journey. Tables 1 and ll show the effect on contact pressures of oversizing at fixed tyre loads. Table lll gives for various loads the tyre size that is required to enable a vehicle to cross very soft sand. Table lV gives the contact pressures involved in Mr. Symon's journeys to Kano and Timbuctoo. Kind regards, Yours sincerely, Tables 1, ll, lll & lV. attached. | ||