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).
Need for a relief valve in the pressure system for high-altitude operation, with references to Pikes Peak and Cadillac cars.
| Identifier | ExFiles\Box 125\1\ scan0020 | |
| Date | 11th August 1920 | |
| contd. -2- The present pressure system without a relief valve would not be safe under these conditions, and the pre-war relief valve would stick because of the sand in the air. It would therefore be necessary to use some such scheme as the Cadillac. It would also be necessary to reduce the compression space of the air pump in order to pump a high enough pressure at the high altitudes. This can be easily arranged by an aluminium plug on the cylinder cap. These are not exceptional conditions except that the cars in this particular case will be called upon to operate continuously under these conditions. Pikes Peak is 14000 ft. and there is a road to the top much used by summer tourists. There are a hundred other mountains with roads up them running from 6000 ft. upwards. sand roads conditons and hot sun conditions are met in all parts of the U.S. It therefore seems highly desirable to incorporate a relief valve somewhat on the lines of the type shown. Mr. Belnap has had long experience with Cadillac cars, and states that he has known the air pressure on these cars to keep up for two months. It is not known what type of air pump delivery valve the Cadillac uses. Yours truly, ROLLS ROYCE OF AMERICA INC. Per M.{Mr Moon / Mr Moore} Olley. MO/G.{Mr Griffiths - Chief Accountant / Mr Gnapp} R.{Sir Henry Royce} R.{Sir Henry Royce} 235A (100T) (S) H.{Arthur M. Hanbury - Head Complaints} 159. 11-8-20 G 2800 | ||