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).
The performance, failure, and cost of car clocks under testing.
| Identifier | ExFiles\Box 164\1\ img188 | |
| Date | 7th April 1938 | |
| -2- Third Week. Voltage constant between 14.15 and 14.1 volts. Time Variation :- No.1 clock gained 2.0 minutes. No.2. clock lost 4.0 minutes. Sum variation over three weeks - No.1 gained 1.0 minutes. No.2. lost 17.0 minutes. It will be seen that one clock made a good average performance, while the other consistently lost at all voltages. At the end of the test, No.1 instrument was removed from the bench rig for fitting on a car. At this point it failed as having stopped during the removal it could not be started again. Assuming that it is not necessary for car clocks to be very accurate and that no objection would be raised to adjusting the hands once a week if necessary then a permissible variation on normal voltage of plus or minus five minutes per week, appears to be reasonable. The faulty clock should be returned to the makers for examination when enquiries might be made concerning the adjustment of this type. A third clock which arrived during the tests has been fitted on car 7.B.Y. The price of this new type is 15 shillings as compared with 28 shillings of the standard instrument. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||