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).
Modification of capillary tubes for gauges and requesting further vehicle testing.
| Identifier | ExFiles\Box 44\4\ Scan169 | |
| Date | 22th January 1930 | |
| Messrs.Rolls-Royce,Ltd., Date 22. 1.30. Page 2 of the facia board. The clip can be removed, however, for attention to the instrument once it has been dismentled from the board. The capillary tubes in these two particular instruments have had to be joined, as the capillaries fused into the small supply of fused glass tubes which we have by us, were not of sufficient length for your gauges. In production gauges in future, they will be a complete piece of tube. As the success of the fused seal is affected by the thickness of the wall of the copper tube used for the capillary, we have been obliged to use an internal bore for the capillary slightly larger than formerly. This means that the drag or break upon the surge of the liquid from the back tube to the front tube is slightly altered. We have imitated the conditions of the existing gauge as far as we could possibly do so on our test bench rig, but without testing it for surge on a car, we cannot be quite certain that we have done so exactly. We shall be obliged, therefore, if prior to sending the car away, you would make one test with the tank approximately full, and do some fast accelerations on the lower gears, to see that the amount of restriction on the passage of the liquid is | ||