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).
Tests to ascertain the effect of a 20 lb load on 40/50 Chassis Brake Springs G335 when heated to various temperatures.
| Identifier | ExFiles\Box 32\2\ Scan047 | |
| Date | 31th August 1923 guessed | |
| By c.to Hs.{Lord Ernest Hives - Chair} H11/EF30823. Y3458 Laboratory. Re Tests to ascertain effect of a 20 lb.load on 40/50 Chassis Brake Springs G335, when heated to various temperatures. Method of Test. A bar of steel 1¼" X ¼" section bent twice at right angles to form a U with arms 7" long and distance between arms 26". To one arm, projecting inwards, a ¼" rod with a hook at inner end was permanently fixed. The spring to be tested was attached to this hook at one end, the other end being attached to a double hook connected by an indicator spring to a fourth hook passing through the other arm and adjustable for tension by a nut. The apparatus was so arranged that when the spring to be tested was in the centre of the furnace, the other spring was right outside the furnace and unaffected by conducted or radiated heat. Centre punch marks on the hooks enabled the extension of the indicator spring to be measured and this formed a measure of the extension of the spring under test, each spring tested having been compared with the indicator spring before heating. Any extension of the spring under test, due to expansion of the apparatus during heating to the temperature required, or to collapse of the spring itself was then taken up at intervals in order to keep the load as constant as possible. Each spring was extended 4 ins. as requested and all temperatures measured accurately with a potentiometer. Results of Tests. Same Spring Test No. Temp. Time (approx) at temp. Overall Length Before. After. Increase. 1. 314°C. 10 mins. 3.16" 3.26" 0.10" 2. 200°C. 10 mins. 3.16" 3.16" Nil. 3. 358/368°C. 30 mins. 3.16" 3.87" 0.71" 4. 314°C. 30 mins. 3.16" 3.35" 0.19" H1. HE | ||