Piston clearances measured at various intervals during a 165-hour bench test.
| Identifier | ExFiles\Box 77\3\ scan0022 | |
| Date | 11th November 1919 | |
| Contd. -6- EH1/LG7.11.19. ============= 1. Bench Test - 165 hours. 4 pistons have run 105 hours. 2 pistons have run 25 hours. The condition of the pistons after this run is as follows:- We measured the clearances of the pistons before the run, after 60 hours at various speeds, and again after a further 45 hours at 2000 R.P.M. The clearances were measured at three points A, B and C. [Diagram of a piston with measurement points A, B, and C indicated] | Piston No. | Start of test. | | | After 60 hours. | | | After 105 hours. | | | |---|---|---|---|---|---|---|---|---|---| | | A | B | C | A | B | C | A | B | C | | No.1 ran 25 hrs. | .007" | .0035" | .002" | .0075" | .004" | .003" | .008" | .005" | .0035" | | No.2 | .0065" | .003" | .0025" | .007" | .004" | .003" | .0085" | .005" | .004" | | No.3 | .007" | .0035" | .0025" | .007" | .004" | .003" | .0085" | .0045" | .004" | | No.4 | .0065" | .0035" | .0025" | .007" | .004" | .0035" | .008" | .005" | .0045" | | No.5 ran 25 hrs. | .0065" | .0035" | .0025" | .0075" | .004" | .003" | .007" | .005" | .004" | | No.6 | .0065" | .003" | .0025" | .0065" | .0035" | .003" | .0085" | .005" | .004" | Contd. [Upside down text at bottom right: R.R. 235A (100) (F.S.P. 576. 16-4-19) (G. {Mr Griffiths - Chief Accountant / Mr Gnapp} 2354).] | ||
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).