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).
Endurance test report for Aerolite pistons on a Bentley No. 7 unit.
| Identifier | ExFiles\Box 86\2\ scan0098 | |
| Date | 25th October 1933 | |
| FILES ----- (2b) 25.10.33. -------------- AEROLITE PISTONS (BENTLEY NO. 7 UNIT). We have recently completed 21 hrs. endurance on Aerolite pistons on the above Bentley unit. The endurance consisted of full throttle running at a minimum speed of 4000 r.p.m. and maximum speed of 4500 r.p.m., each hour being run in the following manner. 30 mins. at 4000 r.p.m. in 5 mins. runs, with 1 min. interval between each run. 25 mins. at 4250 r.p.m. in 5 mins. runs, with 1 min. interval between each run. 5 mins. at 4500 r.p.m. in 1 mins. runs, with 1 min. interval between each run. This endurance test is much more searching than our previous endurance runs which were run as follows:- 45 mins. at 4000 r.p.m. in 5 mins. runs, with 1 min. interval between each run. 15 mins. at 4250 r.p.m. in 5 mins. runs, with 1 min. interval between each run. The pistons when first assembled had clearances shewn in appended chart, from which it will be seen that there was a clearance of .003 measured across the thrust diameter (i.e. at right angles to the axis of the gudgeon pin)). The clearance measured along the axis of the gudgeon pin was .014". Great care was taken in running in the pistons to ensure that the pistons had every possible chance of running satisfactorily. The running in period consisted of 4 hrs. light running at speeds up to 750 r.p.m. with extra oil supplied through the carburetters, before any attempt was made to increase the load. The total running in period consisted of 10 hrs. (approx.) until the unit held its power for 5 mins. at 4000 r.p.m. | ||