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).
Summary of test results for the Aerolite piston, noting its durability, power increase, and susceptibility to cold knocks.
| Identifier | ExFiles\Box 86\2\ scan0141 | |
| Date | 8th November 1933 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/KT. 8.11.33. appreciably worse as the test proceeded. We found that this cyl. bore was slightly oversize. We have had similar knocks on our own flexible skirt pistons when run under very strenuous conditions. Generally speaking however, we should expect the Aerolite piston, which does not rely on a flexible fit in the bore to take up the cold clearance, to be more susceptible to cold knocks than our own, unless the cylinder bores are held to very close limits, but more suitable for high speed high power running. An important feature is that these pistons give an increase of five or six H.P. Summarising the position therefore - (1) We have an Aerolite piston, no heavier than our own, that will outlast several of the major engine components. (2) Under ordinary working conditions we should not expect complaints of knocking. (3) We get about 5 BHP. increase over the standard piston. We attach power curves showing this increase which we have confirmed on two engines. HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||