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).
Various bearing metal combinations for Nitralloy cranks in both chassis and aero engines.
| Identifier | ExFiles\Box 154a\1\ scan0186 | |
| Date | 1st January 1930 | |
| Hs.{Lord Ernest Hives - Chair} BY2/J.1,1.1.30. RE NITRALLOY CRANKS. I think the whole question of the bearing metals to be tried out in conjunction with the above demands serious consideration before we commit ourselves to any further experimental work with cranks in this material. There are quite a number of really sound schemes which should be discussed from which we should decide what is the most likely combination for this particular service to start out with. Below is given a series of schemes and of course there may be a number of others. It is worthy of remark that zinc has a co-efficient of expansion of .000029 against .000019 for Phosphor Bronze which definitely favours Phosphor Bronze. (1) CHASSIS ENGINE. (a) i think the most hopeful combination for the 10000 miles car is chill cast Phosphor Bronze bushings for journals and big ends especially for 40/50 H.P. engines. (b) The Zinc Aluminium Alloy suggested by Hl. This I think should be run on a test bed engine in the first place and confined to 20 H.P. at first, or alternatively run on 20 H.P. in France as well as on the test bed of 20 H.P. engine. (2) AERO ENGINES. (a) Journals in chill cast Phosphor Bronze, big ends in Aluminium Bronze with blade rod in nitralloy or C.H.N.S. (b) Journals in chill cast Phosphor Bronze, big ends Nitralloy, white metalled inside, hardened outside, blade rod with chill cast Phosphor Bronze bushes. (c) Zinc Aluminium Alloy all round as suggested by Hl., but this, one considers, should be first tried out on a 20 H.P. engine in order to keep down charges for repairs if failures occurred. BY.{R.W. Bailey - Chief Engineer} BH | ||