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).
Arguing for the adoption of a satisfactory aluminium piston design for repair engines.
| Identifier | Morton\M3.6\ img020 | |
| Date | 9th June 1919 | |
| AN EXCELLENT CASE FOR THE AL. PISTON' COMPARISON WITH C. IRON To BN.{W.O. Bentley / Mr Barrington} from R.{Sir Henry Royce} Copy to Col. " EH " WOH " EFC ORIGINAL RE PISTONS, FOR REPAIR ENGINES It is of the utmost importance that we get a satis-factory design of aluminium piston for repair cars promptly. My chief object in pressing this forward is that no form of piston has been entirely satisfactory, and in the en-deavour to entirely avoid piston knocks, repair people have been driven to fitting cast iron pistons too tightly, and con-sequently they have seized, and stopped the car, sometimes per-manently. Now my experience with aluminium pistons is that if customers are given to understand that it is impossible to entirely avoid slight knocks from the pistons while the engine is cold, the aluminium pistons are quite satisfactory, espec-ially in the later thick trunk form that has been adopted for the short connecting rods. With this piston we should have a better running engine, less trouble from detonation, slightly more power, that we could remove the balance weights from the crankshaft, which is desirable, that we could lighten the front flywheel, also desirable, so resulting in reducing the weight on the front tyres by nearly 1 cwt. benefitting the steering and general running of the car, and giving an increase for hill climbing of 2½% through this saving of weight alone, but above all things, we have an end to the risk of galling the cylinders through over-tight cast iron pistons, which I am helpless to prevent repairs and service stations from fitting. R.{Sir Henry Royce} | ||