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).
The performance and characteristics of the turbulent head engine component.
| Identifier | ExFiles\Box 14\3\ Scan024 | |
| Date | 26th November 1928 | |
| WOR.{Arthur Wormald - General Works Manager} c. HS.{Lord Ernest Hives - Chair} TURBULENT HEAD. -------------- Referring to BJ9/E.23.11.28, the introduction of the turbulent head was undoubtedly intended, amongst other advantages, to increase the available power, but as this increase of power is dependent upon increasing the compression, and since the increase of the compression increased the re-action vibrations at low speeds, this particular advantage of the turbulent head is not available. Whilst early chassis with the new head showed reduced H.P. this was not a result of the new feature, but was due to what often happens when a new design is introduced e.g. the optimumm conditions for power are not really known, andtherefore until we get well acquainted with the new design less HP. is available than one expects, but this phase has been passed through, and we would now say definitely that up to speeds of 12 miles per hour on top speed the power given by the turbulent head engine is equal to that of its predecessor, and at higher speeds there has been a definite gain, roughly about 4% at 60 miles per hour and over, gradually rising to this from all square at 12 miles per hour for the two types. The answers to BJ's specific questions are as follows :- 1/- Does it give more power with the same compression ? The engine does give slightly more power from 12 miles an hour upwards, with the turbulent head and standard compression. 2/- Does it save petrol consumption in actual practice ? The petrol consumption is unaffected by the turbulent head design. 3/- What is the result of increasing the compression ? If we increase the compression from 4¼ to 1 (our present standard) to 4.75 to 1 we should gain a 10% increase in power without running the risk of detonation becoming troublesome, but the increased explosion pressure would | ||