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).
Coolant jet tests for the Wraith III engine, comparing different jet configurations and recommending deletion from the specification.
| Identifier | ExFiles\Box 10\3\ 03-page059 | |
| Date | 27th August 1937 | |
| To By.{R.W. Bailey - Chief Engineer} o.{Mr Oldham} to Hs.{Lord Ernest Hives - Chair} o.{Mr Oldham} to Da.{Bernard Day - Chassis Design} o.{Mr Oldham} to Mx.{John H Maddocks - Chief Proving Officer} o.{Mr Oldham} to JBR. WRAITH III COOLANT JETS. Tests have been taken on a Bentley unit to determine the efficiency of the coolant jet scheme Lec.5664, whereby jets of water are concentrated upon the exhaust valve seats to effect a reduction in valve temperature. It will be seen from the following results that in their present form, the coolant jets do not merit inclusion on Wraith and should be deleted from the existing specification of the integral cylinder block and cylinder head with improved coring Lec.5824, together with the necessary alteration to the gasket. Running at the peak power at 4000 R.P.M. and at the weakest maintained mixture strength, the temperatures were recorded by means of an optical indicator, the figures quoted being an average of several tests. (1) Std. cylinder head without coolant jets 780°C. (2) " " " with normal circular holes in the coolant jets 776°C. (3) Std. cylinder head with slotted coolant jets 770°C. Despite the above results, we consider that the scheme is worth further investigations in respect of getting the maximum velocity and quantity of water through these jets by reduction in flow through the remaining waterways. This will take some time to complete as several features are involved as per the water flow variation of water temperature in the head. Even after such tests we cannot guarantee any appreciable drop in valve temperature, therefore until we have further information we consider that it be regarded purely as an experiment and deleted from Wraith III. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||