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).
Preliminary unit test report of the B.60 engine, detailing a failure and comparing its performance against a Wraith engine.
| Identifier | ExFiles\Box 123\5\ scan0101 | |
| Date | 30th September 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. Ba/MOS. c. HPS.{Horace Percy Smith - Experimental Factory Mgr} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}9/WH.30.9.38. 1044. UNIT TEST REPORT OF B.60 ENGINE. We give herewith a preliminary report of the B.60 engine which was terminated after several power curves by the failure of the distributor and oil pump drive gear on the camshaft. POWER. We have compared on the attached curve (S.56), the open exhaust power obtained with the B.60 engine against that of a Wraith engine, which is non standard in the fact that it has Aerolite pistons with raised crowns, giving the same compression ratio of 6.45:1 on both engines. Both have the same Wraith induction systems with standard single Wraith Stromberg carburetters, and as the Wraith camshaft is nearer to the B.60 camshaft than any we have, we therefore consider that this is the nearest comparison of the relative types of the two engines that can be obtained. In the above conditions the Wraith engine gives a maximum output of 110 BHP at 3500 R.P.M. whereas the B.60 gives 117.5 BHP at 3500 R.P.M., this being the highest speed reached in the latter engine, owing to the failure of the distributor drive gear on the camshaft. The shape of the curve, however, indicates that the B.60 engine would not reach its maximum until 3750 or 4000 R.P.M. Below 1750 R.P.M., the maximum MEP irrespective of detonations shows the Wraith to be 5 lbs/sq.in. better than the B.60 engine. In analysing these results we consider that in view of the very short duration of the inlet cam, which is 216° over the heavy accelerations as compared with 232° on the Wraith, and 242° on the B.III, we anticipate that by increasing this duration, the high speed power will be appreciably raised. | ||