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).
Test report on the Goshawk blower with the carburetter and chokes removed to analyze changes in air direction and flow.
| Identifier | ExFiles\Box 179b\3\ img398 | |
| Date | 31th March 1933 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Aln. C. Sg.{Arthur F. Sidgreaves - MD} Sor. C. Rg.{Mr Rowledge} By.{R.W. Bailey - Chief Engineer} C. Ir. Rs{Sir Henry Royce's Secretary}/Aln.20/KT.31.3.33. GOSHAWK BLOWER WITH CARBURETTER AND CHOKES REMOVED. A test has been carried out on the Goshawk blower with the carburetter and chokes removed in order to ascertain the effect of the change of direction of the air in entering the carburetter and of passing through the chokes. The test was made with the diffuser having one passage blocked as arranged for the previous test and the comparison curves shown are for that condition. The throttles remained in position set fully open. Curves of delivery, efficiency, horse-power, and depression in the blower inlet passages above the throttles are shown. There is also added a curve of the theoretical depression based on the velocity of the ingoing air in the inlet passages. It will be seen that the actual depression is less than double the theoretical, from which it is concluded that the entering losses to the blower inlet are reasonable. The effect on the boost pressure of removing the carburetter is, of course, quite appreciable and increases as the flow increases. The value at 160 lbs/min. (the approximate working point of the blower) is about 1.7" Hg. higher than with the carburetter in position due to a difference in depression of 0.7". The efficiency has also risen from 57% to 61%, the difference being very slight at the lower air flows. The effect of the carburetter is to increase the depression by about 60% throughout the range. The depression found on the M.{Mr Moon / Mr Moore} blower for the same air velocity through the chokes which are of the same diameter as the Goshawk viz: 70 mm. was about 1.6" whereas in the Goshawk it is about 1.75". The test seems to indicate therefore that the turbulence of the air in entering the carburetter horizontally from opposite sides and turning upward into the chokes involves an appreciable amount of loss and the provision of a smoother flow might noticeably improve the boost obtainable. The working air flow is relatively less than that of the M.{Mr Moon / Mr Moore} carburetter. Hs{Lord Ernest Hives - Chair}/F.J.Allen. | ||