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).
Page 2 of a report detailing engine performance tests related to the deturbulated head, governors, and detonation.
| Identifier | ExFiles\Box 101\2\ scan0151 | |
| Date | 31th October 1936 | |
| ( 2 ) 31.10.36 second in each case. Therefore here again the deturbulated head shows another advantage (Two). The maximum speed and time taken to reach it, shows quite clearly and in almost every case, that the detur- bulated head is superior by a fair margin, and the fact that the maximum speed tests were conducted in conjunction with the other tests and not all run off on one particular day or under one particular condition shows them to be quite reliable. Here again, there is a definate advantage in using the detur- bulated head (Three). There is no doubt that the special governor as supplied by Swindell to I.Waller gives the best result throughout as far as detonations are concerned. The maximum speed at which the detonation can be heard upto an initial setting of 13° ADV. BTDC. is 10 MPH. We consider that the detonations are too prolonged and somewhat loud above an initial setting of 13° BTDC, and that also there is little to be gained in maximum speed and acceleration above this point. The engine is also considerably rougher on pick-up as the diagrams indicate. Below an initial setting of 13° BTDC, there is a drop in maximum speed and the time taken to reach 40 MPH. is longer by approx- imately one second, indicating a fall in power output at low speeds. In our opinion, the best combination of initial settings and governors is, the special governor supplied to Waller set at 13° BTDC. used in conjunction with the deturbulated head. This result we have underlined in red. In order to see whether we could improve on the characteristic curve marked No 4 on enclosed graph BT.{Capt. J. S. Burt - Engineer}26, assuming it to be nearly similar to the curve given by the governor supplied to Waller, as stated by Swindell in memo Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}13/JH. 28.10.36, we have re-checked it using the method of making the governor solid, and find that in order to eliminate detonations, the first part of the curve has to be retarded one degree as shown by inked line. This does away with the slight hump in the old curve, and brings it into line. We are unable to alter our governor to give this characteristic, but would be interested to know if it would diminish the power output to any great extent. ------------------- GWH{George W. Hancock - Head Chateauroux}/H.Hamilton. | ||