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).
Graph showing the advance characteristics of the Goshawk ignition governor.
| Identifier | ExFiles\Box 51\5\ Scan224 | |
| Date | 23th March 1922 | |
| SUMMARY OF THE VARIOUS CURVES SHOWN. A. {Mr Adams} ADVANCE CHARACTERISTIC REQUIRED BY THE ENGINE, A TOTAL OF 12° BETWEEN THE SPEEDS OF 250 AND 1500 R.P.M., ASSUMING THAT THIS IS ALL THE AUTOMATIC ADVANCE REQUIRED TO BE. B. ADVANCE CHARACTERISTIC REQUIRED BY THE ENGINE, SIMILAR TO A BETWEEN THE SPEEDS 250 AND 1500 R.P.M. BUT ALLOWING A TOTAL OF 17° WHEN THE SPEED FALLS FROM 250 R.P.M. TO 0. I. ADVANCE CHARACTERISTIC OBTAINABLE FROM GOVERNOR, AS ORIGINALLY ARRANGED, OF 24° BETWEEN THE SPEEDS OF 250 AND 1500 R.P.M. II. ADVANCE CHARACTERISTIC OF 15° OBTAINABLE FROM GOVERNOR MODIFIED AS WE DESIRED AS TO ALLOW THESE TO COME CLOSER TOGETHER AT THE HIGHEST SPEED, AND UTILISING THE STRONGEST POSSIBLE PORTION OF THE RANGE OF MOTION. III. ADVANCE CHARACTERISTIC OF 15° OBTAINABLE FROM A GOVERNOR SUCH AS THE BOSCH, IN WHICH THE MOVING SYSTEM CAN BE GUIDED TO GET FURTHER ROUND TOWARDS THE 90° POSITION. IV. SIMILAR TO III. BUT UTILISING A STILL HIGHER PORTION OF THE RANGE. N.B. The nearer we select the portion of the range to the 90° position, the weaker must be the controlling spring, and therefore make the given curve more nearly like the curve desired, we may introduce a certain amount of "sloppiness" in the control. V. {VIENNA} ADVANCE CHARACTERISTIC OF 23° ADVANCE OBTAINABLE FROM GOVERNOR BETWEEN SPEEDS 0 TO 1500 R.P.M., AS ORIGINALLY ARRANGED. 1 & 2. ADVANCE CHARACTERISTICS PRACTICALLY OBTAINED BY INSTANTANEOUS VISION METHOD FROM GOVERNOR AS ORIGINALLY ARRANGED. 3. ADVANCE CHARACTERISTIC PRACTICALLY OBTAINED FROM GOVERNOR MODIFIED BY US AS DESCRIBED. N.B. This corresponds very nearly to the derived curve II. A ON DIAGRAM IS REPRESENTATIVE OF THE STRONGEST SPRING WE COULD FIT TO BE CAPABLE OF PRODUCING ON THE GOVERNOR AS MODIFIED BY US, THE EXACT ADVANCE CHARACTERISTIC REQUIRED. Y-Axis: CAM ADVANCE (DEGREES) X-Axis: DISTRIBUTOR R.P.M. Title: ADVANCE CHARACTERISTICS of GOSHAWK IGNITION GOVERNOR. Initials: ETC | ||