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).
Design specifications and limitations for a new starter motor for the B.80 Marine Engine.
| Identifier | ExFiles\Box 133\3\ scan0192 | |
| Date | 25th April 1940 | |
| File To Rm.{William Robotham - Chief Engineer} from Jnr.{Charles L. Jenner} c.c. to Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c.c. to Rm{William Robotham - Chief Engineer}/AA.{D. Abbot-Anderson} Jnr.{Charles L. Jenner}14/JH.25.4.40. s Starter Motor for B.80 Marine Engine. On this engine the flywheel is smaller in diameter than on the car, therefore, we are unable to use any of our previous starter motors. By using 9 teeth pinions we can get a ratio of 15.77-1 which in my opinion will be satisfactory when we keep in mind that on a vessel we are not restricted to the size of the battery. The size of the machine can be anything between 4.5 - 5" diameter, the limitation is where the car-case of the machine must clear the clutch casing bolt as shown on PL.195 herewith. As there will be some oil being flung about by the flywheel, cork or rubber clutch drives for the pinion will be unsatisfactory. Therefore, it appears we shall have to have either a plain Bendix crash start, or a solenoid relay operation. The object of the drawing is to enable Lucas or some other firm to understand the limitations and room available and to offer us the nearest they have existant. Then we can finalise the design. There is one feature which is important on a boat and that is that provision must be made so that the starter pinion can be freed quickly in the event of it becoming stuck. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} will please provide the figures for cold starting torque along with this drawing when it is sent out. Jnr.{Charles L. Jenner} Enclosed print PL.195. | ||