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).
Results of starter motor brake tests and the merits of plotting data on a torque base versus an ampere base.
| Identifier | WestWitteringFiles\G\September1921\ Scan55 | |
| Date | 13th September 1921 | |
| R.R. 285A (100 T) (S.H. 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 EFC1/T13.9.21. -6- Contd. Referring to Mr. Olley's note Cyl/G16.7.21 re starter motor brake tests, in which he made certain remarks (see our report EFC1/T22.6.21) on brake tests of R-R standard starter motor, the ampere base is no doubt quite a good base on which to plot the results of starter motor tests, although we think that in some respects the plotting of these on a torque base gives one a better idea of the relative performances of different motors, the torque being the most natural "independent variable". The engine torque of 1050 lb-inches mentioned by Mr. Olley, as the torque required to turn the engine at the freezing point, we feel is rather less than the actual figure. We have estimated this to be about the figure for torque when the engine is only in what we should call a normally cold condition, after standing overnight, and correspondingly we think that the figure of 50% efficiency must be a good deal below the actual efficiency of the transmission. EFC. | ||