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).
The objections and applications of a testing instrument, particularly for braking tests.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan130 | |
| Date | 25th August 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: HsR/LG25.8.25. The main objection to this instrument is that the records have to be converted first to a velocity-time basis, and then to acceleration-time. This means a considerable amount of work. It is therefore not suitable for a production test. The only possibility of error appears to be that the wheel may leave the track at high speeds. In the case of windage tests where high decelerations are measured at high speeds, this is important. We believe that some inconsistency we have observed in our high speed tractive resistance tests may be due to this cause. Otherwise the tests certainly appear to be better than anything we have been able to obtain previously. Braking tests are conducted in exactly the same way unless the front to rear proportioning is such that the front wheels are likely to lock. In this case an auxiliary wheel of fixed circumference is fitted to the front axle in contact with the ground. the third pen on the Chronograph is connected to the brake pedal - the space time graph then gives :- (1) The exact road speed & sec. before the brake pedal was depressed. (2) The distance and time to rest from the moment the pedal is depressed. This method eliminates the personal factors which have hitherto prevented reasonable figures being obtained. The instrument can be adapted and used for numerous other experimental tests. Hs.{Lord Ernest Hives - Chair} | ||