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).
Front shock damper performance, oil displacement figures, and potential improvements for the Bentley III & 50 models.
| Identifier | ExFiles\Box 154a\4\ scan0066 | |
| Date | 15th February 1938 | |
| LES what do you say to all this Rm {William Robotham - Chief Engineer} To Da. {Bernard Day - Chassis Design} .. From Da {Bernard Day - Chassis Design} /DB. {Donald Bastow - Suspensions} c.c. to By. {R.W. Bailey - Chief Engineer} c.c. to Rm. {William Robotham - Chief Engineer} c.c. to Ev. {Ivan Evernden - coachwork} c.c. to Rm {William Robotham - Chief Engineer} /Les. 1306. Da {Bernard Day - Chassis Design} /DB. {Donald Bastow - Suspensions} 20/N.15.2.38. Front Shockdampers - Bentley III & 50. One of the items discussed during the visit of Rm {William Robotham - Chief Engineer} /FJH. {Fred J. Hardy - Chief Dev. Engineer} and myself to Mr Olley, and mentioned in the subsequent joint report sent out under the reference Rm {William Robotham - Chief Engineer} /FJH. {Fred J. Hardy - Chief Dev. Engineer} 1/AP.23.9.37, was his desire to increase the displacement of shockdamper oil per inch of wheel movement. A typical figure quoted was approx. 0.250 cub.in/in. for the normal lever and bell crank type of damper, and Olley said an attempt was being made to increase this to as much as 0.65 cub.ins/in. by using a damper such as the "flit gun" telescopic damper. Figures for our Phantom III were calculated and incorporated in this previous report, and they are repeated here:- front damper with original small central tube 0.55 cub.in/in. and with large central tube 0.47 cub.in/in. rear damper 0.38 cub.in/in. It seems a pity therefore that the adoption of the Gordon-Armstrong type damper should imply a reduction of the oil displacement figures. The application to the rear end of B.III. for instance, gives a figure of only 0.27 cub.in/in., about that quoted by Olley as being too small for their liking, and for a damper load of 130 lbs. this implies a pressure of about 490 lbs.sq.in. or 750 lbs. sq.in. for a 200 lb. damper load. This figure of 0.270 cub.in/in. is believed to apply also to the application of this type of damper to the present Bentley car, such as fitted to the car now in France. It is significant that on this car there have been consistent complaints in the daily reports of insufficient rear damping. One is even more nervous of the front damper on B.III. which has a displacement of 0.19 cub.in/in. only, and for 100 lb. load at the wheel this corresponds to a pressure of 540 lbs.sq.in. approx., especially in view of the present declared intention of using the suspension incorporating this damper on cars whose front end weight may be as much as 85% of that of the Phantom III. Continued...... | ||