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).
Methodology for testing driving visibility on a skid pan.
| Identifier | ExFiles\Box 155\4\ scan0024 | |
| Date | 26th February 1937 | |
| To Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies} Copy to Rm.{William Robotham - Chief Engineer} E.{Mr Elliott - Chief Engineer} [crossed out] Da.{Bernard Day - Chassis Design} [crossed out] Driving Visibility. As promised to you the other day when we visited the Skid Pan together with a view to examining the best method of marking it out for testing driving Visibility we send herewith a copy of the latest Recommendations to the Ministry of Transport by the Society of Motor Manufacturers and Traders. These Recommendations are based on the results of the investigations on a number of cars made by the Society on the L.P.T.B. Skid Pan at Chiswick. On a graph sheet herewith in pencil we show the lines which we suggest should be marked out on the skid pan preferably in black. Assuming it is impossible to move the central post we suggest that the centre of the 25 ft. circle be struck just to one side of it. The post is marked A in the diagram and can be used by a observer stationed at the point B for ancertaining that the driver's eyes are immediately over the transverse base line. The green line on the graph shows the longitudinal axis of the car and we suggest that this be determined on the skid pan by a post placed about 14" off the longitudinal axis, representing the driver's sight line, and away out on the periphery of the concrete. A line of short length near the base line would serve as a close sight for the driver. In other words all of the green line need not be drawn. With reference to the height of the driver above the compressed seat, we propose that Rm{William Robotham - Chief Engineer}/FD{Frank Dodd - Bodies} should be the observer as his height resembles that of the observer used by the Society, namely 5'8 1/2", and the height of his eyes above a wooden seat is 2'7 1/2". We shall be sending you shortly suggestions for determining what is the corresponding height between the uncompressed cushion and the driver's eye in the case of each car tested by this observer in order to prove or disprove the suggestion made by the Society that a height 2'6" from the uncompressed cushion corresponds to a height of 2'7 1/2" above the compressed cushion. If possible we would like to find some better means of fixing the position of the driver's eye which we could submit to the Society and we shall try to do this. Ev.{Ivan Evernden - coachwork} Att: | ||