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).
Secret report from India on issues with chassis 9.G.111 after 5726 miles, focusing on gearbox and bearing problems.
| Identifier | ExFiles\Box 57\1\ Scan166 | |
| Date | 25th June 1925 | |
| TO HS.{Lord Ernest Hives - Chair} FROM AJS. S E C R E T. X5770 AJS3/M25.6.25. Copy to BY.{R.W. Bailey - Chief Engineer} I N D I A.{Mr Adams} REPORT ON CHASSIS 9.G.111. AFTER 5726 MILES. Referring to the above report in HS{Lord Ernest Hives - Chair}1/LG23625, and that para. dealing with the gearbox oil leaks, it appears from the report that the speedometer drive and change speed lever shaft bearing carrier must be the one shewn on LeC. 1928, which is the original scheme, and not our latest one which is shewn on LeC. 1987, as this latter drawing incorporates the principle features suggested in the report. [Handwritten note: Et is] Referring to the position of the oil drain back to the gearbox which is actually made in the side of the box, and which the report suggests may be 1" further to the rear, we think if any gain is to be obtained from drilling this as far to the rear as is possible with the existing castings, that this should be done, but we do not think it advisable to alter the casting unless it is proved further that our scheme on LeC. 1987. is inefficient. In any case with either scheme on LeC. 1987. or 1928, we cannot see how it is possible for an oil leak to occur as referred to in the above report providing a reasonably good face joint is made between the gearbox and the speedometer drive unit which bolts on to it. [Handwritten note: Hoffmann bearing of New Departure design] With regard to the para. dealing with servo gears we note that the report mentions a Hoffmann ball bearing No.5037. We have carefully examined our drawings, and the catalogues here, but cannot see any bearing of this number in either of them. The bearings supporting the servo drive shaft worm wheel are the New Departure designed to take thrust in one direction, and we can only assume that in the desire to avoid delay in getting this car on the road, some type of Hoffmann ordinary radial bearing was used in place of the New Departure specified, and that this radial bearing had insufficient thrust capacity resulting in the slackness referred to in the report. If our assumptions in connection with the above are incorrect, and there is some further hidden trouble, we should like to hear more concerning the two previous paras. AJS. | ||