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).
Idler gear failures for the Phantom III and exhaust manifold joint issues for the Wraith.
| Identifier | ExFiles\Box 131\3\ scan0101 | |
| Date | 22th June 1939 | |
| - 6 - HM{Capt. W. Hallam - Head Repairs}1/MO.22.6.39 (continued) 7. Idler Gear Failures. Phantom III There have been two failures recently of the Fabroil idler gear. As no fault can be found other than what is peculiar to the material of the gear, and as failure puts the car out of action beyond the possibility of repair on the spot, we are rather concerned as to what we are to expect on other cars in service. Tests are in progress to determine the relative factor of safety of these gears, and we hope to be able to make some recommendation shortly. In the meantime, any replacements are made from a finer grain of Fabroil, A.1047, which was standardised some months ago, and which has a greater mechanical strength. We also have some Atwater gears similar to Wraith, which will be tried. 8. Exhaust Manifold Joint. Wraith It has for some time been felt that the spherical joint on the exhaust downtake pipe was unnecessarily expensive, and not of much value as a means of allowing for mis-alignment. We have therefore run 27.G.VI for the last 5,000 miles with the spherical joint deleted, and with a single flat Corrujoint washer packed with graphite. This is perfectly satisfactory, and the deletion of the spherical joint is justified. B.5 will go into Production with a similar flat joint, and with the front expansion box deleted as on 27.G.VI. The flange will have 3 bolts on the first 50 cars, afterwards going on to 4 bolts. We believe the latter will enable us to use ordinary C & A washers which we would prefer to the Corrujoint washers. Experience on the Phantom I has shown that C & A washers were perfectly reliable, with a 3 bolt flange on the rear downpipe which ran extremely hot under abnormal conditions due to the presence of a choke valve which produced a good deal of back pressure, with resultant increase in heat which must have been at least as high as the present downpipe temperature. [Signature] | ||