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).
Testing and issues found with new rear dampers.
| Identifier | ExFiles\Box 101\2\ scan0162 | |
| Date | 9th November 1936 | |
| 500d GRY.{Shadwell Grylls} HOTEL DE FRANCE, CHATEAUROUX, Indre. France. To. RM.{William Robotham - Chief Engineer} Copy GWH.{George W. Hancock - Head Chateauroux} 22. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} V.{VIENNA} Further to our daily report dated 7th Nov. 1936. We have to-day received the two new rear dampers from Paris. These were identical to those fitted to 22.G.V., apart from the length of the arm which we changed over. We have again struck the same trouble with one of them that we experienced with those on 22.G.V. That is we cannot get more than 80 lbs. on the end of the arm when the bellows are fully loaded i.e. 23 lbs.. On receiving the dampers and having fitted the correct levers, we immediately checked them over for maximum poundage under full load, and we were surprised to find that one gave off 150 lbs. and the other only 80 lbs., with a 14 second duration whilst pulling the lever from bottom to top. We then interchanged the valve chest and bellows from the good damper to each of the defective ones in turn, and fitted the chests and bellows from the defective dampers to the good one, but the result showed that the good damper maintained its poundage and the others still remained defective, clearly pointing out that it was not the valves and bellows at fault but the pistons and barrels. We do not think that the ball valves in the pistons are at fault, otherwise we would undoubtedly get a good stroke upwards and a poor stroke downwards or vice-versa, unless both valves have stuck open at the same time on all three dampers, which is hardly likely. There is in fact only one possible explanation, that is that the clearances between the pistons and the barrels vary, thereby limiting the maximum permissable poundage when the pressure reaches a certain height. We have checked and re-checked every possible cause of failure and have tried everything available in an effort to obtain the necessary damping and are consequently forced to the above conclusion. We would point out however that we have had no difficulty in setting the initial poundage i.e. without any load on the bellows, and that the poundage increases in proportion to the control system load, up to 80 lbs. in the case of the new damper from Paris and just short of 90 lbs. in the case of the other two. This is seriously delaying our results, as the tests are nearly concluded, apart from a final run with slightly more damping at the rear, which we are unable to obtain, and we would be glad of some information to assist us. ----------------------- GWH{George W. Hancock - Head Chateauroux}/HFH.{Hoppy F. Hamilton} H.{Arthur M. Hanbury - Head Complaints} Hamill-Stewart | ||