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 Thermoid clutch facings for 25/30 and Bentley models, detailing performance, bursting speeds and recommendations.
| Identifier | ExFiles\Box 103\1\ scan0244 | |
| Date | 10th September 1937 | |
| To By.{R.W. Bailey - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Hs.{Lord Ernest Hives - Chair} a.{Mr Adams} to Mx.{John H Maddocks - Chief Proving Officer} c. to LA.{L. A. Archer} 512 Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler}7/JH.10.9.37. X re Thermoid Facings on 25/30 and Bentley Clutch. Thermoid faced clutches have been run on Experimental Bentleys as follows :- 5.B.IV. 1063 miles. Long American Plate. 3.B.IV. 1510 " Borg & Beck standard plate. B.23.AE.5131 " " " " B.56.BN{W.O. Bentley / Mr Barrington} 5383 " " " " 6.B.IV Recently fitted. In every case the engagement has been smooth and entirely free from jagger even when no prop. shaft damper is fitted. Similar plates have also been fitted to two customers cars, no further complaints received. With regard to Bursting speed, the Phantom III 13 1/4" Thermoid facings (not segmented) failed at 6193 R.P.M. and at the same R.P.M. the stress on the material of the 11" plate would be 18% less and on the 10" plate 24% less while the bursting speed at same stress would be 6850 and 7180 R.P.M. respectively, we therefore have a very good margin for bursting speeds, (so long as it is not segmented). Borg & Beck are arranging a rig for further bursting tests, and we hope to obtain actual test figures in the course of next week. We recommend changing over to Thermoid on the 25/30 and Bentley as soon as material is available, probably a matter of 5/6 weeks. Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler} | ||