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).
Test report on a reduction gear spring drive for a Kestrel engine.
| Identifier | ExFiles\Box 179\2\ img260 | |
| Date | 18th February 1932 | |
| ORIGINAL To R.{Sir Henry Royce} From He/Tng. c. to Sg.{Arthur F. Sidgreaves - MD} Vor. c. to Rg.{Mr Rowledge} T. c. to Ry. Lr.{Mr Ellor} He/Tng.4/W.18.2.32. X4010. X2965. REDUCTION GEAR SPRING DRIVE - DES.1335. KESTREL 11 - S - 93. A drive to the above scheme has been tried out on a Kestrel engine. This component has been fitted to the engine as an experiment in connection with a vibration period which occurs in flight at 1450 R.P.M. It is a debatable point at the moment whether this period is an engine or an airscrew characteristic, and so in order to decide the matter we have altered the engine torque characteristic by fitting a spring drive between the airscrew and the crankshaft. Attached hereto is a photograph of the complete unit. It will be seen that the drive is incorporated in a modified coupling piece between the crankshaft and the reduction gear and that its torque is taken through a number of laminated steel springs arranged radially. Tests Carried Out. The drive was fitted to Kestrel 11 - S - 93 and running was carried out using Silvertown 7.4 Oil. Tests carried out may be grouped as follows :- (1) Proof of mechanical soundness. (2) Torsion tests on spring stiffness. (3) Proof of airworthiness. Results. (1) A two hours test was run off, viz: 1 hr. 55mins. at 2250 R.P.M. 472 BHP. 5 mins. at 2250 R.P.M. 525 BHP. After the above running the drive was stripped. Everything was found to be in satisfactory condition (Springs H.36822). (2) Curve 283 'F' (attached) shows the results of the torsion tests carried out on the spring blades H.36822. As a result of these tests a weaker set of blades H.36827 were fitted. Curve 284 'F' (attached) shows the results of the torsion tests on these. For the purposes of comparison the results of both tests are shown on the one curve 285 F (attached). | ||