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).
Analysis of cylinder liner distortion and buckling based on tests with various crankcase and liner configurations.
| Identifier | ExFiles\Box 178\4\ img050 | |
| Date | 27th April 1932 guessed | |
| -2- was found to be one similar to a standard with regard to form and top portion, but with lower panel tapered in to the bottom groove (Fig. 11) the groove being produced in the form of a true radius. The maximum distortion with this liner was the section was reduced from .004" to .003" and by inference this figure was further reduced to .002" which is within the limit of distortion obtained with the plain type liner. In order as it is infinitely less stiff, it is desirable that the consideration of the increased section stiff should receive consideration in addition to the other modification. Having evolved a liner which gave good results on single cylinder rig, it was now decided to build up a set of these liners on a standard 1. cylinder Kestrel to ascertain whether the improvement could be maintained under actual assembly conditions. The distortion of the bores was now found to have increased to .004", and it is presumably due to the loss of support under the liner flange caused by the buckling of the crankcase cylinder joint face. Indicator tests have proved that this face sank as much as .003" to .004" between the studs in the longitudinal direction on the inside of the case, and that smaller buckling took place on the outer edge between .0015" to .002". This distortion was registered between the cylinder bores, and this was probably accounted for by the additional support provided by the cell walls and crankcase webbing. These tests were repeated with the new type stiffened crankcase which provided better support for the liner flanges, and distortion was then found to be again reduced to within the limits obtained on the single cylinder test rig. In view of the fact that piston bedding troubles are not so pronounced on this type of "buzzard" engine it was decided to carry out tests on this type of cylinder, and it was found that the maximum bore distortion was approximately similar to that obtained with the old type crankcase. Total stretch and buckled type fracture liners on the stiffened crankcase. Less buckling was found to be present on the standard Neutral, which is presumably accounted for by the additional liner flange support provided by the middle stud boss and bosses. In the light of the results of these tests, it would appear that early troubles due to the fracture of the top between the cylinder bores was caused by tight fitting liners which in their distorted condition over-stressed the cylinder casting all when subjected to vibration produced failure. | ||