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).
Observations on engine bearings, crankcases, airscrew blades, Imperial Airways machines, and compression ignition engines.
| Identifier | ExFiles\Box 23\4\ Scan072 | |
| Date | 26th February 1932 | |
| -3- They are experimenting with "Kelmit" bearings and so far have obtained theirs from Napiers. They are enthusiastic about these. Their present white metal bearings are inter-changeable and big end bearings can be fitted in service without rebedding either on the bearing or the shell and even without removing the engine from the machine. They are fitted by the removal of one or two cylinders. The period between overhauls is extended up to 500 hours. The external part of their crankcases and other exposed aluminium parts are protected from corrosion by a zinc costing process which they say has been so far successful. I saw some blades of three blades steel airscrews they were experimenting. These were made from taper steel tubes being about .250" thick at one end tapering to .020 at the other end. These were formed by flattening to the required contour between dies in an improvised press. The blades were then trimmed off to the requisite plan size form and welded along the edge. The welding was apparently not satisfactory and they are now experimenting with riveted edges i.e. at the trailing edge. They have under construction five machines for Imperial Airways for operation on the Indian route. One machine was being assembled and looked a very pleasing job. It is a high wing cantilever monoplane of the Fokker type and has four engines mounted on the leading edge of the wing. The undercarriage and oleo legs are concealed in the fuselage, only a short length of axle and the wheels being visible. The machine construction is part wood and part metal for cheapness. It is estimated from wind channel experiments to have a cruising speed of 119 M.P.H. They are doing quite a lot of work on compression ignition engines and hope to have their complete engine running in a month. Their injection pumps are on the crankcase but they are considering a scheme for the pumps on the cylinders like Packards - the latter scheme is, however, more complicated from the pump drive point of view. Major Green says this engine has come out rather heavy and they have made everything amply strong until they have found from running experience the extent to which they can lighten the parts. | ||