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).
Experiments and testing procedures for floating bush bearings on the Eagle XVI engine reduction gear.
| Identifier | ExFiles\Box 42\2\ Scan004 | |
| Date | 17th October 1925 | |
| R R 293a (100 T) (S. H.{Arthur M. Hanbury - Head Complaints} 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 TO HS.{Lord Ernest Hives - Chair} FROM AJS. C. to CG., RG.{Mr Rowledge} EAGLE XVI. We have considered that the use of floating bush bearings for the planet wheel and pinions of reduction gear for above engine would get us out of all the troubles connected with the action of centrifugal force on the cages, balls, and rollers, of anti friction bearings, and incidentally reduce the weight and cost of the parts considerably. We are making a design of the above reduction gear shewing these plain type of bearings and in the meantime would ask you to be good enough to put through some experiments embodying the principles shewn in the attached sketch. Prolonged tests should be carried out to make certain of the durability of these bearings under load. We shall be glad if you will put the experiment in hand without delay so that we can have data with which to check up the proportions adopted in the actual designs being made now. These experiments are concerned with more than the present Eagle XVI. reduction gear as it is possible we shall find the floating bushes extremely desirable for second motion shaft gearbox work for eliminating bearing noise, and with this in view, are asking you to conduct further experiments than are immediately connected with the Eagle XVI., although the latter should be given priority. You may consider it expedient to get more than one rig for testing. The first test should be one of a total of 200 hrs. duration, the comditions being reported upon say at intervals of 50 hrs to get some idea without delay as to the probable success from a wearing point of view. The intensity of pressure on the bearing surface immediately on the shaft to be 750 lbs. per sq. in. with an oil pressure varying from 10 to 20 lbs. per sq. in., the RPM. to be 3,700. Surfaces H.{Arthur M. Hanbury - Head Complaints} and S. casehardened. B. to be whitemetalled inside and out. Another test should be made under same conditions as above but with B. fixed in H.{Arthur M. Hanbury - Head Complaints} for turning. If above tests indicate that bearing pressures cause very little wear they should be increased until the max: safe load is determined for this type of bearing at the revs. given, and at other revs., to enable us to get an idea of its capacity under varying conditions. The floating bush type should also be tested under similar varying conditions to the fixed bush, to determine their relative merits. Also gravity oil feed should be tried to determine the possibility of this type of lubrication. We think it may be useful to compare also the relative merits of a plain floating bronze bush with the whitemetalled one. The first experiment mentioned here is urgent in view of Eagle XVI. position. AJS. | ||