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).
Letter addressing issues with a radiator fan, engine revs, and road springs on a car.
| Identifier | ExFiles\Box 82\3\ scan0190 | |
| Date | 12th April 1935 | |
| G.W. Hancock, Esq., Hotel de France, Chateauroux, Indre, France. Handwritten: X200a (3) Many thanks for your note. The radiator has been despatched. We find that, entirely unknown to us, they had fitted a magnesium fan bracket which may have been the cause of your trouble. Obviously if the fan is slightly out of balance the magnesium is likely to fail very soon. In the meantime we are going to carry out careful comparative tests to the destruction of the steel fan and the fan with aluminium blades. If the aluminium blade fan stands up, obviously it will be less likely to be out of balance than the steel blade, and will therefore give the bracket an easier time. However, we think that we shall have to make the fan brackets stronger, probably in RR.53 of slightly increased section. Presumably you will get some sort of bracket to carry on with until we send out the parts to you. We were interested to hear that you found your maximum engine revs were limited to 4650 r.p.m. Can you tell us whether valve bounce was responsible for this, because with the new head you certainly have more power at 4600 revs. than you had with the previous head at 4500. The new head has of course larger inlet valves which will be likely to bounce sooner than the old inlet valves. Actually of course we do not want the engine to do more than 4650 r.p.m. and shall be very glad if the valves do stop it at this point, but want to know what is happening. We have heard nothing of London's complaints about the car. The road spring controversy is rather interesting, and I should have explained to you more clearly exactly what we have done to these road springs. The springs we have fitted are exactly the same poundage as the standard spring, i.e., they are no stiffer or not more flexible than what are being sold to-day. They are however lighter in the sense that they have not so much metal in them. They have also probably less internal damping as they have fewer leaves. I think the main trouble on 5-B-IV is one that always occurs when freshly lubricated springs are fitted to a car, and I think that after you have run for a few days in France you will find an improvement. | ||