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).
Explaining the operation of the Phantom II petrol gauge and the reasoning for its design.
Identifier | ExFiles\Box 17\5\ Scan026 | |
Date | 27th January 1930 | |
To Pt. (Australia) From Hs.{Lord Ernest Hives - Chair} c. to BY.{R.W. Bailey - Chief Engineer} c. to Hn.{F. C. Honeyman - Retail orders} c. to Whr.{Mr Wheeler} 7460 Hs.{Lord Ernest Hives - Chair}1/MJ.27.1.30. PHANTOM II PETROL GAUGE. ------------------------ Replying to Pt.3/PH/19.12.29. You are wrong when you suppose that it is necessary to operate the small pump in order to read the amount of petrol in the tank. Whenever the car is being used the petrol level indicator shews the actual amount of petrol in the tank. The reasonfor fitting the pump is that if the car is left in the garage for two or three days the air which operates the gauge is absorbed in the petrol and it is likely for the gauge to read less than what is actually in the tank. As soon as the car is moving, the motion of the petrol in the tank automatically replenishes the air necessary to operate the gauge. There is no excuse therefore, of a man running out of petrol. Another reason for getting rid of the reserve tank was that now we use the vacuum pump it was essential to have a reserve in the autovac tank in order to get the engine running because without this, if the autovac was run dry the starter motor may not turn the engine sufficiently fast to enable the vacuum pump to replenish the autovac tank. We consider that when you get used to the Phantom II scheme you will like it very much better than the old one. You will also find that the majority of other makes of cars have dropped using a reserve tank since petrol gauges have been fitted on the dash-board. HS.{Lord Ernest Hives - Chair} | ||