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).
Test report on a K.S. Hobson petrol gauge for a 27-EX model.
Identifier | ExFiles\Box 17\5\ Scan104 | |
Date | 7th December 1931 | |
Copy for files. K.S. HOBSON PETROL GAUGE ON 27-EX. Having (a) Single pipe line. (b) Tank unit with air vent N.S.3143. (c) Petrol tank N.S.3144 having short filler. The following tests have been carried out to see if this single pipe line gauge could replace the present 3 pipe line gauge. Test I. Speed of replenishing. Having no hand pump the gauge relies on the swirling of the petrol in the tank to bring the reading to the correct figure, when once the reading has dropped, owing to the disconnection or leak in the pipe line, or over night standing. Figures have been taken therefore on the road showing the reading of the gauge every mile after the line had been disconnected. The first column gives the gauge reading previous to being disconnected. Previous Guage reading. | disconnected. | After 1 mile | 2 miles. | 3 miles. | 4 miles. | 5 miles. | 6 miles. | Type of Driving. 15 | 0 | 1.5 | 5 | 7.5 | 7.5 | 10 | 13 | Normal. 12.5 | 0 | 1.5 | 6.5 | 9 | 12.5 | | | Fast. 11 | 0 | 3.5 | 11 | | | | | Over a series of Hunch-back Bridges. 11 | 0 | 1.5 | 3 | 5 | 10 | 10.5 | | Fast. Normal. Test II. Escape of Petrol through the Air Vent in the Tank Unit When the tank is normally filled to the spilling level of the filler, no petrol escapes from the tank unit when the car is on level ground. If the near side rear wheel is raised 6" the spilling level of the filler is the same height as the spilling level of the gauge unit air vent. Owing to the swirling of the petrol and the extra head of petrol at the filler, when the tank is filled in a hurry to over-flowing, petrol escapes from the air vent when the near side rear wheel is considerably lower than 6" up. On very extreme cases we were able to make petrol show from the air vent with all wheels on level ground. We do not think this is serious however until the near side wheel has been raised 3.5". | ||