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 comparing the effect of altitude-related air pressure on Cambridge and Negretti & Zambra thermometers.
| Identifier | ExFiles\Box 175\4\ img143 | |
| Date | 20th May 1933 | |
| To Ag. From Ha/Gib. c. to Wor.{Arthur Wormald - General Works Manager} c. to Py. c. to Er. c. to Lr.{Mr Ellor} c. to Lp.{Mr Lappin} c. to Mr. Jaques. x3987. x4471 EFFECT OF ALTITUDE ON CAMBRIDGE AND NEGRETTI & ZAMBRA THERMOMETERS. It is suspected that thermometers used on aircraft engines might be affected by varying air pressures due to altitude. A test has therefore been carried out using Cambridge and Negretti & Zambra thermometers. An apparatus was rigged up, which consisted of a glass cylinder supported at both ends by aluminium plates. The two instruments were placed inside the cylinder in such a manner that the dials could easily be read. A suction pipe and gauge were also fitted to the cylinder, the suction being obtained by connecting the pipe to a 40/50 car engine inlet manifold. The whole apparatus was made air tight by using rubber washers. The thermometer bulbs were placed in an electric kettle containing cold water. The two thermometers were calibrated against a glass thermometer which was also placed in the kettle. The water was then heated up and readings taken at intervals with and without suction being applied to the cylinder. The results for the Cambridge thermometer are shown on the attached sheet. It was observed that the Negretti and Zambra thermometer was entirely unaffected by the varying pressures. This may be due to the fact that the Negretti and Zambra thermometer is filled with Mercury and the Cambridge filled with Ether. Hg/T.A.Gibson. Attached: One print. | ||