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 from Cambridge Instrument Company regarding their rotational accelerometer, its function as a vibrograph, and recent improvements.
| Identifier | ExFiles\Box 175\4\ img149 | |
| Date | 24th October 1933 | |
| x 3987 TELEGRAMS: INSTRUMENT, CAMBRIDGE. CODES: A.B.C. (5TH AND 6TH EDITIONS). WESTERN UNION: BENTLEY'S. TELEPHONE: CAMBRIDGE No. 615. CAMBRIDGE INSTRUMENT COMPANY, LIMITED. HEAD OFFICE AND SHOWROOMS: 45, GROSVENOR PLACE, LONDON, S.W.1. WORKS: LONDON AND CAMBRIDGE. REGD. TRADE MARK. MANUFACTURERS OF MECHANICAL & ELECTRICAL INSTRUMENTS OF PRECISION. YOUR REF........... Ha/Gry.{Shadwell Grylls}6/KT CAMBRIDGE, ENGLAND. IN REPLY PLEASE QUOTE... CCM/IB 24th October 1933 Messrs. Rolls Royce Ltd., Experimental Dept., Derby. Dear Sirs, We thank you for your letter of October 23rd, enquiring about our rotational accelerometer. Actually at the speeds you mention this would act as a vibrograph and would record the actual displacements from the [handwritten: mean] speed of the shaft driving the instrument. We have recently considerably improved the instrument by arranging it for four different sensitivities. The instrument will record on celluloid and, therefore, has all the advantages of that type of record, that is to say, the movements do not require magnification with resulting errors in the record due to inertia in the moving levers. However, a microscope is no longer required to measure the results, we now supply a light portable projector which can be used on the spot with a 12 volt battery or from the mains to project an image of the celluloid record, magnified ten times on to a ground glass screen so that the record can be clearly seen by three or four persons simultaneously. The records, therefore, may be discussed at once | ||