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 Kelvin Bottomley & Baird Ltd. regarding the design limitations and frequency range of their K.B.B. Vibrometer.
| Identifier | ExFiles\Box 138\2\ scan0134 | |
| Date | 30th March 1935 | |
| REGISTERED 'Kelvite' TRADE MARK SCIENTIFIC, NAVIGATIONAL AND AERONAUTICAL INSTRUMENTS. ELECTRO-MEDICAL APPARATUS. TEXTILE TESTING APPARATUS. BUROVOX TELEPHONES. TELEPHONE: DOUGLAS 2330. TELEGRAMS: METER, GLASGOW. KELVIN BOTTOMLEY & BAIRD, LTD. 18 CAMBRIDGE STREET, GLASGOW, C.2. CHW/DW. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}3/AP. 1163 30th. March, 1935. Messrs. Rolls-Royce Ltd., DERBY. Dear Sirs, K.B.B. Vibrometer. ------------------ We thank you for your letter of March 29th. Unfortunately the design of the vibrometer does not permit of it to be effectively used at vibration periods higher than about 7000. You will no doubt appreciate that for the higher frequencies a stiffer reed has to be employed, with the result that the amplitude of vibration of the free end when tuned by adjusting the sliding clamp on the reed is correspondingly smaller than with the less stiff reeds. We have occasionally fitted the standard K.B.B. Vibrometer with a reed to run up to about 7,500 per minute frequency, and in such case we have found it impossible to load the end of the reed, in fact we were obliged to make the reed taper with its smallest width at the free end. Accordingly the amplitude of vibration suffered, so that we do not feel that the design permits of dealing with frequencies up to 15,000 per minute. The enclosed pamphlet gives some particulars of the instrument and we may advise you that with three reeds and calibration curves covering frequencies from about 300 to about 5,000 per minute the price is £15. 0. 0. You will no doubt appreciate our desire not to push the instrument beyond its range as at present designed as this would be misleading to our clients. We should be glad to give you any further information in our power, and are. Yours faithfully, KELVIN BOTTOMLEY & BAIRD, LTD. G H Wright Technical Manager. Encl. | ||