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).
The causes of and solutions for roof 'booming' and vibrations.
Identifier | ExFiles\Box 3\1\ 01-page097 | |
Date | 14th November 1913 guessed | |
beyond their usual limit. (4) Large flexible wind screens, which are always vibrating on the road, appears to cause a roof to vibrate. Non-boomers usually have small stiff screens. (5) In limousines fixed hind-quarter windows appear to be bad. When made to fall, their own silent movement possibly prevents the panels acting like a fiddle bridge. (6) Polished wood lining on pillars and panels appears to be bad. Coth lining seems to act somewhat as a "mute" dones on a fiddle bridge. (7) Moving mechanism, shaking wings, lamps, doors, windscreen, etc. all seem to cause vibrations, which travel to the apex roof causing it to "boom" according to its dimensions. (8) Vibrations of large amplitude such as caused by cut-out of the car or a neighbouring car may travel through the air and cause a roof to "boom" badly. (9) The following are methods for minimising "booming" which are all more or less effective. a) Insulate the roof from cantrails by felt or the like (we have done this with success by R.R.method on 2703). b) Strengthen the roof by making of thicker material or by deepening the ribs at mid span. Thus the musical note is caused and the vibrations are not of sufficient amplitude to cause headache. c) Use a wooden lining and carefully pack space between lining and roof with felt or horsehair. This is effective but, unfortunately, adds between 40 and 50 lbs. to the weight of roof and so raises centre of gravity. | ||