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).
Testing a car for a roof drumming issue and potential cures for Limousines.
| Identifier | ExFiles\Box 41\4\ Scan151 | |
| Date | 28th July 1920 | |
| R R £35 (50 T) (N.B. 929. 19-11-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2527. COPY. To - Lord Herbert Scott. Sp{Mr Spinney}2/CM28.7.20. R O O F D R U M M I N G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Following instructions, I tested Mr. Claremont's new Car on the road to-day with special reference to roof drumming. The Body is a large Saloon Limousine with a rather flat roof which, in the ordinary way, is very likely to "drum". We persuaded Messrs. Hoopers in this case to make the roof stiffer than usual, by adding extra head-sticks and fixing angle blocks between head-sticks and roof. The result is, in my opinion, satisfactory. The roof still vibrates, but not with deep booming vibrations so painful to the ears and head. There is now nothing unpleasant in the sound. Our Testers and Hooper's Representative, who were in the Car, believed this Limousine "boomed" less than other post-war Limousines. I suggest we are now able to advise customers and coachbuilders that the "drumming" or "booming" of a Limousine roof can be cured by making it stiffer. Possibly the simplest way of doing this is to stiffen two or more of the head-sticks by means of angle-irons (1"x1"x⅛") or edge-plates about three feet long screwed to them - there is no need for the stiffeners to reach right across the roof; they should stiffen the mid portion only. Such angle-irons or edge-plates would not reduce head room. Perhaps Derby would like to try this on their Saloon Limousine lately bought from Barkers. Sp.{Mr Spinney} | ||