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).
Calculated position of the centre of percussion for the New Phantom and 20HP chassis.
| Identifier | ExFiles\Box 67a\1\ scan0174 | |
| Date | 26th April 1926 | |
| X8410 To BY & HS{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} DA{Bernard Day - Chassis Design}2/M26.4.26. NEW PHANTOMCodename for PHANTOM I SUSPENSION - X.5410. We send herewith N.Sch: 2178. which we have made to give R.{Sir Henry Royce} some information about the centres of gravity of the various cars, and some other particulars regarding the suspension. The particular point we should like to draw HS{Lord Ernest Hives - Chair}' attention to is the calculated position of the centre of percussion about the front axle on the New PhantomCodename for PHANTOM I and the 20HP. We do not profess that the positions given are accurate as we cannot very well calculate the moments of inertia of the various components of the chassis about the centre of gravity. We have made use however, of actual weights, and these, together with their known positions, have been used to estimate the moment if inertia in a way which we think will be found not to be very far out. If there is as much difference as we shew in the position of the point we suggest that it may very well prove to be the explanation of the difference between the 20HP. and the new PhantomCodename for PHANTOM I Chassis as regards the complaint that is at present being investigated, and if HS.{Lord Ernest Hives - Chair} thought it worth while to oscillate the cars either on the bumping rig or by a piston and connecting rod mounted over the front axle, and so directly determine the centre of percussion on a particular car, we believe that it would be very useful information. DA.{Bernard Day - Chassis Design} | ||