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).
Technical assessment of car 19-G-IV, focusing on front suspension, brakes, and ground clearance.
| Identifier | ExFiles\Box 154\1\ scan0244 | |
| Date | 14th January 1935 | |
| -4- HS {Lord Ernest Hives - Chair} /Les.14/KW.14.1.35. Appearance of the Front of the Car. The sight of the spring boxes on the front of 19-G-IV without the carried down type wings is unpleasant. With a narrow frame at the front it is possible to conceal the spring boxes behind the pivots. The spring boxes on 19-G-IV are unnecessarily large. This was done in order that the variable rating leverages could be tried. Brakes. In order to save making all new brake parts, this car is not fitted with front wheel brakes. The operation of the brakes is difficult. Manufacturers generally use either Lockheed tubes, or cable operated brakes with the Dubonnet system. Ground Clearance. The ground clearance of the spring boxes is small on full bump. However, by fitting the spring boxes above the pivots, this system can provide considerably greater clearance than the wishbone system on SpectreCodename for Phantom III. With independent suspension systems where the front springs have half the rating, twice the amount of buffer clearance is necessary; consequently on full bump an adequate ground clearance is difficult to provide. So far we cannot appreciate any very considerable fundamental advantage which the Dubonnet suspension has over the Cadillac scheme. It suffers from the kick up over hump-backed bridges which is our main problem on the SpectreCodename for Phantom III. A fully reversible steering can be used with no road shocks but the Cadillac demonstrates that with the wishbone scheme a satisfactory steering can be obtained. Therefore we do not think it is worth preparing our own designs of the Dubonnet scheme for the time being. The car remains a useful piece of experimental apparatus. HS {Lord Ernest Hives - Chair} /I.A.Leslie. | ||