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).
Performance comparison memorandum between a 12-cylinder Lagonda and a Bentley.
| Identifier | ExFiles\Box 128\3\ scan0103 | |
| Date | 30th June 1940 | |
| Ev.{Ivan Evernden - coachwork} from Rm.{William Robotham - Chief Engineer} c. Jnr.{Charles L. Jenner} 12 CYLINDER LAGONDA. in Rm.{William Robotham - Chief Engineer}10/ML.20.5.40. Herewith the details requested SHEET 1. Curve 1 represents the clutch B.H.P. of the unit in the actual car tested. Curve 2. is an estimated test bed curve for comparison with the figure provided by Jnr.{Charles L. Jenner} The assumption made is that the Lagonda exhaust silencer loss is the same as that on 11.B.V. and that one half of this represents the Lagonda test bed silencer loss. Curve 3. shows the B.M.E.P. corresponding to the B.H.P. curve 2. and compares directly with the figure provided by Jnr.{Charles L. Jenner} SHEET 2. Curves of B.M.E.P. against mean piston speed comparing the 12 cylinder Lagonda with Bentley 80. Curve B. is the B.M.E.P. curve corresponding to the B.H.P. curve 1. Sheet 1. The Bentley curve with it's early peak and falling off characteristic is known to be advantageous for direct gear driving i.e. good low and middle speed acceleration is obtained. The Lagonda curves are in direct contrast to this and offer a very good explanation of the car's lack of animation below 3,000 r.p.m. Practically the only likeable performance feature of this car - that it ran without fuss at 5,000 r.p.m. - is answered by the fact that this is before the peak of the power curve and thus equivalent to about 3,500 r.p.m. on the Bentley. - Continued - | ||