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).
Vehicle performance tests, results, and proposed future modifications for further testing.
| Identifier | ExFiles\Box 29\3\ Scan160 | |
| Date | 1st September 1927 guessed | |
| contd :- -2- the driving seat that valve bounce is not starting. In point of fact, in standard touring trim, the engine was turning over at about 2900 r.p.m. for the whole length of the railway straight and nothing that we did to the car would make it appreciably exceed this speed. Even removing the front wings only made a difference of about 1/10 of a second over the half-mile which was too small to be definitely measured with a stop-watch. However on the full laps we were able to detect a difference when we altered the undershield, tail, bonnet etc. and we anticipate that these differences would be magnified very considerably if the road wheel H.P. curve peaked at 90 m.p.h. We drove the car all out in 3rd. speed and were unable to exceed 63 m.p.h. or 2930 r.p.m. which confirmed our top gear results. We did not think that it would be desirable from any point of view to use a 17-tooth axle on the road, but until the engine power is maintained up to 3200 r.p.m. it will be impossible to obtain the full benefit from the present type of sports body. In order to determine exactly what may be expected from the body, bonnet, balloon tyres etc. when the speed of the car is not limited by valve bounce, we propose to repeat these tests with a 17-tooth axle, stronger valve springs and a Claudel carburetter. Standard car performance. The standard trials car 46-PK lapped at 76.51 m.p.h. and did 78.26 over the half-mile, almost identical figures to those previously obtained on 98-NK car in 1925. contd :- | ||