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).
Comparing the performance of a 20 HP car against an Austro-Daimler, with a focus on engine efficiency.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan100 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.A.H.D. EXPERIMENTAL REPORT. -5- Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG231025 We obtained a both way reading for the max. speed of the car, this appeared to be 58 m.p.h. (corrected). The windage of the body we should say was slightly less than that of a R-R 20 HP. Comparison of 20 HP. RR. and Austro-Daimler. [Graph with Y-axis 'Accn. Ft/Sec^2' from 0 to 3, and X-axis 'Road speed M.P.H.' from 0 to 60] Displacement per ton per wheel rev. approx: RR / AUSTRO D = .92 or Austro Daimler 8.5% better off. BRAKING. As we have previously indicated, this was the worst feature of the car. GENERAL IMPRESSION. We consider that the only point which we are likely to gain useful information on this car is its engine. This is certainly more efficient than the 20 HP. R.R., but this efficiency has been gained at the expense of a certain amount of sweet running. A 20 HP. R-R engine fitted with two carburetters and a higher compression ratio, would not be very much inferior to the overhead camshaft unit of the Austro-Daimler. Possibly, however they have not made the best use of their overhead Camshaft. contd :- | ||