The road trial of a 40 HP Fiat.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan90 | |
| Date | 20th October 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT Expl. No. REF Hm {Capt. W. Hallam - Head Repairs} /Rml/LG231025 ROAD TRIAL OF 40 HP. FIAT. (20.10.25) PARTICULARS OF CAR. Bore 3.35 - stroke 5.5" Displacement 4766 c.c's. Limousine body. Weight - no passengers - 2.15 tons. Direct Drive ratio 4.08 - 1. Overhead valves - push rod operated. Detachable head. Camshaft - chain driven. Spiral bevel final drive. Mono-bloc cyl. casting. 4-bearing crankshaft. Tyres 835 X 135. Steering-worm and wheel. Front wheel brakes - hydraulic servo. Displacement per ton per wheel rev. 9044 c.c's } Tyre dia's Phantom " " " " " 10,400 c.c's } approx. the same Approx. mileage of car by speedometer reading 6,000 miles. CONDITIONS OF TEST. Road surfaces exclusively tarred - wet and greasy - some rain. OBSERVED FEATURES OF THE CHASSIS. Engine. The noisiest feature of the engine is its carburetter air intake. This emits a pronounced suction note at slow speed small throttle openings which is very noticeable from the driving seat. The valve gear was not particularly obtrusive from this position contd :- | ||
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).