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).
Analysis of an American car's performance, including factors for slow speed and the effects of bonnet ventilation and fan belt adjustments.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan099 | |
| Date | 25th January 1932 | |
| -3- 11/BL.25.1.32.Contd. than 13-ET. during this test. We attribute the slow speed of the American car to - (a) No cut-out. (b) Air cleaner. (c) P.I. camshaft and cylinder head and timing for best low speed acceleration. (d) No ventilation of bonnet. (e) Small wheels and consequently low gear ratio. The American car kept commendably cool, top water temperature 85°C., atmospheric temperature 18°C., but we could not do many tests as their cylinder head cracked after a few laps. The speedometer M.P.H. reading was on the whole on the low side once the scuttle had become warmed up. The air valve became unscrewed on 17-EX. This is a trouble that we invariably experience when we do any prolonged speed bursts and might give the impression of petrol shortage to the un-initiated. It was noticeable that the ventilated bonnet improved the high speed performance. Without ventilation the maximum speed of the car is not maintained for more than one lap. Fan effect at High Speed. We took a link out of the fan belt before starting the tests, and ascertained that it was subjected to the correct tension. We compared the radiator temperature in this condition with the fan belt tightened due a bloc and were surprised to note a drop in temperature of 4°C. with the | ||