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).
Graph and text explaining the effect of wind on a car's maximum speed and required horsepower.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan104 | |
| Date | 15th February 1926 guessed | |
| contd :- -2- as it might, owing to the fact that it is under geared to obtain good acceleration and consequently the power available is already falling off at the 'still' air' maximum speed. GRAPH I. EFFECT OF WIND ON CAR MAXIMUM SPEED. TABLE ON GRAPH: H.P. TO DRIVE CAR AT VARIOUS ROAD SPEEDS. A.{Mr Adams} HEAD WIND 20 M.P.H. | MAX: SPEEDS 50 M.P.H. B. HEAD WIND 10 M.P.H. | MAX: SPEEDS 61 M.P.H. C. STILL AIR | MAX: SPEEDS 69.5 M.P.H. D.{John DeLooze - Company Secretary} FOLLOWING WIND 10 M.P.H | MAX: SPEEDS 76 M.P.H. E.{Mr Elliott - Chief Engineer} FOLLOWING WIND 20 M.P.H | MAX: SPEEDS 81.5 M.P.H. GRAPH AXIS & LABELS: Y-AXIS: ROAD WHEEL H.P. X-AXIS: ROAD SPEED M.P.H. LABELS: POWER TO DRIVE CAR, AVAILABLE ROAD WHEEL H.P., HEAD WIND 20M.P.H, HEAD WIND 10M.P.H, STILL AIR, FOLLOWING WIND 10M.P.H., FOLLOWING WIND 20M.P.H., C.O. OPEN, C.O. CLOSED Graph 11. is drawn with the object of demonstrating how the effect of a 10 m.p.h. wind increases with the speed of the car. We have graphed the H.P. required to overcome the wind resistance of the car only, at various road speeds. In this case frictional losses are omitted. It will be observed that if at 30 m.p.h. a head wind of 10 m.p.h. suddenly blows upon the car, the extra H.P. necessary contd :- | ||