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 analysis showing the effect of wind on a car's maximum speed and the required horsepower.
| Identifier | ExFiles\Box 178\1\ img014 | |
| Date | 15th February 1926 | |
| - 2 - 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 FROM GRAPH: H.P. TO DRIVE CAR AT VARIOUS ROAD SPEEDS. MAX: SPEEDS A.{Mr Adams} HEAD WIND 20 M.P.H. | 50 M.P.H. B. HEAD WIND 10 M.P.H. | 61 M.P.H. C. STILL AIR | 69.5 M.P.H. D.{John DeLooze - Company Secretary} FOLLOWING WIND 10 M.P.H. | 76 M.P.H. E.{Mr Elliott - Chief Engineer} FOLLOWING WIND 20 M.P.H. | 81.5 M.P.H. TEXT ON GRAPH: ROAD WHEEL H.P. ROAD SPEED M.P.H. POWER TO DRIVE CAR AVAILABLE ROAD WHEEL H.P. C.O. OPEN C.O. CLOSED HEAD WIND 20M.P.H. HEAD WIND 10M.P.H. STILL AIR FOLLOWING WIND 10M.P.H. FOLLOWING WIND 20M.P.H. Graph II. 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 to maintain the road speed of 30 m.p.h. is only 6 HP. contd. | ||