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).
Windage calculation report for a 1938 Lincoln Zephyr.
| Identifier | ExFiles\Box 127\2\ scan0060 | |
| Date | 20th December 1938 | |
| file To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} c. to Da.{Bernard Day - Chassis Design} c. to Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}19/JH.20.12.38. LINCOLN ZEPHYR (1938) WINDAGE. Horse Power required to drive the car at 80 MPH. = 73 H.P. Wind resistance coefficient. K.{Mr Kilner} = .00163. The K value has been obtained from first principles - H.P.∝ R.V. and R = KAV², and using the Andreau formula for rolling resistance (Rᵣ). The following data is used :- 72 Road wheel dyno B.H.P. at max. speed 80.6 m.p.h. (corrected for an under bonnet temp. 35°C). H.P. required to drive dyno. drums. ............ 2.6 H.P. Frontal area of car ( assumed). .............. 26 sq.ft. Total weight as tested (two passengers)..... 1.83 tons. Weight on front wheels. ..................... 0.94 tons. Tyre pressures .................... Dyno. 45 lbs/in² .................... Road. 28 lb/in.sq. Rolling Resistance Rᵣ ............ Dyno. 36.5 lbs/ton. .................... Road. 27 lbs/ton. Rm{William Robotham - Chief Engineer}/T.A.Swinden. | ||