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).
Technical memo detailing the windage and performance data for a 1939 Humber Super Snipe.
| Identifier | ExFiles\Box 126\2\ scan0105 | |
| Date | 17th March 1939 | |
| 1069+ 1380 To By.{R.W. Bailey - Chief Engineer} 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}1/JH.17.3.39. Humber Super Snipe (1939) Windage. The figures and curves attached refer to the Humber car at present owned by the Experimental Department. A previous memo. Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}2/JH.16.1.39. gives a set of figures for a similar model loaned to Exptl. Dept. by Humbers, and shews about 5 H.P. improvement at the peak for the car which was on loan. No accurate value for K was possible with this car as no maximum speed test was made while it was in Derby. Air resistance coefficient K = .00152. Cx{Major Len W. Cox - Advertising Manager}= 391 K = .594 Power required to drive the car at 80 M.P.H. = 58 HP. ****************** Max. lap speed 80 M.P.H. Road wheel H.P. at max. lap speed corrected to underbonnet temperature, and for power loss in the dyno. 58 H.P. Frontal Area 23.8 sq.ft. Tyre Pressures - Road. 35 lb/in² Dyno. 45 lb/in² Rolling resistance (Andreau formula) - Road 42.5 lb/ton. Dyno. 36.1 lb/ton. Total weight (2 pass). 1.68 tons. Wt. on front wheels 0.82 tons. Rm{William Robotham - Chief Engineer}/T.A.Swinden. | ||