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).
Performance calculation sheet for the Humber Super Snipe, analyzing windage and horsepower requirements.
| Identifier | ExFiles\Box 108\2\ scan0210 | |
| Date | 16th January 1939 | |
| To RM.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}2/JH.16.1.39. HUMBER SUPER SNIPE WINDAGE. H.P. required to drive car at 80 m.p.h. - 48.5 H.P. K Assuming RT = 30 lbs/ton. = .00135 RT by Andreau formula = .00124 RT and K by Andreau formula = .00122 RT by General Motors formula = .00127. *************** Given - Total weight (2 passengers) 1.72 tons. Wt. on front wheels. 0.85 " * Max. lap speed. 86.54 mph. Road wheel HP. at max. lap speed. 58 H.P. H.P. to drive dyno. drums at 86.54 mph. 5.3 H.P. Frontal area of car 25.8 sq.ft. Tyre pressures. Road. 35 lb/in2 Dyno. 45 lb/in2 *Owing to unfavourable weather conditions no maximum speed run could be obtained, and the figure quoted is taken from 'Motor' Road Test reports. This should be accepted with reserve since no mention is made of the number of passengers or of the tyre pressures, which have been assumed to be 35/lbs/in2. Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} | ||