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).
Specification and performance data for a 15.9 Horse Power Humber Car.
| Identifier | Morton\M4.1\ img015 | |
| Date | 12th March 1921 | |
| #S X.1525 ORIGINAL 12.3.21. HUMBER CAR 15.9 HORSE POWER. 4 cylinders. Weight. complete with Pullman Body 4-seater. 1 spare wheel fixed on O.S. Full of petrol, oil and water. Sankey steel wheels with 820 x 120 Dunlop Magnum Tyres. Capacity of water system 5 gallons. " petrol tank 12 " " oil in engine 1 " Tons. cwts. qrs. Front 13 2 Rear 14 2 Total 1 8 0 = 3136 lbs. Gear Ratios. Top direct 4.375 to 1 3rd. 6.75 to 1 2nd. 9.375 to 1 1st. 15.75 to 1 Reverse. 22.5 to 1 Speed at 1000 engine revolutions 21.1 M.P.H. Petrol consumption on road. M.P.H. M.P.G. 20 21 30 19.5 average 17.5 M.P.G. Acceleration. M.P.H. start. Distance. secs. M.P.H. finish. 10 528.3 yds 36 41 20 " 33 41 30 " 29 43 40 " 24 45 Dynamometer test not taken. CONTD:- R'R' SDEV (100. L) (2 H 182' 10-12-20) CP 5841 | ||