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).
Cooling tests and proposed improvements for the 20 HP car.
| Identifier | ExFiles\Box 24\5\ Scan157 | |
| Date | 1st May 1929 guessed | |
| HS.{Lord Ernest Hives - Chair} X766 Hs{Lord Ernest Hives - Chair}/Rnl 20 HP. COOLING. The only cooling tests we have carried out on the 20 HP. car were made in Aug. 1923 when we took 6G. up the Cat & Fiddle. The dimensions of the radiator on this car were :- Face area............ 410 sq.ins. Volume............... 1620 cu.ins. Axle ratio 12/50 - Tyres 32 X 4.5 straight sided having an effective circumference of 101.25". On a 3 miles climb on the Cat and Fiddle with an air temp. at the bottom of the hill of 22.5 to 24.5 C, the cooling water reached a temp. of 96 C at the summit. The bonnet of the car was not ventilated for this test. The present 20 HP. with standard axle 11/50 and wheels which are to be 6" tyres on 19" rims which have an effective rolling circumference of 96", therefore the displacement per ton mile has gone up 5.25% on the tyres, 8.3% on the axle giving a total of 13.5% by altered gear ratio, The proposed increase in capacity is 17.5% making a total increase in displacement per ton mile of 31% since our last over-heating test. Without altering the dimensions of the radiator the two possibilities for improvement are the smaller tube matrix and the fan redesigned on the lines of the 40/50 HP. Rourke | ||