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).
Comparison of boiling temperatures for various radiator matrix types at 30 and 45 MPH.
| Identifier | Morton\M19\ img175 | |
| Date | 20th May 1931 guessed | |
| TYPE OF RADIATOR MATRIX. Figures given Atm. Temp. at which the car will eventually boil if driven for sufficiently long under conditions specified. 30 M.P.H. | 45 M.P.H. Small Hexagon Ended American Tube. Hexagon .305 across Flats Centre .255 Round No. of Dents 18. | 36.5 | 37.5 Large Hexagon Ended American Tube. No. of Dents. 20. Hexagon .360 across Flats. Centre .309 dia. round. | 33.5 | 34. 6.m.m. parallel Square Tube E.81385. Figures from previous tests. | 30.25 | 34. Square Tube E.81389. 6 m.m. square Centre Ends expanded to 7½ m.m. horizontally only. i.e. vertical waterways only. | 26. | 27. Present Standard. 6/7½ m.m. round E.79448. 4 dents/Tube. | X 21.5 | X 24.5 X. these figures are lower than some we have previously attained. All tests taken on 19-EX. Conditions as in Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/KT.21431 These tests are very susceptible to the direction of the wind and are therefore not always comparable from day to day | ||