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).
Water flow test results for an SS.15 unit, comparing four different radiator configurations.
| Identifier | ExFiles\Box 16\2\ Scan012 | |
| Date | 21th April 1931 guessed | |
| Water Flow Tests on SS.{S. Smith}15 Unit. Venturi between cylinder head and radiator. Galls/min. = 8.64 √H ins Hg. (1) Radiator with .268 (small hexagon tubes.) Tube Piece No. R.P.M. | Diff. across Venturi Ins Hg. | Galls/min. | Depn. on Suction Side Pump. | | | Ins. Hg. | lbs/sq.in. 500 | .55 | 6.4 | + 2.9 | + 1.5 1000 | 2.25 | 13.0 | + 1.4 | + .69 1500 | 5.1 | 19.5 | - 1.0 | - .49 2000 | 9.3 | 26.4 | - 4.1 | - 2.0 2500 | 14.8 | 33.3 | - 8.5 | - 4.15 3000 | 18.5 | 37.2 | -10.6 | - 5.2 (2) Standard radiator with 4 dents in each tube E.79448 500 | .6 | 6.7 | + 2.9 | + 1.5 1000 | 2.2 | 12.8 | + 1.6 | + .78 1500 | 5.5 | 20.3 | - .7 | - .35 2000 | 10.0 | 27.4 | - 4.2 | - 2.06 2500 | 15.2 | 33.7 | - 8.3 | - 4.06 3000 | 18.3 | 37.0 | -10.3 | - 5.05 (3) square tube radiator E.81389. 500 | .55 | 6.4 | + 2.85 | + 1.4 1000 | 2.4 | 13.4 | + 1.6 | + .78 1500 | 5.5 | 20.3 | - .8 | - .39 2000 | 10.0 | 27.4 | - 3.9 | - 1.9 2500 | 15.6 | 34.1 | - 7.7 | - 3.8 3000 | 20.6 | 39.2 | -10.8 | - 5.3 (4) Radiator with large hexagon tubes .360 across flats. 500 | .55 | 6.4 | + 2.9 | + 1.5 1000 | 2.25 | 13.0 | + 1.4 | + .69 1500 | 5.2 | 19.6 | - 1.3 | - .64 2000 | 9.6 | 26.8 | - 4.8 | - 2.35 2500 | 15.1 | 33.6 | - 8.9 | - 4.35 3000 | 18.7 | 37.4 | -11.4 | - 5.6 | ||