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).
Test results showing the effects of the water pump, undershields, and bonnet flaps on cooling performance at various speeds.
| Identifier | ExFiles\Box 131\5\ scan0033 | |
| Date | 24th November 1937 guessed | |
| SHEET (2) RESULTS OF TESTS SHOWING EFFECTS OF WATER PUMP UNDERSHIELDS & BONNET FLAPS | PARTICULARS OF TEST | IDLING | 30 MPH | MAXSPEED | SPEED | REMARKS | |---|---|---|---|---|---| | | CRIT. AIR TEMP. & TEMP. DROP ACROSS RADIATOR | CRITICAL AIR (UNCORRECTED) | TEMP DROP ACROSS RADIATOR | CRITICAL AIR (UNCORRECTED) | TEMP. DROP ACROSS RADIATOR | | | | | A-AFTER 15 MILES RUNNING ON ROAD | B-AFTER PROLONGED FLAT OUT RUNNING | | | | | | | | | CRIT. AIR | TEMP. DROP | CRIT. AIR | TEMP. DROP | | | | | | | | ① FAN (17.5" DIA: 5 BLADE TYPE) IN FORWARD POSITION, UNDERSHEET FITTED - BONNET FLAPS OPEN - WRAITH WATER PUMP | 36 | 6.5 | 22 | 6.0 | -- | -- | 46 | 10.5 | 1/2M - 71.5 LAP 70.6 | ONLY GAIN WITH PH.III PUMP IS AT IDLING SPEED | | ② FAN AS ① IN FORWARD POSITION UNDERSHIELDS FITTED, BONNET FLAPS OPEN - PH. III WATER PUMP | 39 | 3.0 | 30 | 3.0 | 51.0 | 7.5 | 46 | 10.5 | 1/2M - 75.0 LAP 73.5 | | | ③ FAN AS ① IN FORWARD POSITION NO UNDERSHIELDS FITTED, BONNET FLAPS, OPEN - PH. III WATER PUMP | 40 | 3.0 | 33 | 2.0 | 51.0 | 7.5 | 46 | 10.0 | 1/2M - 74 LAP 73.5 | NO APPRECIATE EFFECT DUE TO UNDER SHIELDS | | ④ FAN AS ① BUT IN REAR POSITION UNDERSHIELDS FITTED, BONNET FLAPS OPEN - PH. III WATER PUMP | -- | -- | 22 | 2.0 | 49.5 | 7.5 | 46 | 10.0 | 1/2M - 77.0 LAP 73.0 | BONNET FLAPS DEFINATELY INCREASE COOLING | | ⑤ FAN AS ① BUT IN REAR POSITION UNDERSHIELDS FITTED, BONNET FLAPS CLOSED - PH. III WATER PUMP | -- | -- | 14 | 3.0 | 47.0 | 7.0 | 44.4 | 10.3 | 1/2M - 75 LAP 74 | | NOTE AS SHOWN & MENTIONED IN TEXT, IDLING TEST WERE CARRIED OUT AT DERBY & IN PADDOCK AFTER FLAT OUT RUNNING - OWING TO WIND ETC. THE TRACK FIGURES ARE NOT SO RELIABLE FOR COMPARATIVE PURPOSES, BUT SERVE TO INDICATE SETS OF CONDITIONS WHICH CAN ARISE. NOTE ALL CRIT TEMP ARE UNCORRECTED FOR FALL IN WATER FLOW WITH TEMP RISE TO 100°C OUTLET - THIS IS IMMATERIAL FOR COMPARISONS AS AIR TEMPS. DURING TESTS WERE APPROX CONSTANT. | ||