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).
Table of test results showing the effects of different fan types, positions, and speeds on cooling performance and noise levels.
| Identifier | ExFiles\Box 131\5\ scan0032 | |
| Date | 24th November 1937 guessed | |
| RESULTS OF TESTS SHOWING EFFECTS OF FAN TYPE POSITION & SPEED. SHEET (1) TABLE HEADERS: PARTICULARS OF FAN. SPEED RATIO IDLING: CRITICAL AIR TEMP. AFTER HIGH SPEED RUNNING °C (A-AFTER 15 MLS. ON RD, B-AFTER PROLONGED FLAT OUT RUNNING) 30 MPH: CRITICAL AIR TEMP AT 30 MPH FULL THROTTLE °C MAX SPEED: CRITICAL AIR TEMP & SPEED - MAX SPEED FULL THROTTLE (CRITICAL AIR °C, SPEED M.P.H) REMARKS. TABLE DATA: 1) WRAITH FAN AS DESIGNED | Speed Ratio: 1.20 | Idling A: - | Idling B: - | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: EXTREMELY NOISY - TOO OBJECTIONABLE TO BE CONSIDERED 2) WRAITH FAN AT BENTLEY SPEED RATIO | Speed Ratio: .90 | Idling A: SAME LESS THAN 16°C | Idling B: - | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: QUIET - COOLING WHILE IDLING INADEQUATE 3) BENTLEY FAN AT BENTLEY SPEED RATIO | Speed Ratio: .90 | Idling A: - | Idling B: - | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: (as above) 4) 5 BLADE FAN (PH.III TYPE) 19.5" TIP DIA, BLADE FLANGE IN SAME POSITION AS WRAITH (1) | Speed Ratio: .85 | Idling A: - | Idling B: 24 | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: FAIRLY QUIET - NOT OBJECTIONABLE 5) 5 BLADE FAN AS (4) BUT BLADES REDUCED TO 17.5" TIP DIA. | Speed Ratio: .85 | Idling A: 33 | Idling B: 22 | 30 MPH: 48 | Max Speed Temp: 46 | Max Speed MPH: 1/2M. 77 73 MPH LAP | Remarks: QUIET - NOT AUDIBLE IN TOP GEAR 6) 5 BLADE FAN AS (5) | Speed Ratio: .80 | Idling A: 27 | Idling B: - | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: DITTO 7) 5 BLADE FAN AS (5) BUT BLADES & FLANGE MOVED .750 NEARER MATRIX | Speed Ratio: .85 | Idling A: 39 | Idling B: 30 | 30 MPH: 50 | Max Speed Temp: 46 | Max Speed MPH: 1/2M. 75 73.5 MPH LAP | Remarks: QUIET - VERY LITTLE NOISER THAN 6 8) STD 25/30 HP CAR OFF PRODUCTION | Speed Ratio: 1.20 | Idling A: 32 | Idling B: - | 30 MPH: - | Max Speed Temp: - | Max Speed MPH: - | Remarks: FAIRLY NOISY AUDIBLE IN TOP GEAR FOOTNOTES: TESTS Nos 1-7 ON WRAITH CAR WITH SHUTTERS OPEN BONNET FLAPS OPEN, NO UNDERSHIELDS, WRAITH WATER PUMP NOTE: ALL C.A. TEMPS GIVEN ARE UNCORRECTED FOR FALL IN WATER FLOW WITH TEMP. RISE TO 100°C | ||