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 report measuring the slip of the Goshawk fan belt and its effect on radiator airflow.
| Identifier | WestWitteringFiles\I\June1922\ Scan0 | |
| Date | 1st June 1922 | |
| To R.{Sir Henry Royce} Francis. c.c. to CJ. c.c. to Da.{Bernard Day - Chassis Design} c.c. to E.{Mr Elliott - Chief Engineer} c.c. to Hy.{Tom Haldenby - Plant Engineer} ORIGINAL HS{Lord Ernest Hives - Chair}6/T1. 6.22. X4240 X HJC / X76C GOSHAWK II - COOLING. We have measured the slip of the Goshawk fan belt. We had the engine running on the bench fitted with the fan but with no radiator in front so that we could count the revs. of the fan compared with the revs of the crankshaft. The following is a test taken with a reasonably tight fan belt and a slack fan belt :- | Engine revs. | Fan revs. Belt tight. | Belt slack. | |--------------|-----------------------|-------------| | 1000 | 1200 | 1170 | | 2000 | 2300 | 1920 | | 3000 | 2900 | 2200 | We have also taken a test with the radiator fitted in front measuring the difference of the speed of air through the radiator with different degrees of belt tightness. The following is the result :- | Degrees of belt slack. | Air speed through radiator. 1000 R.P.M. | 2000 R.P.M. | |------------------------|-----------------------------------------|---------------| | none. 1 belt tight. | 370 ft. per min. | 750 ft per min.| | 2 | 360 | 750 | | 3 | 370 | 740 | | 4 | 370 | 590 | | 5 | 370 | 590 | | 6 belt slack. | 220 | 460 | Contd. | ||