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 for the Goshawk II engine cooling, measuring fan belt slip and its effect on airflow through the radiator.
| Identifier | ExFiles\Box 24\4\ Scan050 | |
| Date | 1st June 1932 | |
| X1751 To R.{Sir Henry Royce} Frowde. c.c. CJ. c.c. to Dn. c.c. to E.{Mr Elliott - Chief Engineer} c.c. to Ay. GOSHAWK II - COOLING. Y4040 X1751 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 | 1300 | 1170 | | 2000 | 2500 | 1920 | | 3000 | 2900 | 2210 | 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 tight-ness. | Air speed through radiator. | | |-----------------------------|-----------------------------|--------------| | | 1000 R.P.M. | 2000 R.P.M. | | 1 belt tight. | 370 | 750 | | 2 | 360 | 720 | | 3 | 370 | 740 | | 4 | 370 | 590 | | 5 | 370 | 580 | | 6 belt slack. | 220 | 480 | Contd. | ||