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).
Comparative noise test of Cadillac and R.R. fans, and a report on radiator water loss.
| Identifier | ExFiles\Box 91\3\ scan0214 | |
| Date | 23th September 1935 guessed | |
| ( 7 ) We took a comparative test in the garage with the Cadillac and R.R. fans, for the noise factor, flexibility, etc. The result was interesting from the flexibility point, as the static test gave such different results. The R.R. blades actually start earlier to deflex (approximately 40 MPH.) than the Cadillac. The total deflexion is greater by 10% than the Cadillac observed from a side view, no actual measurements taken. The Cadillac fan blades deflects 50% at maximum speed. Noise Test. CADILLAC 30 MPH. No audible noise 40 MPH. Just audible 50 MPH. Slight hum 60 MPH. Hum slightly increased 68 MPH. Fan boom besides wind noise 70 MPH. Hum clearly audible and heard ) distinctly in driving seat ) 80 MPH. Noise clearly defined & heard ) distinctly in driving seat ) R.R. CADILLAC. Ditto " " " Not so noticeable Ditto Higher pitched tone more noticeable. These tests were taken in the quiet garage with Radiator shutters full open. The comparison is given listening in front of the car and in driving seat all closed up. On the road, the higher pitched tone was more noticeable to the critical listner. At 10,600 it was examined and no faults were decernable. RADIATOR & FITTINGS LOP E 87239 LEC 4504 MATRIX E 87003 F 87674 RADIATOR SUPPORT BRACKET. We were losing on an average half a gallon of water from the system during each day's run at the beginning of the test. (We are aware that the D/O's attention has been drawn, to the loss of water on the cars in Derby). We however gave the matter further attention, and found that the design of the spring was a cause for loss of water. The length and diameter of the spring caused it to buckle when compressed to working length. This caused tilting action on the valve (practically leaving one side with no load on the valve). The rush of water up the tube overcame this small poundage and so escaped. We fitted a conical spring, poundage approximately the same, but not tested, shorter in length and larger in diameter. This prevented it from buckling, thereby giving an even load on the valve. For 8,000 miles the loss of water was negligable. The Radiator has been effecient, no boiling has occurred during the mileage with cool atmosphere. The anchorage of the Radiator gave no trouble, rubber mounting and bracket, were in a good condition. [Handwritten note on left margin]: Steadman. Check blow off pressure when this pressure is available. | ||