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).
Effectiveness of the radiator fan for cooling on 40/50 HP and 20 HP chassis.
| Identifier | ExFiles\Box 24\4\ Scan193 | |
| Date | 25th August 1924 | |
| X 766 BY17/H.{Arthur M. Hanbury - Head Complaints} 25.8.24. c. Hs.{Lord Ernest Hives - Chair} ENGINE COOLING OF 40/50 HP & 20 HP. CHASSIS. ----------------------------------------- Referring to PN{Mr Northey}2/DN. 22.8.24. received under cover of BJ21/H.{Arthur M. Hanbury - Head Complaints} 22.8.24. I have come to the conclusion that whilst PN{Mr Northey} had evidently read BY21/H.19.8.24. which he is criticising, he certainly cannot have had a copy of same by him when dictating PN{Mr Northey}2/DN. 22.8.24. My reasons for this conclusion are that practically all the points urged in PN{Mr Northey}'s memo are equally strongly stated in my memo and if the solitary question of the relation of the area covered by the fan is settled, my existing memo BY21/H.{Arthur M. Hanbury - Head Complaints} 19.8.24. might stand as a sufficient and satisfactory reply to the remainder. In regard to the question of the relation of the area covered by the fan to the total matrix area, it should be noted that I said "The effective area for cooling on our radiator is &c." which limited my remarks to our 40/50 HP radiator specifically, whereas PN{Mr Northey} quotes me as saying - "The effective area of a radiator is &c". This error in stating his case vitiates the criticism and comparisons that follow since obviously what PN{Mr Northey} criticises is not the problem I state but an entirely different one. The actual position maintained on Page 2. of BY21/H.{Arthur M. Hanbury - Head Complaints} 19.8.24. is that although approximately 470 square inches of matrix face area are provided, only 375 square inches (i.e. the area of fan) is actually effective. I proved this was so on dynamometer by covering up all the area not covered by fan without affecting the cooling more than 3%, although the area covered was actually 20% of the total. In fact, not only does the air not pass inward through radiator on dynamometer except opposite the fan, but on the other hand the air at higher engine speeds is actually forced out of the radiator over this area. This does not mean that just the immediate area over the fan is the only area that can be effective, it merely means that with our present limitations to clear the air after it passes the fan a total area equal to fan is all that is useful on our 40/50 HP. Chassis; if an area in front of fan is covered, other areas Contd. | ||