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).
Design scheme for a cheaper fan and pulley assembly for Bentley and 25/30 models.
| Identifier | ExFiles\Box 94\5\ scan0087 | |
| Date | 1st December 1936 | |
| SCHEME FOR BENTLEY AND 25/30 FANS WITH CHEAPER CONSTRUCTION NOTE: ANGLE OF DRIVING PULLEY TO BE AS SHOWN ON ATTACHED TABLE SAME COMBINED BRACKET AND WATER OUTLET FOR BOTH 25/30 AND BENTLEY - DIFFERENCE IN ANGLE ETC TO BE TAKEN UP BY MODIFIED RADIATOR OUTLET PIPE ETC. TABLE OF PULLEY DIMS. AND ANGLES FOR THIS FAN USED ON BEN. 25/30 & Ph III CAR | RATIO OF FAN RPM / ENG RPM | DRIVING PULLEY EXT. DIA | DRIVING PULLEY ANGLE OF VEE | WIDTH OF VEE DRIVEN PULLEY | DRIVEN PULLEY EXT DIA | DRIVEN PULLEY ANGLE OF VEE | DRIVEN PULLEY TOP WIDTH OF VEE | BELT LENGTH -TAKEN ON MID-SECTION BENTLEY | .904 | 4.430 | 20°+/-1/4 | .620+/-.015 | 4.850 | 22°+/-1/4 | .625+/-.015 | 39" 25/30 | 1.250 | 5.950 | 24°+/-1/4 | .635+/-.015 | 4.850 | 22°+/-1/4 | .625+/-.015 | 41" Ph III | .904 | 4.430 | 20°+/-1/4 | .620+/-.015 | 4.850 | 22°+/-1/4 | .625+/-.015 | 39" NOTE - DIFFERENT LENGTH BELTS WILL BE REQUIRED FOR BEN AND 25/30 - THE NEAREST STD. SIZES MADE BY BELT MANUFACTURERS SHOULD BE USED IF POSSIBLE SECTIONAL ELEVATION 25/30 BLADE ASSEMBLY (MODIFIED) SCALE 1/1 PLAN VIEW C/L CYLS NOTE (1) FAN IS SHOWN .200" FROM UPPER ADJ. LIMIT - ADJUSTMENT HAS BEEN REDUCED TO .750" THIS RESULTS IN MEAN POSITION BEING .125" LOWER THAN AT PRESENT (2) WHEN DETAILING, MACHINING SHOULD ONLY BE INSTRUCTED WHERE ABSOLUTELY NECESSARY. Annotations on drawing: REAM FOR LOCATION PULLEY DIA (EXT) - 4.850" '.015 END CLEARANCE LIMIT - .010 LIMIT +.010 125 SQ. MM WASHER PLAIN 3/8 SPINDLE 5/16 STD R NUT SAME PIECES .125 DIA PIN 22° +/- 1/4 .625" Signature: b. Allendiman 1/12/36 ROLLS-ROYCE. LTD. PRIVATE ROOM | ||