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).
Brief summary of four different thermostat schemes tested, detailing their advantages and disadvantages.
| Identifier | ExFiles\Box 156\1\ scan0309 | |
| Date | 1st November 1937 | |
| BRIEF SUMMARY OF THERMOSTAT SCHEMES TESTED. (1) LeC.3488 (5/8" bypass automatically cut-off at high water temps.) - scheme as fitted to original 15 Bentley cars for short period. Ran 15,000 miles in France on 3.B.IV. satisfactorily - only defect, slight pocketting of valve head in seating. Disadvantages - expensive - thermostat unit difficult to make to required standard of temperature control owing to lack of adjustment. (2) LeC.5655 (5/8" Bypass automatically cut-off at high water temps.) - Scheme attaining same results as (1) but using 'drop in' British Thermostat Co. unit - proposed in order to reduce cost. Found unsatisfactory owing to large valve head clearance to prevent sticking resulting in poor temperature control and warming up. (3) Rm.{William Robotham - Chief Engineer}415 (3/8" bypass pipe via hot spots to pump, permanently open.) - This scheme was cheapest and simplest possible - does not affect standard cooling - used Vauxhall type thermostat unit. Disadvantage - excessive water pressure in cylinder block (50 lbs/sq.in) causing collapse of bellows support plate. Besides failures due to excessive pressures, two bellows joint failures attributed by makers to being made experimentally instead of in production - no failures with units built by their production people. Approx. total car miles run - 20,000. (4) LCD.182 (1/2" bypass direct to pump, permanently open. Std. hot spot feed.) - Scheme drops max. water pressure from 50 to 25 lbs/sq.in - uses strengthened bellows unit - so far entirely successful. continued | ||