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).
Complaints about the riding qualities of the Phantom II and 25HP models, comparing damping, springs, and weight distribution.
| Identifier | WestWitteringFiles\U\2January1930-September1930\ Scan126 | |
| Date | 19th May 1930 | |
| HS.{Lord Ernest Hives - Chair} [REDACTED] ) FROM R.{Sir Henry Royce} DA.{Bernard Day - Chassis Design} [REDACTED] ) C. to SC. WOB. PN.{Mr Northey} C. to C. ON. FP.{F. Potts} C. TO BE READ AT CONFERENCE ON TUESDAY 19.5.30. ORIGINAL CAR WORK - RIDING QUALITIES. PHANTOM 2. & 25HP. X5770 X7770 I was surprised that there were complaints against P.2., and the 25HP. was compared as being superior. This fundamentally should not be so, and I should like a summary of the complaints and the treatment. There are two things which may effect the impression:- (a) The front axle tramping vibration 10 per sec., which with some people might be thought bad springing. (b) The extra weight, height, etc, of the big car should have at least 50% more damping for the same speed, and since its maximum speed is 15/20% faster this might bring the damping up to 100% greater than the 25HP. What does history say? (1) Unlubricated springs gave bad type of damping - i.e. excessive at slow speeds (even worse than solid friction dampers,) hence all springs must be lubricated. (2) We have times out of number found springs, especially the rear, to be too stiff - (recently HS.{Lord Ernest Hives - Chair} and E.{Mr Elliott - Chief Engineer} at Paris.) (3) On several occasions hydraulic dampers have not been acting - i.e. drilled valves or lost oil. To my mind we have never had these too effective, and I should be much happier if their poundage for the 40/50. were increased, especially the recoil, and definitely do not agree to anything (like drilling) to decrease their effectiveness. To steady the car (so very necessary) dampers must resist slow movements, and at the same time permit quick ones - (we originated this feature in hydraulics.) Assuming the foregoing does not effect satisfaction we must not forget that the weight distribution was found to be superior to the 25HP., and this was the greatest improvement in P.2. over P.1. - i.e. the benefit of weight behind the back axle, and ill effect of weight in centre of chassis and body - spare wheel, heavy glass screens, tools. The wonderful effect of the rear wheel is because it helps so greatly, when the car has only one or two passengers, to avoid the overstiff effect of the rear springing - i.e. it forces the springs to act. (1) | ||