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).
The road testing of four cars, detailing issues with radiator jellying, engine vibration, and brake groans.
| Identifier | ExFiles\Box 28\5\ Scan029 | |
| Date | 1st April 1930 | |
| To: Hs.{Lord Ernest Hives - Chair} N457. Rm{William Robotham - Chief Engineer}1/RJ.1/4/30. Radiator Jellying We tried four cars in London yesterday. They have mended the Hendon road where we used to make our steering tests, but one could get a fair impression of the tendency of a car to jelly. We were agreeably surprised with the steadiness of the cars we tried, two of which had spare wheels at the side, and two spare wheels at the back. The steering on all the cars appears to be reasonably good for selectivity. Naturally more damping would improve this feature, but we should not say there is anything to worry about. Engine vibrations and exhaust noise: We were disappointed with the amount of vibration and noise in the front seats of these cars. At 60 M.P.H. they appear to be worse than the average Experimental car. The bodywork evidently has some bearing on this, because the Hooper car was the worst, while Fairey's car was better than the others, but it is to my mind in every way the worst feature of these cars. Brake groans: JLE.{J. Lee Evans - Chassis Test Manager} tells me that brake groaning has increased considerably since the altered servo leverage and cams were fitted. This was confirmed on the tests we made, two of the cars groaned badly. On arriving here, I find they are in exactly the same trouble with a Phantom II car on which they have just changed the servo cams. It would appear that we are absolutely on the limit of unit pressure on our front brake linings. Theoretically, we have only increased the front braking by a small percentage. The chamfering of the front brake shoes decreased their effective area by over 20%, more than counterbalancing the altered distribution. We sent a note to BY.{R.W. Bailey - Chief Engineer} to ask him to delete the chamfer on production, and we think that it would be advisable to at once fit a few cars on test with unchamferred front brakes to see if there is going to be any improvement. If not, it would seem that we must definitely reduce our front braking, as the present state of groaning cannot be tolerated. We have asked RHC.{R. H. Coverley - Production Engineer} to fit 23-EX with unchamferred brake linings. We do not know whether the thicker liners have been fitted to the front of this car, but if not we think that they are well worth running, as the greater depth of friction material may produce a little more elasticity and so damp resonance. Faireys car: This was the best of the four cars we tried in London. There was a very bad camshaft squawk on it when it left the Coachbuilders, but this was disappearing when I left. The radiator jellying certainly is not very bad. ...... | ||