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).
Brake efficiency tests on a Phantom II model, comparing standard and ribbed brake drums.
| Identifier | ExFiles\Box 12\5\ 05-page285 | |
| Date | 20th April 1931 | |
| To Hs.{Lord Ernest Hives - Chair} From GWH.{George W. Hancock - Head Chateauroux} 87360 Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux}12/KT.20.4.31. RE. EFFICIENCY OF BRAKES. We have carried out the following tests for loss and gain in efficiency of brakes on P.II. 1st Test. Standard brake drums Ferodo linings rear, Ferobestos front. 7 brakings from 70 MPH to 10 MPH consecutively Distance to pull up at start of test 232 ft. Distance to pull up at 7th test 262 ft. equalling a loss of efficiency of 12.93%. 2nd Test. C.I. ribbed brake drums on the rear, standard non ribbed drums on the front, brake linings same as first test. 7 brakings from 70 MPH to 10 MPH consecutively Distance to pull up at start of test 230 ft. Distance to pull up at 7th test 215 ft. equalling a gain in efficiency of 6.52%. This gives a gain in efficiency of the 7th braking with ribbed drums of 17.93% over the 7th braking with plain drums. A noticeable feature is that with the plain drums after the last test the foot pedal movement had decreased .750" indicating expension of the brake shoes, whereas with the ribbed drums the movement of the foot pedal had increased .125". This means that the ribbed drums get rid of the heat generated before it has time to be absorbed by the brake shoes. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||