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 inefficiency of Peregrine brakes, comparing servo performance and recommending design changes.
| Identifier | ExFiles\Box 1\10\ B001_X106 TO X 110-page010 | |
| Date | 2nd November 1932 | |
| X106. R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Cry. c. to Sg.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} Hs{Lord Ernest Hives - Chair}/Cry.1/WA.{Mr Wallis}2.11.32. PEREGRINE BRAKES. We have been trying to find a reason for the inefficiency of the Peregrine brakes particularly after several applications when the servo is warmed appreciably. We attach a table of comparisons of the amount of work the servo has to do for a given deceleration of the three cars P.II, 20/25HP., and Peregrine. From this it is seen that the product of the unit pressure on the servo lining and the rubbing velocity for Peregrine is about 2½ times the Phantom figure. The servo multiplication of torque is less on the smaller car because the mean radius of the fabric has been greatly reduced whereas the working radius of the cam has not, since it is already as small as is practicable. The stroke of the smaller servo is less and hence the multiplication of effort from the servo to the brakes is less. The Peregrine servo heats up very quickly under road use and drops in efficiency about 50%, according to some tests we carried out on Ferodo RAD. material. We recommend for Bensport increasing the di-ameter of the servo so that the unit pressures are decreased and the stroke is increased. It would also be an advantage to run the servo slower than a propeller shaft speed to make up for the low back axle ratio. Hs{Lord Ernest Hives - Chair}/Cry. 1 print att: | ||