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).
Comparison of braking units for the J.III & Peregrine models against the 40/50 & 20/25, with proposed modifications.
Identifier | ExFiles\Box 13\1\ 01-page30 | |
Date | 11th November 1932 | |
V 7360. For Files. 11.11.32. K5360 x4047 J.III BRAKES & PEREGRINE. Comparing the four Cars on the road we get:- Braking 40/50. 20/25. J.III Peregrine. Units. Direct. 377 377 240 220 Rear & 499 524 525 388 Front Servo. Peregrine suffers from too little direct braking. If we make the pedal reach the boards sooner by increasing the direct braking, we can also increase the mechanical advantage between the servo and the shoe, as when the pedal hits the boards we are forced to take up a notch, therefore preventing the servo hitting the stop. On Peregrine, therefore the direct braking is increased from 220 units to 377 units by increasing the length of lever by 377/220 or 70% and the rear and leverage from the servo to the shoe brought up to the original front leverage from the servo to the shoe by increasing the length of lever G.100533 from 2.750 to 4.2 on 53%. With the short levers from the front equalisers forwards, therefore, the distribution of units becomes Direct 377. Servo, front & rear. On J.III the direct is brought up from 240 to 400 units by increasing lever G.55388 from 1.6 to 2.65" or 66%. The servo to front and rear is increased slightly(but only slightly, as with 524 units the 25Hp. servo comes on the stop rather early) by 6% making the servo lever to the rear G.55391, 2.38 instead of 2.25 and the servo to the front lever G.55419 2.00" instead of 1.875. | ||