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).
Leaf spring construction, ratings, and deflection under load for front springs.
| Identifier | ExFiles\Box 106\1\ scan0175 | |
| Date | 15th May 1930 | |
| COPY. X 5410 To Rm.{William Robotham - Chief Engineer} From Oy. c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} ---------- Oy3/DM.{D. Munro}15.5.30. X.5410. X.7410. X.3900. Front Springs. Sec. 7020. ---------- Your suggestion in Hs{Lord Ernest Hives - Chair}/Rml/MJ.14.5.30. of a spring of two ratings is done in leaf spring construction in the rear of certain busses in U.S. It is done by mounting a secondary stiff spring under the main soft spring, the secondary spring coming into play after a predetermined deflection of the main spring. For P.11 it seems particularly applicable to the front springs since we find that adding full passenger load plus 200 lbs. baggage on the large car only increases the front spring load by 100 lbs. So that with springs of 5" deflection the increased deflection from full load is only EX 1/4". We have regularly fitted Am.P.1 with springs having a deflection of 4" when unclipped, though this was reduced to about 3.6" when clipped to axle. The clearance was 2 3/4" before touching rubber. We had no complaints of spring breakage but had steering trouble. 14 plates were used running from .187 to .285. Oy. | ||