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).
Technical document detailing formulas for leaf springs and the relationship between weight, stress, and rating.
| Identifier | ExFiles\Box 154\1\ scan0264 | |
| Date | 26th February 1936 | |
| FILES. X1305 Hs {Lord Ernest Hives - Chair} /Smth.3/KW.26.2.36. Leaf Springs. We have looked into the question of whether the weight of a leaf spring varies with its length for the same max. stress, rating and set up load, and find that the weight is independent of the length. The formula W = (6 E d) / (R P^2) connects W = weight in lbs. E = Young's Modulus = 30 x 10^6 lbs/ins.2 d = Specific Gravity = .282 lbs/ins.3 R = rating in lbs/in. P = stress in lbs/in. for a load of 1 lb. at the centre of the spring. This is independent of the length, the number and thickness of the leaves and the breadth of the spring. The weight of the clips and the clamped portion in the middle of the spring is neglected. The weight is inversely proportional to the square of the stress. This means that if the stress is reduced 10%, the weight will be increased 20% for the same rating. General Formula for Leaf Springs. Rate R = (8n E b t^3) / (3 l^3) Stress p = (3 l L) / (2 n b t^2) Where n = number of leaves b = breadth of spring t = thickness of leaves l = length between eyes. L = load at centre. Hs {Lord Ernest Hives - Chair} /F.Ll.Smith. | ||