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).
Calculations for Rippletto frame stiffness, comparing it to a Bentley V frame.
| Identifier | ExFiles\Box 132\2\ scan0069 | |
| Date | 30th October 1939 | |
| Appendix Sheet 4. Ev.{Ivan Evernden - coachwork}1/JH.30.10.39. Rippletto Frame Stiffness. Equivalent lengths of front arms measuring from the front wheels to the node. B.V. = 40.000 ins. Rippletto = 32.500 ins. (with Ripplet frame). Rippletto = 26.000 ins. (with shortened frame). If h = frequency. W = equivalent single load. w = weight of frame per unit length. l = length of arm. h = 1/(2 II) * sqrt(3EIg / (l^3(W + 33wl/140))) It can be shewn that w, is so small that it may be taken as, zero, then - h = 1/(2 II) * sqrt(3EIg / (l^3 W)) Likewise it has been computed that the ratio of concentrated equivalent weights may be - B.V. = 10 units. Rippletto = 8 units. The I of the sections are as follows - Bentley V = .104 a Rippletto = .064a (with Ripplet frame) Rippletto = .064 x a x 6.25/10 = .041a (with short frame) Comparing B.V. with Rippletto - with Ripplet frame. hBV/hR = ((.104 x 32.5^3 x 8) / (.064 x 40^3 x 10))^(1/2) = .836. | ||