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).
Page of calculations and diagrams analysing mechanical efficiency and the effect of thread angle.
| Identifier | ExFiles\Box 67\4\ scan0334 | |
| Date | 13th July 1927 guessed | |
| contd :- -4- θ + Y = 18º 28' { Y = 6º 23' { μ = .1119 η = tan θ / tan (θ + Y) = .2141 / .334 = 64.15% ------------ (2) corresponds to road 'joggle'. T = Fw r = Fn r tan (θ - Y) tan (θ - Y) = (11 X 20) / (.7 X 3250) = 220 / 2275 = .9968. θ - Y = 5º 32' { Y = 6º 23' { μ = .1148 η = tan (θ - Y) / tan θ = .0968 / .2141 = 45.2% EFFECT OF THREAD ANGLE. P = pressure/sq.in. with 'Acme' thread. p = pres/sq.in. with similar square Thread taking same weight. P cos ø = p Friction in first case = μ P A and in second case = μ p a ∴ a / A = cos ø ∴ a = A cos ø also P = p sec ø ∴ F1 / F2 = (μ . P . A.{Mr Adams}) / (μ . p . a.{Mr Adams}) = sec² ø. WHEN ø = 14½º . F1 / F2 = 1.0329² = 1.067. ------------ Hs{Lord Ernest Hives - Chair}/TSN. | ||