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 and a diagram analyzing the effect of thread angle on friction and mechanical efficiency.
| Identifier | ExFiles\Box 67\4\ scan0330 | |
| Date | 13th July 1927 guessed | |
| contd :- -4- Θ+Y = 18° 28' { Y = 6° 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 = .0968. Θ-Y = 5° 32' { Y = 6° 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 Φ = p Friction in first case = μ P.A. and in second case = μ p.a. a/A = cos Φ .. a = A cos Φ also P = p sec Φ ∴ F1 / F2 = (μ P. A.{Mr Adams}) / (μ p. a.{Mr Adams}) = sec² Φ . WHEN Φ = 14½° , F1 / F2 = 1.0329² = 1.067. ------------------ Hs{Lord Ernest Hives - Chair}/TSN. | ||