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).
Mathematical calculations for the efficiency of a nut and worm mechanism when acting and 'parking'.
| Identifier | ExFiles\Box 67\4\ scan0328 | |
| Date | 13th July 1927 guessed | |
| contd :- -2- ∴ Fw / Fn = (sin Θ cos γ + sin γ cos Θ) / cos γ --------------------------------------------- (cos Θ cos γ - sin Θ sin γ) / cos γ = sin (Θ + γ) / cos (Θ + γ) = tan (Θ + γ) To find the efficiency when acting as in diagram : Let ʃ = 'lead' of nut (or worm). Then work done by nut = Fn . ʃ . and work done by worm = 2 π r Fw but ʃ / (2 π r) = tan Θ [Diagram of a right-angled triangle with angle Θ, opposite side ʃ, and adjacent side 2 π r] ∴ η = (Fn . ʃ) / (2 π r Fw) = (2 π r tan Θ Fn) / (2 π r Fw) = (tan Θ Fn) / Fw = tan Θ / tan (Θ + γ) Efficiency when 'parking' is expressed : by η = tan Θ / tan (Θ + γ) contd :- | ||